Polycythemia following renal transplantation.

Among 60 renal allograft recipients, 3 patients were found to be polycythemic with hematocrits greater than 55 and were studied extensively with various hematologic and radiographic procedures. None of the patients showed evidence of erythropoietin-secreting malignancies, renal cysts, hydronephrosis, or hypoxemia. All had elevated erythropoietin levels, and 1 showed evidence of platelet trapping in his transplanted kidney, suggesting that the chronic polycythemia may be related to transplant rejection.