CD28 and rheumatoid arthritis: Our data revealed that 72 hours after incubation of PBMCs with MTX in RA patients, the levels of RANKL, TNF-α, IL-17 and IL-6 significantly decreased in MTX treated groups compared with Anti-CD3/CD28 group in RA patients (P < 0.05; Table 3; Figures 1, 2, 3, and 4).