Regarding reconstitution of the iatrogenically wiped-out immune system in the context of experimental HCT, a scenario that does have a clinical correlation in the form of clinical HCT, depletion of newly arising CD8+ T cells but not of CD4+ T cells results in disseminated multiple-organ mCMV infection including interstitial pneumonia with a lethal outcome [31,90]. The gene discussed is CD8A; the disease is infection.