FCGR1A and influenza: Similar findings were reported in children with multisystem inflammatory syndrome associated with SARS-CoV-2 infection and adults with severe COVID-19.6,36 Very high neutrophil CD64 (MFI > 1.8 and >80%) has been seen in patients with bacterial infection.22 Lower-grade CD64 expression has been observed in patients with influenza or trauma.16,17