CD4 and rheumatoid arthritis: Collectively, these data show that (i) there is more glucose induced FAD fluorescence in in naïve, non-switched and switched memory B cells as well as CD4+ T cells from HD than in RA donors, (ii) that the glucose-induced FAD is coupled more efficiently to uncoupled respiration in non-switched and switched memory B cells as well as CD4+ T cells from HD than in RA donors.