Free tumor necrosis factor α levels on membranes of monocytes and culture supernatants from healthy donors and rheumatoid arthritis patients after adalimumab treatment. Membrane tumor necrosis factor α (mTNFα) levels on monocytes and culture supernatants were analyzed in rheumatoid arthritis (RA) patients before and after 2, 6 and 12 injections of adalimumab. Graphs show integrated geometric mean fluorescence intensity (iGMFI) of mTNFα in healthy donors (HDs) and RA patients after lipopolysaccharide (LPS) culture (A) and lipoteichoic acid (LTA) culture (B). Graphs shows TNFα concentrations (pg/ml) in healthy donors and RA patients at all time points of adalimumab treatment, after LPS culture (C) and LTA culture (D). A paired t-test was used for statistical analysis between RA patients and number of injections. A t-test was used for statistical analysis between RA patients and healthy donors. *P < 0.05, **P < 0.01.