Bronchoscopy: Bronchoscopy will be performed in patients with refractory or unexplained chronic cough and healthy controls.
Study summary
Chronic cough is a common troublesome symptom which has a global prevalence of approximately 10%, but with wide variations across continents. Patients with refractory and unexplained chronic cough (RCC/UCC) often exhibit dysregulated vagal pathways, necessitating a neuronal biomarker for targeted treatment. ATP, involved in the ATP/P2X3 pathway, may serve as a potential biomarker due to its role in the cough reflex. The study aims to discover if ATP production by the airway epithelium is greater in RCC/UCC patients compared with healthy controls, if the epithelium is a source of ATP, whether gene and protein expression related to ATP production differs between these groups and whether ATP release is triggered by mechanical and chemical stimulation. Additionally, the study seeks to determine if biomarker gene expression signatures can differentiate RCC/UCC patients from healthy controls.
Eligibility
Sex
ALL
Min age
18 Years
Max age
80 Years
Healthy volunteers
Accepted
Inclusion Criteria for RCC/UCC:
* Patients with a history of RCC/UCC.
* Normal Chest X-ray in the last 5 years.
* No Evidence of Airflow Obstruction (FEV1/FVC ratio above LLN)
* Cough Severity VAS ≥ 40 mm at screening.
Inclusion Criteria for Healthy Controls:
* No history of chronic cough, asthma, COPD, or clinical history of bronchiectasis or interstitial lung disease
* No current smokers or those with \>10 pack year history.
* No evidence of airflow obstruction ( FEV1/FVC ratio above LLN).
* Able to understand and give written informed consent.
Exclusion Criteria:
* Participants who are currently established on treatment and their chronic cough is well controlled.
* Unable to perform acceptable and reproducible spirometry.
* Participants with a positive covid-19 test within 2 weeks of screening.
* Current smoker or ex-smoker with ≥20 pack year smoking history and abstinence of ≤6 months
* Symptoms of upper respiratory tract infection in the last 1 month which have not resolved
* Lower respiratory tract infection or pneumonia in the last 1 month
* Asthma exacerbation in the previous month requiring an increase or start of an inhaled corticosteroid (ICS) or oral corticosteroid (OCS)
* Significant other primary pulmonary disorders in particular; pulmonary embolism, pulmonary hypertension, lung cancer, cystic fibrosis, significant radiologically proven emphysema, interstitial lung disease or bronchiectasis.
* History of psychiatric illness, drug or alcohol abuse which may interfere in the participation of the trial.
* Allergy or intolerance to sedation medication including fentanyl and midazolam, or a history of complications during procedural sedation
* Severe coagulopathy, bleeding disorder, or medical need for anti- coagulation that would increase the risk of endobronchial biopsy as determined by the investigator
Primary outcome measure(s)
Difference in expressed genes — At baseline Expression of genes involved in intracellular ATP production, transport, extracellular metabolism in the airway epithelium will be compared in both RCC/UCC and healthy controls.
This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.
We use cookies to analyse site traffic and improve your experience. With your consent, we may also use cookies for advertising. You can change your choice at any time.
