The microbiome in asthma: Role in pathogenesis, phenotype, and response to treatment

Abstract

Objective: To synthesize evidence on the role of microbiota in asthma pathogenesis, phenotype, and treatment outcomes, and to provide perspective on future research directions and challenges.

Data sources: Studies identified from a PubMed search, including all or some of the terms "asthma," "microbiome," "microbiota," "gut," "airway," "respiratory," "lung," "viral," and "fungal".

Study selections: Studies included and referenced based on the authors' opinion of the study design and methods, value of the research questions, and the relevance of the results to the objective of the article.

Results: Many studies have demonstrated an important role for intestinal or upper airway microbiota in mediating the pathogenesis of childhood asthma. Fewer but robust studies have implicated a role for lower respiratory tract microbiota in adult asthma phenotype, including effects of treatments. Bacterial and fungal members of the respiratory microbiota are associated with and may drive specific molecular phenotypes of asthma in adults.

Conclusion: Current evidence supports the role of human microbiota changes in shaping asthma risk, pathogenesis, and clinical presentation. Further understanding of how microbiota functionally mediate these aspects in clinically relevant contexts will require better integration of advanced scientific tools, analytic methods, and well-designed clinical studies. These efforts should be pursued with a systems-level perspective of the complex interactions between human hosts and their microbiomes, and the impact on these interactions of changes in environmental and lifestyle factors across the lifespan.

Figure 1.

Factors that can be critical influences on asthma pathogenesis and phenotype through effects on the gut and/or respiratory microbiomes. Mechanisms are understood for some but not all interactions.