Prognostic value of serum erythropoietin levels in late acute rejection of renal transplants.

Since renal allograft rejection is frequently associated with a blunted erythropoiesis, we investigated erythropoietin (EPO) serum concentrations in 17 patients with acute rejection, eight patients with chronic rejection, and 18 transplant recipients with stable graft function. All rejection episodes were proven by biopsy. Erythropoietin serum levels were significantly reduced in patients with chronic rejection (6.2 +/- 3.4 mU/mL; P < 0.01) compared with individuals with acute rejection (35.6 +/- 33.9 mU/mL) or stable graft function (24.0 +/- 19.7 mU/mL). Suppressed EPO levels were associated with marked anemia in chronic rejection patients. In a subgroup of patients with acute rejection and bad responses to an intensified immunosuppressive regimen or with transplant failure, we found significantly suppressed EPO levels (11.6 +/- 6.1 mU/mL) compared with a subgroup of patients with a beneficial acute rejection outcome (57.0 +/- 34.2 mU/mL; P < 0.01). A correlation between histologic parameters of acute rejection and hormone levels showed that signs of moderate glomerulitis were associated with elevated EPO levels, whereas lesions of moderate tubulitis were associated with low values. We conclude that serum EPO may have prognostic value for rejection outcome in renal transplant recipients.