CD4 and systemic lupus erythematosus: In a previous paper we have shown that in the absence of CD38 there was a significant amelioration of the signs of the disease in the cGVHD-lupus model, including decreased expansion of Tfh cells, GC B cells, plasma cells, and Tbet+CD11chi B cells, while the expansion of Treg cells and Tfr cells was normal, suggesting a defective response of Cd38-/- B cells to allogeneic help from bm12 CD4+ T cells (18).