Insight into the in vivo antigen-presenting cell requirements for Blimp-1+Gzmbhi TRM cell generation was gained by observations of sharply lower numbers of these cells in TGF-βR2Δ/Δ recipients, which during BOS pathogenesis, could produce iMacs and CD11b+ DCs, but not Mo-AMs. The gene discussed is PRDM1; the disease is Buschke-Ollendorff syndrome.