Serum YKL-40 levels and disease characteristics in patients with rheumatoid arthritis

Background: the present study aimed to evaluate serum ykl-40 levels in patients with rheumatoid arthritis (ra) compared to healthy subjects and to search whether there is an association between ykl-40 levels and disease characteristics in ra. methods: in this cross-sectional study, 60 ra patients based on the acr/eular 2010 criteria and 30 age- and sex-matched healthy controls were included. in patients, clinical examination was performed and disease activity score 28 (das-28) measure of disease activity was assessed. serum ykl-40 level was measured using elisa kit. results: the mean±sd age of patients and controls was 54.86±11.65 and 50.71±3.72 years, respectively). serum ykl-40 level was significantly higher in ra patients (951.63±639.98 pg/ml) compared to healthy controls (444.92±150.37 pg/ml) (p<0.001). there was no significant difference in serum ykl-40 level according to the activity of disease (p>0.05). there were significant positive correlations between serum ykl-40 level with disease activity (r=0.347, p=0.007) and rheumatoid factor (r=0.396, p=0.002). there were no significant correlations between serum ykl-40 level with demographic characteristics as well as biochemical measurements including serum creatinine, blood urea nitrogen, erythrocyte sedimentation rate, c-reactive protein and anti-cyclic citrullinated peptide. conclusion: our study revealed higher serum ykl-40 levels in ra patients compared to healthy controls, which correlated positively with disease activity. therefore, ykl-40 can be considered as a novel biomarker for disease activity estimation in ra.