CD4 and systemic lupus erythematosus: Additionally, studies have shown that MSCs could inhibit T cell activation in a dose-dependent manner; inhibit the differentiation of CD4+ T cells into Th1, Th17, and Tfh cells; promote Treg proliferation and secretion of IL-10, reduce the ratio of Th1/Th2; and restore the proportion of Treg/Tfh cells, thereby correcting the abnormally activated T cells and cell subsets in patients with SLE (41, 43).