Increased erythropoietin response to venesection in erythrocytosic renal transplant patients.

Anaemia of end-stage chronic renal failure improves following successful kidney transplantation. However, erythrocytosis occurs in 6.8-17.3% of transplanted patients. Mechanism of post-transplant erythrocytosis (PTE) and its erythropoietin (Epo) dependence are still controversial. Firstly, we compared basal serum Epo levels of 10 PTE patients, 14 non-erythrocytosic renal transplant (non-PTE) patients and 12 healthy blood donors. Then we performed venesection in PTE patients and healthy blood donors and compared their Epo response to venesection 5 hours later. The mean basal serum Epo of 24.3 mU/ml was significantly higher in the PTE group than the 10.8 mU/ml in the non-PTE and 8.6 mU/ml in the healthy blood donor group (p < 0.01). Epo levels in the non-PTE group did not differ significantly from those of healthy blood donors (p > 0.05). Following venesection the mean serum Epo levels increased significantly in both groups, from 24.3 mU/ml to 67.7 mU/ml (p < 0.001) in the PTE group and from 8.6 to 12.1 mU/ml (p < 0.01) in the healthy blood donor group, but the increment in the PTE group was more marked. We conclude that PTE patients have elevated basal serum Epo levels and there is a feedback regulation of Epo secretion in these patients like in healthy blood donors, but in an exaggerated way.