Last Updated: 2002-12-09 17:00:25 -0400 (Reuters Health)

By Merritt McKinney

NEW YORK (Reuters Health) - A small study conducted in Sweden suggests that in some people with eating disorders, the immune system might turn against the body's own tissue. According to the findings, many women with anorexia nervosa, bulimia or both disorders produced antibodies that targeted brain proteins thought to help control eating.

The research is preliminary and by no means proves that anorexia and bulimia are autoimmune diseases, but the possible link between eating disorders and the immune system is worth exploring, according to the study's first author, Dr. Serguei O. Fetissov, of the Karolinska Institute in Stockholm. Such antibodies were also found in some healthy women as well.

"More research is needed before clinical applications of our findings can be considered," Fetissov told Reuters Health. He added, however, that "we hope to be able to explore to what extent there is a link between the nervous and immune systems in anorexia and bulimia nervosa and other stress-related disorders."

The causes of anorexia and bulimia are unknown, but more and more research suggests that neurological factors play a role in the eating disorders. A section of the brain called the hypothalamus is thought to play an important role in regulating how much food we eat, so Fetissov and his colleagues, under the leadership of senior author Dr. Tomas Hokfelt, wondered whether the immune system targets cells in the hypothalamus in people with eating disorders.

Under normal circumstances, the body produces antibodies in response to outside invaders, such as viruses. But in the case of autoimmune disorders, such as rheumatoid arthritis and lupus, the body mistakenly produces antibodies to the body's own cells.

In the study, the researchers screened the blood of 57 women who had either anorexia, bulimia or both. Nearly three out of four women (74%) with an eating disorder had antibodies that targeted at least one type of protein in the hypothalamus or pituitary, the researchers report in the online early edition of the journal Proceedings of the National Academy of Sciences. Such antibodies were also found in 2 of 13 healthy women, or 16%, without eating disorders.

"We do not know if these antibodies are relevant to the development or manifestation of the anorexia/bulimia," Fetissov said. However, he pointed out that several of the targeted peptides are known to be involved with the brain's control of feeding behavior. There are "several scenarios," he said, in which antibodies targeted at these peptides would interfere with the normal regulation of eating.

"I would like to emphasize that some apparently healthy individuals also had such auto-antibodies," Fetissov said, so he cautioned that additional studies are needed before any conclusions can be made.

SOURCE: Proceedings of the National Academy of Sciences Early Edition 2002;10.1073/pnas.222658699.


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