Serum interleukin-18 and interleukin-10 levels in systemic lupus erythematosus: correlation with SLEDAI score and disease activity parameters

The aim of the study was to assess serum levels of interleukin (IL)-18 and IL-10 in systemic lupus erythematosus (SLE) patients and their relationship with disease activity. Thirty patients with SLE and 20 healthy controls were investigated in this study. The serum IL-18 and IL-10 levels were determined using enzyme-linked immunosorbent assay and their correlations with the disease activity were measured using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), and laboratory parameters, including erythrocyte sedimentation rate, anti-ds DNA antibody, complement 3, and complement 4 levels were analyzed. The serum IL-18 and serum IL-10 levels were significantly higher (mean values 1770.2 ± 360.4 and 842.65 ± 315.37 pg/ml for IL-18 and IL-10, respectively) in SLE patients compared with the controls (110.65 ± 30.37 vs. 76 ± 14.2 pg/ml, respectively, P < 0.001). The increase in serum levels of IL-18 and IL-10 directly and significantly correlated with each other (r = 0.404, P = 0.037). Furthermore, such an increase in the levels of these two cytokines showed a highly significant positive correlation with the SLEDAI scores and anti-ds DNA in the studied patients ( P < 0.001). The circulating IL-18 and IL-10 concentrations were significantly elevated in SLE patients and correlated with the SLEDAI score. The study emphasized that there exists an upregulated proinflammatory as well as anti-inflammatory responses in patients with active SLE; however, the anti-inflammatory response is not enough to suppress the active disease. Identifying the exact contribution of the currently studied cytokines might provide future insights for targeted therapeutic strategies in SLE.