[Local immunologic system of the nose and paranasal sinuses]

The mucus membranes of the nasal chambers may be compared to a local immune system which has been called the NALT. The submucosa contains a lymphoid infiltration of T-helpers, T-suppressors and a set of plasma cells capable of synthetizing four IgG subgroups, IgM, IgA and IgD. The IgA plasma cells are most numerous. There is no local synthesis of IgE. Macrophages and langerhans' giant cells are present. The epithelium is an immunological entity which is composed, in addition to secretory cells, of uliated cells, lymphocytes, and M cells. The epithelium is able to synthesize secretory component and allows the transport of IgA and IgM into the secretions. The NALT has multiple immunological functions: antigenic information, humoral immune response, and expression of local cellular immunity. Modifications in T lymphocyte subpopulations are observed in allergic rhinitis. Secreted interleukins modify the local efflux and affluence of effector cells (mastocytes and eosinophils). Abnormalities of the NALT are characteristic of deficiency in humoral IgA and IgG subgroups. The possible presence of alterations of cellular immunity in chronic rhinosinusitis has been suggested.