CD40 and systemic lupus erythematosus: Similarly, in a chronic graft versus host disease (GVHD) model of SLE generated by transfer of splenocytes from 6.C-H2bm12/KhEg mice into BL6 or BL6 miR-21−/−, lack of miR-21 showed a drastic reduction in autoantibody titers, CD40:CD40L and CD28:CD80/86 stimulation signals [78].