Cytokine IL-6 and IL-10 as biomarkers in systemic lupus erythematosus.

There is a great deal of interest in the identification of biomarkers that are closely associated with disease activity in systemic lupus erythematosus (SLE), but few biomarkers have been validated. Cytokines play an important role in the pathogenesis of SLE. Therefore, we evaluated the levels of cytokines and their possible association with disease activity. In the present study, we found that the SLE patients had higher IL-6, IL-10, IL-12, and IFN-gamma levels, but lower IL-2, than normal controls. Serum IL-6 level was significantly elevated in active SLE patients and correlated with the SLE activity index (SLEDAI), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP). Serum IL-10 level was also significantly elevated in active SLE patients and revealed positive correlation with SLEDAI and anti-double-stranded DNA (dsDNA) titer and negative correlation with C3, C4, and lymphocyte counts. No significant differences in the levels of cytokines were observed between SLE patients with nephritis and those without nephritis. These data suggest that IL-6 and IL-10 may be a useful biomarker for disease activity in SLE.