Prolonged effect of allergen sublingual immunotherapy to grass pollen

Background: The prolonged effect of allergen immunotherapy is unknown, especially in older patients. Objective: The three-year effect of sublingual allergen-specific immunotherapy (AIT) to grass pollen on elderly patients with allergic rhinitis was analyzed. Methods: Thirty-eight elderly patients (63.18 +/- 3.12 yrs.) underwent AIT to grass pollen, were monitored for three years and were compared to a placebo group. AIT was performed with the use of an oral Staloral 300 SR grass extract (Stallergens Greer, London, UK) or a placebo. Symptoms and medication scores, represented by the average adjusted symptom score (AAdSS), the serum level of IgG4 to Phl p5 and the quality of life were assessed immediately after AIT and three years later. Results: After AIT, the AAdSS was significantly decreased and remained lower than in the placebo group during the three years after AIT. Serum-specific IgG4 against Phl p5 increased during the AIT trial in the study group. For the three years of observation after AIT, there were no significant changes in specific IgG4 levels against the analyzed allergens in comparison to the results immediately after AIT. The quality of life, based on the Rhinoconjunctivitis Quality of Life Questionnaire, was significantly decreased in patients who received AIT, from 1.83 (95%CI: 1.45-1.96) to 0.74 (95%CI: 0.39-1.92) (p < 0.05) to 0.82 (95%CI: 0.45- 1.04) three years after AIT. Conclusion: A prolonged positive effect after AIT to grass pollen was observed in elderly patients with allergic rhinitis. Further trials are needed to confirm this effect.