Given that the transferred bm12-CD4+ T cells were CD38 sufficient and the allo-reactive donor bm12 CD4+ T cells activated by host MHC II provide cognate help for host B cells to initiate lupus (36), these data support the role for Ag-presenting, B-cell-intrinsic CD38 in the induction of autoreactive immune responses. The gene discussed is CD4; the disease is systemic lupus erythematosus.