Mice lacking a specific immune cell are unable to develop asthma, researchers say.
The hallmark of asthma is airway hyper-reactivity (AHR) which is a narrowing of the tiny passages in the lungs in response to a trigger such as house dust mite. AHR is orchestrated by the immune system and leads to the characteristic wheezing and coughing symptoms of an asthma attack.

Researchers at the Lucile Packard Children's Hospital at Stanford University have been studying mice that lack a specific type of immune cell called natural killer (NK) cells. These mice do not get asthma, despite being exposed to the usual triggers.

The researchers suggest that maybe people with asthma have abnormally large numbers of NK cells in their lungs, or that their NK cells are abnormally responsive to provocation. Further research is needed but it could be that targetting NK cells will be a fruitful new approach in asthma therapy.