Copyright ©ERS Journals Ltd 1993
European Respiratory Journal
ISSN 0903 - 1936
Eur Respir J, 1993, 6, 1529- 1543
Printed in UK - all rights reserved
SERIES 'PULMONARY IMMUNE CELLS'
Edited by U. Costabel and C. Kroegel
Pulmonary immune cells in health and disease:
Polymorphonuclear ·neutrophils
Y. Sibille, F-X. Marchandise
Pulmonary immune cells in health and disease: Polymorphonuclear neutrophils. Y.
Sibil/e, F-X. Marchandise. @ERS Journals Ltd 1993.
ABSTRACT: The pulmonary vasculature represents the largest reservoir of polymorphonuclear neutrophils (PMNs) in the human body. This is in striking contrast
with the paucity of PMNs present in the normal airways and alveoli.
However, the respiratory tract constitutes an easy access for microorganisms and
particles present in inhaled air and, therefore, efficacious defence mechanisms are
required. When the mucociliary clearance and the alveolar macropbages are overwhelmed, the rapid recruitment of PMNs from the lung vasculature appears to be
a crucial response of the host against tbe pathogens. Tbe regulation of adherence
of PMNs to endothelial cells (EC), followed by the transendotbelial migration are
now better understood, and are under the control of a series of adhesion molecules
modulated by bacterial and inflammatory mediators.
In addition to their defensive role, PMNs have also been implicated in acute and
chronic injurious diseases of the lung. Clearly, PMNs contain enough cytotoxic and
proteolytic material to induce lesional changes. However, the release of thi<> material is likely to be dependent on environmental factors, including mediators derived
from other inflammatory and immune ceiJs. The presence or absence of these factors could explain the fact that high numbers of PMNs can be observed in the airways and alveoli without major lesions whilst in other conditions, a marginal increase
of PMNs in the respiratory tract can be associated with major damage and irreversible architectural changes in the lung.
Eur Respir J., /993, 6, 1529-1543.
In the absence of an inflammatory process, the polymorphonuclear neutrophils (PMNs) are almost exclusively confined to the intravascular compartment, where
they comprise the majority of circulating leucocytes.
However, in response to inflammatory stimuli, a rapid
and often massive influx of PMNs can be driven to the
inflamed tissues. This is particularly true in the lung,
where PMN traffic can be facilitated both by a rather
thin barrier separating the alveolar space from the capillary lumen and by the sequestration of PMNs in the
pulmonary vasculature. Some of these PMNs appear to
adhere to the endothelium of the postcapillary venules,
even in normal conditions, providing a pool of rapidly
recruited cells.
The PMNs are considered as major effector cells in
acute inflammatory processes, and their role in the defence
of the host against bacterial and fungal invasion is welldocumented. This role is best illustrated by the frequent
and severe infections associated with neutropenia. More
recently, PMNs have also been implicated in the pathogenesis of tissue injury related to chronic inflammation,
generally leading to lung fibrosis. The purpose of the
present review is to discuss the function of PMNs, and
their migratory and secretory profile in the normal lung,
as well as in pulmonary diseases.
Pulmonary Section and Experimental
Medicine Unit (lCP), Catholic University
of Louvain, Belgium.
Correspondence: Y. Sibjlle
Pulmonary Section
Catholic University of Louvain
B-5530 Yvoir
Belgium
Keywords: Degranulation
migration
polymorphonuclear neurrophil
pulmonary diseases
surface receptors
Received: 19 March 1993
Accepled after revision 30 July 1993
Origin, maturation and ageing
PMNs have an estimated life-span of 6-8 h in peripheral blood and this probably explains their production at
the astonishing rate of2.5 billion cells·h-1 [1]. Like other
leucocytes, PMNs originate from a common pluripotent
stem cell in the bone marrow. In order for the bone
marrow to follow the PMN turn-over, two conditions are
required: the maintenance of enough stem cells and the
differentiation of these cells towards mature cells, under
the control of several growth factors [2-4]. The totipotent stem cells are the progenitors for all blood cells,
including lymphocytes, and can be recognized by their
ability to form blast colonies in vitro. The totipotent
stem cell is the precursor of the colony forming units
(CFU) - multipotential cell (GEMoMe). The GEMoMe,
characterized by a limited ability of self-renewal, represents the common source for granulococytes (G), erythrocytes (E), monocytes (Mo) and mega.karyocytes (Me).
The GEMoMe differentiates to the CFU - granulocyte/monocyte (G/Mo), and then to the CFU - granulocyte cells, the precursors of PMNs. In contrast to PMNs
and monocytes, the bone marrow stem cells of eosinophils
and basophils are still the subject of controversy.
Within the last decade, a series of growth factors for
1530
Y. SIBILLE, F-X. MARCHANDISE
bone marrow stem cells have been identified and their
gene cloned. Briefly, three groups of glycoproteins have
been characterized according to their effects on progenitor cells. The first group of molecules act preferentially
on early progenitor cells and, unlike true growth factors,
they stimulate cell differentiation and act synergistically with other factors. This group includes interleukin
(ll.,)-1, IL-4 and IL-6. A second group, essentially ll..,3 and granulocyte/macrophage colony stimulating factor
(GM-CSF), appear as the major growth factors , since
they induce multipotential stem cells (GEMoMe) and
progenitor cells of the myeloid, erythrocyte and megakaryocyte lineage to form colonies. The last group of growth
factors which include G-CSF for PMNs regulates the differentiation of more committed stem cells towards mature
granulocytes. When leaving the bone marrow, the PMNs
are fully differentiated and equipped with the complete
spectrum of surface receptors and intracytoplasmic granules with their secretory products. For instance, the transcription of messenger ribonucleic acid (mRNA) for
neutrophil elastase and myeloperoxidase is only observed
in myelocytic precursor cells and not in mature PMNs
[5].
In addition to their role on bone marrow progenitor
cells, growth factors also act on mature leucocytes. Thus,
GM-CSF can modulate PMN migration and degranulation, via the binding of specific surface receptors (see
below) [6, 7}.
The large scale production of recombinant forms of
these growth factors (M-, G-, GM-CSF and IL-3) has
enabled their use in clinical trials to accelerate bone marrow recovery, particularily after chemotherapy. Randomized
studies are under way to evaluate the benefit provided
by such adjuvant treatments [2].
Whilst the production of granulocytes is critical for
the host, the disposal of these cells appears to be equally crucial. In particular, with the impressive number of
PMNs continuously produced by the bone marrow, it is
important to consider the fate of these phagocytes in the
blood and in tissues. Among the mechanisms implicated in the removal of PMNs, apoptosis or programmed
cell death appears to play a central role. Apoptosis is
characterized by morphological changes, including chromatin condensation and cytoplasmic vacuolization [8}.
This process is associated with deoxyribonucleic acid
(DNA) fragmentation, and can be induced by ageing
PMNs in culture for 24 h. Recently, the aged PMNs
were found to be specifically recognized and phagocytosed intact by alveolar macrophages, suggesting one
mechanism of disposal of senescent PMNs from the respiratory tract, thereby preventing further release of potentially toxic secretory products [9].
Membrane receptors and membrane associated
proteins
A series of membrane receptors have been identified
on the surface of PMNs and are listed in table 1. These
receptors constitute the link between PMNs and their
environment, and modulate PMN functions, including
adherence, migration, degranulation and phagocytosis.
Table 1. - List of polymorphonuclear neutrophil (PMN)
major surface ligands
Surface ligand
Complement component
CRI
C3b (CR3)
C5a R
Decay accelerating factor (DAF)
Membrane cofactor protein
Immunoglobulins
FcyRll and FcyRIUB
FeaR
lgE (S-lectin, Mac2h:BP)
Bacterial peptides and endotoxins (LPS)
FMLP (FPR)
LPS (CDI4 and SIP)
Colony stimulating factors
G and GM-CSF
Chemotaxins
NAP- 1/IL-8, NAP-2, gro!MGSA
LTB 4
PAF
Adhesion moelcules
~2 -integrins (LFA-1, Mac- 1, p 150,95)
L-selectin
Others
ANP
Adenosin (A2 )
TNF-a
[Ref.]
[10]
[10]
[11]
[12]
[12]
[13, 14]
[15]
[16]
[ 17]
[18, 19]
[20]
[21]
[22]
[23)
[24)
[24]
[25]
[26]
[27]
lgE; immunoglobulin E; LPS: lipopolysaccharide; FMLP:
formyl methionyl-leucyl-phenylanine; FPR: formyl peptide
receptor; BIP: bacterial permeability increasing protein; G
and GM-CSF: granulocyte and granulocyte macrophage
colony-stimulting factor; NAP: neutrophil-activating peptide; IL: interleukin; MGSA: melanoma growth stimulatory
activity; LTB 4 : leukotriene 8 4 : PAF: platelet-activating factor; LFA-1: lymphocyte function antigen- ); ANP: atrial natriuretic peptide; TNF-a: tumour-necrosis factor-a.
Recent studies have focused both on molecular and on
functional characterization of PMN surface molecules.
It has been known for many years that immunoglobulin (Ig) G can mediate phagocytosis, both in PMNs
and in macrophages [28, 29]. Also, IgG immune complexes are potent inducers of PMN migration and degranulation, and have, therefore, been implicated in the
recruitment and activation of PMNs in inflammatory processes [30].
Two receptors for the complement activating fragment
(Fe) portion of IgG (FcyR) have been characterized on
PMNs: FcyRII and FcyRDIB, two low affinity receptors
binding preferentially aggregated forms of lgG [13, 14].
Receptors for JgA (FeaR) have also been identified
on the cell surface of PMNs. This receptor is a 60 Kd
protein, and appears structurally similar to the FeaR
described on mononuclear phagocytes [15]. The function of FeaR in PMNs is still the subject of controversy,
in particular its role in PMN mobility. Thus, some authors
have found an inhibition of PMN migration towards an
IgA concentration gradient (chemotaxis), whilst others
have reported an increase in PMN random migration
(chemokinesis) in the presence of IgA [31, 32}. Moreover,
ROLE OF POLYMORPHONUCLEAR NEUTROPHIL$
lgA can mediate phagocytosis in PMNs, and haematopoietic growth factors, such as GM-CSF and G-CSF can
enhance this function, via an increase in FeaR expression on PMNs [33]. This suggests a synergistic mechanism between IgA and growth factors for PMN activation,
since a limited number of high affinity receptors for G
and GM-CSF have been demonstrated on mature PMNs
[20].
