CD4 and cardiac arrest: In particular, CD4+CD25+Treg cells, CD11b+CD11c+ and CD11b–CD11c+ DCs, and CD11b+Ly6C+Ly6G+ PMN-MDSCsare strongly correlated with neuronal injuries and neuroinflammation.The pattern of collective changes in these circulating immune cellscan be exploited to devise a future strategy for the prognosticationof outcomes in cardiac arrest patients.