Pilot study of intratonsillar immunotherapy for timothy grass pollen.

BACKGROUND: Allergen-specific immunotherapy (AIT) is a treatment for upper airway allergy that is resistant to optimal symptomatic management. Traditionally, it is administered via repeated subcutaneous injections (subcutaneous immunotherapy, SCIT) or daily sublingual tablets/drops (sublingual immunotherapy, SLIT) for 3–5 years. Direct allergen exposure has also been attempted through intralymphatic immunotherapy (ILIT) via injections into inguinal lymph nodes. OBJECTIVE: To evaluate the clinical and immunological effects of intratonsillar allergen immunotherapy for timothy grass pollen allergy. METHODS: This uncontrolled, prospective, cross-sectional, pilot study included 12 patients with allergic rhinoconjunctivitis to timothy grass pollen, refractory to symptomatic treatment. Each patient received a dose of 1 mL 10,000 SQ-U standardized, aluminum hydroxide-adsorbed depot grass pollen extract (Alutard, ALK-Abelló, Denmark) for SCIT at four-week intervals. Follow-up was conducted 18 months after the final injection. RESULTS: During the first two injections, 7 out of 12 patients developed systemic adverse reactions within minutes, including generalized itching, edema with rashes, tiredness, and mild dyspnea, all resolving spontaneously within two hours without epinephrine administration. Patients reported significant symptom improvement, including reduced nasal congestion, rhinorrhea, sneezing, mouth breathing, and ocular itching. Immunologically, the antibody responses to timothy pollen (IgE and IgG4) showed similarities to patterns previously described for SLIT, SCIT and ILIT. CONCLUSIONS: Intratonsillar depot grass pollen extract injections improved symptoms of timothy-induced allergic rhinoconjunctivitis. It also induced immunological alterations characteristic for allergen-specific immunotherapy. To our knowledge, this is the first study to report the intratonsillar administration of AIT for grass pollen allergy.