Activated microglia/macrophages and infiltrating immune cells (ie, monocytes and neutrophils) are present in the infarct and in the peri-infarct area after ischemic stroke.14 Previous research showed microglial IL-1β expression 24 hours after stroke.13 NLRP3 is also described to be expressed in infiltrating cells at a similar time point.12 To further characterize the inflammatory response occurring after ischemia, we used flow cytometry of brain homogenates to measure microglia and immune cell infiltrates. The gene discussed is NLRP3; the disease is ischemic stroke.