Japanese cedar pollen sublingual immunotherapy is effective in treating seasonal allergic rhinitis during the pollen dispersal period for Japanese cedar and Japanese cypress

Recent developments in immunotherapy approaches for allergic rhinitis

Allergic rhinitis (AR) poses a significant global health burden, with the potential to progress to asthma, thereby impacting patients' quality of life. Immunotherapy has demonstrated effectiveness in mitigating clinical symptoms by altering the underlying disease mechanisms of AR. This article provides a thorough review of the current state of immunotherapy for AR, encompassing various facets of immunotherapeutic strategies, elucidating their mechanisms and clinical implications. By presenting a nuanced understanding of the present landscape of immunotherapy for AR, this review aims to serve as a valuable reference for informing clinical treatment strategies. The subsequent analysis of diverse immunotherapeutic pathways offers a comprehensive understanding of their mechanisms and clinical implications. A meticulous examination is conducted on subcutaneous immunotherapy, sublingual immunotherapy, oral immunotherapy, intralymphatic immunotherapy, and innovative intravenous gold-induced autologous serum injection therapy. Each pathway is systematically elucidated, with its distinctive features and potential contributions to managing AR emphasized. In conclusion, synthesizing epidemiological insights, immunotherapeutic nuances, and pathway-specific analyses encapsulates a profound understanding of immunotherapy for AR.

From the genesis to the present: The evolution of sublingual immunotherapy for cedar pollinosis

In 2004, we started the initial attempt to evaluate the efficacy of SLIT for Japanese cedar pollinosis (JCP) using Japanese cedar (JC) pollen extract solution through a multicenter, placebo-controlled, double-blind comparative study. Based on its success in demonstrating the substantial efficacy of SLIT, we next conducted a larger-scale study by administering JC pollen to all JCP patients recruited. It was because of aiming to ascertain the effectiveness and safety of SLIT and its underlying mechanisms by comparing high- and non-responder patients. Despite limitations posed by liquid medication, significant effectiveness and safety demonstrated by the 2-year treatment served as the foundation for launching the first SLIT medicine for JCP, in 2014. Furthermore, in addition to the clearer Th1/Th2-imbalanced property in the high-responders, the possible involvement of bitter taste receptors in CD4+ T cells, apoptosis pathways in CD4+ T cells and basophils, and inducing a mast cell degranulation inhibitory molecule in the effect of SLIT was demonstrated. To solve the limitations posed by liquid medication, clinical trials evaluating JC pollen sublingual tablets started in 2014. Due to the minimal side effects, ease of administration, and convenient storage, the sublingual tablet medicine was launched in 2018. Giving the ongoing rise in demand for SLIT and considering that more than 1% of JCP patients are currently undergoing SLIT, the practical use of this treatment for multiple allergens is becoming increasingly important.

Cha o 3, a cypress pollen allergen, does not activate basophils in Japanese cypress pollinosis

Background

In Japan, pollinosis caused by the Japanese cypress (JCy) Chamaecyparis obtusa is among the very common seasonal allergies. In JCy pollinosis, Cha o 1 is the first major allergen, and Cha o 2 is the second major allergen. Recently, Cha o 3 was identified as a new JCy pollen allergen in JCy pollinosis. However, the relative contribution of Cha o 3 to JCy pollinosis compared with that of Cha o 1 and that of Cha o 2 has not been fully elucidated.

Objective

This study aimed to clarify the allergenicity of Cha o 3 compared with that of Cha o 1 and Cha o 2 in JCy pollinosis.

Methods

We recruited 27 patients with JCy pollinosis and performed the basophil activation test (BAT) with native (n) Cha o 1, Cha o 2, and Cha o 3 purified from JCy pollen. In addition, we a performed JCy-specific IgE suppression test.

Results

In the BAT, 26 of 27 patients (96%) and 18 of 27 patients (67%) showed positive basophil activation in response to n Cha o 1 and n Cha o 2, respectively, as judged by CD203c expression. Little CD203c expression in response to n Cha o 3 was seen. The presence of n Cha o 3 marginally reduced the titer levels of JCy-specific IgE.

