• Posted January 22, 2025

“Chameleon” Immune Cells Linked To Severe Asthma

A set of chameleon-like immune cells could be contributing to severe asthma in some patients.

Intermediate group 2 innate lymphoid cells (ILC2s) appear to be able to get around cutting-edge asthma treatments by transforming into another type of immune cell.

Targeted biologic drugs have revolutionized the treatment of severe asthma driven by eosinophils, which are white blood cells linked to ILC2s, researchers noted in a recent study in the journal Science Translational Medicine.

However, not all patients respond to these biologic drugs -- and the fact that ILC2s can transform themselves could be a reason why, researchers said.

Intermediate ILC2s share traits of both ILC2s and another type of immune cell called group 3 innate lymphoid cells, or ILC3s. ILC3s are tied to another type of white blood cell called neutrophils.

An inhaler is less likely to calm an asthma attack involving eosinophils and neutrophils, researchers said.

“When asthma is associated with both eosinophils and neutrophils cells, individuals are generally less responsive to treatment with glucocorticosteroids -- which are the mainstay of treatment for severe asthma,” researcher Dr. Parameswaran Nair said in a news release. He's chair in airway diseases at McMaster University in Hamilton, Ontario, Canada.

Severe asthma that resists standard therapies is believed to affect up to 10% of people with asthma, researchers said in background notes.

“The findings from this research pave the way for discovering new therapeutic targets for difficult-to-treat asthma,” Nair said.

For this study, researchers took mucus samples from 34 people with severe asthma. They analyzed the mucus for the presence of immune cells that might play a role in making asthma tougher to treat.

They found that ILC2s are associated with higher numbers of eosinophils in mucus, while ILC3s are associated with higher amounts of neutrophils – both of which are often seen in difficult-to-treat asthma.

The ability of some ILC2s to change and take on features of ILC3s in the airways of asthma patients is a new discovery that could lead to better treatments for severe asthma, researchers said.

They also found growth factors that encourage the formation of intermediate ILC2s.

This suggests that controlling intermediate ILC2 levels could keep counts of troublesome white blood cells down, thus potentially preventing severe asthma symptoms, the team said.

More information

The Asthma and Allergy Foundation of America has more on eosinophilic asthma.

SOURCE: McMaster University, news release, Jan. 15, 2025