CRIPTOP4 and COVID-19: Although the CR-mediated cytokine response was abrogated by the presence of virus-specific Abs through FcγRII (CD32) engagement, CR3 and CR4 are also highly expressed on monocytes and monocyte-derived macrophages, two key players in the COVID-19-associated hyperinflammation, which may respond differently to Ab- and complement-opsonized virus particles [45,46].