Immunological processes that may contribute to the outcome of macrophage- viral induced pathology include antibody enhancement of infection (ADE) and inflammation (ADI), and neutrophil NETosis. Anti-spike antiserum can induce hyperinflammation via macrophage FcR, depending on IgG glycosylation and Syk involvement [71]. Cross-reacting antibodies from previous benign coronavirus infections also contribute to enhanced pathology [72]. Dendritic cell dysfunction, ascribed to down regulated HLA-DR expression [67,72] and defective antigen presentation to T and B lymphocytes, may result from lack of costimulatory signals, aborting lymphocyte proliferation and activation and mediating widespread clonal death. Haemophagocytosis, a feature of the macrophage activation syndrome (MAS), is also observed in other viral infections.