Increased spontaneous activity of antibody-forming cells in the peripheral blood of patients with active SLE.

Thirty-seven patients with criteria for systemic lupus erythematosus (SLE) and 18 normal controls were studied for their spontaneous background IgM antibody plaque-forming clell number to specific chemical haptens. Active SLE patients had significantly more plaque-forming cells in their peripheral blood to a total of five chemical determinants than did patients with inactive disease or controls. This increased number of plaque forming-cells correlated with depressed serum C3 levels by Spearman rank-order analysis. The finding of elevated numberof spontaneous IgM plaque-forming cells to defined chemical haptens supports the concept that active SLE demonstrates a generalized increase in B-cell activity toward a variety of antigens.