Comparison of serum IL-1β, sIL-2R, IL-6, and TNF-α levels with disease activity parameters in ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic, inflammatory, rheumatological disease affecting primarily the sacroiliac joint and vertebral column, with an etiology that remains obscure. Cytokines are soluble proteins that have specific roles in inflammatory response, arranging the interaction between cells of the immune system both in natural and specific immune reactions. This study was planned to evaluate the relation between the level of cytokines and the clinical and laboratory findings of patients with AS compared to healthy subjects. In this study, we demonstrated increased serum levels of soluble interleukin-2 receptor (sIL-2R), Interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in patients with AS compared with healthy subjects. Only IL-1β levels were not increased in AS patients. We found a correlation between C-reactive protein and IL-6 levels and between erythrocyte sedimentation rate and sIL-2R, IL-6 and TNF-α levels. Only the sIL-2R level was correlated with Bath AS Metrology Index and Bath AS Functional Index. We suggest that sIL-2R, IL-6, and TNF-α may have a role in the pathogenesis of AS and that their serum levels can be used as disease activity parameters and tools for diagnosis.