Potential DC-based therapies for GVHD. TolDCs can be used as a negative cellular vaccine after in vitro generation via their pharmacologic manipulation, cell sorting (subsets), or expansion after interaction with other immune regulatory cell populations. In vivo, DCs can be targeted by the inhibition of molecular pathways (HDAC; NF-κB) or the expression of maturation markers or costimulatory molecules (eg, CD80/CD86; CD83). Other cellular therapies, such as MSCs, MDSCs, and T_reg, mediate immunosuppressive effects through DCs. VIP indicates vasoactive intestinal peptide. Professional illustration by Alice Y. Chen.