The serum CD40 levels were significantly higher in the group of patients with SLE than those in the control group [(mean +/− SD 58.5 +/− 22.8 pg/ml, n = 205) vs, (mean +/− SD 41.7 +/− 13.2 pg/ml, n = 220); P <0.001] (Fig. 1). This evidence concerns the gene CD40 and systemic lupus erythematosus.