1 Department of Pediatrics, Emory University, Atlanta, Ga.
2 Pediatrics Section of Allergy, Immunology and Rheumatology, University of Wisconsin School of Medicine and Public Health, Madison, Wis.
3 Department of Public Health Sciences, College of Medicine, Penn State University, Hershey, Pa.
4 Children's Hospital Colorado, The Breathing Institute, and University of Colorado School of Medicine, Aurora, Colo. Electronic address: Stanley.Szefler@childrenscolorado.org.