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Abstract
Introduction and objectives Neutrophilic inflammation is a key component of many chronic lung diseases including COPD, asthma and cystic fibrosis. Despite progress in the treatment of eosinophilic airways disease neutrophilic inflammation still requires a deeper understanding of underlying biology to aid treatment development. Recent studies have identified three types of neutrophils present in broncho-alveolar lavage; banded, segmented and hypersegmented. Hypersegmented neutrophils have been shown to be elevated in patients with airways disease and linked to a reduction in lung function.1 We aimed to determine if these subtypes could be identified in the sputum of patients with three distinct lung diseases and how they differ between disease types and healthy controls.
Method Sputum samples from 24 patients with airways disease (10 asthmatics, 10 COPD and 4 CF) and 7 healthy controls was collected. Sputum was processed as per standard protocol. Neutrophils were classified based on morphology into segmented (2–4 clearly defined lobes), banded (1 lobe) and hyper-segmented (>4 lobes).
Results We were able to identify each sub-group of neutrophil in the sputum of the 4 different groups analysed. There are distinct differences in the distribution of these sub-types of neutrophils (Segmented p=0.016; Banded p=0.008; Hyper-segmented p=0.070), specifically between segmented and banded neutrophils across the 4 groups (figure 1). COPD had significantly less banded neutrophils (p=0.008) and more hypersegmented neutrophils (0.060) than healthy controls.
Conclusion There is a variation in neutrophil sub-groups in sputum across lung diseases and healthy controls. COPD patients have significantly lower proportions of immature banded neutrophils perhaps suggesting a distinct activating environment.
Reference
Lokwani, R., et al., Hypersegmented airway neutrophils and its association with reduced lung function in adults with obstructive airway disease: an exploratory study. BMJ Open, 2019. 9(1): p. e024330.
