KLRK1 and stroke disorder: nKG2A is an inhibitory receptor expressed on the surface of NK cells, and nKG2D is an activating receptor, in which there is no significant ipsilateral and contralateral expression of nKG2A The difference suggests that left basal ganglia infarction caused not only ipsilateral but also contralateral immune responses, thus showing that stroke is not a localized injury but an active whole-brain immunity.