Immunotherapy Prevents Asthma Over Long Term in Children With Allergic Rhinitis

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August 10, 2007 ? Specific immunotherapy for allergic rhinitis in children prevents the development of asthma for up to 7 years after treatment ends, according to results of a follow-up of the Preventive Allergy Treatment (PAT) study.

The PAT study investigated whether the clinical effects of 3 years of subcutaneous specific immunotherapy persist in children with seasonal allergic rhinoconjunctivitis caused by birch and/or grass pollen allergy as they grow up. The results at 10 years after the start of treatment appear in the August issue of Allergy.

Dr. L. Jacobsen from ALK-Abello, Horsholm, Denmark and colleagues evaluated the primary clinical effect and secondary preventive effect on the development of asthma in 147 participants in the PAT study 7 years after termination of specific immunotherapy.

Among 117 children who were free of asthma at baseline, those treated with SIT were 4.6 times more likely than those treated with placebo to remain free of asthma during the 10 years of follow-up, the authors report.

Specifically, 24 of 53 control patients developed asthma, compared with 16 of 64 patients in the specific immunotherapy group.

The beneficial clinical effect on conjunctivitis and rhinitis following specific immunotherapy also persisted 7 years after completion of 3 years of treatment.

Neither group showed significant bronchial hyperresponsiveness after 5 or 10 years, the investigators say, and there were no differences between the treatment and placebo groups in bronchial responsiveness to methacholine (as measured by change from baseline).

"This 10-year follow-up study demonstrates that specific immunotherapy for 3 years with high-dose standardized allergen extracts shows persistent long-term effect on clinical symptoms after termination of treatment and long term, preventive effect on later development of asthma in children with seasonal rhinoconjunctivitis," Dr. Jacobsen and colleagues conclude.

"In this light," they write, "specific immunotherapy should be recognized not only as first line therapeutic treatment for allergic rhinoconjunctivitis but also as secondary preventive treatment for respiratory allergic disease."

Allergy. 2007;62:943-948.