RECOMBINANT-HUMAN-ERYTHROPOIETIN MODULATES ERYTHROCYTE COMPLEMENT RECEPTOR-1 FUNCTIONAL-ACTIVITY IN PATIENTS WITH LUPUS NEPHRITIS

Deposition of immune complexes (IC) is an important step in the pathog enesis of lupus nephritis. Impairment of IC-clearance contributes to t he accumulation of IC. It may be partly attributed to decreased comple ment containing immune complex (ICC) binding by erythrocytic complemen t receptor 1 (ECR1). Stimulating erythropoiesis with recombinant human erythropoietin (rHuEPO) may enhance the IC-clearance as increasing EC R1 expression and/or functional activity. Ten anemic patients with lup us nephritis were treated with 50 IU rHuEPO (Eprex) per kg body weigth three times a week during a five week period. ICC-binding capacity of ECR1 was determined with I-125-labelled, C3ib containing BSA-anti-BSA complexes. In addition to effective correction of anemia, indicated b y increased red blood cell count (RBC), hemoglobin concentration and r eticulocyte ratio, rHuEPO significantly improved decreased ECR1 functi onal (ICC-binding) activity in patients with lupus nephritis. This imp rovement correlated with the increase in reticulocyte ratio. Although patients were kept on their previous therapy during Eprex administrati on, their clinical condition also improved. That was shown by a decrea se in Westergreen ratio, serum creatinine concentration and anti-dsDNA level and also by an increase in creatinine clearance. Results sugges t a beneficial immune modulatory effect of rHuEPO in lupus nephritis.