IFNG and graft versus host disease: Furthermore, adoptive transfer of allogeneic CIK cells confers other advantages, such as the reduced risk of causing GvHD in comparison to T cell therapies, due to limited proliferative capacity and release of cytokines by CIK cells, such as IFN-γ, and lack of further severe side effects, which may protect against GvHD [156,157,158].