Sputum neutrophil elastase and its relation to pediatric bronchiectasis severity: A cross‐sectional study

Abstract

Background and Aims: Sputum neutrophil elastase (NE) is a marker of neutrophilic airway inflammation in bronchiectasis. Yet, not much is known about its role in pediatric bronchiectasis severity. This study aimed to assess the sputum NE value as a biomarker of clinical and radiological severity in pediatric bronchiectasis.Methods: This was a cross-sectional study assessing sputum NE in a total of 50 bronchiectasis patients under the age of 18 years-30 patients with cystic fibrosis (CF) and 20 patients with non-CF bronchiectasis were included. Bronchiectasis severity was assessed using Shwachman-Kulczycki (SK) score, CF-ABLE score, and CF risk of disease progression score, among CF patients, and bronchiectasis severity index (BSI) and FACED criteria among non-CF bronchiectasis patients, associations between sputum NE and bronchiectasis severity were assessed in both patient groups.Results: Sputum NE was directly correlated with C-reactive protein (r = 0.914, p < 0.001), (r = 0.786, p < 0.001), frequency of exacerbations (r = 0.852, p < 0.001) (r = 0.858, p < 0.001), exacerbations severity (r = 0.735, p = 0.002), (r = 0.907, p < 0.001), and the number of hospital admissions (r = 0.813, p < 0.001), (r = 0.612, p =0.004) in the last year among CF, and non-CF bronchiectasis patients, respectively. Additional linear correlations were found between sputum NE, CF risk of disease progression score (p < 0.001), CF-ABLE score (p < 0.001), and lower forced expiratory volume 1% of predicted (p = 0.017; ρ = −0.8) among CF patients. Moreover, sputum NE was positively correlated with the neutrophil count (p = 0.018), and BSI severity score (p = 0.039; ρ = 0.465) among non-CF bronchiectasis patients.Conclusions: Sputum NE may be considered a good biomarker of bronchiectasis severity in both CF and non-CF bronchiectasis patients, as confirmed by the exacerbations rate, CF risk of disease progression, and BSI scores.

Bacteriophage: A new therapeutic player to combat neutrophilic inflammation in chronic airway diseases

“…Another recent pediatric cross-sectional study of both CF and non-CF related bronchiectasis also found that sputum NE significantly correlated with exacerbation severity and frequency, as well as number of hospitalizations ( 77 ). For CF bronchiectasis it was specifically observed that NE correlated with risk of disease progression and increased lung function decline, while for non-CF bronchiectasis, sputum NE positively correlated with airway neutrophil counts and severity of lung disease ( 77 ). Asthma is a chronic lung disease with a much broader range of inflammatory phenotypes, and while eosinophil activity is critical to some cohorts, some of the more severe forms of asthma are primarily a result of airway neutrophilic inflammation ( 78 ).…”

“…Sputum NE was elevated during exacerbations and reduced in response to antibiotic therapy targeting organisms such as P. aeruginosa and H. influenzae, highlighting a relationship between release of NE and bacterial respiratory infection (76). Another recent pediatric cross-sectional study of both CF and non-CF related bronchiectasis also found that sputum NE significantly correlated with exacerbation severity and frequency, as well as number of hospitalizations (77). For CF bronchiectasis it was specifically observed that NE correlated with risk of disease progression and increased lung function decline, while for non-CF bronchiectasis, sputum NE positively correlated with airway neutrophil counts and severity of lung disease (77).…”

Endotypes of Paediatric Cough—Do They Exist and Finding New Techniques to Improve Clinical Outcomes

“…BAL fluid has been considered the gold standard for clinicians to assess infection and inflammation in the lungs, with secretions providing an optimal source of inflammatory cells directly from the lower airway [104]. Research has shown that neutrophil elastase from BAL predicted pulmonary exacerbations in young children with cystic fibrosis [105].…”

“…Unlike BAL fluid, expectorated sputum has been used as a less invasive alternative to measure airway inflammation [110]. The measurement of sputum neutrophil elastase has been suggested as a promising biomarker for bronchiectasis severity, with increased levels indicating the need for aggressive management [104]. However, most children have difficulties in expectorating, and most downstream assessments of sputum require a large yield.…”

“…However, most children have difficulties in expectorating, and most downstream assessments of sputum require a large yield. One technique to produce sputum is induction with nebulized hypertonic saline [104].…”