Another study compared TRPV1 immunoreactivity in synovial sections from human patients with OA, rheumatoid arthritis (RA), and post mortem (PM) controls without known joint pathology, and showed an increased fraction of TRPV1 immunoreactivity in synovial sections from patients with OA (7.3%) and RA (5.2%) compared to PM controls (0.0%) [26]. This evidence concerns the gene TRPV1 and rheumatoid arthritis.