FCGR3A and Sepsis: CD89 appears to act as an innate immune receptor that binds and triggers phagocytosis and killing bacteria in macrophages (de Tymowski et al., 2019), while CD16A binds to E. coli to activate an ITAM-inhibitory pathway that prevents phagocytosis and contributes to sepsis (Pinheiro da Silva et al., 2007).