In general, the inflammatory state can hamper Treg homeostasis and reduced the population as shown in autoimmune murine models including OVA‐induced bronchial asthma and experimental autoimmune encephalomyelitis and colitis.40, 41, 42 Furthermore, Treg decrease can result in the increase of Tfh through the reduced function of CTLA‐4.23 Here, CTLA4 is linked to experimental autoimmune encephalomyelitis.