CTSG and graft versus host disease: However, severe xeno-graft-versus-host disease in mice renders the test window very short, so a team of researchers developed NOG-dKO mice (NOD.Cg-Prkdcscid Il2rgtm1Sug H2-Ab1tm1Doi B2mtm1Unc/Jic (NOG-Iabnull B2mnull: N O G–dKO)) that lack MHC classes I and II [42].