The spontaneous in vitro production of IgM, IgG, and IgA by peripheral blood mononuclear cells from SLE patients was strongly induced by rIL-10 and was decreased by an anti-IL-10 mAb, indicating that the immunoglobulin production by SLE B-cells is largely IL-10 dependent, and that the increased production of IL-10 by SLE B-cells and monocytes may represent a critical mechanism in the emergence of the autoimmune manifestations of the disease [78]. The gene discussed is CD40LG; the disease is systemic lupus erythematosus.