Enhancement of granulocyte oxidative metabolism in sera from patients with C2 deficiency and systemic lupus erythematosus.

Serum or plasma from 3 patients with C2 deficiency (C2D) and systemic lupus erythematosus (SLE) significantly enhanced chemiluminescence and superoxide anion production by polymorphonuclear leukocytes (PMN) after stimulation with phorbol myristate acetate or latex beads. PMN from patients and normal individuals were supranormally activated when resuspended in plasma from these patients. No such effect was seen with plasma from a patient with C2D but with no evidence of SLE, from patients with SLE but not C2D, from patients with C1q or C8 deficiency, from C4-deficient guinea pigs, or NZB-NZW mice. Because oxygen-derived free radicals may cause joint or tissue damage, C2D patients who have or develop this activity in their plasma may be more prone to SLE or other collagen-vascular diseases.