1 Division of Asthma and Allergic Disease, Park Nicollet Health Services, St. Louis Park, Minn. Electronic address: anickels@alumni.nd.edu.
2 Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, Mass.
3 Division of Allergy and Immunology, Nationwide Children's Hospital, Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio.