INTERTUBULAR CAPILLARY CHANGES IN THE CORTEX AND MEDULLA OF TRANSPLANTED KIDNEYS AND THEIR RELATIONSHIP WITH TRANSPLANT GLOMERULOPATHY - ANULTRASTRUCTURAL-STUDY OF 12 TRANSPLANTECTOMIES

Twelve kidney allografts removed 3 to 98 months (mean, 44.8 months) af ter transplantation were investigated. The presence and severity of in tertubular capillary changes, which were characterized by splitting an d multilayering of the basement membrane, were carefully noted. These changes were graded as mild, moderate, and severe according to the num ber of basement membrane layers. They were found in both cortical and medullary capillaries in all but one kidney and were always associated with transplant glomerulopathy. Ultrastructural changes observed in t he glomeruli and capillaries were similar, suggesting that they share the same pathogenetic mechanisms, probably connected to immune-mediate d endothelial cell damage. Although glomeruli can be absent in small b iopsy specimens, intertubular capillaries are easily detectable. Becau se capillary changes can be considered a marker of transplant glomerul opathy, which is known to have ominous prognostic significance, the id entification of such changes acquires clinical relevance. Electron mic roscopic investigation is therefore strongly advisable whenever a rena l biopsy is performed to identify transplant glomerulopathy.