GSK3B and COVID-19: Remarkably, and in agreement with the shift in macrophage subsets that takes place in severe COVID-19 lungs (loss of AMØ, appearance of monocyte-derived pro-fibrotic macrophages) (Vega et al., 2020; Wendisch et al., 2021; Liao et al., 2020; Grant et al., 2021), the level of phosphorylated Ser21-GSK3α and Ser9-GSK3β was very significantly augmented in lung macrophages (CD68+) from severe COVID-19 patients, an increase that correlated with a robust enhancement of the macrophage expression of both MAFB and the MAFB-dependent protein CD163 (Figure 6H).