RESUMO
BACKGROUND: The aim of the study was to investigate oxidant/antioxidant status by determining serum ischemia-modified albumin (IMA) levels with oxidative/antioxidant parameters in patients with ankylosing spondylitis (AS) compared to the controls. METHODS: The serum concentrations of IMA, IMA/albumin ratio (IMAR), malondialdehyde (MDA), total oxidant status (TOS), oxidative stress index (OSI), superoxide dismutase (SOD), glutathione peroxidase (GPx), and total antioxidant capacity (TAC) were measured in 40 AS patients and 35 healthy controls. RESULTS: Mean serum IMA, IMAR, MDA, TOS, and OSI levels were increased in patients with AS when compared to the control group (p < 0.05 for all). Serum levels of SOD and GPx were significantly lower in the patient group than in the healthy subjects (p < 0.001 for both). Serum TAC levels were decreased in patients with AS compared to the controls but the statistical difference was not significant. Serum IMA levels were found to be positively correlated with BASDAI, BASFI, BASMI, and ASDAS-CRP (r = 0.356, r = 0.370, r = 0.412, r = 0.353, respectively, and p < 0.05 for all). IMAR values showed significant correlations with BASFI, BASMI, and ASDAS-CRP (r = 0.351, p = 0.026; r = 0.400, p = 0.010; and r = 0.379, p = 0.016, respectively). CONCLUSIONS: Depletion in antioxidant systems and overproduction of free radicals leading to formation of the oxidative stress may play a role in the development of AS. Increased levels of IMA might provide important contributions to the underlying oxidative stress in AS.