CD4 and systemic lupus erythematosus: Treatment of SLE patients with hypovitaminosis D with 100,000 U of VitD3 weekly for 4 weeks and then monthly for 6 months resulted in an increase in naïve CD4+ T cells and CD3+CD4+CD25hiCD127–Foxp3+Tregs and decreases in CD19+ B cells, anti-ds DNA antibody titers, and proteinuria (222).