Controlled study of preseasonal immunotherapy with grass pollen extract in tablets: effect on bronchial hyperreactivity

Abstract

Background: Based on experimental results, the sublingual route for immunotherapy (IT) has been accepted as a viable alternative to the injection route, but few data on the effects on asthma are so far available.

Objective: In the present open controlled trial we evaluated whether a preseasonal IT with grass polllen in orosoluble tablets added to pharmacotherapy, can improve non-specific bronchial hyperreactivity. The clinical efficacy was evaluated as well.

Methods: Fifty-one patients (mean age 27.4 years) suffering from rhinoconjunctivitis and/or mild-intermittent/mild-persistent asthma due to grass pollen were allocated to two groups receiving pharmacotherapy alone (n = 25) or pharmacotherapy plus IT in tablets (n = 26). A methacholine test was performed in asthmatic subjects out of the pollen seasons at baseline and after 3 years of treatment. Symptom scores and drug intake were evaluated during pollen seasons by a diary card.

Results: A significant increase p = .01) in the PD20 at the methacholine test was observed in the IT group compared to the control group. A significant clinical improvement both for rhinitis (p = .001) and asthma (p = .001) was observed in the IT group, and this improvement was paralleled by a clear-cut reduction of drug intake (p = .001). An improvement of rhinitis symptoms without modification of drug intake was seen in the control group (p = .01) The treatment was well tolerated and no relevant side effect was reported during the 3 years.

Conclusion: The investigated local IT reduced the nonspecific bronchial hyperreactivity. Furthermore, it was clinically effective and safe.