CD79A and infection: Given that IgA serves as the first line of defense against infection [29], we further investigated a diverse panel of influenza antigen‐specific IgA levels in the BALF (Figure 3C) and NALF (Figure 3D), including PR8, swH1N1, WHO‐recommended seasonal H1N1 vaccine strains (2009–2025), and heterologous influenza virus strains including X31 (H3N2), Darwin21 (H3N2), Cam07 (H5N1), and HK99 (H9N2).