It is hardly surprising that one of the medical programmes most important exams is stressful for students. However, research now shows that this mental stress also affects the students immune defence systems, especially amongst those suffering from allergies.

While diseases like asthma and allergies are becoming increasingly common in the West, a number of people think that we are living ever stressful lives. A new study from Karolinska Institutet backs up what a number of people have suspected: that there are important links between mental stress and the complex physical inflammation reactions characteristic of allergies.

In order to understand the link between stress and allergy, the researchers have examined how a major medical exam at Karolinska Institutet affects feelings of stress, stress hormone levels, the immune system and lung function amongst students with and without allergies. The extensive tests were made on two occasions, first with the students during a calm period of study with no exam in sight, and then shortly before a major exam. Twenty two students with hayfever and/or asthma and 19 healthy students took part.

For the first time on record, researchers were able to show that a group of cells that are central to the human immune system known as regulatory T cells appear to increase sharply in number in response to mental stress. A regulatory T cell is a kind of white blood cell that controls the activity of many other types of immune cell. This increase was observed in both groups of students.

The study also showed that blood concentrations of a group of inflammation products called cytokines had changed and shifted against a pattern linked to allergic inflammation in the allergic students, but remained normal in the healthy students.

As per Mats Lekander, who is leading the research group, the two discoveries might very well be linked.

"There is much to suggest that the regulatory T cells are dysfunctional in people with allergies," he says. "When people become stressed, they increase in number and normally have an anti-inflammatory effect. If this system does not work in people with allergies, it could explain the changed cytokine balance that we have observed in them".



Posted by: Jenn    Source

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