Infliximab, a TNF-targeting drug, was initially indicated for rheumatoid arthritis, but this indication has been expanded to the treatment of more than 10 immune diseases, such as Behcet’s disease, Kawasaki disease, psoriasis, psoriatic arthritis, ankylosing spondylitis, Crohn’s disease, and ulcerative colitis. This evidence concerns the gene TNF and psoriatic arthritis.