Efficacy and safety of intratonsillar immunotherapy for allergic rhinitis: A randomized, double-blind, placebo-controlled clinical trial

Background: A lower adherence rate existed in patients receiving allergen-specific immunotherapy due to its lengthy period and adverse effects even though it is the only curative treatment for IgE-mediated allergies. Therefore, exploring innovative allergen-specific immunotherapy routes is necessary. Objective: To explore the efficacy and safety of the intratonsillar injection of house dust mite (HDM) extract in patients with HDM-induced allergic rhinitis (AR). Methods: A randomized, double-blind, placebo-controlled clinical trial was conducted. A total of 80 patients with HDM-induced AR were randomized to receive 6 intratonsillar injections with HDM extract or placebo in 3 months. The total nasal symptom score (TNSS), visual analogue scale of nasal symptoms, combined symptom and medication score, mini rhinoconjunctivitis quality of life questionnaire, and serum allergen-specific IgG4 to Dermatophagoides pteronyssinus were all monitored at baseline and 3 months, 6 months, and 12 months after the treatment was finished. The intent-to-treat and per-protocol set (PPS) are both analyzed. Results: The primary end points TNSS and DTNSS were improved significantly at 3 months after the patients with AR finished a 3-month 6-injection intratonsillar immunotherapy compared with those in the placebo treatment in both intent-to-treat and PPS. Results of visual analogue scale, combined symptom and medication score, and mini rhinoconjunctivitis quality of life questionnaire were also improved significantly at 3 months after the treatment in PPS. However, the improvement effect of intratonsillar immunotherapy at 6 and 12 months was limited and uncertain based on the data. The increase of serum Der p IgG4 in the active group was significantly higher than that in the placebo group at 3, 6, and 12 months after the treatment was finished. Adverse events were monitored, and no systemic adverse reactions were observed. Conclusion: The clinical trial revealed that intratonsillar injection with HDM extract was safe and effective in patients with AR. Optimizing the protocol and allergen formulations is expected to increase and maintain the efficacy of this novel approach. (c) 2023 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)