The Role of Indoor Air Microbiomes on Lung Health and Asthma

Alex Moir ’23

Figure 1: New research suggests the indoor air microbiome may affect asthma severity.

Asthma is a chronic inflammatory disease affecting the lungs that can vary in severity and symptoms, usually characterized by difficulty breathing and periodic lung spasms referred to as asthma “attacks.” The direct cause of asthma is unclear; however, recent research has pointed to the human lung myco- and microbiomes as contributing factors. The mycobiome refers to the community of fungi in the lower respiratory tract, while the microbiome refers to the similarly located community of bacteria. These resident fungi and microbes play important regulatory roles in maintaining respiratory health. In a recent study, researcher Louise-Eva Vandenborght and her team investigated how indoor microbial exposure influenced lung microbiome diversity and the impact of lung microbiome diversity on asthma symptoms and severity in patients. 

Using inflammatory markers, the researchers characterized 55 patients with asthma as having type 2 inflammation high or low asthma. Type 2 inflammation is characterized by a nonspecific allergic response, with groups of immune cells, such as mast cells, releasing cytokines and histamine. The patients were given electrostatic dust collectors (EDCs) to collect indoor microbe and fungi samples from the air in their homes over a 10 week period. Out of the 55 patients, 22 were able to produce sputum samples, a mix of saliva and mucus coughed up from the lower respiratory tract. DNA was extracted from the sputum and EDC samples, followed by qPCR amplification of the DNA sequences, and Next Generation Sequencing to determine what species of fungi and bacteria made up each sample. Results showed that type 2 high asthma samples had lower overall mycobiome diversity and higher microbiome diversity compared to type 2 low samples, as well as higher prevalence of fungal and bacterial species known to be associated with the development of asthma and other inflammatory diseases. Additionally, indoor mycobiome samples and patient lung mycobiome samples correlated significantly in their species composition only during periods of exacerbated asthma in type 2 high patient samples, suggesting that particular fungal species in the air may be responsible for inducing chronic allergic responses in such patients.

The team’s findings demonstrate a clear role of indoor air microbiome and mycobiome exposure in affecting patient asthma type and severity. These insights could both aid in the development of possible environmental interventions against asthma, as well as provide the groundwork for further research and understanding of asthma pathology. 

Works Cited:

[1] L. Vandenborght, et al., Type 2–high asthma is associated with a specific indoor mycobiome and microbiome. Allergy and Clinical Immunology 147, 1-16 (2020). doi: 10.1016/j.jaci.2020.08.035

[2] Image retrieved from:


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