De novo hemolytic uremic syndrome in renal transplant recipients immunosuppressed with cyclosporine.

Three renal transplant recipients were studied who developed the hemolytic uremic syndrome (HUS) during cyclosporine (CsA) immunosuppression. All patients displayed characteristic findings including normocytic, normochromic anemia, thrombocytopenia, erythrocyte morphologic abnormalities, increased numbers of reticulocytes, bone marrow hyperplasia, and renal failure. The clinical studies support the diagnosis of an extrinsic hemolytic process. Renal biopsy specimens demonstrated fibrin deposition and glomerular thrombosis. The renal failure was not responsive to antirejection therapy. The first patient was converted to azathioprine and consequently had a gradual improvement in renal function. Failure to convert the second patient resulted in adequate immunosuppression and subsequent graft loss. The third patient's improvement corresponded with a moderate CsA dose reduction. The occurrence of HUS in these patients represents a de novo presentation after CsA immunosuppression. An analysis of these cases indicates that CsA should be discontinued if HUS persists after moderate dose reduction.