ICOS and autoimmune hepatitis: The observation that TFR cell expresses proteins typically expressed by TFH cell, such as ICOS and PD‐1, as well as proteins typically expressed by Tregs, like CD25 and CTLA4, is consistent with studies showing that TFR cells are thymic‐derived Treg that migrate into the follicle in a TFH cell‐dependent manner, and up‐regulate CXCR5 and PD‐1 in a manner similar to plasma cell.16, 17, 18 Like TFH cell, we found significantly higher levels of PD‐1+TFR and ICOS+TFR cells in AIH patients.