These data suggest that IgA might be produced locally which was further supported by a study of Heinen and colleagues which compared the influenza specific activity (ratio of NP-specific titer to total Ig concentration) between serum and mucosal sites (21) and found local production of NP-specific IgA and IgG1 in the BAL, and IgA in the nasal mucosa. The gene discussed is CD79A; the disease is influenza.