The early activation of innate immunity and the release of immune cytokines exert detrimental effects in acute phase of stroke,6, 7 which are not related to adaptive immunity.8 However, the adaptive immunity to brain antigens occurs in the later phases and may have important roles in neurovascular remodeling and functional recovery during stroke recovery.5 Among various immune cytokines secreted by immune cells, we focused on interleukin-17 A (IL-17 A) owing to three recently proposed ideas. The gene discussed is IL17A; the disease is Stroke.