S100A8 and Encephalopathy: Monocytic MDSCs, a subtype of myeloid cells characterized by reduced MHC-II expression and increased neutrophil activation-associated genes (e.g., S100A8/A9), was identified to be significantly elevated in COVID-19 patients with encephalopathy, especially acute necrotizing encephalopathy (Fig. 2 and Supplementary Fig. 3).