Compared with HCs, the SLE patients exhibited significant reductions in the numbers of T (p < .001), B (p < .001), CD4+ T (p < .001), CD8+ T (p = .001), NK (p < .001), Th1 (p = .002), Th2 (p = .043), Th17 (p = .004), and Treg cells (p < .001), implicating these cells in SLE pathogenesis. Here, CD4 is linked to systemic lupus erythematosus.