Should lung biopsies be performed in patients with severe asthma?

Abstract

Asthma, and severe asthma, in particular, is increasingly recognised as a heterogeneous disease. Identifying these different phenotypes of asthma and assigning patients to phenotype-specific treatments is one of the current conundrums in respiratory medicine. Any diagnostic procedure in severe asthma (or any disease) should have two aims: 1) better understanding or identifying the diagnosis, and 2) providing information on the heterogeneity of asthma phenotypes to guide therapy with the objective of improving outcomes. Lung biopsies can target the large and small airways as well as the lung parenchyma. All compartments are affected in severe asthma; however, knowledge on the distal lung is limited. At this point, it remains uncertain whether lung specimens routinely add diagnostic information that is unable to be obtained otherwise. Indeed, whether a lung biopsy is indicated in the workup of a patient with severe asthma remains an individual decision. It is hoped this review will support rational decision-making and provide a detailed synopsis of the varied histopathological features seen in biopsies of patients with a diagnosis of severe asthma. Due to limited data on this topic this review is primarily based on opinion with recommendations arising primarily from the personal experience of the authors.

Bronchoscopic mucosal cryobiopsies as a method for studying airway disease

“…As a consequence of the inadequacy of the currently available methods for endobronchial sampling, obtainment of lung biopsies in severe asthma has been proposed . As seen with transbronchial cryobiopsies in interstitial lung disease, we believe the cryotechnique can be used for obtainment of both trans and endobronchial biopsies to support new findings to better understand pathophysiological changes in the airways as was the case with lung biopsies .…”

A Comprehensive Evaluation of Nasal and Bronchial Cytokines and Chemokines Following Experimental Rhinovirus Infection in Allergic Asthma: Increased Interferons (IFN-γ and IFN-λ) and Type 2 Inflammation (IL-5 and IL-13)

“…Indeed, the need for new biomarkers of inflammation in asthma has been highlighted in a recent study of an IL-13 neutralising monoclonal antibody (Brightling et al, 2015), where measurement of airway IL-13 levels might be a more relevant biomarker than blood eosinophils and serum periostin. Since endobronchial mucosal biopsy in severe asthma is sometimes clinically indicated (Doberer et al, 2015), bronchosorption could be performed during the same bronchoscopy procedure. Hence, we speculate that precision sampling of airway lining fluid, enabling assessment of interferon and type 2 immune responses in the nose and bronchi, has the potential for selection and monitoring of asthmatics in relation to monoclonal antibody therapy.…”

Aberrant epithelial remodeling with impairment of cilia architecture in non-cystic fibrosis bronchiectasis

“…This is an important area to investigate as different lung compartments play different roles and interact to cause lung damage. In recent years, the small airway (<2 mm in diameter) is recognized to be the major site of airflow limitation in chronic inflammatory airway diseases such as asthma and chronic obstructive pulmonary disease (COPD) (11,12). However, small airways haven't been well studied in non-CF bronchiectasis as thoracic high-resolution computed tomography (HRCT) and spirometric tests cannot accurately assess small airway dysfunction.…”