MADCAM1 and graft versus host disease: Approaches that specifically prevent alloreactive T cell infiltration into GVHD target tissues include the following (Table 1): 1) targeting chemokine or chemokine receptors, such as CCR5, CXCR3, MAdCAM-1; 2) anti-CD3-preconditioning that depletes host DCs that imprint alloreactive T cell tissue tropism; 3) FTY720 that prevents alloreactive T cell egress from lymphoid tissues; and 4) neutralizing or blockade signaling pathways of inflammatory cytokines such as TNF-α and IL-6.