Patients with Exacerbated Asthma Have Unique Nasal Microbiomes

Patients with exacerbated asthma have a distinct nasal microbiome from those with controlled asthma and those without an asthma diagnosis, according to a recent study.

Although the lower airway microbiome has been frequently studied in asthma, the nasal microbiome has received much less scrutiny, lead author Supinda Bunyavanich, MD, associate professor in the Department of Pediatrics-Allergy/Immunology, at the Icahn School of Medicine at Mount Sinai, New York, told MD Magazine®.

“Given the possible roles for upper airway microbiota in asthma pathobiology, our study fills an important niche in airway microbiome research and ease of airway sampling for monitoring and investigation of asthma,” said Bunyavanich.

The microbiome has been a rich area of research since its discovery in the late 1990s. It consists of the genetic material, including bacteria and viruses, which live on and inside human bodies.

According to the University of Washington’s Center for Ecogenetics and Environmental Health, the genes of one person’s microbiome contains 200 times the number of genes than the human genome itself. Much of the bacteria in the microbiome are beneficial, responsible for many biological functions, including food digestion and regulation of the immune system.

The study included 72 participants, aged 10 to 73 years. Racial demographics included Latinos (34.7%), African-Americans (27.8%), Caucasians (19.4%), Asian (5.6%) and Other (12.5%).

The group was then divided into those with exacerbated asthma (20), nonexacerbated asthma (31) and nonasthmatics (21). Recruitment occurred from the Mt. Sinai Health System’s emergency department clinics in New York City, over a 12-month period.

The results showed that, at the phylum level, Bacteroidetes and Proteobacteria were significantly elevated in those with both nonexacerbated and exacerbated asthma, compared to nonasthmatics (Wilcoxon-Mann-Whitney, r = .033, P = 5.1x10^-3 and r = 0.29, P = 1.4x10^-2, respectively).

There were also differences in nasal bacteria composition based on asthma activity. Prevotella (Bacteroidetes), Alkanindiges (Proteobacteria), and Gardnerella (Actinobacteria), were elevated in those with exacerbated asthma, while Dialister (Firmicutes) was higher in those with nonexacerbated asthma.

“Our findings lend insight into mechanistic considerations about host and microbiome interactions in asthma,” said Bunyavanich. “This may enable the development of nasal microbial markers of asthma for detection and disease monitoring.”

Bunyavanich adds that further studies should focus on populations from multiple health care centers.

The study, “The nasal microbiome in asthma,” was published in The Journal of Allergy and Clinical Immunology.