Effect of natural grass pollen exposure on exhaled nitric oxide in asthmatic children.

Exhaled nitiric oxide (NO) is increased in exhaled breath of asthmatic patients. The aim of this study was to investigate the longitudinal changes of exhaled NO outside and during the pollen season in pollen-allergic asthmatic children. Twenty-one children (age 6 to 16 yr), with a seasonal allergic asthma sensitive to grass pollen, underwent measurements of exhaled NO and pulmonary function before (March), during (May), and after (November) the pollen season. Exhaled NO was measured by a tidal breathing method with a chemiluminescence analyzer and NO steady-state levels were recorded. The timing of the measurements during the pollen season was based on the atmospheric pollen count. Exhaled NO values of asthmatic children were compared with those of 21 sex- and age-matched healthy children. Pulmonary function and symptoms of asthma were also evaluated at each visit. The mean value of exhaled NO before the grass season was 12.7 +/- 5.1 ppb (mean +/- SD), significantly higher when compared with controls (7.8 +/- 2.7 ppb, p < 0.001). In the pollen season there was a significant (p < 0.001) twofold increase in exhaled NO (21.4 +/- 7.6 ppb) that, after the season, returned to values similar (12.8 +/- 5.8 ppb, p = NS) to those found before the season. There were no significant changes in FEV1 before and during the season (98.6% predicted versus 101% predicted, p = NS). We conclude that natural allergen exposure is related to an increase of exhaled NO in asthmatic grass pollen-allergic children even in absence of significant changes in airways function. We speculate that measurement of exhaled NO could be a sensitive noninvasive marker of asthma disease activity.

[1]  C. White,et al.  Comparison of exhaled nitric oxide, serum eosinophilic cationic protein, and soluble interleukin‐2 receptor in exacerbations of pediatric asthma , 1997, Pediatric pulmonology.

[2]  B. Gaston.  Expired nitric oxide in pediatric asthma: emissions testing for children? , 1997, The Journal of pediatrics.

[3]  E. Baraldi,et al.  Corticosteroids decrease exhaled nitric oxide in children with acute asthma. , 1997, The Journal of pediatrics.

[4]  P. Barnes,et al.  Exhaled and nasal nitric oxide measurements: recommendations. The European Respiratory Society Task Force. , 1997, The European respiratory journal.

[5]  B. Gaston,et al.  Expired nitric oxide as a marker for childhood asthma. , 1997, The Journal of pediatrics.

[6]  E. Weitzberg,et al.  Exhaled nitric oxide in paediatric asthma and cystic fibrosis. , 1996, Archives of disease in childhood.

[7]  P. Howarth,et al.  Effect of natural allergen exposure during the grass pollen season on airways inflammatory cells and asthma symptoms. , 1996, Thorax.

[8]  P. Barnes,et al.  Exhaled nitric oxide: a new lung function test. , 1996, Thorax.

[9]  D. Yates,et al.  Changes in the dose of inhaled steroid affect exhaled nitric oxide levels in asthmatic patients. , 1996, The European respiratory journal.

[10]  P. Barnes,et al.  Allergen-induced late asthmatic reactions are associated with elevation of exhaled nitric oxide. , 1995, American journal of respiratory and critical care medicine.

[11]  J. Polak,et al.  Expression of inducible nitric oxide in human lung epithelial cells. , 1994, Biochemical and biophysical research communications.

[12]  I. Adcock,et al.  Inducible nitric oxide synthase is increased in murine lung epithelial cells by cytokine stimulation. , 1994, Biochemical and biophysical research communications.

[13]  P. J. Barnes,et al.  Increased nitric oxide in exhaled air of asthmatic patients , 1994, The Lancet.

[14]  P. Howarth,et al.  Induction of nitric oxide synthase in asthma , 1993, The Lancet.

[15]  E. Weitzberg,et al.  Increased amount of nitric oxide in exhaled air of asthmatics. , 1993, The European respiratory journal.

[16]  L. Boulet,et al.  Influence of natural antigenic exposure on expiratory flows, methacholine responsiveness, and airway inflammation in mild allergic asthma. , 1993, The Journal of allergy and clinical immunology.

[17]  K. Lam,et al.  Investigation of the tendency to wheeze in pollen sensitive patients , 1992, Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology.

[18]  R. Bellomo,et al.  Mechanism of grass-pollen-induced asthma , 1992, The Lancet.

[19]  G. Larsen.  Current concepts : astma in children , 1992 .

[20]  A. B. Kay,et al.  Asthma and inflammation. , 1991, The Journal of allergy and clinical immunology.

[21]  S. Durham,et al.  Identification of activated T lymphocytes and eosinophils in bronchial biopsies in stable atopic asthma. , 1990, The American review of respiratory disease.

[22]  P. Mandrioli.  The Italian Network for the allergenic pollen monitoring , 1988 .

[23]  U. Pipkorn,et al.  The cellular response of the human allergic mucosa to natural allergen exposure. , 1988, The Journal of allergy and clinical immunology.

[24]  A. Wardlaw,et al.  Eosinophils and mast cells in bronchoalveolar lavage in subjects with mild asthma. Relationship to bronchial hyperreactivity. , 1988, The American review of respiratory disease.

[25]  N. Thomson,et al.  Asthma and increases in nonallergic bronchial responsiveness from seasonal pollen exposure. , 1983, The Journal of allergy and clinical immunology.