Correction of anaemia following renal transplantation: serial changes in serum immunoreactive erythropoietin, absolute reticulocyte count and red-cell creatine levels.

Improvement of erythropoiesis following successful human renal transplantation in eight patients was monitored by sequential measurements of haemoglobin, red-cell creatine, absolute reticulocyte count and estimates of serum immunoreactive erythropoietin (siEp). SiEp increased in five patients after transplant, in three cases almost immediately after a return to normal of plasma creatinine. The increase in siEp was followed by a rise in the absolute reticulocyte count and red-cell creatine and finally by an increase in the haemoglobin level. As the haemoglobin approached normal levels a decline in the absolute reticulocyte count preceded a fall in siEp levels. Red-cell creatine also fell, though more gradually than the reticulocyte count. Acute graft rejection (in two patients) was associated with a fall in siEp. Chronic rejection (in one patient) was associated with persistent increases in siEp, reticulocyte count and red-cell creatine; this patient subsequently developed erythrocytosis.