Despite different forms of IL-33 administration in diseases such as intracerebral hemorrhage, spinal cord injury, glioma, and AD, an increase in the percentage of microglia expressing M2 markers (Arginase-1 or CD206) is consistently induced by IL-33 treatment (Pomeshchik et al., 2015; Fu et al., 2016; Chen et al., 2019; De Boeck et al., 2020). This evidence concerns the gene IL33 and intracerebral hemorrhage.