Efficacy of sublingual specific immunotherapy in Cupressaceae allergy using an extract of Cupressus arizonica. A double blind study.

Background: non-injective routes of immunotherapy in respiratory allergy have being proposed as an alternative to conventional immunotherapy. We carried out a study to evaluate the clinical efficacy and effects sublingual immunotherapy (SLIT) in patient with Cupressaceae pollen respiratory allergy.

Methods: twenty patients with Cupressaceae pollen (C. sempervirens) rhinoconjunctivitis, mild asthma or both were randomly chosen for sublingual immunotherapy (10 patients) or placebo treatment (10 patients) using a double blind placebo controlled technique. We have used an extract of Cupressus arizonica because of its better stability in solution and its crossreactivity with Cupressus sempervirens. The patients underwent treatment for 12 months (from april 1999 to april 2000). Symptoms and drug scores as well as nasal provocation tests were recorded. The pollen counts were carried out, during all the same period.

Results: we found significantly lower symptom scores (p < 0.05) and drug consumption scores (p < 0.05) in the immunotherapy group than in the placebo group, during the pollen season, after the first year of therapy. Besides threshold of allergen reactivity in nasal provocation tests was increased in the active group (p < 0.01). No untoward reactions have been observed.

Conclusions: SLIT with Cupressus arizonica (pollen extracts) produced, after one year treatment, a significant improvement of allergic symptoms and a decrease of drug consumption scores and allergen-specific nasal reactivity. SLIT with Cupressus arizonica appeared to be effective and safe in the treatment of Cupressaceae pollen respiratory allergy.