PERITUBULAR CAPILLARY BASEMENT MEMBRANE REDUPLICATION IN ALLOGRAFTS AND NATIVE KIDNEY DISEASE: A Clinicopathologic Study of 278 Consecutive Renal Specimens

Background. An association has been found between transplantglomerulopathy (TG) and reduplication of peritubular capillary basementmembranes (PTCR). Although such an association is of practical and theoreticalimportance, only one prospective study has tried to confirmit. Methods. We examined 278 consecutive renal specimens (from 135transplants and 143 native kidneys) for ultrastructural evidence of PTCR. Inaddition to renal allografts with TG, we also examined grafts with acuterejection, recurrent glomerulonephritis, chronic allograft nephropathy andstable grafts (“protocol biopsies”). Native kidney specimensincluded a wide range of glomerulopathies as well as cases of thromboticmicroangiopathy, malignant hypertension, acute interstitial nephritis, andacute tubularnecrosis. Results. We found PTCR in 14 of 15 cases of TG, in 7 transplantbiopsy specimens without TG, and in 13 of 143 native kidney biopsy specimens.These 13 included cases of malignant hypertension, thrombotic microangiopathy,lupus nephritis, Henoch-Schonlein nephritis, crescentic glomerulonephritis,and cocaine-related acute renal failure. Mild PTCR in allografts without TGdid not predict renal failure or significant proteinuria after follow-upperiods of between 3 months and 1year. Conclusions. We conclude that in transplants, there is a strongassociation between well-developed PTCR and TG, while the significance of mildPTCR and its predictive value in the absence of TG is unclear. PTCR alsooccurs in certain native kidney diseases, though the association is not asstrong as that for TG. We suggest that repeated endothelial injury, includingimmunologic injury, may be the cause of this lesion both in allografts andnativekidneys.