B cell activity and regulatory T cell function in systemic lupus erythematosus by human B cell colony formation.

We have examined the ability of B cells from patients with systemic lupus erythematosus (SLE) to form colonies in vitro. Significantly more B cell colonies growing in the absence of irradiated T cells were observed in patients with active SLE. Helper T cell function of active SLE was normal. Culture supernatants of SLE T cells had significantly less activity to support the B cell colony formation. Our results suggest that the hyperactivity of B cells in SLE may reside in the lupus B cells themselves and that SLE T cells are defective in releasing the soluble factor.