Leukopoiesis
 the
development of white blood cells (WBCs)
except lymphocytes occurse in the same
location as erythropoiesis
 Leukocytes – it exist to defend the organism
against nonself agents through intricate
cooperation among cells.

- divided into granulocytes and
lymphocytes
 Contain
visible granules and develop solely in
the bone marrow
 Subdivided as granulocytes containg large
granules (neutrophil, basophil, eosinophil)
and granulocytes containing minute granules
(monocytes)
 Can
be found in four locations also called
granulocyte pools:
a) In the bone marrow
b) Circulating in peripheral blood
c) Marginating against the endothelium of
blood vessels
d) In the tissues
 Has
a)
b)
c)

3 functions:
Proliferation
Maturation
Storage
Proliferating component – contain cell
capable of mitotic divisions (myeloblasts,
promyelocytes, and myelocytes)
 Maturation
component – contain cells that are
incapable of mitosis but not yet fully functional
(metamyelocytes and bands)
 Storage component – contains bands and
polymorphonuclear leukocytes
 Circulating pools contain approximately 50% of total
peripheral blood granulocytes levels and the other
50% in the marginating pools
 Hematopoietic
stem cell – mature into a
stem cell specific for bone marrow-derived
or myeloid cells (CFU-GEMM)
 CFU-GEMM – matures into another progenitor
cell called the colony-forming unit
granulocyte-monocyte/macrophage (CFUGM)
- this is controlled by by a complexof
interaction humoral factors, such as
interluekins and CSFs
•Usually
15-20 micrometers
•Nucleus is delicate with
prominent nucleoli
•Cytoplasm is meager that
contains RER, developing Golgi
apparatus, and the initial
presence of primary or
azurophilic granules
•The granules colors positive
for enzyme MYELOPEROXIDASE
•Incapable of motility,
adhesion, and phagocytosis
• < 1% in the normal bone
marrow compartment
•Size
may exceed 20 micrometers
•Nuclear chromatin pattern may
show slight clumping
•Nucleoli begin to fade
•Dominant characteristic of PRIMARY
GRANULES
•Motility may be present
• 1 to 5% in the bone marrow
reduced nicotinamide adenine
dinucleotide phosphate oxidase and
flavocytochrome B – activates
neutral proteinases cathepsin G,
elastase, proteinases for killing to
take place
<10% of the total marrow cell
population
•Nucleus may be round to oval with
flattened side near Golgi apparatus
•Nuclear chromatin shows clumping
and nucleoli no longer visible
• characteristic is the production of
SECONDARY OR NEUTROPHILIC
granules
•Last stage capable of mitosis
•Second of the 3 major type of
granules is synthesized causing “dawn
of neutrophilia or faint blush of pink
near the Golgi apparatus
•
•Result
after the cessation of all active
DNA synthesis
•Nucleus is indented
•Cytoplasm has collection of primary and
secondary granules ( major feature of
cytoplasm)
•The granules constitute the major
component necessary to kill and
degrade non self agents
•Incapable of reacting to chemotactic
factors
• 13 – 22% of normal bone marrow
differential
•At the end of this stage GELATINASE
GRANULE is made
•Band
shape, a transitional form because
it is considered to be part of maturation
and storage pools in the bone marrow
and peripheral blood
• constitutes 40% of white blood cells
but < 6% in the peripheral blood
•Non segmented
•Nucleus have uniform or parallel width
•Nuclear indention is less than half the
width of the nucleus (horse shoe
shaped)
•Possess full motility, adhesion
properties and phagocytic ability
•Membrane is characterized by changes
in the cytoskeleton, surface charge and
presence of receptors
•Nucleus
continues its indention until
thin it become a lobed nucleus
•Nucleus is easily deformable because of
active motility of the cell
•Polymorphonuclear means “many
shaped nucleus”
•Part of storage pool in bone marrow
and circulating and marginating pools
• 50 – 70% of total WBC differential
•Nuclei have visible segments
•10 – 12 microns
 Studies
have indicated that there is a heterogeneous
population of mature neutrohils
 Neutrophils with increased mobility, numbers of CD 15
receptors in lymphocye homing, CD21 that binds to C3
 Positive for CD62 – an adhesion molecule active on
neutrophils and epithelial cells
 Performs phagocytosis (involves larger material) and
pinocytosis (involves small material)
 chemotactic
factors cause the
polymorphonuclear cell to migrate to source
 Neutrophils periodically determine whether
the vessel endothelium is expressing surface
molecules, which enhance a more firm
contact (adhesion)
 Egress of neutrophil outside the blood
circulation (diapedesis) in response to
chemical gradient
 It
adhere to particles that initiated the attraction
then pseudopods extend the around the particle,
engulfing it and forming a phagosome
 Cytplasmic granules combine with the phagosome
forming phagolysosome and dump their contents in it
 Primary granules – contribute to proteolysis
 Secondary granules – increase complement fixation
and chemotactic response
- causes degradation and
detoxification of material
 Prominent
secondary granules are stained
heavily with the eosin dye with Romanowsky
based stains
 Requires IL-3, IL-5 and GM-CSF and inhibited
by interferon
 Developed from CFU-GEMM to CFU-Eo
 Similar to neutrophil in the myeloblast and
promyelocyte stage
 In
the myelocyte stage, it is distinguish from
neutrophil by presence of numerous large round
granules containing crystalloid compound
compromising major basic protein
 Its granules contain proteolytic enzymes but no
secretory vesicles
 Spends less than 1 week in the peripheral blood
•Nucleus
with 2 or 3 lobes connected by
thin strand
•Large, uniform sized granules stain
orange red with acidic dyes that do not
obscure the nucleus
•10 – 12 microns
•1 -3 % of circulating WBCs
Charcot-Leyden crystals – water soluble,
needle shaped crystals as the result of
eosinophil disintegration
 Process
of maturation from the stem cell in
not well known
 May parallel the development of eosinophils
 Can be differentiated into myelocytes,
metamyelocytes, bands and
polymorphonuclear cells on the basis of
nuclear development, although nuclei with
more than two lobes are extremely rare
•Large
dark purple variable sized
granules stain with basic dyes that
obscure the nucleus
•Irregular shaped bilobed nucleus
•8 – 10 microns
•0 – 1% of circulating WBCs
•Have specific high affinity for the Fc
region of IgE
•Involved in allergic inflammation and
initiate localized and system
anaphylaxis
- granules contain heparin,
chondroitin sulfate, histamin,
serotonine, and other vasoactive and
immunomodulatory mediators
 1.
last stage of granulopoesis that is capable
of mitosis
a) Myeloblast b) promyelocyte c) myelocyte d)
metamyelocyte
 2. neutrophil maturation stage where it is
part of both storage and maturation pool in
the bone marrow
a) Metamyelocyte b) band c) myelocyte d)
segmented neutrophil
 3.
responsible for the staining of the granules
of eosinophils
a) Major basic protein b) peroxidase
c) proteolytic enzymes d) myeloperoxidase
 4. the common myeloid progenitor
a) CFU-GM b) GM-CSF c) CFU-GEMM d) G-CSF
 5. involved in allergic inflammation and
initiate localized and system anaphylaxis
a) BAND neutrophil b) basophil c) PMN
d) eosinophil