Studies have shown that Toll-like receptor 4 (TLR4) deficiency increases the number of neutrophils (N2), which is related to neuroprotection after stroke, suggesting that the regulation of neutrophil polarization is the main target of TLR4 and emphasizing the key role of TLR4 in the prognosis of stroke (43). The gene discussed is TLR4; the disease is Stroke.