IFNG and graft versus host disease: Fig 1E shows the number and phenotypes of infiltrated hPBMCs in the spleen for each treatment group. The numbers of T and B cells were markedly reduced in the ATG group but not in the alemtuzumab and PTCY groups compared to the GVHD group. The serum IFN-γ level was also significantly decreased in the ATG and PTCY groups compared to the GVHD group (Fig 1F).