New Delhi, June 26 : While biological drugs or biologics have improved the lives of many people with severe asthma, a new study shows that some immune cells with high inflammatory potential are not completely eradicated after treatment.

The findings may explain the reason for the return of inflammation of the airways as soon as the treatment is discontinued, said researchers from Karolinska Institutet in Sweden.

In a new study published in the scientific journal Allergy, the team explored what happens to the immune cells of patients being treated with biologics -- which has become an important tool in the treatment of severe asthma.

They analysed blood samples from 40 patients before and during treatment. They found that instead of disappearing during treatment, certain types of immune cells -- which play a key part in asthma inflammation -- actually increased.

'This suggests that biologics might not attack the root of the problem, no matter how much they help asthma patients during treatment,' said Jenny Mjösberg, professor of tissue immunology at Karolinska Institutet's Department of Medicine in Huddinge.

'Continued treatment might be necessary to keep the disease under control,' she added.

The team used advanced methods such as flow cytometry and single cell sequencing to determine the properties and function of the immune cells.

They discovered 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,' said Lorenz Wirth, doctoral student at Karolinska.

The team said while biologics like mepolizumab and dupilumab help most patients keep their symptoms under control, little is still known about their long-term effects since they are relatively new and have been prescribed asthmatics for less than 10 years.

The team next plans to analyse samples from patients with a long treatment history and to study lung tissue to see how the immune cells are affected in the airways.

/IANS