Besides, serum ITGB2 mRNA expression levels significantly discriminated RA patients from OA patients with an AUC = 0.705, 95% CI = 0.5812 to 0.829, P = 0.002, with a sensitivity of 93.02% and a specificity of 42.42% at a cutoff > 2.901-fold (Fig. 5C). Here, ITGB2 is linked to rheumatoid arthritis.