Conclusion

Cha o 3 showed little ability to activate basophils and suppress JCy-specific IgE titers compared with Cha o 1 or Cha o 2 in patients with JCy pollinosis. Thus, Cha o 3 may not be a major allergen in JCy pollinosis.

Circulating exosomal has-miR-24-3p and has-miR-128-3p reflect early efficacy of sublingual immunotherapy in allergic rhinitis

OBJECTIVE

Sublingual immunotherapy (SLIT) can improve the symptoms of allergic rhinitis (AR) and modify its natural course, but its effectiveness varies among individuals. This study aims to analyze miRNAs from serum exosomes and evaluate their predictive values for the early response of SLIT in AR.

METHODS

RNA sequencing was performed to investigate the differential expressions of serum exosomal miRNAs between ineffective and effective AR patients who treated with SLIT. The identified candidate miRNAs were validated in two independent cohorts, and the predictive capabilities of these miRNAs and alterations of their expression levels between pre- and 1 year post-SLIT were evaluated.

RESULTS

The serum exosome-derived miRNA profiles were significantly different between the effective and ineffective groups. The five most up-regulated and down-regulated miRNAs were verified in the first validation cohort, and the results demonstrated that serum exosomal has-miR-24-3p and has-miR-206 were reduced, while has-miR-128-3p was increased in the effective group compared to the ineffective group (P < 0.05). Additionally, the receiver operating characteristic (ROC) curves revealed that serum levels of has-miR-24-3p and has-miR-128-3p displayed potential values for predicting the early efficacy of SLIT (P < 0.05). In the second validation cohort, it was observed that the baseline levels of serum exosomal has-miR-24-3p were significantly lower, while has-miR-128-3p levels were significantly higher in the effective group compared to the ineffective group (P < 0.05). After 1 year of SLIT, there was a significant decrease in serum exosomal levels of has-miR-24-3p compared to baseline. On the other hand, effective patients showed a notable increase in serum exosomal levels of has-miR-128-3p (P < 0.05).

CONCLUSION

Serum exosome-derived miRNAs have the potential to impact the efficacy of SLIT in AR patients. Among them, serum exosomal has-miR-24-3p and has-miR-128-3p show promise as biomarkers for predicting the early effectiveness of SLIT and monitoring therapeutic outcomes.

Efficacy of Japanese cedar pollen sublingual immunotherapy tablets for Japanese cypress pollinosis

Background

We previously demonstrated the efficacy of Japanese cedar (JC) pollen sublingual immunotherapy (SLIT) tablets for treating seasonal allergic rhinitis in a clinical trial (trial no. 206-2-1) that covered 5 pollen dispersal seasons from 2015 to 2019.

Objective

Our aim was to perform post hoc analysis of the 206-2-1 trial data to evaluate the efficacy of JC pollen SLIT tablets for patients with rhinitis induced by pollen from Japanese cypress (JCY), a related Cupressaceae species that has a pollen dispersal season overlapping with that of JC.

Methods

Data were analyzed for 240 patients who received placebo during the first pollen dispersal season in 2015, were then rerandomized to receive JC SLIT tablets (the PA group) or placebo (the PP group) for 18 months (the 2016 and 2017 dispersal seasons), and were observed untreated for 2 years (the 2018 and 2019 dispersal seasons). The PA and PP groups were assigned to "high" and "low" subgroups if their rhinitis symptoms were exacerbated/did not change or decreased, respectively, during the peak JCY pollen dispersal period in 2015. The mean total nasal symptom and medication scores and other outcomes were compared for the high-PP, high-PA, low-PP, and low-PA groups during the 2016 to 2019 peak JCY pollen dispersal periods.

Results

The mean total nasal symptom and medication scores were significantly lower for the high-PA and low-PA groups than for the corresponding PP groups over the 4 years of treatment and observation. JCY pollen-specific IgE levels increased in both PA groups.

Conclusion

JC pollen SLIT tablets effectively suppressed JCY pollinosis symptoms, supporting the clinical relevance of immunologic cross-reactivity between JC and JCY allergens.