Biological therapies have significantly improved the quality of life for many individuals suffering from severe asthma. However, new research from Karolinska Institutet in Sweden reveals that some inflammatory immune cells may persist in the bloodstream even after treatment, raising questions about the long-term effectiveness of these drugs.
While biologic drugs like mepolizumab and dupilumab are effective at controlling asthma symptoms, their precise impact on the immune system has remained largely unknown. Valentyna Yasinska, a pulmonary medicine consultant at Karolinska University Hospital and a doctoral student at the university, notes that although these drugs help most patients manage their condition, there's still more to learn about how they work at the cellular level.
The new study, published in the journal Allergy, investigated the immune responses of 40 patients undergoing biologic treatment. Researchers analyzed blood samples taken before and during treatment and found that, contrary to expectations, certain immune cells linked to asthma-related inflammation actually increased in number rather than decreased.
“This finding suggests that biologic drugs may not eliminate the root cause of inflammation,” said Professor Jenny Mjösberg of Karolinska Institutet. “This could mean patients need to stay on these medications continuously to keep the disease in check.”
Using techniques such as flow cytometry and single-cell sequencing, the research team was able to closely examine the nature and function of these persistent immune cells. Lorenz Wirth, a doctoral student involved in the study, explained that the increase in inflammatory cells could be a reason why asthma symptoms often return when treatment is reduced or stopped.
Because biologic treatments have only been in use for less than a decade, their long-term immunological effects are still poorly understood. The researchers plan to continue their work by studying patients who have been on long-term biologic therapy and by analyzing lung tissue to better understand how these immune cells behave in the airways.
