title: Local nitric oxide levels reflect the degree of allergic airway inflammation after segmental allergen challenge in asthmatics.
abstract: Nitric oxide (NO) levels are increased in the exhaled air of asthmatics. As NO levels correlate with allergic airway inflammation, NO measurement has been suggested for disease monitoring. In patients with asthma, we previously demonstrated that intrabronchial treatment with a natural porcine surfactant enhanced airway inflammation after segmental allergen provocation. We studied whether local levels of NO reflect the degree of allergic airway inflammation following segmental allergen challenge with or without surfactant pretreatment. Segmental NO, as well as nitrite and nitrate in bronchoalveolar lavage (BAL) fluid, was measured before and after segmental challenge with either saline, saline plus allergen, or surfactant plus allergen in 16 patients with asthma and five healthy subjects. The data were compared with inflammatory BAL cells. Segmental NO levels were increased after instillation of saline (p < 0.05), or surfactant plus allergen in asthmatics (p < 0.05), and values were higher after surfactant plus allergen compared to saline challenge. Nitrate BAL levels were not altered after saline challenge but increased after allergen challenge (p < 0.05) and further raised by surfactant (p < 0.05), whereas nitrite levels were not altered by any treatment. Segmental NO and nitrate levels correlated with the degree of eosinophilic airway inflammation, and nitrate levels also correlated with neutrophil and lymphocyte numbers in BAL. In healthy subjects, NO, nitrite, and nitrate were unaffected. Thus, segmental NO and nitrate levels reflect the degree of allergic airway inflammation in patients with asthma. Measurement of both markers can be useful in studies using segmental allergen provocation, to assess local effects of potential immunomodulators.
authors: Fraunhofer Institute of Toxicology and Experimental Medicine, Hannover, Germany.
authors: Veit J
authors: VJ
authors: Erpenbeck
authors: Rudolf A
authors: RA
authors: Jörres
authors: Marc
authors: M
authors: Discher
authors: Harald
authors: H
authors: Krentel
authors: Dimitrios
authors: D
authors: Tsikas
authors: Birgit
authors: B
authors: Luettig
authors: Norbert
authors: N
authors: Krug
authors: Jens M
authors: JM
authors: Hohlfeld
mesh_terms: D001249:Asthma / Q000378:metabolism / Q000473:pathology*; D001985:Bronchial Provocation Tests; D001992:Bronchoalveolar Lavage Fluid; D016022:Case-Control Studies; D006801:Humans; D006967:Hypersensitivity; D007249:Inflammation / Q000175:diagnosis* / Q000209:etiology; D007958:Leukocyte Count; D009566:Nitrates / Q000032:analysis; D009569:Nitric Oxide / Q000032:analysis / Q000378:metabolism*; D009573:Nitrites / Q000032:analysis; D011237:Predictive Value of Tests; D012137:Respiratory System / Q000276:immunology / Q000473:pathology*; D012720:Severity of Illness Index
chemical_list: D009566:Nitrates; D009573:Nitrites; D009569:Nitric Oxide