Polycythaemia following renal transplantation.

Polycythaemia has developed in 10 of 59 regularly reviewed patients with renal transplants surviving more than three months. The pathology of the raised haemoglobin level was heterogeneous. Three patients had a picture characterized by a normal red cell mass and reduced plasma volume. Seven patients had a raised red cell mass; in 3 of these this was associated with a period of abnormal liver function and fitted with the state of raised red cell mass in association with hepatic transaminitis. The remaining 4 patients form a unique, previously undefined group with no features to explain the underlying aetiology of the polycythaemia. The patients had a trouble-free post-transplant course with early establishment of graft function. It is proposed, from the data obtained from in vitro culture studies, that the early return of good renal function allows the erythroid compartment to expand in response to circulating erythropoietin. The establishment of an erythron of increased size allows for a persistently raised haemoglobin in the presence of normal erythropoietin levels.