Two receptors for IgE have been described: Fcc:RI, a
high affinity receptor present on mast cells, and FceRII,
a low affinity receptor present on macrophages, and
recently found to be similar to Fc-yRII and Rill, at least
in mice [34, 35]. None of these receptors are present
on PMNs. However, PMNs can interact with IgE through
its binding to the Mac-2/e-binding protein of the S-lectin
family present on their surface [ 16]. This interaction
appears to account for the activation of the PMN respiratory burst by lgE immune complexes.
Bacteria-derived polypeptides and their synthetic analogue formyl-methionyi-Jeucylphenylalanine (FMLP) are
potent activators of PMN chemotaxis and respiratory
burst. These peptides interact with PMN via a specific
formyl peptide .receptor (FPR) [17]. The intracellular
signal triggered by FPR activation involves a cytosolic
protein. Several molecules including G and GM-CSF
can upregulate the cell surface expression of FPR and,
recently, FcyRIIIB was shown to modulate the FPRmediated functions via a mechanism which probably
involves an intracellular transduction pathway common
to the two receptors [14]. Thus, binding of aggregated
IgG to the Fc-yRIIIB diminishes the subsequent chemotactic response of PMN to FMLP. This effect appears
to be selective, since PMN response to other chemoattractants is not altered. Endotoxin (lipopolysaccharide(LPS)), derived from Gram-negative bacteria, also
interacts with the PMN surface via the binding of severalligands. Among these ligands, the LPS-binding protein (CDI4) and the bacterial permeability increasing
protein (BIP) have been reported to be the predominant
binding sites for LPS on PMNs [18, 19].
Most of the PMN chemoattractants also act on PMNs
via binding to specific membrane receptors. This is now
established for neutrophil activating peptide (NAP)-IIIL8 which shares two classes of PMN receptors with two
other PMN activators, namely NAP-2 a closely related
variant and gro/melanoma growth-stimulatory activity
(gro/MGSA) [21]. Also, the arachidonic acid metabolite leukotriene B4 (LTB 4 ) binds to specific receptors present on PMNs [22].
Receptors for complement fragments represent an important group of surface ligands on PMNs. Several receptors for the complement component C3 have been reported
in PMNs [10]. Thus, CRI is primarily implicated in
immune complexes binding and processing, while CR3,
the iC3b receptor also called Mac-! or Mo I and classified as CD!lb/Cl8, is part of the CD18 complex (~2•
integrins) together with lymphocyte function antigen-!
(LFA-1, COlla) and p 150,95 (CDllc) [24]. The CR3
is primarily involved in phagocytosis, but also plays an
important role in adherence of PMNs to endothelial cells
(EC). Two additional C3-binding proteins, namely the
1531
decay accelerating factor (DAF) and the membrane cofactor protein (MCP) are present on PMNs, and essentially protect tissues and cells carrying these binding
proteins from unrestrained C3 and C5 convertase activation [12]. CRi, DAF and MCP, together with CR2
present on B-cells, some T-lymphocytes and epithelial
cells, form the regulators of complement activation (RCA).
C5a receptors are also present on PMNs and mediate adherence, chemotaxis, degranulation and oxygen radical release
induced by C5a [11]. In contrast, with CRI and CR3, C5a
receptors are not upregulated by secretogogues [36].
Finally, PMNs express, on their cell membrane receptors for adenosine, tumour necrosis factor-alpha (TNFo:) and atrial natriuretic peptide (ANP) [25-27]. Although,
as single agents the latter two have minimal effect on
PMNs, they can potentiate PMN activation induced by
other factors, such as FMLP. Adenosine also enhances
FMLP-induced chemotaxis, and this activity was found
to be mediated by the engagement of adenosine 2 (~)
receptors present on PMNs.
Adherence and migration
A rapid extravasation of PMNs towards infected tissues is crucial for the defence of the host against invading microorganisms. In the lung, two thirds of intravascular
PMNs adhere loosely to the endothelium, forming the
marginated pool of PMNs. Recent studies have characterized a series of molecules involved in adherence
between PMNs and ECs [37]. The adhesion molecules
on PMNs include ~2 -integrins (LFA-1, Mac-1 and p
150,95) and L-selectins. These PMNs adhesins bind to
corresponding molecules present on the surface of ECs,
mostly in postcapillary venules. The regulation of expression of adhesion molecules, both on PMNs (or monocytes) and ECs is critical for adherence and migration
of leucocytes. In particular, the importance of integrins
is well illustrated by the frequent episodes of infection
in patients with ~2-integrins deficiency. These patients
are neutropenic, and their PMNs display impaired adherence and chemotaxis.
Compared to PMNs, the role of ECs in the regulation
of migratory processes is likely to be equally important,
as documented by recent literature. Thus, binding properties have now been demonstrated for a series of EC
surface proteins, including P-selectin and the intercellular adhesion molecule-1 and 2 (ICAM-1/ICAM-2), members of the Ig supergene family [38]. ICAM-I is expressed
on unstimulated ECs and represents the corresponding
binding site for both LFA-1 and Mac-1 of the PMNs,
whilst ICAM-2 only binds LFA-1. Binding of ICAM1 to ~2-integrins is involved in adherence, and appears
to play a major role in transendothelial migration of
PMNs.
Several mechanisms can increase PMN adherence to
ECs. Firstly, ~2 -integrins and ICAM-1 expression on the
cell surface can be upregulated, providing an increased
number of anchorage sites. This upregulation can be
induced by cytokines, such as TNF-a and I L-1 for ECs
and by GM-CSF and bacteria-derived formyl peptides
1532
Y. SIBILLE, F-X. MARCHANDISE
for PMNs [36]. Secondly, in the absence of upregulation of adhesion molecules, the interaction between ECs
and PMN ligands can be strengthened, either by configurational modulation, involving cytoskeletal changes
and protein kinase C activation, or by increased local
concentration of divalent cations (Mn++, Mg++), or by the
autocrine secretion by PMNs of binding factors, such as
integrin modulating factor [24]. A third mechanism of
modulation of EC and PMN recognition involves platelet
activating factor (PAF), and is implicated in thrombin
or histamine activation of endothelium [39]. Under these
conditions of activation, ECs synthesise and express PAF
on their cell surface [23]. Together with P-selectin, PAF
then binds to its receptor present on PMNs and induces
an increase in Mac-! expression, as well as a rapid but
transient (30 min) enhancement of PMN adhesiveness to
ECs.
E- and L- selectins represent an additional group of
molecules implicated in the regulation of leucocyte-EC
interaction [24]. Thus, E-selectins are only expressed
by activated ECs and bind to L-selectins and probably
other PMN surface ligands. The recruitment of E-selectins
at the EC surface is at least one of the mechanisms
involved in ll...-1 and TNF-a-induced enhancement of
PMN adherence to ECs [39). Increased adherence begins
one hour after ll...-1 stimulation, in contrast to the shortlived effect of thrombin or histamine stimulation involving P-selectin and Mac-1. This strongly suggests the
possibility of a sequential regulation of PMN-EC interactions.
Besides its direct adhesive properties, L-selectin, in its
soluble form, has been found to upregulate CR3 expression on PMNs, thereby acting as a signal transducer [40].
This dual effect of L-selectin could explain why this
adhesion molecule is equally important for PMN adherence to ECs as the ~2 -integrins [41]. L-selectin expression on the cell surface can also be upregulated under
appropriate PMN activation. Shortly after this upregulation and binding to ECs, L-selectin undergoes proteolytic cleavage, followed by its release in the extracellular
compartment, where its function remains to be defined.
Despite some uncertainties in the adherence process
of leucocytes to ECs, this interaction represents an area
of research where considerable information has accumulated, with a better understanding of this crucial prerequisite step of inflammation [42]. At this stage, it is
tempting to speculate on the potential sequence of events
in response to an inflammatory stimulus. Thus, in resting conditions, PMNs are confined to the intravascular
compartment, part of them forming the marginated pool,
mostly in the postcapillary venules. These physiological conditions could involve a limited interaction between
~2 -integrins and ICAM-1 expressed at a low level. Shortly
after stimulation, L-selectins are recruited to the PMN
surface and bind to counter receptors (E-selectin and
other not yet defined ligands), inducing an enhanced
interface with EC. This could result in the "rolling" of
PMNs on the EC surface. This slow motion of PMNs
on the endothelial layer, together with changes in blood
flux, could initiate and enhance the interaction between
ECs and PMNs. Further stimulation induces the shed-
ding of L-selectins and the increased expression of ~2integrins and ICAM-1 , respectively, on PMNs and ECs
leading to a more intimate contact between the two cells.
In addition, upon stimulation e.g. by IL-l , ECs express
on their surface E-selectins not present in resting conditions. Other factors, such as PAF, also contribute to
reinforcing the binding of PMNs to ECs through configurational changes of P-selectins and induction of Macl upregulation.
Once immobilized, PMN can become polarized and
the transmigratory process can take place. In the induction of PMN transmigration, L-selectin appears critical,
since the shedding of L-selecti n is required for the extravasation process to start. The majority of the mediators
involved in the adherence process are also implicated in
the regulation of PMN migration [43]. It seems, therefore, reasonable to assume that the concentration of these
mediators is likely to be critical in the determination of
which of the two activities, adherence or migration, is
favoured. For C5a, it has been demonstrated that high
concentrations increase PMN adherence and decrease
migration, whilst the reverse is observed for concentrations below 1 nM [44]. Moreover, it has been shown
that PMN migration occurred along a gradient of C5a
molecules bound to a substrate (haptotaxis), rather than
from the lowest to the highest concentration of C5a
(chemotaxis) [45]. These substrate-bound molecules create a pathway for the PMNs through the endothelial barrier, the interstitial tissue and, potentially, through the
epithelial cells. The different structures encountered by
PMNs during migration can also influence their motile
behaviour. For example, the potency of various chemoattr2.ctants was shown to vary in vitro according to the
transgressed barrier, with LTB 4 inducing better transendothelial migration than FMLP, and the reverse for
transepithelial passage [46].
