Biological drugs,also known as biologics,have become a cornerstone in managing severe asthma. These medications offer targeted therapies that can considerably improve the quality of life for many patients.

According to Valentyna yasinska,consultant in pulmonary medicine at Karolinska university Hospital and doctoral student at Karolinska Institutet’s Department of Medicine in Huddinge,”They help most patients to keep their symptoms under control,but exactly how these drugs affect the immune system has so far remained unknown.”

The new study, featured in the scientific journal Allergy, investigated the impact of biologics on immune cells in treated patients. Researchers at Karolinska Institutet analyzed blood samples from 40 patients before and during their treatment. The findings indicated that specific immune cell types, crucial in asthma-related inflammation, actually increased instead of decreasing during the treatment period.

Jenny Mjösberg,professor of tissue immunology at Karolinska Institutet’s Department of Medicine in Huddinge,notes,”This suggests that biologics might not attack the root of the problem,no matter how much they help asthma patients during treatment. Continued treatment might be necessary to keep the disease under control.”

The research utilized data from the BIOCROSS study, focusing on patients with severe asthma.Advanced techniques like flow cytometry and single-cell sequencing were employed to analyze the characteristics and functions of the immune cells.

“we were surprised to find that blood levels of inflammatory cells increased rather than decreased,”

Lorenz Wirth, doctoral student at Karolinska Institutet, commented, “we were surprised to find that blood levels of inflammatory cells increased rather than decreased. This could explain why inflammation of the airways often returns when the treatment is tapered or discontinued. It is important that we understand the long-term immunological effects of these drugs.”

The long-term effects of biologics such as mepolizumab and dupilumab remain largely unknown, as these treatments have been available for less than a decade.

Future research will involve analyzing samples from patients with extended treatment histories and examining lung tissue to assess the impact on immune cells within the airways.

Funding for the study was provided by grants from the EU (Horizon 2020), the Swedish Heart-Lung Foundation, the Center for Innovative Medicine, the Swedish state, the Torsten Söderberg Foundation, Karolinska Institutet and the ChAMP Consortium.

The researchers have declared any potential conflicts of interest in the published paper.