Correlation of serum interleukin-10 level with disease activity and severity in systemic lupus erythematosus

Systemic lupus erythematosus (SLE, lupus) is a syndrome of multifactorial etiology, characterized by widespread inflammation, most commonly affecting women during the childbearing years. Virtually, every organ and/or system of the body may be involved. Interleukin-10 (IL-10) production is increased in SLE. The aim of the study was to assess serum levels of IL-10 in SLE patients and their relationship with disease activity and severity parameters. Totally, 50 patients with SLE and 20 healthy controls were investigated in this study diagnosed according to Systemic Lupus International Collaborating Clinics (SLICC) classification criteria for SLE. Clinical assessment of the disease activity was performed using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score. Assessment of SLE disease severity was carried out using the SLICC/American College of Rheumatology Damage Index and laboratory parameters, including erythrocyte sedimentation rate, C-reactive protein (CRP), 24 h urinary proteins, anti-dsDNA antibodies, complement 3, and complement 4 levels. The serum IL-10 levels were determined using enzyme-linked immune sorbent assay technique. The serum IL-10 levelswere significantly higher in SLE patients (mean: 23.07±33.19 pg/ ml) compared with the controls (0.52±0.86 pg/ml, P=0.000*). The increase in serum levels IL-10 significantly correlated with the SLEDAI scores (P=0.016*) and CRP (P=0.042*) in the studied patients. There were no significant correlations between IL-10 and SLICC, age, disease duration, erythrocyte sedimentation rate, 24 h urinary protein, anti-DNA, and complement 3–complement 4 (P=0.735; r=0.05, P=0.890, P=0.521, P=0.529; r=0.09, P=0.430; r=0.11, P=0.263; r=0.16, P=0.195; r=0.19, respectively). There was no significant difference between mean IL-10 levels in different classes of lupus nephritis (P=0.702). The circulating IL-10 concentrations were significantly elevated in SLE patients and correlated with the SLEDAI score and CRP.