The major findings of this study are (1) the kinetics of perforin+CD45+ cells invading the ischemic area, (2) the fact that perforin exerts a deleterious impact after ischemic stroke, and (3) the fact that perforin-mediated direct neurotoxicity controls the number of infiltrating γδ T cells and may further increase the secretion of the proinflammatory cytokines IL-17 and IFN-γ. This evidence concerns the gene IL17A and ischemic stroke.