SPP1 and graft versus host disease: Zhao showed blockade of osteopontin(OPN) could reduce alloreactive CD8+ T cell-mediated GVHD in animal model: OPN promoted the migration and infiltration of naive and alloreactive CD8(+) T cells into host organs; it also facilitated activation and viability of donor-derived CD8(+) T cells via synergizing with CD3 signaling.