This Instructional Course provides an update from Japan on recent advances in allergen immunotherapy and intranasal vaccine for upper airway diseases. First, Japan’s national strategy for allergic rhinitis (AR) will be introduced, with a focus on early detection through ICT-based school health platforms and the timely initiation of sublingual immunotherapy (SLIT). Second, recent clinical evidence for Japanese cedar pollen SLIT will be reviewed, including its effects on nasal symptoms, sleep disturbance, and quality of life (QOL), as well as the additional benefits of dual SLIT in polysensitized patients. Finally, novel intranasal vaccine strategies against nontypeable Haemophilus influenzae will be discussed, highlighting the induction of protective mucosal and systemic immunity for the prevention of acute otitis media. Together, these topics illustrate current Japanese contributions to disease modification, mucosal immunotherapy, and prevention.

The burden of allergic rhinitis in Japan and the role of sublingual immunotherapy

Masafumi SAKASHITA, University of Fukui, JAPAN

AR affects nearly half of the Japanese population, with Japanese cedar pollinosis affecting 38.8%. The increasing prevalence among children has become a major public health concern. In response, Japan has launched a national strategy promoting pollen reduction, early diagnosis, and disease prevention. The Japanese AR guideline recommends allergen avoidance, pharmacotherapy, surgery, biologics, and SLIT, the only disease-modifying treatment that can alter the natural course of allergic disease. This presentation highlights Japan’s efforts to promote early detection through school-based digital health platforms using ICT and real-world data. Combining early diagnosis with SLIT may reduce the long-term burden of AR and support disease prevention in younger generations.

Current clinical evidence for sublingual immunotherapy in Japanese cedar pollinosis

Yoshiaki Kitamura, University of Tokushima, Japan

This study evaluated the clinical efficacy of SLIT for Japanese cedar (JC) pollinosis under various clinical conditions. Nasal symptoms, sleep disturbance, and QOL were assessed, and SLIT was compared with preseasonal antihistamine therapy. The efficacy of dual SLIT with JC pollen and house dust mite allergens was also investigated. SLIT significantly improved nasal symptoms, sleep, and QOL, showing greater clinical benefit than antihistamine therapy during high pollen seasons. Compared with JC pollen SLIT alone, dual SLIT provided greater improvement in nasal obstruction during the JC pollen season. Overall, SLIT provides broad clinical benefits, with dual SLIT offering additional therapeutic advantages for polysensitized patients.

Induction of mucosal immunity against nontypeable Haemophilus influenzae via intranasal vaccination.

Takashi Hirano, University of Oita, Japan

Nontypeable Haemophilus influenzae (NTHi) is a major cause of pediatric acute otitis media. This study evaluated the efficacy of intranasal NTHi vaccination. BALB/c mice were intranasally immunized with NTHi outer membrane proteins combined with adjuvants (MPL) or an anti-PD-L1 antibody. Antibody titers, tissue immune responses, and bacterial clearance were analyzed.The vaccine successfully induced antigen-specific mucosal IgA—including within the middle ear mucosa—and systemic IgG. Adjuvants and anti-PD-L1 modulation significantly boosted antibody production, enhanced tissue immune responses, and accelerated bacterial clearance following live challenge. Intranasal vaccination effectively induces protective mucosal and systemic immunity against NTHi. Combining antigens with innate adjuvants or immune checkpoint modulators is a promising strategy to prevent acute otitis media.