B cell derived B cell stimulatory factors in patients with systemic lupus erythematosus

Abstract

We investigated the relation between polyclonal B cell activation and B cell derived B cell stimulatory factors (BSF) in patients with systemic lupus erythematosus (SLE). B-BCGF activity and IL-1 activity were detected in SAC stimulated B cells supernatant. No significant difference in BCGF-like activity was observed among the active SLE group, inactive SLE group and normal subjects. BCDF-like activity, however, was higher in the active SLE group than the inactive SLE group and normal subjects. Furthermore, IL-1 activity in the active SLE group was also higher than in the other two groups. Anti-human IL-1 antibody inhibited BCGF-like and BCDF-like activity. The inhibition rate was highest in the active SLE group. These results suggested that IL-1 production by SAC stimulated B cells was much higher in active SLE than in inactive SLE, and (that) IL-1 could act as inducer of antibody production. B cell derived IL-1 may be involved in polyclonal B cell activation. As B cells of some patients in the active SLE group spontaneously produced IL-1 and B-BCGF, we speculated that B cells had already been activated in vivo.