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NIAID Clinical Studies Offer Relief for Asthma Sufferers
NIAID vigorously pursues research on asthma and allergic diseases by supporting cooperative clinical studies and research within NIAID labs. This work ranges from demonstration and education projects that teach people how to reduce allergens in the home to identifying causes of respiratory illness to exploring new treatments for allergies.
In 2001, NIAID’s Inner-City Asthma Study (ICAS), co-funded with the National Institute of Environmental and Health Sciences, concluded a trial that tested the effectiveness of two environmental interventions in reducing asthma morbidity in inner-city children with moderate to severe asthma.
The first intervention was a feedback letter that ICAS project members provided to the primary care physicians of the children with asthma. The letter included detailed information on participants’ recent asthma symptoms and medication use, as well as ICAS recommendations for changes in therapy.
The second intervention was an in-home visit from trained environmental counselors, who educated families about asthma risk factors such as tobacco smoke and allergens from cockroaches, house dust mites, mold, furry pets, and rodents. Participating families received air filters and allergen-free mattress and pillow covers and bed sheets. In some cases, professional pest control was provided to exterminate cockroaches and eliminate cockroach allergens.
A total of 937 children between the ages of 5 and 11 years were evaluated during a one-year intervention period and then a one-year follow-up period. At the conclusion of the study, ICAS investigators found that the second intervention, teaching families how to reduce indoor allergen exposure, reduced symptoms associated with asthma.1 The first intervention, the physician feedback letter, resulted in reduced unscheduled doctors’ and emergency room visits but no change in symptoms.2
Acute and chronic asthma occur when two types of white blood cells involved in allergies and asthma, called mast cells and eosinophils, release cysteinyl-leukotrienes (cys-LTs). There are two known receptors for cys-LTs, but researchers in the NIAID Asthma and Allergic Diseases Cooperative Research Centers program may have found a third receptor.3 The presence of a third receptor could explain why existing leukotriene inhibitor drugs respond in varying ways when managing bronchial asthma and reveal a new target for treating asthma.
An important NIAID intramural study is examining how allergen immunotherapy (AIT) reduces or prevents reactions to allergens such as pollen, dust, or cat dander. People who undergo AIT treatments receive gradually larger doses of an allergen to promote immune tolerance. Although AIT is only modestly effective in treating asthma, it is the only known therapy that treats allergic asthma disease and not just its symptoms.
Certain types of white blood cells, called Th2 cells, produce substances that contribute to the development of allergies, while others, called Th1 cells, produce substances that can inhibit the development of allergies. This study will determine whether AIT changes how the immune system responds to allergens by reducing the number of Th2 cells or by converting them into Th1 cells. A better understanding of the mechanisms underlying AIT might help scientists to discover new approaches to treating allergies and asthma.
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Last Updated February 08, 2012
Last Reviewed October 24, 2006