CD4 and Stroke: Evidences have shown that a second peak of infiltration of CD4+ lymphocytes to the ischemic hemisphere occurs around day 14 and persists until day 30 after stroke (Sakaguchi et al., 2009), and a strong accumulation and proliferation of Tregs in the ischemic hemisphere was observed for up to 30 days after stroke (Stubbe et al., 2013).