IL4 and Stroke: At the onset of ischemic and hemorrhagic stroke (attack phase), emerging evidence has revealed that stroke induced a local inflammatory reaction and a plethora of innate immune responses in the brain where antigen-presenting cells became prominent; following the onset of stroke, inflammatory components (IL-4 or IFN-γ), which are produced by innate immune cells (e.g., microglia, NK cell) with the stimulation of blood proteins at the neurovascular unite, promote detrimental cellular or humoral responses and lead to diffuse neuron and oligodendrocyte damage (101–105).