We assessed 115 patients with active IA (64 rheumatoid arthritis (RA), 31 psoriatic arthritis and 20 ankylosing spondylitis) before and after using methotrexate (MTX) alone or tumor necrosis factor inhibitor (TNFi) with or without MTX co-medication (TNFi±MTX). This evidence concerns the gene TNF and psoriatic arthritis.