The relationship of ischemia-modified albumin levels to disease activity scores and HLA-B27 in patients with ankylosing spondylitis Orıgınal Article PT&R Cite this article as: Sertpoyraz FM, Colak A, Dikici A, Erdinc Gunduz N, Zeytinli Aksit M. The relationship of ischemia-modified albumin levels to disease activity scores and HLA-B27 in patients with ankylosing spondylitis. North Clin Istanb UNCORRECTED PROOF A nkylosing Spondylitis (AS) is a chronic rheumatic disease that is characterized by inflammatory low back pain, is often accompanied by peripheral arthritis, and has a prevalence of 0.9% worldwide [1]. It often affects young men, causing loss of function and deterioration in the quality of life [2]. AS is characterized by the inflammation of the sacroiliac joint, peripheral enthesis, and subchondral bone marrow. The mechanism of pathogenesis has not been fully elucidated; however, several genes including human leukocyte antigen (HLA) B27, chronic inflammation caused by intestinal bacteria, cytokines, and oxidative stress are known to have a role in pathogenesis [3]. In an organism, the rate of formation and elimination of free radicals are at equilibrium, which is called oxidative equilibrium. When the oxidative equilibrium is achieved, free oxygen radicals do not affect the organism; oxidative stress occurs when this balance is uneasy.