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BEER-SHEVA, Israel, April, 2013 – Chronic stress increases the susceptibility to an autoimmune disease similar to multiple sclerosis, which is characterized by damage to the nervous system as a result of a directed attack by the immune system on the myelin coating of the nerve cells in the brain, Ben-Gurion University of the Negev researchers have proven. The researchers, Dr. Idan Harpaz and Prof. Alon Monsonego, in conjunction with Prof. Hagit Cohen, characterized for the first time the leading mechanisms which cause damage to immunoregulatory functions of the immune system in mice under chronic stress. 

The researchers’ findings were recently published in the European Journal of Immunology. The researchers showed that the phenomenon is caused, among other things, by damage to release adequate levels of glucocorticoids (steroid hormones termed cortisol in humans and corticosterone in rodents) in response to stimulus and more importantly due to a lack of sensitivity in specific cells of the immune system, which cause pathogenic inflammation, to glucocorticoids. As a result, glucocorticoids cannot effectively inhibit the cells that encourage inflammation, which is what usually happens. Moreover, the researchers showed that exposure to high levels of glucocorticoids in those suffering from chronic stress reduced the number of immune cells in such a way that increased the number of cells that encourage pathogenic inflammation compared to those that inhibit it. It is important to note, that the mechanisms appeared more significantly in females than in males and may explain, in part, the higher rates of autoimmune disease in women than in men. The researchers developed their findings through experiments on mice.

Exposure to stress is one of the most common sources of damage both physically and emotionally. The reaction to stress is characterized by the release of important hormones such as glucocorticoids (released following brain signaling to the adrenal cortex; the hypothalamic-pituitary-adrenal axis) that enable the organism to handle stressful situations (fight or flight). At the same time, high levels of glucocorticoids in those suffering from chronic stress harm the body’s immune system and its ability to adequately cope with immune challenges essential to gain homeostasis. 

Altogether, the results of the current study suggest that while a high level of glucocorticoids generally protect against the worsening of autoimmune diseases, for those under chronic stress, such treatment could lead to a worsening of the symptoms of the autoimmune disease. Therefore, even though steroids is one of the treatments for chronic inflammation, use of such a treatment, particularly in patients suffering from chronic stress, should be carefully weighed and considered.

The researchers believe that testing the function of the HPA axis can be an important diagnostic tool that can be used to determine how well the immune system is operating. The researchers are also investigating the effects of glucocorticoids in aging and age-related neurodegenerative diseases, such as Alzheimer’s, and report that there is apparently a connection between the effects of glucocorticoids on the immune system and aging.

Monsonego and Harpaz are from the Shraga Segal Department of Microbiology and Immunology in the Faculty of Health Sciences. Monsonego is also a member of the National Institute for Biotechnology in the Desert. Cohen is the head of the Anxiety and Stress Research Unit, Division of Psychiatry, Faculty of Health Sciences.