Dai et al. [45] found that IGU combined with leflunomide could significantly decreased serum inflammatory cytokines (TNF-α, sTREM-1), and increase the level of bone metabolic markers (25(OH)D and TPINP) in patients of RA compared with etanercept monotherapy (P < 0.05). This evidence concerns the gene TNF and rheumatoid arthritis.