CD4 and graft versus host disease: Besides their HLA-independent recognition of antigens and their reduced induction of a graft-versus-host disease, an additional advantage of simultaneously activated γδ T cells is their capacity to present antigens, their possibility to induce maturation of DC, and their production of Th1 cytokines such as IFN-γ and TNF-α, which could compensate for a decreased number of CD4+ T cells (producing Th1 cytokines) at the tumor-site of PDAC patients (33–35, 72).