T H E AMERICAN JOURNAL OF CLINICAL PATHOLOGY
Vol. 47, No. 6
Copyright © 1967 by The Williams & Wilkins Co.
Printed in
U.S.A.
RENAL HOMOTRANSPLANTATION
T H E CYTOLOGY OF THE URINE SEDIMENT
TILDE S. KLINE, M.D., AND JOHN E. CRAIGHEAD, M.D.
Department of Pathology, Peter Bent Brigham Hospital, Boston, Massachusetts 02115
111 recent years, renal transplantation has
become established surgical procedure. Two
types of grafts are employed—the isograft,
or isogeneic graft between monozygotic
twins, and the homograft, or allogeneic
graft. In the latter, the donor and recipient
are genetically dissimilar. A major problem
in the clinical management of renal homotransplant recipients is immunologic rejection of the graft. At this hospital, an analogue of 6-mercaptopurine-azathioprine and
corticosteroids are administered routinely
after transplantation, in an attempt to
prevent this complication.11 Despite treatment with these immunosuppressive drugs,
rejection "crises" develop during the postoperative period. Much larger dosages of
corticosteroids, actinomycin C, and azaserine are given at such times, in order to
depress the rejection reaction. Although
there are clinical and pathologic changes
that indicate threatened and established
rejection, the process is often subtle and
occasionally goes unrecognized.*
A variety of bacterial, mycotic, and viral
infections develops in homotransplant recipients, presumably as a result of the
chronic administration of immunosuppressive drags.13 Generalized cytomegalic inclusion disease due to systemic cytomegalovirus infection occurs frequently.7 Indeed,
it is the most frequently recognized nonbacterial, microbial complication of transplantation. Although the infection can be
Received, September 14, 1966.
Presented in part at the meeting of the
American Cytology Society, November, 1965,
New York, New York.
* Clinical features of threatened acute immunologic rejection usually include fever, swelling and
tenderness of the graft, failing renal function, and
leukocytosis.11 Histopathologic changes are interstitial edema and mononuclear cell infiltration,
tubular degeneration and atrophy, and proliferative vasculitis.4
diagnosed by time - consuming virologic
means, or at autopsy, its prompt recognition
in individual patients during life is not possible at present.
The study reported here was undertaken
to determine whether or not cytologic examination of the urine sediment would assist
in the diagnosis of threatened homograft
rejection and cytomegalic inclusion disease
after transplantation.
MATERIAL AND METHODS
Urine from 15 recipients of renal homotransplants was examined during a 10month period. The sediments were obtained
by centrifugation, layered on glass slides
as a thin film, and stained by the method of
Papanicolaou.12 The number of specimens
from each individual ranged from three to
42. Urine from 10 patients was obtained at
random intervals from 1 to 30 months after
transplantation. Five additional homograft
recipients were studied daily during the
immediate postoperative period.
Seven of the patients experienced episodes
of threatened rejection during the 10 months
of the study. Four of these seven died. The
clinical course of the remaining eight was
relatively uneventful. All patients were
administered azathioprine (2 to 4 mg. per
kg.) and prednisone (15 to SO mg.) daily.
Those showing signs of threatened rejection
were given increased dosages of corticosteroids (200 to 600 mg. per day), actinomycin
C (6 ixg. per kg. per day), and azaserine
(0.5 to 1.0 mg. per kg. per day).
RESULTS
Sediment of the urine from each of the 15
homotransplant recipients contained many
epithelial cells and histiocytes. Varying
numbers of lymphocytes and plasma cells
were also found in the majority of the
specimens. In addition to the usual squamous and transitional cells, two distinct
802
F I G . 1 (upper left). Urine sediment from patient 10 days after transplantation. Note clusters of
small cells with fairly uniform nuclei (type 1). Papanicolaou preparation. X 410!
F I G . 2 (upper right). Urine sediment from patient 13 months after transplantation, with a wellfunctioning homograft. Note cell with enlarged hyperchromatic nucleus with thickened nuclear
membrane (type 2). Papanicolaou preparation. X 700.
F I G . 3 (lower left). Urine sediment from patient 19 months after transplantation with a wellfunctioning homograft. Note cell with markedly enlarged hyperchromatic nucleus, with scant,
irregularly shaped cytoplasm (type 2). Papanicolaou preparation. X 700.
F I G . 4 (lower right). Renal biopsy from patient 6 months after transplantation. Note cells with
enlarged hyperchromatic nuclei lining renal tubules. Hematoxylin and eosin. X 410.
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KLINE AND CRAIGHEAD
kinds of epithelial cells were recognized,
and were classified as type 1 and type 2.
Type 1 cells were small (7 to 9 n in diameter)
and clustered in groups of approximately
five to 20. They possessed scant cytoplasm
and hyperchromatic nuclei that varied
somewhat in size, but not in shape (Fig. 1).
They could be distinguished from lymphocytes by their special grouping, their slightly
larger size, and their nuclear staining
characteristics. Type 2 cells were larger (10
to 40 M in diameter) and were scattered
individually in the sediment. They often
had irregular cell margins, enlarged nuclei,
and clumped nuclear chromatin (Figs. 2 and
3).
Clusters of type 1 epithelial cells were
present in the urine during the period immediately following transplantation, a 1to 2-week period preceding death, and episodes of threatened rejection. They were not
observed in urine from patients with wellfunctioning grafts. Type 2 cells were found
at one time or another in the sediment of all
15 patients. In contrast to the type 1 cell,
their presence in increased numbers was not
associated with the operative procedure,
threatened rejection, or death.
During the 10 months of the study, renal
biopsies were obtained from five of the homograft recipients; the kidneys of the four
patients who died were examined after death.
