Clinical Studies
The Inner-City Asthma Study, cofunded by NIAID and the National Institute of Environmental and Health Sciences (NIEHS), was a from seven inner cities. The environmental intervention decreased multicenter, randomized controlled trial that tested the effectiveness of two interventions in reducing asthma morbidity among inner city children with moderate to severe asthma. The study concluded in 2001. One intervention provided physicians with more detailed and up-to-date information on participants’ recent asthma symptoms and medication use. The other intervention reduced exposure to environmental triggers such as tobacco smoke, allergens derived from cockroaches, house dust mites, mold, furry pets, and rodents. Participants were evaluated during both the 1-year intervention period and a 1-year followup period. The study included 937 children between the ages of 5 and 10 years, exposure to indoor allergens, including cockroach and house dust mite and tobacco smoke, resulting in reduced asthma associated morbidity.22 The physician feedback letter resulted in no change in symptoms, but a 24 percent reduction in emergency room visits.23
One project within the Inner-City Asthma Study evaluated the impact of indoor and outdoor fine particles and co-pollutants on respiratory illnesses. Recently published data from this study, which was funded by NIAID, NIEHS, and the U.S. Environmental Protection Agency, demonstrate that approximately 25 percent of indoor particle concentration is contributed by outdoor particles. These data also show that smoking is the major source of indoor particles and that indoor concentrations of fine particles peak in the late evening in homes where smoking occurs, perhaps reflecting the influence of after-dinner smoking. Analysis of data pertaining to the effects of particle concentrations on asthma symptoms is currently underway.
An important NIAID intramural study is examining how allergen immunotherapy (AIT) reduces or prevents reactions to allergens such as pollen, dust, or cat dander. Although the efficacy of AIT in asthma is modest, it is nonetheless the only disease-modifying therapy for allergic asthma currently known. 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 the immune response to allergens by reducing the number of Th2 cells or by converting them into Th1 cells. A better understanding of the mechanisms underlying the clinical effectiveness of AIT might help scientists to discover new approaches to treating allergies and asthma.
All federally and privately supported clinical trials: ClinicalTrials.gov
References
22 Morgan WJ et al. Results of a home-based environmental intervention among urban children with asthma.N Engl J Med. 351:1068-80 (2004).
23 Katten M Et al. Cost-effectiveness of a home-based environmental intervention for inner-city children with asthma. J Allergy Clin Immunol. 116(5):1058-63 (2005).
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