Nose as a window to the lungs: what extracellular vesicles tell us about asthma in children

Controlled does not mean cured

Asthma is the most common chronic respiratory disease in children: it affects about one in ten school-age children. In most cases, the symptoms are well managed with inhaled medications, so asthma is considered well controlled. The problem is that good symptom control does not necessarily mean the remission of the disease. A chronic inflammatory process and tissue remodeling may still be underway below the surface, and the available studies give only an indirect picture of the situation.

Vesicles that carry a message

I began searching for a method that would help assess what actually happens under the surface of well-controlled asthma focusing on extracellular vesicles. Extracellular vesicles are membrane-bound structures released by almost all body cells, including respiratory epithelial cells. Their protein composition reflects the state of the cell at the time of their formation and changes under the influence of inflammatory activation or cell damage. The research question was whether this signal can be read in a simple and safe way for the child, for example from nasal lavage?

One question, three types of research data

We invited 20 school-age children (median age – 9 years) to participate in the study: 11 with mild, well-controlled asthma and 9 healthy peers. Three types of samples were collected from each child during one visit: nasal lavage, exhaled breath condensate and the blood. The first two methods do not even require using needles which is of considerable importance when working with children. 
We isolated extracellular vesicles from each sample and analyzed their protein content with one of the most sensitive mass spectrometry techniques available today. We wanted to find out which of the three sources provided the most information about asthma and whether the signal from the follicles reflected the known biology of the disease in any way.

Nasal lavage as the richest source of information

In nasal lavage vesicles, we identified several thousand different proteins, clearly more than in vesicles obtained from the blood or exhaled breath condensate. However, no single protein that differentiated children with asthma from healthy ones was present in all three samples simultaneously. Completely different molecules were predominant in exhaled breath condensates and in the blood serum compared to those in nasal lavage. Therefore, nasal lavage is not a poorer equivalent of blood, but thanks to the proximity of the area affected by the disease, it is a separate and particularly important source of information. The obtained results indicate that the simultaneous analysis of all three biological samples provided a more complete picture of molecular changes than the analysis of a single sample.

Trace of inflammation despite well-controlled disease

Proteins whose levels were elevated in the vesicles obtained via nasal lavage from children with asthma included the major alkaline protein of eosinophils, which is released by these cells during an allergic reaction. These proteins are markers of the so-called type 2 inflammation that underlies the most common, allergic form of the disease. One such protein was detected only in children with asthma. We also observed a strong relationship: the amount of the major alkaline protein of eosinophils in nasal lavage corresponded to the number of eosinophils in the blood. It means that a simple nasal lavage had a potential to reflect what was happening throughout the child's body. At the same time, the levels of proteins typical of acute neutrophilic inflammation (a type of body defense response) were lowered, which may partly reflect the effects of inhaled drugs. This signal persisted despite anti-inflammatory treatment.

Damage invisible to the naked eye 

A separate group of proteins whose levels were elevated in nasal lavage were proteins associated with the epithelial barrier and the repair of damaged cell membranes. Their presence suggests that even with mild, stable asthma, the epithelial remodeling process is still ongoing, although it is not clinically manifested. This phenomenon remains invisible in standard diagnostics and is revealed only in molecular analysis.

Confirmation in an independent group of almost 700 children

Due to the small size of the study group (20 children), the results were validated in an independent data set, including genetic data of almost 700 children from an American cohort study.

Although a different type of material was analyzed (gene activity in nasal epithelial cells, and not protein in vesicles), the consistency of the direction of changes between the two data sets was statistically significant. Moreover, the same protein, which, in our study, was present exclusively in children with asthma, also emerged as the most strongly differentiating gene in the group of children with the so-called T2-high asthma in the American study. 
Two independent studies based on different methods and conducted in geographically distant populations indicated the same underlying biology of the disease.

What could be the implications for the future of asthma diagnosis in children
Our goal was not to create a ready-to-use test, but to verify if it was worth pursuing this direction. The answer is "yes": painlessly collected nasal lavage provides information about type 2 inflammation, eosinophil activity and epithelial remodeling at the same time. This is especially valuable in the youngest patients, in whom classic lung function tests are sometimes difficult to perform. Before such a method reaches clinical practice, larger validation studies are necessary. I treat this project as a starting point for further research, not a ready-to-use tool for a physician's office.

Success of interdisciplinary team

Conducting the study was possible thanks to a team combining clinical, laboratory and analytical competences. The clinical part of the project was carried out in the Department of Pediatric Respiratory Diseases and Allergology WUM, headed by Prof. Marek Kulus. Dr Joanna Peradzyńska and Karolina Dumycz, MD, participated in the recruitment and care of patients. Natalia Stalony, MD, from the Department of Pediatric Gastroenterology and Nutrition WUM helped recruit children from the control group. Sample preparation and the development of methodology was coordinated by Dr Anna Stelmaszczyk-Emmel.

Isolation and characterization of extracellular vesicles were carried out by Dr Magdalena Długołęcka and Dr Małgorzata Czystowska-Kuźmicz from the Department of Biochemistry WUM, and mass spectrometry analyses were performed by Bianka Świderska, MSc, and Dr Ewa Sitkiewicz from the Institute of Biochemistry and Biophysics of the Polish Academy of Sciences (PAS).

Characterization of extracellular vesicles using electron cryomicroscopy (cryo-TEM) was performed in cooperation with Dr Tomasz Góral from the Cryomicroscopy and Electron Diffraction Core Facility, Centre of New Technologies at the University of Warsaw. Prof. Mariola Dietrich from the Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences in Olsztyn participated in the processing and interpretation of the data. The entire project was supervised by Prof. Wojciech Feleszko from the Department of Pediatric Respiratory Diseases and Allergology WUM.

Award at the INSPiRED 2026 congress 

A paper describing the results, prepared under the scientific supervision of Prof. Wojciech Feleszko, was awarded the 1st prize in the Young Investigator Award competition during the 4th Congress of the International Society of Pediatric Respiratory Diseases (INSPiRED) in Bologna in June 2026. INSPiRED is the only congress in the world dedicated exclusively to respiratory diseases in children. The jury of the competition included Prof. Andrew Bush, one of the world's most recognized specialists in pediatric pulmonology from Imperial College London.

The project is financed under the PRELUDIUM 20 grant of the National Science Centre.