IDO1 and hemophilia A: In F8 KO mice, the animal model of hemophilia A, CpG-ODN administration and consequent induction of IDO1 in dendritic cells (DCs) was shown to prevent generation of anti-FVIII antibodies while promoting FVIII-specific FoxP3+ Tregs, which effects required both IDO1 and AhR in host immune cells (76).