Additionally, the co-expression level of CD3+ CTLA4+ was highest in the control group (MFI = 17.11 ± 2.22), significantly higher than in mild SLE (MFI = 13.22 ± 2.53, p = 0.002) and severe SLE (MFI= 14.37 ± 1.45, p = 0.012) (Figure 4b). The gene discussed is CTLA4; the disease is systemic lupus erythematosus.