School of Medicine

Asthma may reduce risk of brain tumors — but how?

Asthma has been associated with a lowered risk of brain tumors, and researchers at Washington University School of Medicine in St. Louis now think they know why: Immune cells activated under conditions of asthma are less able to promote the growth of brain tumors. The findings could lead to new therapeutic approaches. (Photo: Getty Images)

There’s not much good that can be said about asthma, a breathing disease in which the airways become narrowed and inflamed. But there’s this: People with asthma seem to be less likely to develop brain tumors than others. And now, researchers at Washington University School of Medicine in St. Louis believe they have discovered why.

It comes down to the behavior of T cells, a type of immune cell. When a person — or a mouse — develops asthma, their T cells become activated. In a new mouse study, researchers discovered that asthma causes the T cells to behave in a way that induces lung inflammation but prevents the growth of brain tumors. What’s bad news for the airways may be good news for the brain.

The findings, available online in Nature Communications, suggest that reprogramming T cells in brain tumor patients to act more like T cells in asthma patients could be a new approach to treating brain tumors.

“Of course, we’re not going to start inducing asthma in anyone; asthma can be a lethal disease,” said senior author David H. Gutmann, MD, PhD, the Donald O. Schnuck Family Professor of Neurology. “But what if we could trick the T cells into thinking they’re asthma T cells when they enter the brain, so they no longer support brain tumor formation and growth? These findings open the door to new kinds of therapies targeting T cells and their interactions with cells in the brain.”

The idea that people with inflammatory diseases, such as asthma or eczema, are less prone to developing brain tumors was first proposed more than 15 years ago, based on epidemiologic observations. But there was no obvious reason why the two very different kinds of diseases would be linked, and some scientists questioned whether the association was real.

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