Quantification of the complement receptor function on polymorphonuclear leukocytes: its significance in patients with systemic lupus erythematosus.

The function of complement receptors (CR1) on polymorphonuclear leukocytes (PMN) was assessed by C3b mediated binding of immune complexes (IC) to PMN. The binding of IC to CR1 on PMN depends on the activation of the classical complement pathway and was inhibited by the antibody to CR1 or C3b. CR1 function of PMN from patients with systemic lupus erythematosus was reduced compared with those from normal controls or patients with rheumatoid arthritis.