Karolinska Researchers Measure Viral Antibodies in Exhaled Air
“Antibodies in the nasal mucosa are important for protection against respiratory infections, but immune responses further down the lungs are also crucial, particularly for preventing severe disease such as pneumonia,” said Charlotte Thålin, an adjunct professor at the Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet. Researchers have now successfully measured virus-specific antibodies in exhaled breath for the first time, providing a non-invasive window into the lower respiratory tract’s immune status.
- The PExA method captures particles from the small airways of the lungs without the need for invasive procedures like bronchoscopy.
- Researchers identified IgA and IgG antibodies targeting SARS-CoV-2, influenza, and RSV in the exhaled breath of study participants.
- IgG levels in exhaled particles mirrored blood levels, while IgA patterns suggested a distinct, local immune response within the lungs.
The PExA Method for Lower Airway Analysis
The study, published in the journal eBioMedicine and reported by UA.News, utilized a technique known as Particles in Exhaled Air (PExA). Participants breathe into a specialized instrument designed to collect tiny particles originating from the fluid lining the small airways. By analyzing these samples, the team at Karolinska Institutet, in collaboration with Uppsala University and SciLifeLab, was able to detect virus-specific antibodies that were previously difficult to quantify without intensive clinical intervention.
Before this development, obtaining biological samples from the deep regions of the lungs required invasive methods such as bronchoscopy. The current methodological study, which included 28 participants from the COMMUNITY cohort at Danderyd Hospital, opens up new possibilities for understanding immunity in the lower airways.
Viral Antibody Patterns in Exhaled Breath
Of the 28 participants, 18 had recently experienced a respiratory tract infection. The researchers collected and compared paired samples from blood, nasal secretions, and exhaled breath. Their analysis revealed the presence of IgA and IgG antibodies directed against SARS-CoV-2, influenza virus, and respiratory syncytial virus (RSV).
The data showed a divergence between the two antibody types. Virus-specific IgG levels found in the lower airway samples largely corresponded to the levels observed in the participants’ blood. In contrast, the IgA levels displayed a different pattern. This finding is consistent with a significant contribution from local mucosal antibody responses.
Future Directions for Respiratory Immunity Research
While the study provides a new tool for clinical research, the authors emphasize that these results represent an initial methodological study. The limited sample size necessitates further validation in larger clinical cohorts to confirm the reliability of the PExA method for broader diagnostic or research applications.
This approach could allow for more detailed investigations into how immune responses in the lower airways shift following infections or the administration of various vaccinations. It may also provide a pathway for evaluating the efficacy of preventive treatments.
The research was funded by the European Research Council (ERC), the Knut and Alice Wallenberg Foundation, and the Swedish Society for Medical Research (SSMF).
Disclaimer: The information provided in this article is for educational and scientific communication purposes only and does not constitute medical advice.