aDivisions of Pediatric Pulmonology

bAllergy & Immunology, Department of Pediatrics, University of North Carolina School of Medicine

cChildren's Research Institute, University of North Carolina, Chapel Hill, North Carolina, USA

Correspondence to Michelle L. Hernandez, MD, 5008C Mary Ellen Jones Building 116 Manning Drive, CB #7231 Chapel Hill, NC 27599-7231, USA. Tel: +1 919 962 5136; fax: +1 919 962 4421; e-mail: [email protected]