Efficacy of immunotherapy to ragweed antigen tested by controlled antigen exposure.

Abstract

BACKGROUND:

Immunotherapy is a recognized component in the management of allergic rhinitis. Its efficacy has been evaluated in a number of clinical field trials. These methods of evaluation are limited by control of antigen exposure.

OBJECTIVE:

A study was designed to evaluate the efficacy of immunotherapy in ragweed-induced rhinoconjunctivitis using an environmental exposure unit.

METHODS:

Forty-three subjects were grouped into (1) immunotherapy group: ragweed-allergic subjects on maintenance ragweed immunotherapy for at least 2 years (N = 16), (2) positive control group: ragweed-allergic subjects who had never received immunotherapy (n = 16), and (3) negative control group: ragweed-nonallergic subjects (N = 11). Ragweed specific skin tests and ragweed IgE levels were obtained prior to exposure. The study was done in a room where levels of 2,500 to 3,000 grains m3 of ragweed were maintained over three hours. Symptoms were recorded every 15 minutes.

RESULTS:

Nasal symptoms in the immunotherapy group were significantly less than in the positive control group after 45 minutes (P = .025). Significant differences were not observed for ocular symptoms. Combined nasal and ocular scores were 50% less in the immunotherapy group than in the positive control group by 75 minutes (P = .039). Ragweed-specific skin tests and IgE were significantly less in the immunotherapy group than in the positive control group. Rhinoconjunctivitis symptoms in the negative control group were absent throughout.

CONCLUSIONS:

Controlled ragweed pollen exposure in this setting demonstrated that ragweed immunotherapy significantly reduced symptoms of ragweed-allergic rhinitis but had no significant effect on ocular symptoms. This system presents opportunities for additional studies on immunotherapy for allergic respiratory conditions.

• Authors: J P Donovan, D L Buckeridge, M P Briscoe, R H Clark, J H Day
• Journal: Annals of allergy, asthma & immunology : official publication of the American College of Allergy, Asthma, & Immunology (Ann Allergy Asthma Immunol) Vol. 77 Issue 1 Pg. 74-80 (Jul 1996) ISSN: 1081-1206 [Print] United States
• PMID: 8705641 (Publication Type: Clinical Trial, Controlled Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Allergens
• Plant Proteins

Topics

• Adolescent
• Adult
• Aged
• Allergens (administration & dosage, adverse effects, therapeutic use)
• Environment, Controlled
• Female
• Humans
• Immunotherapy, Active
• Male
• Middle Aged
• Plant Proteins (administration & dosage, adverse effects, therapeutic use)
• Pollen (immunology)
• Rhinitis, Allergic, Seasonal (immunology, therapy)