For example, gene polymorphisms in Pdcd1 are associated with the susceptibility of autoimmune diseases including rheumatoid arthritis (RA), type 1 diabetes mellitus (T1DM), systemic lupus erythematosus (SLE), ankylosing spondylitis (AS) and MS [43–47]. Here, PDCD1 is linked to systemic lupus erythematosus.