SESSION TITLE: Allergy and Airway Poster Discussions
SESSION TYPE: Original Investigation Poster Discussion
PRESENTED ON: Wednesday, October 28, 2015 at 08:45 AM - 10:00 AM
PURPOSE: The assessment of airway inflammation by sputum induction is an essential tool in the evaluation of severe asthmatic patients. Treatment guidance using eosinophil and neutrophil differential cell counts is now well established, but the significance and the interpretation of high macrophages in induced sputum (IS) is still poorly understood. The aim of this study was to assess the clinical and sputum characteristics of a series of asthma patients with inadequate control among whom IS macrophage differential counts were elevated and to compare subgroups based on their inflammometry phenotype.
METHODS: Between January 2010 and Mars 2015, we retrospectively selected all asthma patients treated at our institution with ≥ 70% macrophages in there IS differential cell counts. Subgroups of specimens with and without eosinophilic phenotype (≥ 3% eosinophils) in our population were also compared.
RESULTS: A total of 28 IS specimens (24 asthma patients) were eligible for this study. Sputum showed a mean total cell count of 3.99 ± 3.65 ×106 cells/g, a mean macrophage differential of 78% ± 7%, a mean sputum weight of 0.120 ± 0.044 g, and a mean viability of 46% ± 14%. Our population mean age was 48 years (age range, 22 to 78 years) and 92% were female. The patient characteristics were as follow: 13% and 25% were smokers and ex-smokers respectively; 50% were atopic; the mean FEV1 was 2.57 L (94% predicted); and 89% were treated with a moderate to high dose of inhaled corticosteroids on the day of their IS test. A total of 12 specimens (11 patients) had a high-eosinophils/high-macrophages phenotype (mean eosinophil differential of 8.7% ± 6.8%) and 16 specimens (16 patients) had a low-eosinophils/high-macrophages phenotype (mean eosinophil differential of 0.7% ± 0.6%). Total mean neutrophil differential was 10.3% ± 7.2%. Patients from the low-eosinophils/high-macrophages subgroup were more obstructed compared to the high-eosinophils/high-macrophages subgroup (predicted FEV1 88% vs 102% and FEV1/FVC ratio 71 vs 77 respectively).
CONCLUSIONS: In our population, patients with low-eosinophils/high-macrophages IS differential had a tendency to a more obstructive spirometry (p 0.06) compared to patients with high eosinophils/high macrophages.
CLINICAL IMPLICATIONS: Macrophages seem to play an important role in airways inflammation. Further studies targeting a high macrophages phenotype are certainly needed.
DISCLOSURE: The following authors have nothing to disclose: Philippe Lachapelle, Pascale Rioux, Lyne Despars, Pierre Ernst
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