12 December 2006
Background/Aims: The prevalence of anti-erythropoietin antibodies in renal patients without clinical evidence of pure red cell aplasia (PRCA) who respond poorly to epoetin is unknown. This study tested for anti-erythropoietin antibodies in hemodialysis patients who were either hypo- or normoresponsive to epoetin treatment. Methods: Epoetin hyporesponsiveness (hemoglobin ≤10.5 g/dl and epoetin ≧9,000 IU/week) and normoresponsiveness (hemoglobin >10.5 g/dl and epoetin <7,000 IU/week) were arbitrarily defined. Prevalence of anti-erythropoietin antibodies in hemodialysis patients without symptoms of PRCA was determined by screening sera of 536 patients from 35 German KfH dialysis units, using enzyme-linked immunosorbent assay (ELISA). Positive results were verified by radioimmunoprecipitation assay (RIP) and neutralizing activity was determined by bioassay. Results: Anti-erythropoietin antibodies were detected in 3 hyporesponsive and 3 normoresponsive patients using ELISA. One patient per group was verified as borderline by RIP testing; the other 4 were negative. The bioassay was negative for 1 patient; the other died unrelated to PRCA before testing. Follow-up with RIP testing after 15 months under continuous epoetin treatment was negative (4 patients, 2 deceased). Conclusion: This survey did not identify anti-erythropoietin antibodies in hemodialysis patient’s hyporesponsive to epoetin and does not support presumptive antibody screening as a routine work-up in these patients.