アレルギー性鼻炎に対する特異的免疫療法 臨床効果と効果発現機序

Abstract

Immunotherapy for allergic diseases is a time-honored method; it has been widely used for more than 90 years. However, in the opinion of many physicians, it represents a controversial treatment of allergic diseases. The exact working mechanisms behind the clinical efficacy of immunotherapy still remain to be definitively determined. In the present study, the current concept of the clinical efficacy and the working mechanisms of immunotherapy for allergic rhinitis were reviewed. Recent double-blind placebo-controlled studies have clearly demonstrated the clinical efficacy of immunotherapy for allergic rhinitis, and this therapeutic method has several unique advantages over conventional pharmacological treatment. Immunotherapy might be inferior to pharmacological treatment in the short term but, in the long term, Immunotherapy is substantially superior to pharmacological treatment in terms of clinical efficacy. The most fascinating advantage is that immunotherapy has the potential to permanentally alleviate the abnormal immunological responses and to cure the nasal symptoms for a long time even after discontinuation of the injection course. In addition, immunotherapy can prevent the onset of new sensitizations in allergic patients, and may prevent the progression of rhinitis to asthma. Therefore, immunotherapy has an interesting possibility to alter the natural history of allergic sensitization and clinical manifestations. These lines of clinical evidence would have an impact on the long-term therapeutic strategy of allergic rhinitis.Modern molecular biological techniques have suggested that immunotherapy may affect allergen-induced Th responses or cytokine profiles, but there is no general agreement among different investigators. However, IL-5 is likely to be the most important cytokine involved in the clinical efficacy of immunotherapy, and the suppression of allergen-induced IL-5 synthesis is most likely to be involved in the working mechanisms of immunotherapy.