PMN adherence to epithelial cells has also been demonstrated, with increased attachment to epithelial cells previously incubated with cigarette smoke or infected by
respiratory viruses, such as parainfluenza virus type 2
[47]. ICAM-1 expression and upregulation on epithelial cells appears to play a predominant role in the regulation of this adherence process. The modulation of
the interaction between epithelial cells and PMNs could
have revelant clinical implications in respiratory infections, where PMN adherence could facilitate their microbicidal activity. By contrast, in chronic bronchitis,
increased adherence of PMNs to activated epithelial cells
could induce uncontrolled neutrophil-mediated cytotoxicity, leading to epithelial damage.
A number of mediators, such as biologically active
phospholipids, cytokines and bacterial products, have
been reported to influence PMN motility. However, discrepancies have been observed between in vivo and in
vitro studies. These discrepancies appear to reflect the
complex interactions between cells, mediators and matrix
components involved in PMN migration towards tissues.
Among the inflammatory mediators, C5a, NAP-1/IL-8,
PAF, the arachidonic acid metabolites LTB 4 and 5 hydroxyeicosatetraenoic acid (5 HETE) are considered as the
major chemoattractants for PMNs, at least in vitro.
ROLE OF POLYMORPHONUCLEAR NEUTROPHIL$
TNF-a and IL-l also induce PMN extravasation, but
only in vivo. This activity is probably related to the
enhancement of PMN adherence to ECs as discussed
previously, and to the stimulation of other inflammatory cells to release PMN chemoattractants.
In particular, the alveolar macrophages (AMs) appear
to play a pivotal role in PMN traffic to the alveoli and
the distal airways [43]. Thus, AMs clear most of the
occasional particles and microorganisms reaching the
lower respiratory tract. The clearance involves mechanisms which do not require major cell activation, and
this combined with the poor accessory cell activity of
AMs prevent a permanent inflammatory and immune
response in the lung. However. when AMs are overwhelmed, either by the size of the inoculum or by the
type of pathogen, they can contribute to PMN recruit-
1533
ment, via the release of NAP-1/IL-8, LTB 4 , PAF, 5 HETE,
IL-l~ and TNF-a (figs. I and 2).
In addition to these chemoattractants, AMs also release
at least one low molecular weight inhibitor of PMN motility and respiratory burst [48]. This compound has recently been shown to be present in airway secretions, and
its presence correlates inversely with the intensity of
bronchoconstriction induced by inhalation challenge, suggesting a potential protective role in airway hyperreactivity [49). Other inhibitors ofPMN migration have been
described: 1) serum factors which inhibit C5a-induced
PMN chemotaxis; 2) a protein initially isolated from lymphocyte culture supernatants, called neutrophil inhibiting factor, and now recognized as GM-CSF; and 3) lipoxin
A4 (LXA4 ), an arachidonic acid metabolite derived from
leukotriene A4 (LT A4) released by PMNs and further
Mtcroorgi:ni.$m
.. looculum $Ire
I
/ :... /
Fig. I. - Schematic illustration of the initial events associated with bacterial infection in the alveolar space. When the pathogens bypass
the mucociliary and alveolar macrophage (AM) clearance. bacterial products and AM activa tion initiate the inflammatory response. Ep I
and EP 11: alveolar type I and type 11 epithelial cell; cap: pulmonary capillary; LPS: lipopolysaccharide.
Fig 2 . - Polymorphonuclear neutrophil recruitment. Alveolar macrophages ( AMs), as the residential phagocytes. are activated to release
a series of mediators (IL-8. LTB., PAF) which. together with the complement fragment C5a, induce PMN adherancc and extravasation.
Additional AM-derived cytokines (IL-l I} and TNF-o:) indirectly promote PMN migration. IL: interleukin; TNF: lllmour necrosis factor;
TGF: transforming growth factor; PAF: platelet-activating factor; LTB,: leukotriene B,: PMN: polymorphonuclear neutrophils.
1534
Y. SIB!LLE, P-X. MARCHANDJSE
metabolized by platelets through the sequential activity
of 5 and 15 lipoxygenase [50-52). Both the C5a inhibitor
and LXA4 have been detected in bronchial washings, and
GM-CSF can be produced by AMs. When PMN extravation needs to be reduced or completely blocked, the
PMN inhibitors must rapidly take over the activators in
order to prevent further PMN activation {fig. 3). In this
context, the fate of NAP-1/IL-8, a cytokine with major
effects on PMNs {fig. 4), is instructive. Firstly, when
PMNs are continuously exposed to high concentrations
of intravascular IL-8, they undergo surface expression
and shedding of L-selectin before contact with ECs and,
as a consequence, these PMNs lose their capacity to
appropriately initiate their extravasation [53]. Secondly,
red cells were shown to bind the majority of TL-8 present at biologically active concentration in the blood, via
specific high affinity binding sites [54]. Finally, a recent
study has documented the presence of circulating antiNAP-1/JL-8 antibodies in peripheral blood [55). Together,
these mechanisms illustrate the complex network of events
potentially implicated in the regulation of PMN adherence and migration.
Fig. 3. - Polymorphonuclear neutrophils (PMNs) recruited in the alveoli release their secretory products upon stimulation by bacterial
polypeptidcs, LPS and bioactivc mediators (y-IFN, IL-6, IL-8, GM-CSF). Some mediators (IL-8, GM -CSF) implicated in the initital attraction and activation of PMNs. as well as inhibitory factors such as Lhe alveolar macrophage-derived inhibitor of PMN (AMDCI) and nitric
oxide (NO) derived from ECs can block PMN migration, providing an attractive mechanism to downregulate the inflammatory reaction
after the eradication of the pathogens. y-IFN: gamma-interferon; GM-CSF: granu locyte macrophage colony st imulating factor; EC: endothelial cell. For further abbreviations see figures I and 2.
r
'
1. T polatlzalion and
themota.~is
2. T adt>etence 1o re sling
endothelium
1 adherence lo activated
er>CSothellum
3. I colcJum mobifirollon
4.. l uurophll gr-a.nu-'es
<ltgtanulallon
Fig. 4. - NAP-l/IL-8 represents a major stimulus for polymorphonuclear neutrophils (PMNs). As illustrated, NAP- 1/lL-8 can interact
with PMNs at several levels, including adherence, migration and degranulation. Part of these effects could be mediated by the increase in
transmembrane Ca>+ flux . NAP-1/IL-8: neutrophil-activating peptide-1/interleukin-8; i : increase; .t : decreased.
ROLE OF POLYMORPHONUCLEAR NEUTROPHILS
Secretory product and biological functions
After extravasation, and upon stimulation, PMNs release
a series of secretory products able to react with pathogens
and host tissue cells and matrix. These PMN-derived
products are mostly stored in lysosomal granules. These
granules are subdivided into azurophil {primary) and specific {secondary) granules, according to their morphology and content {table 2). After PMN activation, the
granules migrate to the cell membrane and the fusion
with the membrane initiates the exocytosis, followed by
the release of the granule content into the extracellular
medium.
In addition to these intracellular products, PMNs can
undergo a respiratory burst and release substantial amounts
of reactive oxygen metabolites, including superoxide
anion (02), hydrogen peroxide (H 20 2), hypochloride, and
hydroxyl radical (OH•) [56]. The one electron reduction of molecular 0 2 generates o;, and the reaction is
mediated by the nicotinamide-adenine-dinucleotide-phosphate {reduced form) {NADPH) oxidase complex. Most
of o; produced by PMNs is enzymatically converted to
HP2 by a Cu-Zn superoxide dismutase. PMNs can either
detoxify ~02 to H20 through the glutathione redox system, or produce hypohalous acids in the presence of
halide and myeloperoxidase. PMNs contain substantial
amounts of myeloperoxidase in their azurophil granules,
and using Cl as a substrate release large quantities of
HOC!. Hydroxyl radicals (OH•) are formed in the Haber
Weiss reaction, by the combination of 0 2 and HP 2 in
the presence of Fe++-+. Together with H20 2 and HOC!,
OH• represent potent oxidative metabolites, accounting
for a large part of PMN microbicidal activity. In addition, PMNs also generate long-lived oxidants {half-life
of 8 h) such as N-chloramines, capable of inducing a
prolonged oxidative reaction.
The role of these oxygen metabolites in vivo is best
emphasized in patients with chronic granulomatous disease {CGD) characterized by a defect in the respiratory
Table 2. -
burst of phagocytes [57]. The disease is inherited, either
X-linked (most common form) or autosomal recessive,
and is caused by an impaired function of the NADPH
oxidase complex. Patients with CGD present in their
childhood with severe, frequent and prolonged infectious
problems, in particular pneumonia and soft tissue infections, with cold abcesses. The organisms most commonly isolated from infected sites are Staphylococcus
aureus, Pseudomonas spp. and Nocardia spp. In contrast to patients with CGD, patients with myeloperoxidase deficiency suffer only minor infectious episodes,
suggesting that in these patients PMNs can compensate
with other microbicidal mechanisms.
Several other secretory products of PMNs can contribute to killing the pathogens. Firstly, lysozyme, present in both azurophil and specific granules can induce
the hydrolysis of glycosidic linkages in bacterial cell
walls. Lactoferrin, a protein stored in PMN specific
granules, is also considered to have a bactericidal activity, partly, but not exclusively, dependent on its iron
binding capacity [58]. More recently, a group of endogenous antibiotic proteins, stored in azurophil granules, has
been found to have bactericidal properties [59]. This
group includes cathepsin G and the defensins (human
neutrophil peptides (HNP-1 to 4), cationic antimicrobial
protein (CAP) 37, azurocidic and bactericidal/permeability increasing protein (BIP). Although -the precise
contribution of each individual molecule to the in vivo
antimicrobial activity of PMNs remains to be established,
it is possible that these antibiotic proteins provide alternative bactericidal agents in anaerobic conditions.
