CTLA4 and autoimmune lymphoproliferative syndrome: A highly proliferative and unconventional CD38+CD45RA+T-BET− IL-10-producing polyclonal T-cell population is identified in autoimmune lymphoproliferative syndrome, which is tightly controlled by FAS and CTLA4 and maintained by mammalian target of rapamycin (mTOR) and STAT3 signals (Maccari et al., 2021, Fuchs et al., 2021).