Serum levels of interleukin 15 in patients with rheumatic diseases

Objective. The role of the cytokine interleukin 15 (IL-15) in rheumatic dis ease is unclear. We examined serum levels of IL-15 in patients with various rheumatic diseases. Methods. Serum levels of IL-15 were determined by sandwich ELISA. Results. Serum levels of IL-15 were significantly increased in patients wit h poly myositis/dermatomyositis, polyarteritis nodosa, and systemic scleros is; and significantly increased as well in disease complicated by interstit ial pneumonitis (IP). hemophagocytic syndrome (HPS), and/or vasculitis. Pat ients with serum IL-15 levels less than or equal to 5 pg/ml showed signific antly high rates of survival. Conclusion. IL-15 is related to the pathogenesis of IP, HPS, and/or vasculi tis. Serum IL-15 level could possibly be used as a marker of prognosis.