Both azurophil and specific granules contain proteolytic enzymes active on fibres and proteoglycans of the
interstitial matrix. Neutrophil elastase, a neutral serine
protease. represents quantitatively the major azurophil
granu.le component (3 J..Lg· l ().fi cells). The activity of neutrophil elastase is not restricted to elastin fibres. since
type I. II. Ill anc.l IV collagen. glycoprotcins such as
fibronectin and proteoglycans, can also be cleaved by
Polymophonuclear neutrophil (PMN) granule content
Proteolytic enzymes
Other enzymes
--------·--------------------Vesicles
Azurophil
Specific
Lysozmye
Serine elastase
Cathepsin G
Proteinase 3
Lysozyme
Collagenase
(type I)
Gelatinase
Heparinase
Plasma proteins
Gelatinase
Myeloperoxidase
Mac- I
CDllb/CDI8
Integrins
Bactericidal protein
1535
Lactoferrin
Defensins (HNP 1-4)
BIP
CAP 3,fazurocidin
Albumin, lgG
Alkaline phosphatase
Cytochrome b558
Tetranectin
HNP: human neutrophil peptide; BIP: bactericidaVpermeability increasing protein; CAP: cationic
antimicrobial protein; IgG: immunoglobulin G; CD: cluster designation.
1536
Y. SIBILLE, F-X. MARCHANDISE
this neutral protease [43]. In the lung, PMN elastase
has been implicated in the pathogenesis of destructive
diseases such as emphysema associated with a 1-protease
inhibitor (a1-PI) deficiency [60]. In addition to its proteolytic properties, PMN elastase can influence, at least
in vitro, endothelial cell functions. Thus, detachment of
endothelial cells from their matrix support, as well as
cell lysis, can be induced by PMN elastase [61, 62].
Also, several functions of epithelial cells appear to be
affected by PMN elastase. More specifically, a decrease
in the frequence of ciliary beats on ciliated cells, an
increased secretion of mucus, and an enhanced expression of mRNA transcripts for IL-8 in transformed epithelial cells have been documented in the presence of PMN
elastase [63]. If these changes occur in vivo, they would
provide a role for this serine protease, not only in emphysema but also in bronchial diseases, such as chronic bronchitis, asthma and cystic fibrosis. Moreover, when
complexed to a 1-PI (its major antiprotease) PMN elastase is chemotactic for PMNs, illustrating the difficulty
of globally evaluating the interaction between proteases
and antiproteases. Recently, a serine protease, different
from elastase and present in azurophil granules, was
shown to degrade elastin fibres, and was identified as
proteinase 3 [64]. At acidic pH (6.5), the digestion of
elastin by proteinase 3 and elastase are similar.
In addition to an elastolytic activity, PMNs can secrete
a collagenase, preferentially active on type I as compared to type Ill collagen, and stored in its latent form
in specific granules [65]. The secondary granules also
contain two enzymes with specific proteolytic activity
on matrix components: heparanase inducing the hydrolysis of heparan sulphate, a proteoglycan from the basement membrane, and gelatinase, a metalloproteinase with
specific activity on type V collagen, a major constituent
of the basement membrane [66, 67). The release of these
enzymes can be selective, and can be achieved with low
concentrations of stimuli, suggesting that they can contribute to facilitate the PMN migration through the interstitial matrix, without major structural changes in tissues.
Although gelatinase has been reported to be eo-localized
with lactoferrin in the specific granules, other studies
suggest that gelatinase is stored apart from azurophil and
specific granules. in intracytoplasmic vesicles. The content of these vesicles has recently been characterized to
be mainly albumin, together with other plasma proteins,
such as tranferrin, IgG and tetranectin [68). These proteins are internalized, and not synthesized by PMNs.
Alkaline phosphatase, cytochrome b558, and CRI are
also stored in these vesicles. Interestingly, the exocytosis of intracytoplasmic vesicles is induced by concentrations of chemotactic factors lower than those required
for degranulation of azurophil and specific granules.
Moreover, these vesicles were recently shown to contain
Mac-1 (COli b/CD18), providing one mechanism by
which PMNs can rapidly recruit and increase the expression of ~2 -integrins on their membrane. This process
probably plays a role when PMN are exposed to sustained stimulation of chemotactic factors [69).
PMNs also contribute to the pool of inflammatory
mediators, via the release of bioactive lipids, essentially
LTB4 and PAF, and the secretion of cytokines (IL-l and
NAP- 1/IL-8). The production of lL-1 a and l3 by PMNs
has been convincingly demonstrated, as well as the concomitent release of an IL-l inhibitor [70-72]. Recently,
PMNs were found to synthesize and secrete significant
amounts of NAP-l/IL-8 in response to phagocytosis
[73].
With their arsenal of secretory products, PMNs appear
as first line effector inflammatory cells, potentially activated by various stimuli. Thus, the activation of the respiratory burst and the induction of degranulation in PMNs
can be achieved in vitro after exposure to several stimuli, including bacterial peptides, immune complexes, complement fragments, GM-CSF, LPS, IL-6, IL-8, TNF-a,
LTB4 and PAP [74]. However, the presence of inhibitory mechanisms is equally important, since they can
prevent an inadequate and prolonged activation of PMNs,
which could lead to tissue damage. Such inhibitors of
PMN function have been identified as secretory products derived from ECs (prostacyclin, adenosine and nitric
oxide), from AMs (prostaglandin E2 , alveolar macrophage
derived PMN inhibitor) and from platelets (LXA4) [43,
75].
PMNs in respiratory diseases
Neutrophils and antimicrobial defences
PMNs are primarily implicated in the defence of the
respiratory tract, where their protective role contributes
to prevent bacterial growth and to eradicate the infectious process when pathogens proliferate [76). PMNs are
therefore considered as major cellular components in the
defence of the lung against bacterial and fungal infection. Animal models of infection, as well as clinical
studies. strongly suggest that the ability to remove bacteria from the respiratory tract depends essentially on the
number of PMNs present in the lesions [77). It is well
recognized that patients with marked neutropenia or severe
defects in PMN function often present with respiratory
problems, such as recurrent pneumonia, and other types
of life-threatening bacterial and fungal infections [78).
However, in these patients, infections do not always
occur. suggesting that other host defence mechanisms
are involved and could compensate for the decrease in
PMN number or function. Several acquired and congenital diseases, characterized by abnormalities of PMN
function, have been reported [57]. Despite recent progress
in the understanding of PMN functions, the biochemical
or morphological basis of the defects associated with
these diseases are often complex, and the relevance of
the neutrophil defect to the presentation of the disease
is sometimes unclear. As already discussed, the adherence properties of PMNs influence their transendothelial migration and, indirectly, their antibacterial role at
the sites of infection. In this context, CR3 deficiency,
a rare autosomal recessive disorder, affects the adherence-related functions of PMNs. In CR3 deficient patients,
PMNs exhibit a decreased capability to aggregate, a
ROLE OF POLYMORPHONUCLEAR NEUTROPHILS
decreased adherence to ECs, a poor phagocytosis of
opsonized microorganisms, defective spreading, a decreased
spontaneous mobility and chemotaxis. This results in an
inappropriate inflammatory response and life-threatening
bacterial and fungal infections [57]. Additional congenital defects in PMN function, associated with recurrent infections, include abnormal respiratory burst associated
with the CGD as already discussed previously, and the
Chediak-Higashi syndrome, characterized by a lysosomal dysfunction [78].
The acquired PMN deficiencies largely outnumber the
congenital disorders, and include mostly neutropenia,
associated with myeloproliferative diseases and induced
by cancer chemotherapy and radiation therapy [43].
Both Gram-positive and Gram-negative infections are
observed in patients with neutropenia, although the latter
are more frequent. This is in agreement with animal
studies supporting a predominant role for PMNs in models of Klebsiella and Peudomonas pneumonia. For Grampositive organisms, such as Staphylococcus aureus, small
inoculi are generally cleared by AMs whilst larger numbers of pathogens require the cooperation of PMNs.
Neutrophils and lung injury
In addition to their role in infectious disorders, PMNs
are implicated in the pathogenesis of bronchopulmonary
diseases, such as chronic bronchitis, asthma, cystic fibrosis, the adult respiratory distress syndrome, idiopathic
pulmonary fibrosis, collagen vascular disorders and emphysema.
The oxidative and proteolytic mediators released by
PMNs to kill microorganisms can also act on adjacent
host tissues and, therefore, be involved in the pathogenesis of a number of noninfectious diseases of the lower
respiratory tract. Virtually absent in the lung parenchyma
and airways of healthy subjects, PMNs can be attracted
from the pulmonary circulation by PMN chemotactic
factors. Some of these factors have been found to be
increased in the airways of patients with parenchyma!
lung diseases associated with increased alveolar PMN
counts.
Smoking, chronic bronchitis and emphysema. In cigarette smokers, there is an increase of both peripheral
blood and BAL PMNs in comparison with nonsmoking
controls [79]. It is unlikely that tobacco smoke directly attracts PMNs to the lung, since no chemotactic activity for PMNs is observed in vitro with smoke extracts.
However, alveolar macrophages from nonsn:tokers in the
presence of tobacco smoke increase their release of chemotactic factors in vitro. The consequences of PMN accumulation in the airways of smokers are difficult to interpret
Thus, the higher number of PMNs in the airways could
increase the antimicrobial defence but could also impair
bronchial cell function. These functional changes could
prevent the normal response to the bacterial challenge
[80]. In vitro studies on the effect of cigarette smoke
on PMN function are controversial, some authors reporting enhanced functions, others suggesting depressed reac-
1537
tivity [81-83]. Moreover, the relevance of active smoking on PMN function in vivo remains speculative.
In chronic bronchitis, PMN counts in the airways are
increased but the changes of PMN function are also a
subject of controversy. Some authors report that PMNs
from chronic bronchitis patients have a defect in chemotaxis, phagocytosis and killing of Candida [84]. Also,
the oxidative metabolism of PMNs has been reported to
be significantly reduced, and a constitutional defect in
neutrophil response could be an underlying cause for the
increased susceptibility to infections associated with
chronic bronchitis. Other authors report that the chemotactic responses of PMNs are enhanced [85]. The latter
observation provides a mechanism for the increased
recruitment of PMNs to the airways of these patients
[86]. Whether this increase represents a cause or a consequence of the disease is unknown. However, through
the release of oxygen radicals and proteases, PMNs could
contribute to inflammation, bronchial damage and mucus
hypersecretion, three characteristic features in chronic
bronchitis.
