Newswise — A new study provides support for the combined therapy of inhaled corticosteroids and antileukotriene drugs in the treatment of asthma.

The study, "Bronchial responsiveness to leukotriene D4 is resistant to inhaled fluticasone propionate" , can be found in the July 2006 issue of the Journal of Allergy and Clinical Immunology (JACI), the peer-reviewed journal of the American Academy of Allergy, Asthma and Immunology (AAAAI).

Pär Gyllfors, MD, Karolinska University Hospital, Solna, Stockholm, Sweden, and colleagues investigated whether bronchial responsiveness to leukotriene D4 (a naturally-occurring substance that is increased in many asthmatic lungs, and that produces allergic reactions much like a histamine) is reduced by a commonly prescribed inhaled corticosteroid treatment, fluticasone propionate.

The researchers conducted their research by having the study's 13 volunteers participate in an inhalation challenge with methacholine (a drug that stimulates secretions and smooth muscle activity) and leukotriene D4 on consecutive days before and after two weeks of treatment with inhaled fluticasone twice daily.

Study results showed that although the fluticasone propionate therapy vs. placebo for two weeks caused a significant improvement (reduction) in methacholine sensitivity (a measure of airway hyper-responsiveness) and in exhaled nitric oxide (a naturally exhaled gas that increases in concentration in inflamed asthmatic lungs), it had no effect in blocking the broncho-constriction that occurs when leukotrienes are inhaled (nor does it influence the production of leukotrienes, as measured in the urine). The clinical implication of the study, according to the authors, supports synergistic therapy with an inhaled corticosteroid as well as an oral antileukotriene for certain, persistent asthmatic patients.

The AAAAI is the largest professional medical specialty organization in the United States representing allergists, asthma specialists, clinical immunologists, allied health professionals and others with a special interest in the research and treatment of allergic disease. Allergy/immunology specialists are pediatric or internal medicine physicians who have elected an additional two years of training to become specialized in the treatment of asthma, allergy and immunologic disease. Established in 1943, the AAAAI has more than 6,000 members in the United States, Canada and 60 other countries. The AAAAI serves as an advocate to the public by providing educational information through its Web site at

For more information and access to the archive of past JACI news releases, visit the Media Center of the AAAAI Web site,

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Journal of Allergy and Clinical Immunology (Jul-2006)