CD4 and Stroke: Studies on T cells and monocytes/macrophages have shown a significant increase in ipsilateral thalamic CD4+ and CD8+ T cells by flow cytometry 14 days after stroke, and the sites of T-cell aggregation overlap with the areas of activated macrophage aggregation, which suggests that there may be interactions between T cells and macrophages [253]; however, there is also evidence that T-cell-produced IL-4 can promote the conversion of macrophages to the M2 phenotype, thereby suppressing inflammation [254, 255].