Expired nitric oxide and airway reactivity in infants at risk for asthma

• Published in: Journal of allergy and clinical immunology 2008-10, Vol.122 (4), p.760-765
• Main Authors: Tepper, Robert S., MD, PhD, Llapur, Conrado J., MD, Jones, Marcus H., MD, PhD, Tiller, Christina, RRT, Coates, Cathy, RN, Kimmel, Risa, RN, Kisling, Jeffrey, RRT, Katz, Barry, PhD, Ding, Yan, MS, Swigonski, Nancy, MD, MPH
• Format: Article
• Language: English
• Subjects: Age; airway reactivity; Allergies; Allergy and Immunology; Asthma; Asthma - etiology; Asthma - metabolism; Atopy; Babies; Biological and medical sciences; eczema; Eczema - complications; Eczema - metabolism; Families & family life; Female; Food Hypersensitivity - complications; Food Hypersensitivity - metabolism; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Illnesses; Immunoglobulin E - blood; Infant; Male; Medical sciences; Milk; Nitric Oxide - analysis; Nitric Oxide - metabolism; Premature birth; Pulmonary Ventilation; Respiratory Sounds; Risk Factors; Sarcoidosis. Granulomatous diseases of unproved etiology. Connective tissue diseases. Elastic tissue diseases. Vasculitis; Smoking
• ISSN: 0091-6749; 1097-6825
• DOI: 10.1016/j.jaci.2008.07.022

Background Family histories of atopy, as well as histories of atopic dermatitis and food allergy, are important risk factors for an infant to have asthma. Although atopic sensitization appears to contribute to the development of asthma, it is unclear when the airways become involved with the atopic process and whether airway function relates to the atopic characteristics of the infant. Objective We sought to evaluate whether atopic infants without prior episodes of wheezing have increased expired nitric oxide (eNO) levels and heightened airway reactivity. Methods Infants with eczema were recruited, and atopic status was defined by specific IgE levels to foods or aeroallergens and total IgE levels. eNO, forced expiratory flow at 75% exhaled volume (FEF75 ), and airway reactivity to inhaled methacholine were measured in sedated infants. Airway reactivity was quantified by using the provocative concentration to decrease FEF75 by 30%. Results Median age for the 114 infants evaluated was 10.7 months (range, 2.6–19.1 months). Infants sensitized to egg or milk compared with infants sensitized to neither egg nor milk had lower flows (FEF75 : 336 vs 285 mL/s, P < .003) and lower lnPC30 (mg/mL) provocative concentrations to decrease FEF75 by 30% (−0.6 vs −1.2, P < .02) but no difference in eNO levels. Infants with total serum IgE levels of greater than 20 IU/mL had higher eNO levels compared with infants with IgE levels of 20 IU/mL or less (14.6 vs 11.2 ppb, P < .023) but no difference in forced flows or airway reactivity. Conclusions Our findings suggest that atopic characteristics of the infant might be important determinants of the airway physiology of forced expiratory flows, airway reactivity, and eNO.