CEACAM1 and viral infectious disease: In addition, viral infection may compromise the epithelial barrier, alter the mucosal surface environment, degrade antimicrobial peptides, and expose adhesion receptors, such as ICAM-1, CEACAM-1, platelet-activating factor receptor (PAFr), and Fn, thereby facilitating bacterial adhesion and growth (McCullers and Rehg, 2002; Bosch et al., 2013; Su et al., 2018).