Post-renal transplant erythrocytosis.

Erythrocytosis is a relatively common phenomenon following renal transplantation. It is not only associated with some special clinical conditions, but also increases the risk of thromboembolism. We therefore studied the clinical manifestations and possible risk factors of erythrocytosis in our renal-transplant patients. Study of 175 patients showed that erythrocytosis, defined as Hct > or = 50%, was found in 17 patients (9.7%), 14 males and 3 females. Among these 17 patients, 13 received cadaveric grafts and the other 4 living-related grafts. True erythrocytosis, defined as erythrocytosis with elevated red blood cell (RBC) mass, was found in 7 patients. Relative erythrocytosis, defined as erythrocytosis with normal RBC mass, was found in the other 10 patients. Six patients developed acquired renal cysts of the native or graft kidneys during the post transplant period. The incidence of acquired renal cysts in the erythrocytosis group was significantly higher than that in the non-erythrocytosis group. The clinical and demographic characteristics were similar in terms of age, gender, serum albumin, and serum creatinine in the erythrocytosis and non-erythrocytosis groups. The incidences of abnormal liver function, and hypertension were similar between the 2 groups. Seventeen of the 161 patients (10.6%) receiving cyclosporine regimen developed erythrocytosis, but none of the 14 patients receiving non-cyclosporine regimen developed erythrocytosis (p > 0.05). Only one patient with true erythrocytosis had an elevated serum erythropoietin (EPO) level and no thromboembolic complications occurred in the erythrocytosis group. We conclude that: (1) the incidence of erythrocytosis in our transplant patients was 9.7%; (2) a higher incidence of acquired renal cysts was found in the erythrocytosis group; (3) most of the patients with erythrocytosis had a normal serum EPO level; (4) no thromboembolic complications occurred in our patients.