However, genetic deficiency of CD73 in the donor or recipient also increased splenic CD4+ and CD8+ T cell numbers, serum IFNγ and IL-6 concentrations, histological damage in target organs, and mortality in allogeneic mouse models of GVHD [111,112] supporting a role for CD73 in limiting GVHD progression. Here, IL6 is linked to graft versus host disease.