In addition, cultures of liver tissue suspension from GVHD-free recipients of WT CD8+ T cells showed very little bacterial growth, but 37% (17/45) cultures from recipients of IFN-γ−/−CD8+ T cells showed exuberant bacterial growth, and anti-IL-22-treatment markedly reduced the frequencies of bacterial growth (Fig. 6b). Here, CD8A is linked to graft versus host disease.