A new scientific study by researchers at Karolinska Institutet, Danderyd Hospital and Uppsala University demonstrates that samples collected using a non-invasive method called PExA can be used to measure virus-specific antibodies from the small airways.
Published in eBioMedicine, part of The Lancet Discovery Science, the study opens new opportunities in vaccine research, immunology and drug development, paving the way for broader applications of PExA's instruments and technology.
For the first time, researchers led by Professor Charlotte Thålin at Karolinska Institutet have demonstrated that antibodies targeting specific viruses can be analysed in samples collected non-invasively from the small airways, deep within the lungs. PExA's technology enables these samples to be collected without bronchoscopy or other invasive procedures and subsequently examined using advanced analytical methods.
For pharmaceutical companies and researchers, this opens the possibility of investigating whether future vaccines generate the desired immune responses deep within the lungs, rather than only in the blood or upper airways. This could be particularly valuable in developing new vaccines against respiratory infections such as influenza, COVID-19 and RSV.
Ultimately, the aim is to investigate not only whether the body responds to a vaccine, but also whether the appropriate immune response develops where protection is needed.
The company PExA AB has developed PExA 2.1, a patented research instrument enabling non-invasive small airway liquid biopsy. The technology allows researchers to collect biological samples from the small airways of the lungs, providing molecular insights directly from the site of action and supporting biomarker discovery, pharmacokinetic and pharmacodynamic (PK/PD) studies, immunology research and future diagnostic applications.
The researchers analysed samples from 28 individuals. Using PExA, samples were collected from the small airways and subsequently analysed using sensitive immunological methods. This enabled the researchers to measure IgA and IgG antibodies targeting three important respiratory viruses: influenza, SARS-CoV-2 and RSV.
The results demonstrate that these antibodies can be measured with high precision in the collected samples. The study also reveals differences in antibody profiles between the blood, nose and lower airways, highlighting the importance of being able to investigate immune responses directly in the lungs.
Study co-author Charlotte Thålin, Professor at Karolinska Institutet and affiliated with Danderyd Hospital, commented: “Being able to analyse antigen-specific antibodies in samples from the lower airways without invasive sampling gives us new opportunities to study the immune system in the lungs. This is particularly interesting for the development of future mucosal vaccines, where we need to understand how immunity differs between different parts of the respiratory tract.”
An important part of the research has been the use of sensitive analytical methods that make it possible to measure specific antibodies in the very small sample volumes collected using PExA's technology.
The development of new vaccines against respiratory infections is a major international research field. One important objective is to develop vaccines that not only generate a systemic immune response but also strengthen local immunity in the respiratory tract.
The newly published study represents a concrete step forward, demonstrating that researchers can analyse virus-specific antibodies in samples collected non-invasively using PExA. The findings strengthen the potential for future applications of the technology to study local immune responses, compare vaccine candidates and monitor how the immune system responds over time.
Tomas Gustafsson, CEO of PExA commented: “Charlotte Thålin and her colleagues have presented very exciting results that could have a significant impact on future vaccine research and drug development. We already collaborate with pharmaceutical companies in other areas of lung disease, and we now see how these findings could open the door to an entirely new application area. The ability to collect samples non-invasively from the small airways could become highly valuable for both vaccine researchers and pharmaceutical companies.”
- Aguilera K, Hober A, Norin NG, et al. Non-invasive quantification of lower airway antigen-specific antibodies using exhaled breath particles - an observational proof-of-concept study. EBioMedicine. Published online November 2, 2026. doi:10.1016/j.ebiom.2026.106538