Additionally, young Ripk1ΔCD4Casp8ΔCD4 mice showed no lymphopenia of peripheral CD4+ T cells (Figs. 7D), confirming our earlier findings that RIPK1 is required for the protection of peripheral CD4+ T cells from apoptosis (Huysentruyt et al, 2024). The gene discussed is CD4; the disease is lymphopenia.