[Clinical efficacy of sublingual immunotherapy for allergic rhinitis].

The prevalence of allergic rhinitis (AR) reached 49.2% in 2019. In particular, the prevalence of Japanese cedar (JC) pollinosis is 38.8%, and the onset age of pollinosis is becoming younger. AR is known to be a risk factor for the development of allergic asthma, a potentially life-threatening condition. Allergen immunotherapy (AIT) is a well-documented, safe, effective treatment option for respiratory allergic disease. It has been demonstrated that AIT can provide relief from clinical symptoms and that AIT has the potential to provide long-term post-treatment effect. Unlike pharmacotherapy, AIT addresses the basic immunological mechanisms that are responsible for the development and persistence of allergic conditions. Currently, two main routes of AIT administration, subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT), are commonly available. In Japan, house dust mite (HDM) SLIT tablets have been available since 2015, and JC SLIT tablet had been approved by 2018 without any age limitation. The randomized double-blind, placebo-controlled trials that included pediatric patients have been conducted in Japan. In phase II/III trail with JC SLIT tablets, treatment effect-size (improvement of clinical symptoms compared to placebo) was 46.3% after three years treatment. In addition, AR was improved in 40% (1 year) and 30% (2 years) after discontinuation of SLIT. Several future initiatives including the AIT against cedar pollen allergies were announced by Japanese government. This review covered the findings to date, including immunotherapy not only for JC pollinosis- but also for HDM-induced perennial AR.