In a haploidentical HCT mouse model, administration with a reduced dose of cyclophosphamide (PTC) followed by α-galactosyl ceramide induces an NKT2 rather than NKT1 phenotype and early recovery of CD4+ Foxp3+ Tregs, which prevents GVHD while maintaining GVL effects (54). Here, CD4 is linked to graft versus host disease.