CD4 and cerebral infarction: Though an upward trend in P2X7 MFI was observed across all lymphocyte populations in the cerebral infarction hemisphere from the acute phase (3 days) through to the chronic phase (28 days), only the MFI of P2X7 was significantly elevated in CD4+ and CD8+T cells at day 3 and day 7 (subacute stage), as well as throughout the entire duration of brain damage (Figure 1C).