CD4 and systemic lupus erythematosus: Because the difference in IL-17+ T cell subsets between patients and the control group was not found at Day 0, the higher percentages of IL-17+ T cells after ex vivo stimulation strongly implies that T cells in the PBMCs of SLE patients preferentially skew towards IL-17 production and expand more vigorously than those of the control, both in the CD4+ and CD8+ compartments.