Adequate surface protection of the upper airway tract depends on intimate co-operation between natural non specific defence mechanisms such as ciliary function and acquired adaptative immunity. The latter is mediated by specific antibodies mainly belonging to secretory immunoglobulin A (SIgA) and to lesser extent secretory IgM (SigM) as well as by serum derived and locally produced IgG. Immunoglobulin's deficiency may exist in a significant percentage of patients with chronic or recurrent infections of the upper respiratory tract. So an immunologic screening should be extended to patients who have persistent sinus infection, despite normal mucocilary and ventilation patterns, inadequate response to antimicrobial therapy, culture of unusual pathogens from the upper respiratory tract or history of infection at other side, mainly bronchopulmonary. The therapeutic aspects include immunoglobulin replacement or mucosal immunogens whose efficacy is related with both an unspecific and a specific way. In the future, cytokines will probably become the strongest therapy of the immunoglobulin's deficiency.