Activated MHC-II–deficient DC, in turn, drive the activation of CD8 T cells (Loschko et al., 2016; Wohn et al., 2020; Zhou et al., 2023), which results in lethal CD8 T cell–mediated autoimmunity in both conditional mutants with DC-specific MHC-II deletion and in mixed bone marrow chimeras that received MHC-II−/− and WT bone marrow (Muth et al., 2012; Zhou et al., 2023). The gene discussed is CD8A; the disease is Autoimmunity.