CD4 and systemic lupus erythematosus: The expansion of Tregs by RA in the presence of 1 ug/ml of TGFβ (Figure 6a) or by the combination of RA and 1 ug/ml of TGFβ (Figure 6b) was negatively correlated with the percentage of memory CD4+ T cells in the PBMCs of SLE patients.