Emphysema is believed to be caused by an impaired
balance between proteolytic and antiproteolytic activities
in distal airways and alveoli [87]. This is best illustrated in patients deficient in a,-PI, the major antiprotease against PMN elastase. These patients develop
emphysema early in life. However, a 1-PI deficiency
accounts for only a minority of cases of emphysema. By
contrast, cigarette smoking represents a major risk factor, although individual susceptibility is likely to play an
important role, since not all heavy smokers will eventually have emphysema [88]. One mechanism contributing to the exposure of smokers to the risk of emphysema
is the retention of PMNs within the pulmonary microvasculature, associated with active smoking. This slower
wash-out of PMNs could potentially lead to lesions of
lung cells and matrix [89]. In addition to its role on PMN
recruitment and activation, the cigarette smoke contains
various oxidants capable of damaging epithelial and
endothelial cells and inactivating a,-PI via the oxidation
of it<; protease binding site. This could result in unrestrained PMN elastase activity, leading to interstitial
matrix degradation. Moreover, the intimate binding of
PMNs to tissue could prevent the access of antiprotease
macromolecules to the site of proteolytic burden. This is
also likely to be critical for the outcome of injurious
processes.
Asthma. Although PMNs are probably not the dominant
cells in asthma, they may contribute to the inflammatory process underlying the disease [90]. Thus, PMNs
are increased in bronchial biopsies, as well as in airway
washings, from asthmatic patients. Other inflammatory
and immune cells implicated in asthma, such as mast
cells, eosinophils and lymphocytes, represent major
sources of PMN chemotaxins. Among these chemotaxins, LTB 4 and PAF have been found to be present in
BAL fluid from asthmatics [91, 92]. Moreover, chemotactic activity for PMNs can also be detected in the serum
after antigen-induced late phase asthmatic reaction
[93].
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Y. SIBILLE, F-X. MARCHANDISE
PMNs are believed to play an important role in several models of airway hyperreactivity. Thus, bronchial
hyperreactivity induced by chemicals (toluene diisocyanate) or by vegetable extracts (cotton bract) are associated with PMN activation [94, 95). In the cotton bract
model, PMN functions appear to correlate with the degree
of bronchoconstriction. More recently, an inhibitory
activity for PMN motility and respiratory burst was found
to parallel the low responsiveness of the airways of normal subjects to the cotton bract challenge [48). To further support a role for PMNs in asthma, METZGER et al.
[96] reported that 0 2 production by blood PMNs from
asthmatics correlates with the severity of bronchial
constriction [96]. A similar role for oxygen radicals
has also recently been suggested in nocturnal asthma,
although the contribution of PMNs to the o; production
by airway cells from asthmatics remains to be defined
[97).
Cystic fibrosis. Cystic fibrosis (CF) is a genetic disorder caused by an impaired permeability for chloride ions
in epithelial cells, leading to progressive and destructive
airway disease and bronchiectasis in children and young
adults [98]. The disease is characterized by chronic airway infection and inflammation, invariably dominated
by PMNs. The fluid lining the respiratory epithelium
contains large numbers of PMNs and active PMN elastase. PMN elastase can damage epithelial cells by direct
toxic effect, can hinder normal host defence by interfering with ciliary clearance, increasing mucus production, cleaving immunoglobulins and complement, and by
impairing phagocytosis and killing of Pseudomonas aeruginosa by lung pbagocytes [99]. Moreover, PMN elastase appears to be the dominant signal capable of inducing
the expression of the ll..-8 gene, and the release of ll..-8
by the respiratory epithelium [63]. Thus, IL-8 has been
detected in airways secretions from CF patients, and is
likely to contribute to the recruitment of PMNs [100].
Until now, the treatment of CF mostly consisted in preventing recurrent infections in the respiratory tract.
However, the recent recognition of the CF regulator gene,
and the progresses made in gene therapy, could change
the prognosis of this lethal genetic disease in the reasonably near future [101, 102].
Cancer. The ability of PMNs to kill in vitro tumour
cells by oxidative and non-oxidative mechanisms, such
as defensins and cathepsin G, is well-documented [103].
By contrast, the increased secretion of protease by PMNs
can contribute to the invasive behaviour of cancer cells,
and local proteolysis can be enhanced by surface receptors for proteases on the tumour cells. PMNs are often
the first host cells to infiltrate the tumour, and can elicit
the influx of secondary effector cells, such as macrophages,
natural killer (NK) cells and cytolytic T -lymphocytes,
into the tumour bed, and possibly participate in their activation. A question concerning the clinical relevance of
this phenomenon is whether stimuli are present in vivo
and can activate the tumoricidal activity of PMNs. Recent
studies suggest that cytokines such as y-interferon (IFN),
IL- l, TNF-a and CSFs could provide these required acti-
vation signals. Because these recombinant molecules
are now available for experimental therapy, activation of
tumoricidal PMNs in patients may become feasible.
Adult respiratory distress syndrome (ARDS). Although
ARDS can occur in neutropenic patients, several lines
of evidence suggest that PMNs are involved in the initiation and the severity of acute lung injury in ARDS
patients with normal PMN supplies. In most individuals with ARDS, there is a marked increase of PMNs
in the alveolar spaces, where they often account for 85%
or more of the total cells recovered by BAL ( 104]. PMN
extravasation, by itself, probably does not induce alveolar damage, since bacterial pneumonia associated with
high alveolar counts of PMNs generally clear, without
major parenchyma! lesions. However, lung injury probably occurs when PMNs migrating into the alveoli are
stimulated to secrete elastase and myeloperoxidase. Thus,
PMN elast_ase, collagenase and myeloperoxidase concentrations in BAL were reported to be increased, and
to correlate with the severity of gas exchange abnormality in the lung of ARDS patients [ 105]. When stimulated by complement fragments or phorbol esters,
phagocytes, including PMNs, can produce toxic oxygen
metabolites, and Hp2 has been detected in exhaled air
from ARDS patients [106]. Other studies have demonstrated that endothelial cells, initially injured by free radicals increase their adhesiveness for PMNs and become
more susceptible to further injury by PMNs. Additional
evidence for an important role of oxygen free radicals
in endotoxin-induced lung vascular injury is provided by
the observation that N-acetylcysteine, a fre.e radical scavenger, diminishes the degree of microvascular injury
[107J. Numerous studies have implicated oxygen metabolites in the pathogenesis of acute lung injury, and PMNs
are considered as major sources of free radicals.
Recently, several PMN chemotaxins, such as LTB4 ,
TNF-a and IL-8, released mainly by activated macrophages,
were found in the epithelial lining fluid of patients with
ARDS [108, 109]. This explains why PMNs, normally
absent, are attracted from the peripheral blood to the respiratory tract. ln particular, the major influx of PMNs
into the alveolar space observed in ARDS is associated
with high levels of NAP- 1/IL-8 in BAL [110]. Moreover,
NAP-1/lL-8 appears to be the major PMN chemotactic
activity present in BAL from these patients. As a clinical correlate, highest levels of NAP-1/IL-8 in BAL were
generally found in patients who eventually died. More
importantly, a preliminary study reported that in patients
at risk for ARDS, those with high levels of BAL NAPl/IL-8 were more likely to develop ARDS [111]. In
addition to its chemoattractive activity, ll..-8 activates
PMNs, induces the respiratory burst, and the release of
proteases and LTB 4 [112]. In Gram-negative sepsis,
endotoxin contributes largely to the accumulation of
PMNs responsible for lung injury, through the release
of cytokines active both on PMNs and ECs. The accumulation of PMNs is followed by ultrastructural evidence
of pulmonary endothelial injury, and subsequent increased
lung vascular permeability. These lesional changes can
be prevented by PMN depletion.
ROLE OF POLYMORPHONUCLEAR NEUTROPHILS
Wegener's granulomatosis. The discovery of antibodies
directed against neutrophil products (ANCA) in serum
of patients with vasculitis, such as Wegener's disease,
have at least suggested a role for PMNs in these disorders [ 113, 114]. Briefly, three groups of autoantibodies
have been described, according to their pattern of immunofluorescence staining [115]. The first group essentially
stains the perinuclear area (pANCA) and primarily recognizes mye1operoxidase and to a lesser extent elastase
and lactoferrin. The second group of antibodies (cANCA)
stains the cytoplasm of PMNs and has the proteinase 3
and probably the natural antibiotic CAP57 as targets.
These cANCA are frequently associated with Wegener's
granulomatosis. The third group of autoantibodies
(xANCA) with a mixed (cytoplasmic and perinuclear)
staining pattern recognizes cathepsin G, and is mostly
present in ulcerative colitis.
As recently reviewed, circulating cANCA have a sensitivity of 75% for active Wegener's disease, and this
sensitivity increases to 90% when pANCA are also present [116]. The speciticity of cANCA for Wegener's
disease is close to 100%. Beyond their role as diagnostic tools, ANCA have also been shown to induce the
release of several mediators (TNF-a, o;, proteolytic
enzymes) which are toxic for endothelial cells. Further
investigations will probably elucidate the contribution of
these autoantibodies to vasculitis more precisely.
Interstitial lung diseases
The presence of PMNs infiltrating the lung parenchyma is generally associated with injurious and fibrotic disorders, such as idiopathic pulmonary fibrosis (IPF) and
collagen vascular disorders (CVD). Thus, enhanced
chemotactic activity for PMNs is detected in BAL fluid
from both IPF and CVD patients [ 117, 118]. Collagenase
activity is also present in BAL fluid from these patients,
as well as PMN elastase [ 119, 120]. It is recognized
that some CVD patients without overt pulmonary involvement can also have elevated PMN counts in their BAL
[1211. The significance of this alveolar neutrophilia is
unknown. However, only CVD patients with ILD have
detectable levels of PMN elastase in their BAL, suggesting that in CVD patients without ILD, either the
products of PMN granules are not secreted, or these products are rapidly neutralized by antiproteases.
PMN accumulation in the alveolar space is a common
hallmark in IPF patients [122]. Thus, the number of
BAL PMNs correlates with the increased expression of
mRNA for IL-8 by alveolar macrophages in these patients,
providing at least one mechanism of PMN recruitment
[123]. Although PMNs can contribute to the lesional
changes observed in fibrotic ILD, via the release of proteases and/or oxidants, as illustrated by increased levels
of oxidized glutathione and methionine residues in BAL
[124, 125], their role in fibrotic changes is unclear. In
particular, there is little evidence that PMNs release major
fibroblast growth factors or promote the production of
collagen fibres. Moreover, the prognostic value of high
numbers of PMNs in BAL from IPF patients is uncer-
1539
rain. For example, in smoking patients with IPF, a persisting high number of BAL PMN is not associated with
functional deterioration [ 122]. This is in contrast with
the presence of eosinophils in BAL from IPF patients,
usually associated with a poor prognosis, and the presence of high lymphocyte counts frequently associated
with better prognosis [ 126].
