Renal fibrin deposition associated with isoimmune haemolysis in monkeys: observation by light, electron and immunofluorescence microscropy.

Abstract

Summary.Following control renal biopsies, five cynomolgus monkeys received an infusion of incompatible isoimmune plasma. Renal biopsies were obtained at 2 or 4 hr, 24 hr, and 7 days after infusion and were examined by light and electron microscopy, as well as immunofluorescence microscopy for platelet antigens and fibrinogen related antigen(s) (FRA). Test animals receiving incompatible plasma showed evidence of haemolysis and disseminated intravascular coagulation. Renal tissue changes varied according to the severity of the transfusion reaction and the time of biopsy. Light microscopy revealed mild glomerular and tubular changes. In early biopsies, immunofluorescence studies showed deposition of FRA in glomerular capillaries and tubule cells. By day 7, glomerular FRA was no longer present, and tubule cell FRA had been displaced into the renal interstitium. Platelet antigen was not seen in any biopsy. Electron microscopy demonstrated proximal tubule cell damage with phosphotungstic acid positive staining granules, intravascular clot formation, and foot process fusion. Two control monkeys received compatible plasma and showed no evidence of renal injury. It appears that renal fibrin deposition and tubule cell damage occur even during mild haemolytic transfusion reactions. This study provides evidence for local fibrinolysis of glomerular fibrin and the transfer of FRA from tubular lumens to the interstitium. In addition, tubule cell FRA appears to be associated with structural damage.