TNF and psoriatic arthritis: Biologic agents in the category of TNF-α inhibitors, including etanercept, infliximab, adalimumab, certolizumab pegol, and golimumab, have proven efficacious in controlling disease activity of various rheumatic and autoimmune diseases, including RA, psoriatic arthritis, and ankylosing spondylitis, because of their action against the TNF-α molecule [9].