Rapid Method for Detection of Anti-Recombinant Human Erythropoietin Antibodies as a New Form of Erythropoietin Resistance

Abstract

Recombinant human erythropoietin (rHuEPO) is a sialoglycoprotein hormone that appears to be immunologically and biologically equivalent to the endogenous compound, enhancing erythropoiesis dose-proportionally. The recombinant product is structurally very similar, if not identical, to native human erythropoietin, being a 193-amino acid peptide from which a 27-amino acid leader sequence is cleaved. Evidence indicates that the arginyl residue at the carboxyl terminus is also removed. The 165-amino acid mature protein contains two disulfide bonds, and one O-linked and three N-linked carbohydrate chains. The major carbohydrate units are sialated tetraantennary saccharides, which are required for stability in vivo (1). Two different rHuEPO products have been developed, alpha and beta, with differences in carbohydrate structure (glycoforms). In spite of the fact that rHuEPO is produced in mammalian cell lines and despite its widespread use, relatively little information is available regarding its immunogenic character. To date, few reports have been published on the development of anti-rHuEPO antibodies (2)(3)(4)(5). Because of anemia, with hemoglobin of 65 g/L, a patient with end-stage renal disease in chronic hemodialysis required treatment with rHuEPO. rHuEPO-alpha, 20 U/kg body weight three times weekly (Eprex, Cilag, Switzerland), was scheduled, with good initial hematological response. In the …