In histological sections of lungs of the Rag2–/–Il2rg–/–mice transplanted with either human pHSCs from LTBI or mouse pHSCs from Mtb-infected mice, we observed increased cellularity in the lungs indicative of an inflammatory infiltrate in response to an active infection 3 weeks after pHSC transfer (Fig 6D). The gene discussed is IL2RG; the disease is infection.