Changes of Serum IL-6, IL-17, and Complements in Systemic Lupus Erythematosus Patients

Cytokines activation and low complement levels are common in systemic lupus erythematosus (SLE) patients. This study is aimed to explore the relationship and clinical significance of cytokines and complements with SLE activity. Serum samples of 140 SLE patients and 36 age- and gender-matched healthy controls (HC) were collected. Serum interleukin (IL)-6, IL-17, high-sensitivity C-reactive proteins (hsCRP), and complements (C3, C4) were measured in all samples. These patients were divided into 3 subgroups based on clinical disease activity with SLE Disease Activity Index 2000 (SLEDAI-2K): stationary status subgroup, mild activity subgroup, and moderate/severe activity subgroup. The serum IL-6, IL-17, and hsCRP levels in SLE patients (4.72 ± 0.28 pg/mL, 23.34 ± 1.32 pg/mL, and 4.78 ± 0.34 mg/mL) were significantly higher than those in the HC group (1.51 ± 0.05 pg/mL, 18.28 ± 1.93 pg/mL, and 1.32 ± 0.29 mg/mL), whereas C3 and C4 levels in SLE patients (0.80 ± 0.28 and 0.21 ± 0.08 g/L) were significantly lower than those in the HC group (1.49 ± 0.08 and 0.36 ± 0.02 g/L). A positive correlation was noted between the SLEDAI-2K scores and serum IL-6, IL-17, and hsCRP levels. These results support the proinflammatory cytokines and complements in the pathogenesis of SLE. The serum IL-6, IL-17, and hsCRP levels were correlated with the disease activity.