Although IgM autoantibodies have been considered as protective in lupus, total IgM and/or IgM anti-DNA are used as readout for disease activity in TACI-Ig or BAFF-R-Ig treated lupus mice experiments, and their reduction correlates systematically with disease amelioration [11], [14]. The gene discussed is CD40LG; the disease is systemic lupus erythematosus.