T cells and the immune response: down-regulation via mucosal exposure.

It appears that more attention is again being paid to regulatory T cells. While the model of T helper (TH) 1 and TH2 pathways has helped in the understanding of how inflammation of various sorts occurs, regulatory T cells, which are antigen specific, will have to be taken into account in the future. It is reasonable to predict that when the forthcoming information about regulatory T cells is combined with the information on lung inflammation that already exists, new therapeutic approaches will be developed. The potentially deleterious immunoglobulin E and other T cell-dependent immune responses in the lung may eventually be downregulated either by local (nasal or respiratory) exposure to low doses of antigen or through their introduction via the gastrointestinal tract (oral). Exciting times are ahead in terms of newer therapies for old diseases such as rhinoconjunctivitis and asthma.