Microbiome and Exacerbations in Neutrophilic Asthma

Recruiting

• Conditions: Microbiome; Asthma; Exacerbation
• Interventions: Diagnostic Test: Polymerase Chain Reaction (PCR) for viruses and bacteria in nasal swab; Diagnostic Test: Induced sputum microbiome

• Registration Number: NCT04260282
• Lead Sponsor: Fundació Institut de Recerca de l'Hospital de la Santa Creu i Sant Pau

Brief Summary

Neutrophilic asthma (NA) is the least known severe asthma phenotype. It is associated with more exacerbations, worse control and impaired lung function. One of its possible etiologies is bronchial infections. The study of bronchial microbiology and its relationship with exacerbations is a new line of research.

Objectives: 1) To analyze bronchial microbiome in patients with AN and non-neutrophilic (ANN), with frequent exacerbations and without exacerbations. 2) To relate the presence of bronchial infections with differences in the microbiome. 3) Correlate the characteristics of the microbiome with other evidence used in exacerbations.

Methods: Prospective study involving 40 non-smoking asthmatics without bronchiectasis (20 with AN and 20 with ANN). Of these, 10 in each group will have frequent exacerbations (\>2 rounds of systemic steroids in the last year, of \>3 days each) and 10 non- frequent exacerbations. AN will be defined as \>65% neutrophils in stable phase sputum. All patients will have two stable visits in which clinical variables, asthma control, lung function and induced sputum samples will be collected (for analysis of bronchial inflammatory cell count and for the study of the microbiome by 16 subunit rRNA). Specific Immunoglobulin A (IgA) for Chlamydia Pneumoniae will be determined. In exacerbations, sputum samples will be collected for culture and nasopharyngeal smears for the study of major respiratory viruses and bacteria by multiple polymerase chain reaction.

Detailed Description

See above

Study Timeline

• Study First Submitted: 2020-01-23
• Study First Submitted QC: 2020-02-05
• Study First Posted: 2020-02-07
• Study Start: 2021-01-01
• Status Verified: 2023-01
• Last Update Submitted: 2023-01-26
• Last Update Posted: 2023-01-30
• Primary Completion: 2024-01-01
• Study Completion: 2025-01-01

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 40

Inclusion Criteria

• Age between 18 -80
• Confirmed diagnose of asthma
• Severe persistent asthma

Exclusion Criteria

• Respiratory infection during the previous month
• Other significant lung disease

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Neutrophilic asthma	Polymerase Chain Reaction (PCR) for viruses and bacteria in nasal swab	Patients with asthma diagnosed according to guidelines, with eosinophils \<300/mm3 in blood and \<3% in induced sputum
Eosinophilic asthma	Induced sputum microbiome	Patients with asthma diagnosed according to guidelines, with eosinophils \>300/mm3 in blood and/or \>3% in induced sputum
Eosinophilic asthma	Polymerase Chain Reaction (PCR) for viruses and bacteria in nasal swab	Patients with asthma diagnosed according to guidelines, with eosinophils \>300/mm3 in blood and/or \>3% in induced sputum
Neutrophilic asthma	Induced sputum microbiome	Patients with asthma diagnosed according to guidelines, with eosinophils \<300/mm3 in blood and \<3% in induced sputum

Primary Outcome Measures

Name	Time	Method
Differences between neutrophilic and non-neutrophilic asthma, with and without frequent exacerbations in bronchial microbiome using 16S rDNA sequencing	6 months	Qualitative and quantitative analysis of bronchial microbiome in patients including bacterial communities and major bacterial phyla in neutrophilic and non-neutrophilic asthma, with frequent exacerbations and without exacerbations.

Secondary Outcome Measures

Name	Time	Method
Changes in absolute and relative abundance using 16S rDNA sequencing of bronchial microbiota due to asthma exacerbations, in patients with neutrophilic and eosinophilic asthma	1 year	Influence of bronchial infections in qualitative and quantitative characteristics of lung microbiome. (Bacterial communities and major bacterial phyla)
Changes in absolute and relative abundance of bronchial microbiota over a year using 16S rDNA sequencing	1 year	Qualitative and quantitative changes of lung microbiome (Bacterial communities and major bacterial phyla)
Relationship between lung microbiome andlevels of specific immunoglobulin A of C. pneumoniae, PCR, and immunoglobulin G of aspergillus	6 months	Relationship between qualitative and quantitative characteristics of lung microbiome with levels of specific IgA C. pneumoniae, PCR, IgG aspergillus

Trial Locations

Locations (1)

Hospital de la Santa Creu i Sant Pau. Carrer Mas Casanovas 90.; 🇪🇸 Barcelona, Spain