By in situ hybridization and immunohistochemistry, IL-17 expression gradually increases in the cerebrum tissues of rats from 1 h to 6 days following cerebral ischemia, and the T cell infiltration correlates positively with the area of the cerebral injury, which demonstrates that IL-17 and T cells are involved in cerebral injury (Li et al., 2005). Here, IL17A is linked to brain ischemia.