CEACAM1 and graft versus host disease: However, in the presence of steroid resistance and dysbiosis, Ceacam1 deficiency on IECs resulted in prevention of acute SR-Gut-GVHD, with reduced bacterial translocation and an increase in regulatory CX3CR1hi MNPs, as well as with reduced infiltration of proinflammatory Th1 and Th17 cells, but an increase of IL-22+ pTregs, although the mechanisms remain unclear.