C4A and systemic lupus erythematosus: Cross-sectional analysis at baseline (online supplemental figure 6): at the baseline, using data from a total of 42 patients, which included both BEL-treated patients (BEL-G, n=22) and non-BEL-treated controls (CON-G, n=20), we investigated correlations between the proportions of Tregs and TCL11 and SLE disease activity indicators: SLEDAI-2K, anti-dsDNA antibodies, CH50, C3, C4 and PGA.