One such example is the cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) glycoprotein, present on the surface of T-helper cells, transmitting an inhibitory signal to T-lymphocytes [52], the increased expression of which is associated with protective effects against several autoimmune diseases, such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), T1D, and juvenile idiopathic arthritis (JIA) [50]. Here, CTLA4 is linked to autoimmune disease.