Characteristics of Induced-Sputum Inflammatory Phenotypes in Adults with Asthma: Predictors of Bronchial Eosinophilia

Abstract

Purpose

The objectives of this study were, for patients attending a specialist asthma clinic at a tertiary care hospital, to determine, from sputum induction (SI), proportions of bronchial inflammatory phenotypes, demographic, clinical and functional characteristics of each phenotype, and the most accessible non-invasive inflammatory marker that best discriminates between phenotypes.

Patients and Methods

Included were 96 patients with asthma, attending a specialist asthma clinic at a tertiary care hospital, who underwent testing as follows: SI, spirometry, fractional exhaled nitric oxide (FeNO), blood eosinophilia, total immunoglobulin E (IgE), and a skin prick test.

Results

SI phenotypes were 46.9% eosinophilic, 33.3% paucigranulocytic, 15.6% neutrophilic, and 4.2% mixed. No significantly different clinical or functional characteristics were observed between the phenotypes. A positive correlation was observed between SI eosinophilia and both emergency visits in the last 12 months (p = 0.041; r = 0.214) and FeNO values (p = 0.000; r = 0.368). Blood eosinophilia correlated with SI eosinophilia (p = 0.001; r = 0.362) and was the best predictor of bronchial eosinophilia, followed by FeNO, and total blood IgE (area under the receiver operating characteristic curve (AUC-ROC) 72%, 65%, and 53%, respectively), although precision was only fair.

Conclusion

In consultations for severe asthma, the most frequent phenotype was eosinophilic. Peripheral blood eosinophilia is a reliable marker for discriminating between different bronchial inflammatory phenotypes, is useful in enabling doctors to select a suitable biologic treatment and so prevent asthma exacerbation, and is a better predictor of bronchial eosinophilia than FeNO and IgE values.

Keywords:

• asthma
• sputum induction
• phenotype
• eosinophilia

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Characteristics of Induced-Sputum Inflammatory Phenotypes in Adults with Asthma: Predictors of Bronchial Eosinophilia [Corrigendum]

Abbreviations

ACT, Asthma Control Test; ANOVA, analysis of variance; ATS, American Thoracic Society; AQLQ, Asthma Quality of Life Questionnaire; AUC, area under the curve; BMI, body mass index; CI, confidence interval; ED, emergency department; ELISA, enzyme-linked immunosorbent assay; EOS, absolute eosinophils; ERS, European Respiratory Society; FeNO, fractional exhaled nitric oxide; FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; GEMA, Spanish Asthma Management Guidelines; GINA, Global Initiative for Asthma; IgE, immunoglobulin E; IL-5, interleukin-5; QoL, quality of life; ROC, receiver operating characteristic; SD, standard deviation; SI, sputum induction.

Acknowledgments

The authors would like to thank Ailish M J Maher for translating and reviewing the article.

Disclosure

AC-L has received fees in the last 3 years for talks at meetings sponsored by AstraZeneca, Bial, Boehringer Ingelheim, Chiesi, Ferrer, GlaxoSmithKline, MSD, Novartis, Orion Pharma, and Sanofi, has received travel and attendance expenses for conferences from Bial, Gebro, GlaxoSmithKline, Novartis, and TEVA, and has received funds/grants for research projects from several state agencies, non-profit foundations, and AstraZeneca and GlaxoSmithKline. EC reports non-financial support from ALK, AstraZeneca, Novartis, and Menarini, personal fees from Boehringer-Ingelheim and TEVA, and personal fees/non-financial support from Chiesi outside the submitted work. This paper is part of the doctoral thesis of EC. EP has received travel and attendance expenses for conferences from Gebro Pharma, Chiesi, FAES Farma, Rovi, GlaxoSmithKline, and Sanofi, and has received funds/grants for research projects from state agencies, non-profit foundations, and Alpha Bioresearch. LS-R has received fees in the last 3 years for talks at meetings sponsored by AstraZeneca, Diater, Chiesi, and GlaxoSmithKline, has received travel and attendance expenses for conferences from Sanofi, Allergy-Therapeutics, Hal Allergy, and FAES Farma, has acted as a consultant for Sanofi, Stallergenes-Greer, GlaxoSmithKline, and AstraZeneca, and has received funds/grants for research projects from Spanish Allergy and Clinical Immunology Society (SEAIC), a non-profit foundation. VP has received fees in the last 3 years for talks at meetings sponsored by AstraZeneca, Boehringer-Ingelheim, Merck Sharp & Dohme, and Chiesi, has received travel and attendance expenses for conferences from AstraZeneca, Chiesi, and Novartis, has acted as a consultant for ALK, AstraZeneca, Boehringer, Merck Sharp & Dohme, MundiPharma, and Sanofi, and has received funds/grants for research projects from several state agencies, non-profit foundations, and AstraZeneca, Chiesi and Menarini. EFMM and ABS and SSM declare no conflicts of interest in this work.