CD4 and rheumatoid arthritis: Several studies emphasized potential therapeutic roles for CD4+ and CD8+ Tregs in autoimmune diseases [28] (such as experimental autoimmune encephalomyelitis [29], [30], Rheumatoid arthritis [31]–[33], lupus [34], and diabetes mellitus type 1 [35]), pulmonary inflammation [8], transplantation [36], and inflammatory bowel disease [37].