A benefit of flu: protection from asthma?

The number of people with asthma has increased sharply over the past few decades. It has been suggested that this is a result of decreased childhood exposure to microorganisms. A team of researchers — led by Dale Umetsu, at Harvard Medical School, Boston; Michio Shimamura, at the University of Tsukuba, Japan; and Petr Illarionov, at the University of Birmingham, United Kingdom — has now provided concrete evidence in mice to support this idea and identified an underlying mechanism to explain this protection, which the team hope could be exploited to develop ways to prevent asthma.

In the study, infection of suckling mice with influenza A virus protected the mice as adults in a model of asthma. Protection was associated with the expansion of a subset of immune cells known as NKT cells. Importantly, NKT cell–mediated protection in the model of asthma studied could also be induced by treating suckling mice with a molecule derived from the bacterium Helicobacter pylori. The authors therefore suggest that treating children with therapeutics that activate the NKT cell population might prevent the development of asthma.