Hypersensitivity pneumonitis (HP) is characterized by
a delayed type reaction to organic or chemical antigens,
and by an intense immune response in the lung. The
dominant cells are T-lymphocytes, with a majority ofTsuppressor/cytotoxic cells (CD8). However, PMNs are
often increased, and can account for more than 5% of
BAL cells. This increase in PMNs is more striking when
BAL is performed in HP patients shortly after specific
antigen challenge, probably in the context of an acute
inflammatory response (127].
The presence of PMNs in lungs from patients with
pulmonary sarcoidosis is not a usual feature in a disease
characterized by the infiltration of the interstitium by
granuloma, formed by a mixture of epithelioid and giant
cells and T -lymphocytes. Although the presence of PMNs
infiltrating the interstitium has originally been associated
with chronic and fibrotic disease, moderate increases in
BAL PMN counts have also occasionally been observed
in more recent cases of sarcoidosis and, therefore, the
relevance of this increase in non-fibrotic forms of the
disease is uncertain [128, 129].
Finally, an increased number of PMNs has been reported in bronchiolitis obliterans with organizing pneumonia (BOOP), an interstitial lung disease characterized by
focal distortion of distal airways and alvoli by granulomas. An increase in BAL lymphocytes represents the
dominant picture, although PMNs, eosinophils and mast
cells, are also increased, but to a lesser extent [ 130].
In summary, PMNs have frequently been associated
with injurious and fibrotic forms of lLD. However, it
remains to be established to what extent these phagocytes
contribute to perpetuation of the damage, and whether
they trigger the fibrotic reaction.
References
I. Weisbart RH, Gasson JC, Golde DW. - Colonystimulating factors and host defense. Ann Intern Med 1989;
110: 297-303.
2. Laver J, Moore MAS. - Clinical use of recombinant
human hematopoietic growth factors. J Natl Cancer lnst 1989;
8 1: 1370-1382.
3. Monroy RL. Davis TA, MacYittie TJ. - Granulocytemacrophage colony-stimulating factor: more than a hemopoietin. Clin Immunol lmmunopathol 1990; 54: 333- 346.
4. Cosman D. - Colony-stimulating factors in vivo and in
vitro. lmmunol Today 1988; 9: 97- 98.
5. Yoshimura K, Crystal RG. - Transcriptional and posttranscriptional modulation of human neutrophil elastase gene
expression. Blood 1992; 79: 2733-2740.
6. Amaout MA, Wang EA, Clark SC, Sieff CA. - Human
recombinant granulocyte-macrophage colony-stimulating factor increases cell-to-cell adhesion and surface expression of
adhesion promoting glycoproteins on mature granulocytes. J
Clin Invest 1986; 78: 597-601.
1540
Y. SIBILLE, F-X. MARCHANDISE
7. Devereux S, Porter JB, Hoyes KP, Abeysinghe RD,
Saib R, Linch DC. - Secretion of neutrophil secondary granules occurs during granulocyte-macrophage colony stimulating
factor induced margination. Br J Haematol 1990; 74: 1723.
8. Newman SL, Henson JE, Henson PM. - Phagocytosis
of senescent neutrophils by human monocyte-derived macrophages
and rabbit inflammatory macrophages. J Exp Med 1982; 156:
430-442.
9. Savill JS, Henson PM, Haslet! C. - Phagocytosis of aged
human neutrophils by macrophages is mediated by a novel
"charge-sensitive" recognition mechanism. J Clin Invest 1989;
84: 1518-1527.
10. Holers VM, Kinoshita T, Molina H. - The evolution of
mouse and human complement C3-binding proteins: divergence
of form but conservation of function. Immunol Today 1992;
13: 231-236.
11. Chenoweth DE, Hugli TE. - Demonstration of specific
C5a receptors on intact human polymorphonuclear leukocytes.
Proc Natl Acad Sci USA 1978; 75: 3943.
12. Coyne KE, Hall SE, Thompson ES, et al. - Mapping of
epitopes, glycosylation sites, and complement regulatory domains
in human decay accelerating factor. J lmmunol 1992; 149:
2906-2913.
13. Unkeless JC. - Function and heterogeneity of human Fe
receptors for immunoglobulin G. J Clin Invest 1989; 83:
355-361.
14. Kew RR, Grimaldi CM, Furie MB, Fleit HB. - Human
neutrophil FcyRIIlB and formyl peptide receptors are functionally linked during formyl-metbionyl-leucyl-phenylalanine
induced chemotaxis. J lmmunol 1992; 149: 989-997.
15. Albrechtsen M, Yearnan GR, Kerr MA. -Characterization
of the IgA receptor from human polymorphonuclear neutrophils.
Immunology 1988; 64: 201-205.
16. Truong MJ, Gruart V, Kusnierz JP, et al. - Human oeutrophlls express immunoglobulin E (lgE)-binding proteins (Mac2/eBP) of the S-type lectin family: role in IgE-dependent
activation. J Exp Med 1993; 177: 243-248.
17. Becker EL. - The formylpeptide receptor of the neutrophil. Am J Pathol 1987; 129: 16-24.
18. Wcersink AJL, van Kessel KPM, van den To! ME, et al.
- Human granulocytes express a 55-kDa lipopolysaccharidebinding protein on the cell surface that is identical to the
bactericidaUpermeability-increasing protein. J lmmunol 1993;
150: 253-263.
19. Worthen GS, Avdi N, Vukajlovich S, Tobias PS. Neutrophil adherence induced by lipopolysaccharide in vitro.
- Role of plasma component interaction with lipopolysaccharide. J Clin Invest 1992; 90: 2526-2535.
20. Dipersio J, Billing P, Kaufman S, Eghtesady P, Williams
RE, Gasson JC. - Characterization of the human granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor. J Bioi Chem 1988; 263: 1834-1841.
21. Moser B, Schumacher C, von Tscharner V, Clark-Lewis
I, Baggiolini M. - Neutrophil-activating peptide 2 and
gro/melanoma growth-stimulatory activity interact with neutrophil activating peptide-1/interleukin-8 receptors on human
neutrophils. J Bioi Chem 1991 ; 266: 10666-10671.
22. Martin TR, Pistorese BP, Chi EY, Goodman RB, Matthay
MA. - Effects of leukotriene 84 in the human lung. Recruitment
of neutrophils into the alveolar spaces without a change in protein permeability. J C/in Invest 1989; 84: 1609-1619.
23. Dent G, Ukena D, Chanez P, Sybrecht G, Bames P. Characterization of PAF receptors on human neutrophils using
the specific antagonist, WEB 2086: correlation between receptor binding and function. FEBS Lett 1989; 244: 365-368.
24. Pardi R, Inverardi L, Bender JR. - Regulatory mecha-
nisms in leukocyte adhesion: flexible receptors for sophisticated travellers. lmmunol Today 1992; 13: 224-230.
25. Wiedermann CJ, Niedermtihlbichler M, Braunsteiner H.
- Priming of polymorphonuclear neutrophils by atrial natriuretic peptide in vitro. J Clin Invest 1992; 89: 1580-1586.
26. Rose FR, Hirschhom R, Weissmann G. Cronstein BN. Adenosine promotes neutrophil chemotaxis. J Exp Med 1988;
167:1186-1194.
27. Shalaby MR, Palladino MA Jr, Hirabayashi SE, et al. Receptor binding and activation of polymorphonuclear neutrophils by tumor necrosis factor-alpha. J Leukocyte Bioi 1987;
41: 196-201.
28. van de Winkel JGJ, Anderson CL. - Biology of human
immunoglobulin G Fe receptors. J Leukocyte Bioi 1991; 49:
511.
29. Anderson CL, Looney RJ. - Human leukocyte Ig Fe
receptors. lmmunol Today 1986; 7: 264-266.
30. Reynolds HY. - Mechanisms of inflammation in the
lungs. Am Rev Med 1987; 38: 295- 331.
31. Van Epps DE, Williams RC Jr. - Suppression of leukocyte chemotaxis by lgA myeloma components. J Exp Med
1976; 144: 1227-1242.
32. Sibille Y, Delacroix DL, Merrill WW, Chatelain B, Vaerman
JP. - 1gA-induced chemokinesis of human polymorphonuclear neutrophils requirement of their Fc-alpha receptor. Mol
Immunol 1987; 24: 551- 559.
33. Weisbart RH, Kacena A, Schuh A, Golde DW. - GMCSF induces human neutrophil lgA-mediated phagocytosis by
an lgA Fe rcceptor activation mechanism. Nature 1988; 332:
647-648.
34. Metzger H, A1caraz G, Holman R, Kinet JP, Pribluda V,
Quarto R. - The receptor with high affinity for immunoglobulin E. Annu Rev lmmunol 1986; 4: 419.
35. Taldzawa F, Adamczewslci M, Kinet JP. - Identification
of the low affinity receptor for immunoglobulin E on mouse
mast cells and macrophages as FcyRII and FcyRIII. J Exp Med
1992; 176: 469-476.
36. Van Epps DE, Simpson SJ, Johnson R. - Relationship
of C5a receptor modulation to the functional responsiveness
of human polymorphonuclear leukocytes to C5a. J lmmunol
1993; ISO: 246-252.
37. Zimmerman GA, Prescott SM, Mclntyre TM. - Endothelial
cell interactions with granulocytes: tethering and signaling molecules. lmmunol Today 1992; 13: 93-99.
38. Pelletier RP, Ohye RG, Vanbuskirk A, et al. - Importance
of endothelial VCAM-1 for inflammatory leukocytic infiltration in vivo. J lmmunol 1992; 149: 2473- 2481.
39. Kuijpers TW, Hak.kert BC, Hoogerwerf M, Leeuwenberg
JFM, Roos D. - Role of endothelialleukocyte adhesion molecule- I and platelet-activating factor in neutrophil adherence
to IL-1-prestimulated endothelial cells. Endothelial leukocyte
adhesion molecule-1-mediated CDI8 activation. J lmmunol
1991; 147: 1369- 1376.
