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). Here, FAS is linked to autoimmune lymphoproliferative syndrome.