It has been demonstrated that calcitriol has a synergic effect with monoclonal antibody against TNF-α (tumor necrosis factor-α) in inhibiting the pro-inflammatory pathway of Th17 cells in RA [14]; this suggests that vitamin D combined with TNF-i (TNF-inhibitor) could produce a better response in the treatment of RA patients. Here, TNF is linked to rheumatoid arthritis.