Interleukin 23 is elevated in the serum of patients with SLE

Aim: Interleukin-23 (IL-23) is a cytokine that promotes the differentiation of T cells into pro-inflammatory Th17. We have previously shown that IL-23 is upregulated in systemic lupus erythematosus (SLE) patients and lupus prone mice. As SLE is highly heterogeneous, we asked whether IL-23 production correlates with different manifestations of the disease. Methods: We recruited 56 subjects who fulfilled the ACR criteria for SLE. Interleukin-23 was measured in the serum by ELISA. Results: IL-23 levels were positively correlated with the overall SLE disease activity as measured with the SLEDAI. Moreover, IL-23 correlated with the skin, renal domains of SLEDAI and arthritis but not with cytopenias or serositis. IL-23 did also correlate with anti-dsDNA antibody positivity and inversely correlated with C3 levels. We found no relationship between patients' demographics, prior disease manifestations, medications, or autoantibody profile and IL-23 levels. No immunomodulatory medication seemed to be affecting IL-23 levels suggesting that current medications used in SLE are not as effective in shutting down the IL-23/IL-17 axis. Conclusions: IL-23 levels track SLE disease activity mostly in the renal, skin and musculoskeletal domains. Our data suggest that IL-23 inhibitors may be helpful in combination with current standard of care in alleviating arthritis, renal and cutaneous manifestations of the disease.