The Fig. 1b, c showed that peripheral serum C4 concentration was positively correlated with Treg percentage (R2 = 0.5907, p < 0.001) and TGFβ concentration (R2 = 0.5641, p < 0.001) respectively in SLE patients. The gene discussed is TGFB1; the disease is systemic lupus erythematosus.