Rheumatoid arthritis (RA) is a complex autoimmune disease that affects about 1% of the world's population, which is characterized by the erosion and destruction of cartilage and bone [1,2]. As a systemic disease, RA not only damage synovial joints, in severe cases, it also lead to systemic complications, resulting in excess disability and early mortality [3]. At present, a large number of studies have shown that, gene polymorphism may be an important factor on the population heterogeneity of autoimmune diseases among individuals [4,5].
