Levels of TNF-α in the RA group (median: 16.2 pg/ml; IQR, 12.53–24.00 pg/ml) were remarkably higher compared to the healthy controls (median, 10.45 pg/ml; IQR, 8.05–17.33 pg/ml; P = 0.017) and the OA group (median, 14.4 pg/ml; IQR, 11.03–20.58 pg/ml), although this difference was not statistically significant (P = 0.410). Here, TNF is linked to rheumatoid arthritis.