40. Lobb RR, Chi-Rosso G. Leone DR, et al. - Expres-sion
and functional characterization of a soluble form of endothelial-leukocyte adhesion molecule l. J lmmunol 1991; 147 :
124-129.
41. Simon SI, Chambers JD, Butcher E, Sklar LA. - Neutrophil aggregation is 132-integrin- and L-selectin-dependent in
blood and isolated cells. J lmmunp/ 1992; 149: 2765-2771.
42. Anderson DC, Springer TA. - Leukocytc adhesion deficiency: an inherited defect in the MAC- I, LFA-1, and pl50,95
glycoproteins. Annu Rev Med 1987; 38: 175- 194.
43. Sibille Y, Reynolds HY. - Macrophages and polymorphonuclear neutrophils in lung defense and injury. Am Rev
Respir Dis 1990; 141: 471-501.
44. Charo IF, Yuen C, Perez HD, Goldstein IM. - Chemotactic
ROLE OF POLYMORPHONUCLEAR NEUTROPHJLS
peptides modulate adherence of human polymorphonuclear
leukocytes to monolayers of cultured endothelial cells. J lmmunol
1986; 136: 3412-3419.
45. Rot A. - Endothelial cell binding of NAP- 1/IL-8: role
in neutrophil migration. lmmunol Today 1992; 13: 291- 294.
46. Robbins RA, Koyama S, Spurzem JR, et al. - Modulation
of neutrophil and mononuclear cell adherence to bronchial
epithelial cells. Am J Respir Cell Mol Bioi 1992; 7: 19- 29.
47. Tosi MF, Stark JM, Hamedani A, Smith CW, Gruenert
DC, Huang YT. - Intercellular adhesion molecule- 1 (!CAMI)-dependent and ICAM-1-independent adhesive interactions
between polymorphonuclear leukocytes and human airway
epithelial cells infected with parainfluenza virus type 2 . J
lmmunol 1992; 149: 3345- 3349.
48. Sibille Y, Merrill WW, Naegel GP, Care SB, Cooper JAD,
Reynolds HY. - Human alveolar cells release in vitro a factor(s) which inhibits neutrophil chemotaxis. Am J Respir Cell
Mol Bioi 1989; 1: 407-416.
49. Cooper JAD Jr, Sibille Y, Zitnik RJ, Bayles G, Buck MG,
Merrill WW. - Isolation of an inhibitor of neutrophil function from bronchial lavage of normal volunteers. Am J Physiol
1991; 260: L501- L509.
50. Goetzl EJ. - Plasma and cell-derived inhibitors of human
neutrophils chemotaxis. Ann NY Acad Sci 1975; 256: 210-221.
51. Gasson JC, Weisbart RH, Kaufman SE, et al. - Purified
human granulocyte-macrophage colony-stimulating factor: direct
action on neutrophils. Science 1984; 226: 1339- 1342.
52. Fiore S, Serhan CN. - Formation of lipoxins and
leukotrienes during receptor-mediated interactions of human
platelets and recombinant human granulocyte/macrophage
colony-stimulating factor-primed neutrophils. J Exp Med 1990;
172: 1451-1457.
53 . Hechtman DH, Cybulsky MI, Fuchs HJ, Baker JB, Gimbrone
MA Jr. - Intravascular IL-8. Inhibitor of polymorphonuclear
leukocyte accumulation at sites of acute inflammation. J lmmunol
1991 ; 147: 883- 892.
54. Darbonne WC, Rice GC, Mohler MA, et al. - Red blood
cells are a sink for interleukin-8, a leukocyte chemotaxin. J
Clin Invest 1991; 88: 1362-1369.
55. Sylvester I, Yoshimura T. Sticherling M, et al. - Neutrophil
attractant protein-1-immunoglobulin G immune complexes and
free anti-NAP- 1 antibody in normal human serum. J Clin Invest
1992; 90: 471-481.
56. Fantone JC, Ward PA. - Role of oxygen-derived free
radicals and metabolites in leukocyte-dependent inflammatory
reactions. Am J Pathol 1982; 107: 397-418.
57. Malech HL, Gallin JI. - Current concepts: immunology. Neutrophils in human diseases. N Engl J Med 1987; 317:
687-694.
58. Lima MF, K.ierszenbaum F. - Lactoferrin effects on
phagocytic cell function. II. The presence of iron is required
for the lactoferrin molecule to stimulate intracellular killing by
macrophages but not to enhance the uptake of particles and
microorganisms. J lmmunol 1987; 139: 1647- 1651.
59. Spitznagel JK. - Antibiotic proteins of human neutrophils.
J Clin Invest 1990; 86: 1381- 1386.
60. Laurell CB, Eriksson S. - The electrophoretic alpha- 1globulin pattern of serum in alpha- 1-antitrypsin deficiency.
Scand J Clin Invest 1963; 15: 132-140.
6L Harlan JM, K.illen PD, Harker LA, Striker GE, Wright
DG. - Neutrophil-mediated endothelial injury in vitro.
Mechanisms of cell detachment. J Clin Invest 1981; 68 :
1394-1404.
62. Smedly LA, Tonnesen MG, Sandhaus RA, et al. Neutrophil-mediated injury to endothelial cells. Enhancement
by endotoxin and essential role of neutrophil elastase. J Clin
Invest 1986; 77: 1233- 1243.
1541
63. Nakamura H, Yoshimura K, McE1vaney NG, Crystal RG.
- Neutrophil elastase in respiratory epithelial lining fluid of
individuals with cystic fibrosis induces interleukin-8 gene expression in a human bronchial epithelial cell line. J Clin Invest
1992; 89: 1478-1484.
64. Kao RC, Wehner NG, Skubitz KM, Gray BH, Hoidal JR.
- Proteinase 3. A distinct human polymorphonuclear leukocyte proteinase that produces emphysema in hamsters. J Clin
Invest 1988; 82: 1963- 1973.
65. Macartney HW, Tschesche H. - Latent and active human
polymorphonuclear leukocyte collagenases. Isolation, purification and characterisation. Eur J Biochem 1983; 130: 71- 78.
66. Hibbs MS, Bainton DF. - Human neutrophil gelatinase
is a component of specific granules. J Clin Invest 1989; 84:
1395- 1402.
67. Matzner Y, Barner M , Yalahom J, Ishae-Michaeli R,
Fuks Z, Vlodavsky I. - Degradation of heparan sulfate in the
subendothelial extracellular matrix by a readily released heparanase from human neutrophils. Possible role in invasion
through basement membranes. J Clin Invest 1985; 76: 13061313.
68. Borregaard N, Kjeldsen L, Rygaard K, et al. - Stimulusdependent secretion of plasma proteins from human neutrophils.
J Clin Invest 1992; 90: 86-96.
69. Hughes BJ, Hollers JC, Crockett-Torabi E, Smith CW. Recruitment of CDilb/CD18 to the neutrophil surface and
adherence-dependent cell locomotion. J C/in Invest 1992; 90:
1687- 1696.
70. Tiku ML. Tiku K, Skosey JL. - lnterleukin-1 production by normal human polymorphonuclear neutrophils. J
Jmmunol 1986; 136: 3677- 3685.
71. Tiku K, Tiku ML, Liu S, Skosey JL. - Normal human
neutrophils are a source of a specific interleukin-1 inhibitor.
J lmmunol I 986; 136: 3686-3692.
72. Lindemann A, Riedel D, Oster W, et al. - Granulocyte
macrophage colony-stimulating factor induces interleukin-1
production by human polymorphonuclear neutrophils. J lmmunol
1988; 140: 837- 839.
73. Bazzoni F, Cassatella MA, Rossi F, Ceska M, Dewald B,
Baggiolini M . - Phagocytosing neutrophils produce and release
high amounts of the neutrophil-activating peptide- 1/interleukin8. J Exp Med 1991; 173: 771-774.
74. Borish L, Rosenbaum R, Albury L, Clark S . - Activation
ofneutrophils by recombinant interleukin-6. Ce/llmmuno/1989;
121: 280-289.
75. Clancy RM, Leszczynska-Piziak J, Abramson SB. - Nitric
oxide, an endothelial cell relaxation factor, inhibits neutrophil
superoxide anion production via a direct action on the NADPH
oxidase. J C/in Invest 1992; 90: 1116-1121.
76. Reynolds HY. - Respiratory infections may reflect
deficiencies in host defense mechanisms. Dis Mon 1985; 3 1:
1- 98.
77. Mason GR, Hashimoto CH, Dickman PS, Foutty LF, Cobb
CJ. - Prognostic implications of bronchoalveolar lavage neutrophilia in patients with Pneumocystis carinii. Am Rev Respir
Dis 1989; 139: 1336-1342.
78. Lehrer RI, Ganz T, Selsted ME, Babior BM, Cumutte JT.
- Neutrophils and host defense. Ann Intern Med 1988; 109:
127- 142.
79. Marcy TW, Merrill WW. - Cigarette smoking and respiratory tract infection. Clin Chest Med 1987; 8: 381- 391.
80. Venge P, Rak S, Steinholtz L , Hakansson L, Lindblad G.
- Neutrophil function in chronic bronchitis. Eur Respir J
1991; 4: 536-543.
81. Ludwig PW, Hoidal JR. - Alterations of leukocyte oxidative metabolism in cigarette smokers. Am Rev Respir Dis 1982;
126: 977- 980.
1542
Y. S1BILLE, F-X. MARCHANDISE
82. Bridges RB, Fu MC, Rehm SR. - Increased neutrophil
myeloperoxidase activity associated with cigarette smoking.
Eur J Respir Dis 1985; 67: 84-93.
83. Corberand J, Nguyen F, Do AH, et al. - Effect of tobacco smoking on the functions of polymorphonuclear leukocytes.
Infect lmmunol 1979; 23: 577- 581.
84. Fietta A, Bersani C, De Rose V, et al. - Evaluation of
systemic host defense mechanisms in chronic bronchitis.
Re~piration 1988; 53: 37-43.
85. Burnett D, Cbamba A, Hill SL, Stockley RA. - Neutrophils
from subjects with chronic obstructive lung disease show
enhanced chemotaxis and extracellular proteolysis. Lancet 1987;
ii: 1043- 1046.
