LILRB4 and influenza: Interestingly, a few reports document increased expression of LILRB4 during acute infection with lymphocytic choriomeningitis virus (LCMV), influenza, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (3, 20, 21), and its expression is associated with robust antibody responses in patients with influenza (20) as well as development of effector CD8+ T cells in mice (14).