A wide range of histologic alterations was
found; many of the changes suggested immunologic rejection of varying degrees of
severity.4 Scattered tubules in the majority
of the kidneys were lined by or contained
within their lumina atypical cells with enlarged hyperchromatic nuclei (Figs. 4 and 5).
These cells were morphologically similar to
the type 2 epithelial cells described above.
Of the 15 homograft recipients, 13 were
studied virologically during life or at autopsy. Cytomegalovirus was isolated from
the urine of 7 patients on one or more occasions. Several excreted the virus for
periods of 2 to 4 months, and one did so for
longer than 1 year. Cytomegalovirus was
isolated from the tissues of the three patients in whom virologic postmortem studies
were made.7
Occasionally, cells with intracytoplasmic
or intranuclear inclusions were observed in
urine sediment of both infected and noninfected patients. These inclusions varied in
size, shape, and tinctorial properties. They
were similar to the nonspecific inclusions
described by others. 2 ' 10 Intranuclear, "owleye" inclusion bodies characteristic of cytomegalic inclusion disease were not found.1
DISCUSSION
15
Taft and Flax noted a variety of atypical cells in the urine of renal homo transplant recipients during episodes of threatened rejection. Kauffman and associates8
found increased numbers of lymphocytes
under similar circumstances. These workers
claimed that lymphocytes in the urine were
an indication of immunologic rejection.
Clusters of type 1 epithelial cells were
found in the urine of our patients during the
period immediately following transplantation and shortly before death. They also
were present during episodes of threatened
rejection. It seems likely that these cells
were exfoliated from the renal tubules as a
result of ischemia. Cells identical to our
type 1 have been observed in the urine of
persons with intact kidneys at times of
renal tubular necrosis.15
Lymphocytes, plasma cells, and histiocytes were found in most specimens of urine.
Since their presence did not correlate with
episodes of rejection, they probably were
evidence of inflammation in the urinary
tract. As might be expected, chronic bacterial infections are a frequent complication
of transplantation.
Varying numbers of enlarged hyperchromatic epithelial cells (type 2) were seen in the
urine of each of the 15 patients. They were
not associated with rejection "crises" or
episodes of renal ischemia. Indeed, one
patient with an uneventful clinical course
exfoliated bizarre cells on a number of occasions. We, like others, have observed
atypical cells in the urine of leukemic patients receiving methotrexate, 6-mercaptopurine, and Cytoxan. 6 ' 9 ' 1 7 In this laboratory, atypical cells have been found in the
bladder epithelium after administration of
Cytoxan. Dammin 3 has noted a variety of
unusual cells in the renal tubules of dogs
treated with azathioprine only. It seems
likely that type 2 cells do not result from
June 1967
RENAL H0M0TRANSPLANTAT10N
805
F I G . 5 (left). Renal section obtained a t autopsy from patient 7 months after t r a n s p l a n t a t i o n . Note
cells with markedly irregular, enlarged hyperchromatic nuclei within tubular lumen. Lumen also contains nonspecific calcium granules. Hematoxylin and eosin. X 410.
F I G . 0 (right). Urine sediment from patient 3 weeks after transplantation. Note large histiocyte with
multiple inclusions. Papanicolaou preparation. X 410.
transplantation or immunologic rejection
•per se, but represent an effect of immunosuppressive drugs.
Workers at this hospital have found large
cells with numerous intracytoplasmic inclusions in fresh urine from homotransplant
recipients, especially when they are examined by phase contrast microscopy. It is
our impression that these cells are histiocytes. Stained, fixed preparations of urine
sediment from both infected and noninfected
patients showed intracytoplasmic inclusions
in both small and giant histiocytes (Fig. 6).
Melamed and Wolinska1" and Bolande2 have
claimed that such inclusions represent nonspecific degenerative processes within the
cells.
Cytomegalovirus infection and the resulting cytomegalic inclusion disease are common complications of immunosuppressive
drug therapy. 7 In some patients, the infection results in pneumonia and death; in
others, its clinical significance is not known.
Since cytomegalic inclusion disease defies
clinical recognition, rapid diagnostic tech-
nics must be developed if specific antiviral
chemotherapeutic agents are to be employed
in the future.
Cytomegalic cells with typical intranuclear inclusion bodies have been found in
the urine of infants with generalized cytomegalic inclusion disease.1 Urine cytology
thus provides a prompt, easily performed
means of diagnosis. However, in the study
reported here, characteristic cells of cytomegalic inclusion disease were not recovered
from patients with established urinary tractviral infections and disseminated cytomegalic inclusion disease. The reasons for
our failure to demonstrate the cells in urine
sediment are not known. Technical factors
would not appear to be important. It seems
more likely that the diagnostic cells are not
formed in the kidneys or urinary tract, or
that they are not present in sufficient numbers to allow their recovery. We have seen
inclusion body-bearing cells in the grafted
kidney of only one transplant recipient at
autopsy, and have never demonstrated the
cells elsewhere in urinary tract epithelium.
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KLINE AND CRAIGHEAD
Cytomegalovirus has been recovered from
the urine of young children with asymptomatic or subclinical forms of infection.14'16
As in our patients, urine from these children
does not contain diagnostic inclusion bodybearing cells.6
SUMMARY
Cytologic studies were carried out on the
urine sediment from 15 renal homotransplant recipients. Two distinctly different
types of atypical epithelial cells were found.
Clinical and pathologic observations suggest
that these cells resulted from either renal
ischemia or immunosuppressive drug therapy. Cells diagnostic of immunologic rejection of the homograft were not observed.
Characteristic cells with intranuclear inclusion bodies were not recognized despite
the common occurrence of cytomegalic inclusion disease in these patients.
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3. Dammin, G. J.: Personal communication.
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Vol. 47
6. Hanshaw, J. B.: Personal communication.
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