XmAb5871 (also known as obexelimab), a monoclonal antibody targeting CD19 and FcγRIIb, was found to inhibit calcium transport, proliferation, and co-stimulatory molecule expression in B cells in SLE patients and healthy volunteers, thereby suppressing humoral immunity and reducing IgM, IgG and IgE levels (Horton et al., 2011). This evidence concerns the gene CD40LG and systemic lupus erythematosus.