IL1B and hematoma: Caspase-1 activation contributes to increased classically-activated (proinflammatory) M1-type microglia polarization and reduced the number of (anti-inflammatory) M2-type cells surrounding the hematoma (Franco and Fernandez-Suarez, 2015; Hu et al., 2015; Lin et al., 2018), with a huge amount of M1 polarization induced by an increase in IL-1β secretion after hemorrhagic stroke (Zhang et al., 2017b).