Allergen-specific immunotherapy in childhood asthma

Immunotherapy has been shown to prevent rhinitis symptoms in seasonal allergic rhinitis, and to prevent anaphylaxis to hymenoptera and fire ant stings. The evidence supporting its effectiveness in the treatment of asthma is much more limited; it appears that clinical trials, until the past year, have only tested therapy for single allergens such as house dust mite, cats, pollen, and mold. In the past year, a double-blind placebo-controlled clinical trial was completed that tested immunotherapy with a mixture of multiple allergen extracts in 121 perennial asthmatic children. This was the first test of treatment with allergen mixtures. The trial showed that over 30% of children underwent a complete or partial remission during the 2.5 years of therapy, but the changes were almost identical in both treatment and placebo control groups. Other trials were reported that examined injection therapy using synthetic fragments of the major allergen responsible for allergic reactions to cats. In this trial, acute rhinitis and asthma during exposure to naturally occurring airborne particles of cat allergen were reduced significantly.