86. Martin TR, Raghu G , Maunder RJ, Springmeyer SC. The effects of chronic bronchitis and chronic airflow obstruction on lung cell populations recovered by bronchoalveolar
lavage. Am Rev Respir Dis 1985; 132: 254-260.
87. Janoff A. - Proteases and lung injury. A state-of-theart mini-review. Chest 1983; 85: s54-66.
88. Janoff A. - Biochemical links between cigarette smoking and pulmonary emphysema. J Appl Physiol: Respirat
Environ Exercise Physiol 1983; 55: 285- 293.
89. MacNee W, Wiggs B, Belzberg AS, Hogg JC. - The
effect of cigarette smoking on neutrophil kinetics in human
lungs. N Engl J Med 1989; 321: 924-928.
90. McFadden ER, Gilbert IA. - Asthma. N Engl J Med
1992; 327: 1928-1937.
91. Stenton SC, Court EN, Kingston WP, et al. - Plateletactivating factor in bronchoalveolar lavage fluid from asthmatic subjects. Eur Respir J 1990; 3: 408-413.
92. Lam S, Chan H, LeRiche JC, Chan-Yeung M, Salari H.
- Release of leukotrienes in patients with bronchial asthma.
J Allergy C/in lmmunol 1988; 81: 711-717.
93. Nagy L, Lee TH, Kay AB. - Neutrophil chemotactic
activity in antigen-induced late asthmatic reactions. N Engl J
Med 1982; 306: 497- 501.
94. Paggiaro P, Bacci E, Paoletti P, et al. - Bronchoalveolar
lavage and morphology of the airways after cessation of exposure in asthmatic subjects sensitized to toluene diisocyanate.
Chest 1990; 98: 536-542.
95. Cooper JAD Jr, Merrill WW, Rankin JA, Sibille Y, Buck
MG. - Bronchoalveolar cell activation and arachidonic acid
metabolism after inhalation of a soluble extract of cotton bracts.
J Appl Physio/ 1988; 64: 1615-1623.
96. Metzger S, Goldberg B, Lad P, Easton J. - Superoxide
generation and its modulation by adenosine in the neutrophils
of subjects with asthma. J Allergy Clin lmmunol 1989; 83:
960-966.
97. Jarjour NN, Busse WW, Calhoun WJ. - Enhanced production of oxygen radicals in nocturnal asthma. Am Rev Respir
Dis 1992; 146: 905-911.
98. Welsh MJ, Pick RB. - Cystic fibrosis. J Clin Invest
1987; 80: 1523-1526.
99. Fick RB, Naegel GP, Squier S, Wood RE, Gee JBL,
Reynolds HY. - Proteins of the cystic fibrosis respiratory
tract: fragmented immunoglobulin G opsonic antibody causing
defective opsonophagocytosis. J Clin Invest 1984; 74: 236-248.
100. Fick RB, Standiford TJ, Kunkel SL, Stricter RM. Interleukin-8 and neutrophil accumulation in the inflammatory airways disease of cystic fibrosis. Clin Res 1991; 39: 292A,
(Abstract).
101. Rommens JM. Iannuzzi MC, Kerem BS, et al. Identification of the cystic fibrosis gene: chromosome walking
and jumping. Science (Wash, DC) 1989; 245: 1059-1065.
102. Reddel RR, Ke RY, Gerwin BI, et al. - Transformation of human bronchial epithelial cells by infection with
SV40 or adenovicus-12 SV40 hybrid virus, or transfection via
strontium phosphate coprecipitation with a plasmid containing
SV40 early region genes. Cancer Res 1988; 48: 1904-1909.
103. Lichtenstein A. - Granulocytes as possible effectors of
tumor immunity. lmmunolAllergy Clin N Am 1990; 10:731-745.
104. Tate RM, Repine JE. - Neutrophils and the adult respiratory distress syndrome. Am Rev Respir Dis 1983; 128:
S52- 59.
105. Lee CT, Fein AM, Lippman M, Holtzman H, Kimbel P,
Weinbaum G. - Elastolytic activity in pulmonary lavage fluid
from patients with adult respiratory distress syndrome. N Engl
J Med 1981; 304: 192- 196.
106. Baldwin SR, Simon RH, Grum CM, Ketai LH, Boxer LA,
Devall U. - Oxidant activity in expired breath of patients
with adult respiratory distress syndrome. Lancet 1986; i: 11- 14.
107. Bemard GR. - Potential of N-acetylcysteine as treatment for the adult respiratory distress syndrome. Eur Respir
1 1990; 3 (Suppl 11): 496S-498S.
108. Chollet-Martin S, Montravers P, Gibert C, et al. Subpopulation of hyperresponsive polynuclear neutrophils
in patients with adult respiratory distress syndrome. Role
of cytokine production . Am Rev Respir Dis 1992; 146:
990-996.
109. Suter PM, Suter S, Gardin E, Roux-Lombard P, Grau GE,
Dayer JM. - High bronchoalveolar levels of tumor necrosis
factor and its inhibitors, interleukin-1, interferon, and elastase,
in patients with adult respiratory distress syndrome after
trauma, shock, or sepsis. Am Rev Respir Dis 1992; 145: 10161022.
110. Miller EJ, Cohen AB, Nagao S, et al. - Elevated levels
of NAP-1/interleukin-8 are present in the airspaces of patients
with the adult respiratory distress syndrome and are associated with increased mortality. Am Rev Respir Dis 1992; 146:
427-432.
111. Donnelly SC, Stricter RM, Kunkel SL, et al. - 1nterleukin8 (IL-8) and the development of the adult respiratory distress
syndrome (ARDS) in at-risk patient groups. Am Rev Respir
Dis 1993; 147 (Suppl.): A732.
112. Baggiolini M, Walz A, Kunkel SL. - Neutrophilactivating peptide-1/interleukin-8, a novel cytokine that activates neutrophils. J C/in Invest 1989; 84: 1045- 1049.
113. Davies D, Moran ME, Niall JF, Ryan GB. - Segmental
glomerulonephritis with antineutrophil antibody: possible
arbovirus aetiology. Br Med J 1982; 285: 606.
114. Hall JB, Wadham B, Wood CJ, Ashton V, Adam WR. Vascubtis and glomerulonephritis: a subgroup with antineutrophil cytoplasmic antibody. Aust NZJ Med 1984; 14:277-278.
ll5. Gross WL, Csemok E, Schmitt WH. - Antineutrophil
cytoplasmic autoantibodies: immunobiological aspects. Klin
Wochenschr 1991; 69: 558-566.
116. Beer DJ. - Editorial: ANCAs aweigh. Am Rev Respir
Dis 1992; 146: 1128-1130.
117. Hunninghake GW, Gadek JE, Lawley TJ, Crystal RG. Mechanisms of neutrophil accumulation in the lungs of patients
with idiopathic pulmonary fibrosis. J Clin Invest 1981; 68:
259-269.
118. Rossi GA, Bitterman PB, Rennard SI, Ferrans VJ, Crystal
RG. - Evidence for chronic inflammation as a component of
the interstitial lung disease associated with progressive systemic sclerosis. Am Rev Respir Dis 1985; 131: 612-617.
119. Gadek JE, Kelman JA, Fells G, et al. - Collagenase in
the lower respiratory tract of patients with idiopathic pulmonary
fibrosis. N EJngl J Med 1979; 301: 737- 742.
120. Sibille Y. Martinot JB, Polomski LL, et al. - Phagocyte
enzymes in bronchoalveolar lavage from patients with pulmonary sarcoidosis and collagen vascular disorders. Eur Respir
J 1990; 3: 249-256.
121. Wallaert B, Hatron PY, Grosbois JM, Tonne! AB, Devulder
ROLE OF POLYMORPHONUCLEAR NEUTROPHILS
B, Voisin C. - Subclinical pulmonary involvement in collagen-vascular diseases assessed by bronchoalveolar lavage: relationship between alveolitis and subsequent changes in lung
function. Am Rev Respir Dis 1986; 133: 574-580.
122. Watters LC. Schwan MI, Chemiaclc RM, et al. - Idiopathic
pulmonary fibrosis. Pretreatment bronchoalveolar lavage
cellular constituents and their relationships with lung histopathology and clinical response to therapy. Am Rev Respir Dis
1987; 135: 696-704.
123. Carn~ PC, Mortenson RL, King TE Jr, Noble PW, Sable
CL. Riches DWH. - Increased expression of the interleukin8 gene by alveolar macrophages in idiopathic pulmonary fibrosis. J Clin Invest 1991; 88: 1802- 1810.
124. Cantin AM, North SL, Fells GA, Hubbard RC, Crystal
RG. - Oxidant-mediated epithelial cell injury in idiopathic
pulmonary fibrosis. J Clin Invest 1987; 79: 1665-1673.
125. Maier K, Leuschel L, Costabel U. - Increased levels of
oxidized methionine rcsidues in bronchoalveolar lavage fluid
proteins from patients with idiopathic pulmonary fibrosis. Am
Rev Respir Dis 1991; 143: 271 - 274.
1543
126. Turner-Warwick M, Haslam PL. - The value of serial
bronchoa1veolar lavages in assessing the clinical progress of
patients with cryptogeruc fibrosing alveolitis. Am Rev Respir
Dis 1987; 135: 26-34.
127. Foumier E. Tonne! AB. Gosset P, Wallaert B, Arneisen
JC, Voisin C. - Early neutrophil alveolitis after antigen inhalation in hypersensitivity pneumonitis. Chest 1985; 88:
563-566.
128. Roth C, Huchon GJ, Amoux A. Staruslas-Leguem G,
Marsac JH, Chretien J. - Bronchoalveolar cells in advanced
pulmonary sarcoidosis. Am Rev Respir Dis 198 1; 124: 912.
129. Sibille Y, Naegel GP, Merrill WW, Young KR Jr. Care
SB, Reynolds HY. - Neutrophil chemotactic activity produced by nonnal and activated human bronchoalveolar lavage
cells. J Lab Clin Med 1987; 110: 624-633.
130. Costabel U, Teschler H. Guzman J. - Bronchiolitis obliterans organizing pneumonia (BOOP): the cytological and
immunocytological profile of bronchoalveolar lavage. Eur
Respir J 1992; 5: 79 1- 797.