Cb. Drachenberg et al., SPECIFICITY OF INTERTUBULAR CAPILLARY CHANGES - COMPARATIVE ULTRASTRUCTURAL STUDIES IN RENAL-ALLOGRAFTS AND NATIVE KIDNEYS, Ultrastructural pathology, 21(3), 1997, pp. 227-233
The pathophysiology of chronic rejection of renal allografts is poorly
understood and specific morphologic markers are being sought for its
diagnosis. Ultrastructural splitting and reduplication of the basal la
mina of the intertubular capillaries (ITCs) have been shown to be cons
istently associated with transplant glomerulopathy (TG) in renal allog
rafts and have been used as a marker of chronic allograft rejection. A
lthough the presence of ITC abnormalities is extremely helpful diagnos
tically and has been considered a surrogate for the diagnosis of TG wh
en glomeruli are not available for examination, their specificity has
not been tested. This study examined 135 biopsy specimens from renal a
llografts and native kidneys and categorized the ITC basal lamina alte
rations into 5 patterns. The results showed that although marked ITC b
asal lamina abnormalities are characteristically seen in association w
ith TG, lesser degrees of these changes may also be found in native ki
dneys and in transplants with other types of glomerulopathies. in nati
ve kidneys, splitting and reduplication of the ITC basal lamina were o
bserved in cases of active lupus nephritis, membranoproliferative glom
erulonephritis type I, crescentic glomerulonephritis, cryoglobulinemia
, and hypertension. In allografts, ITC changes were seen in postinfect
ious proliferative glomerulonephritis, acute cyclosporin toxicity, and
hemolytic uremic syndrome, in addition to cases with TG. The histopat
hologic diagnosis in renal diseases relies heavily on clinical, immuno
fluorescence, and ultrastructural findings. Therefore, in the transpla
ntation setting, with other less common pathological processes ruled o
ut, the presence of abnormalities of the ITC basal lamina is highly in
dicative of TG. This association is particularly true for cases with s
evere ITC abnormalities.