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Sputum induction elicits different peripheral airways responses in healthy subjects, asthma and allergic rhinitis patients

par Haccuria, Amaryllis ;Doan, Vi;Michils, Alain ;Van Muylem, Alain
Référence The European respiratory journal, 49, S59, PA1072
Publication Publié, 2015

Article révisé par les pairs

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Résumé :

Background: Induced sputum (IS) is considered as the gold standard non invasive technique to assess airway inflammation. So far, the impact of the procedure on peripheral airways function is unknown.Aim: to assess whether IS procedure is associated with airways alterations using both ventilation distribution test (single-breathwashout, SBWO) and exhaled nitric oxide (FENO) as markers of peripheral airway impairment.Methods: We measured, before and after 20' of induction with hypertonic saline, FEV1, FENO and the phase III slope (S) of the SBWO, using gases with different diffusivities, helium (He) and sulfur hexafluoride (SF6), in 17 asthma patients, 10 rhinitis subjects and 13 healthy subjects.Results: After nebulisation, all changes (Δ in %baseline) were significant except for FEV1 in healthy subjects. ΔSHe >ΔSSF6 in rhinitis (+184±198 vs 123±123%; p=0.008) and in asthma (+92±55 vs +49±36%; p=0.016) whereas ΔSHe = ΔSSF6 in healthy subjects (83±70 vs 100±80%; p=0.953). ΔFENO is larger in rhinitis (-56±14%, p=0.006) and in asthma (-56%±11%, p=0.001) than in healthy subjects (-36±13%). ΔFEV1 is greater in asthma patients (-19±14%) than in rhinitis (-6±3%, p=0.005) and in normal subjects (-6±9%; p=0.039).Discussion: SI resulted in airway alterations in the 3 subjects categories. However, the impairment location appears to be different: proximal and up to lung periphery in asthma while restricted mostly to small airways in healthy and allergic subjects.Conclusion: SI impacts peripheral airways in all subjects tested in this study. However, asthma patients differ from all other subjects by an additional response in more proximal airways.