Expression of TSLP Isoforms in Asthma

August 24, 2026 updated by: Medical University of Warsaw

TSLP and Its Isoforms (Short and Long Form TSLP) in Different Asthma Phenotypes

Asthma is a heterogeneous disease characterized by chronic airway inflammation, leading to variable airflow obstruction, bronchial hyperresponsiveness, excessive mucus secretion, and, consequently, structural airway remodeling. Asthma is defined by the presence of symptoms such as wheezing, dyspnea, chest tightness, and cough, with variable intensity and frequency.

Thymic stromal lymphopoietin (TSLP) is a cytokine produced primarily by epithelial cells in the lungs. Two distinct isoforms of TSLP have been identified: a long form (lfTSLP) and a short form (sfTSLP). The long isoform is induced during inflammatory conditions and promotes a T2-dependent immune response. In contrast, the short isoform is believed to exert homeostatic and anti-inflammatory functions and exhibits antimicrobial properties.

Studies have demonstrated an association between elevated serum and airway TSLP levels and increased disease severity, as well as reduced spirometric parameters. However, the literature contains limited data regarding the expression of TSLP isoforms across different asthma phenotypes and their relationship with the degree of disease control.

The goal of this study is:

  1. To assess the expression of TSLP protein and TSLP mRNA, including its isoforms (sfTSLP and lfTSLP), in serum and in airway-derived samples (nasal epithelial cells),
  2. To compare these levels among patients with different asthma phenotypes (allergic and non-allergic asthma; eosinophilic, neutrophilic, and paucigranulocytic asthma; early-onset and late-onset asthma; obesity-associated asthma; cough-variant asthma), as well as between patients with asthma and healthy controls.
  3. To analyze the correlations between the expression of TSLP isoforms (sfTSLP and lfTSLP) and asthma severity, level of disease control (as measured by the Asthma Control Questionnaire [ACQ]), pulmonary function parameters, blood eosinophil count and other clinical parameters.

Study Overview

Study Type

Observational

Enrollment (Estimated)

70

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

    • Warsaw
      • Warsaw, Warsaw, Poland, 02-097
        • Recruiting
        • Department of Internal Medicine, Pulmonary Diseases and Allergy, Medical University of Warsaw, Warsaw, Poland,
        • Contact:
        • Principal Investigator:
          • Marta Dąbrowska, MD, PhD, Associate Professor
        • Sub-Investigator:
          • Izabela Orzołek, MD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Patients with severe asthma, with different asthma phenotypes (allergic and non-allergic asthma; eosinophilic, neutrophilic, and paucigranulocytic asthma; early-onset and late-onset asthma; obesity-associated asthma; cough-variant asthma).

Description

  1. Inclusion criteria

    • age > 18 years, without the upper age limit,
    • asthma (diagnosis in accordance with the GINA 2023 guidelines),
  2. Exclusion criteria

    • other respiratory diseases (e.g., chronic obstructive pulmonary disease [COPD]);
    • active cigarette smoking or a smoking history of >10 pack-years;
    • active malignancy;
    • active pulmonary tuberculosis or active respiratory tract infection;
    • use of antibiotics within 4 weeks prior to study enrollment;
    • current long-term home oxygen therapy (>15 hours per day);
    • current treatment with monoclonal antibody therapies (e.g., omalizumab, mepolizumab, reslizumab, dupilumab, tezepelumab, or other biologics);
    • pregnancy.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Study group consists of patients with severe asthma (diagnosed according to GINA guidelines)
  1. Inclusion criteria Adults aged 18 years, without the upper age limit, diagnosed with asthma established in accordance with the GINA 2023 guidelines.
  2. Exclusion criteria Presence of other concomitant respiratory diseases (e.g., chronic obstructive pulmonary disease [COPD]); Current use of systemic glucocorticoids or immunosuppressive therapy, or use within 4 weeks prior to study enrollment; Active cigarette smoking or a smoking history of >10 pack-years; Active malignancy; Active pulmonary tuberculosis or active respiratory tract infection; Use of antibiotics within 4 weeks prior to study enrollment; Current long-term home oxygen therapy (>15 hours per day); Current treatment with monoclonal antibody therapies (e.g., omalizumab, mepolizumab, reslizumab, dupilumab, tezepelumab, or other biologics); Pregnancy.
This study is designed as a cross-sectional, observational investigation. No therapeutic or diagnostic interventions beyond routine clinical care will be introduced as part of the study. All procedures performed are limited to standard, minimally invasive sample collection and data acquisition for research purposes. Clinical management of participants will remain unchanged and will be conducted entirely at the discretion of the treating physicians. Participation in the study will not influence treatment decisions or patient care.
Control group
  1. Inclusion criteria Age above 18 years old and without the upper age limit. Negative medical history for asthma and allergic diseases.
  2. Exclusion criteria Diagnosed asthma or any other respiratory disease; Atopic dermatitis, allergic rhinitis, or other allergic diseases; Autoimmune diseases; All other exclusion criteria identical to those applied to the asthma patient group.
This study is designed as a cross-sectional, observational investigation. No therapeutic or diagnostic interventions beyond routine clinical care will be introduced as part of the study. All procedures performed are limited to standard, minimally invasive sample collection and data acquisition for research purposes. Clinical management of participants will remain unchanged and will be conducted entirely at the discretion of the treating physicians. Participation in the study will not influence treatment decisions or patient care.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
TSLP mRNA expression, including the sfTSLP and lfTSLP isoforms in nasal epithelial cells and TSLP protein expression in blood and nasal epithelial cells
Time Frame: This is cross-sectional studies; blood and nasal epithelial cells (nasal swab) will be taken from each study participant at one study point - through study completion, an average of 2 years

The primary endpoint of the study is the quantitative assessment of TSLP protein expression and TSLP mRNA expression, including the sfTSLP and lfTSLP isoforms, in biological material obtained from serum and nasal epithelial cells.

Peripheral venous blood samples will be collected and centrifuged to obtain serum, which will be aliquoted and stored at -80°C until analysis. Nasal epithelial cells will be collected using sterile cytology brushes. All biological samples will be processed promptly and stored under appropriate conditions prior to laboratory analysis.

TSLP protein concentrations will be measured using commercially available enzyme-linked immunosorbent assay (ELISA) kits in accordance with the manufacturer's instructions. Measurements will be performed in duplicate, and optical density will be determined using a microplate reader. Concent

This is cross-sectional studies; blood and nasal epithelial cells (nasal swab) will be taken from each study participant at one study point - through study completion, an average of 2 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 30, 2024

Primary Completion (Estimated)

November 1, 2026

Study Completion (Estimated)

November 1, 2026

Study Registration Dates

First Submitted

January 23, 2026

First Submitted That Met QC Criteria

August 24, 2026

First Posted (Actual)

August 26, 2026

Study Record Updates

Last Update Posted (Actual)

August 26, 2026

Last Update Submitted That Met QC Criteria

August 24, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

  • Medical University of Warsaw
  • 31/M/MB/N/24 (Other Grant/Funding Number: Young Scientist Grant, Medical University of Warsaw)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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