# Longitudinal changes of the sputum microbiome in adult asthma and its association with asthma exacerbations

> **NIH NIH R21** · WASHINGTON UNIVERSITY · 2024 · $233,250

## Abstract

Abstract
About 18.7 million adults have asthma in the United States. The airway microbiome has emerged as an essential
regulatory factor in asthma immune responses. Patients with asthma harbor altered bacterial compositions in
their airways compared to healthy individuals; the most important alteration is a decrease in beneficial
commensals and an increase in pathogenic bacteria. Our study that compared sputum bacterial compositions
between adult asthma patients and healthy individuals revealed that asthma was associated with microbial
alterations at the community and taxa levels, including changes in the abundances of Streptococcus salivarius,
Lactobacillus species, and Haemophilus species. These results are consistent with those of previous
independent human studies and have plausible biological mechanisms. However, current data on the airway
microbiome in adult patients with asthma are predominantly derived from case-control and cross-sectional
studies, which cannot evaluate temporal relationships between airway microbiota alterations and longitudinal
asthma morbidity. There is strong evidence from multiple longitudinal studies on chronic obstructive pulmonary
disease (COPD) suggesting that the airway microbial composition is closely correlated with asthma
exacerbations and immune responses. However, it remains to be established whether these states are
correlated in asthma. New study approaches are needed to fill this important knowledge gap. Here, we will
perform a longitudinal cohort study with adult patients with asthma and healthy controls. We will collect induced
sputum samples at several time points over 6 months and additional sputum samples during asthma
exacerbations. We will utilize an FDA-approved electronic inhaler sensor system that will be attached to a rescue
inhaler to identify asthma exacerbations and collect induced sputum soon after these exacerbations (within 24
hours). We will perform 16S ribosome RNA gene sequencing and shotgun metagenomic sequencing to identify
the sputum bacterial community and relative abundance of different species. We have two aims in this study.
Aim 1 is to evaluate compositional fluctuations of the sputum microbiome over time. Aim 2 is to Characterize
temporal relationships of the sputum microbiome with asthma exacerbations. This proposed study will enable us
to longitudinally evaluate the relationship of airway bacteria with asthma morbidity and characterize the changing
dynamic patterns of the airway microbial community during asthma exacerbations. Successful completion of this
study could provide valuable insights and evidence for a scaled study to include immune biomarkers and clinical
indicators for further investigation.

## Key facts

- **NIH application ID:** 10810994
- **Project number:** 1R21AI178627-01A1
- **Recipient organization:** WASHINGTON UNIVERSITY
- **Principal Investigator:** James Krings
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $233,250
- **Award type:** 1
- **Project period:** 2023-12-06 → 2025-10-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10810994

## Citation

> US National Institutes of Health, RePORTER application 10810994, Longitudinal changes of the sputum microbiome in adult asthma and its association with asthma exacerbations (1R21AI178627-01A1). Retrieved via AI Analytics 2026-06-07 from https://api.ai-analytics.org/grant/nih/10810994. Licensed CC0.

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