Have you ever wondered...

How stress can make you ill

Stress interacts with immune cells and can affect how these respond to allergens, causing symptoms and disease. New research carried out by Michigan State University, US, examined what happens in detail.

The study showed how a stress receptor called CRF1 (corticotropin-releasing factor) can send signals to certain immune cells, called mast cells, and control how they defend the body.

Adam Moeser, an associate professor who specialises in stressinduced diseases, said: “Mast cells become highly activated in response to stressful situations the body may be experiencing.

“When this happens, CRF1 tells these cells to release chemical substances that can lead to inflammatory and allergic diseases such as irritable bowel syndrome, asthma, life-threatening food allergies and autoimmune disorders such as lupus.”

One chemical substance, histamine, is known to help the body get rid of invading allergens such as pollen, dust mites or the protein of a particular food like peanuts or shellfish. The histamine causes an allergic reaction and helps the body get rid of the allergen.

During the study, Moeser compared the histamine responses of mice to two types of stress conditions – psychological and allergic – where the immune system becomes overworked. One group of mice had CRF1 receptors on mast cells and the other group hadn’t.

While the mice with CRF1 exposed to stress had high histamine levels and disease, the mice without CRF1 had low histamine levels, less disease and were protected against both types of stress.

The CRF1-deficient mice exposed to allergic stress had a 54% reduction in disease, while those mice who experienced psychological stress had a 63% decrease.

These results could change the way everyday disorders such as asthma and the debilitating gastrointestinal symptoms of irritable bowel syndrome are treated by targeting mast cells.