RA is one of the most common and the typical representative of autoimmune diseases, characterized by synovial tissue inflammation and progressive destruction cartilage, which is one of the strongest predictors of long-term outcome and disability in RA patients.[26,27] Environmental and genetic factors participate in the pathogenesis of RA.[28,29] Recently, studies have focused on the identification of genes that influenced the susceptibility to this disease, among them was PDCD1, which was an important negative regulator of autoimmunity. Here, PDCD1 is linked to autoimmune disease.