However, previous studies have reported inconsistent findings regarding the effect of TNF-α inhibitor treatment on spinal radiographic progression in patients with AS5–9, whereas TNF-α inhibitors have been effective in preventing structural damage as well as reducing disease activity in psoriatic arthritis and rheumatoid arthritis (RA), in which bone erosion dominates bone formation10,11. This evidence concerns the gene TNF and rheumatoid arthritis.