MRC1 and COVID-19: Additionally, an increased amount of especially sinus-associated CD163 (and CD206)-positive M2-polarized macrophages (median 30% compared to 0%, p=0.011) (Figures 2D and 3) and a decreased amount of both sinus-associated and paracortical lysozyme (and HLA-DR)-positive M1-polarized macrophages was noted in COVID-19 (median 4% compared to 15%, p=0.027) (Figure 2C).