Eating disorders may have autoimmune roots.

A new study adds to evidence that the eating disorders anorexia nervosa and bulimia nervosa could be autoimmune diseases.

Three years ago, Serguei Fetissov of the Karolinska Institute in Stockholm and his colleagues studied 57 people with anorexia or bulimia and found that three-quarters of them had blood antibodies against melanocortin peptides. Previous research had shown that these peptides control appetite and stress responses.

To investigate whether the antibodies are associated with specific symptoms of the eating disorders, Fetissov's team recently administered questionnaires to 12 people diagnosed with anorexia, 42 people with bulimia, and 41 volunteers who had no known eating disorder. The survey had been designed to measure the severity of people's eating disorders. The researchers also took blood samples from all the study participants and tested them for concentrations of antibodies to the melanocortin peptides.

In people with anorexia, Fetissov and his colleagues found a positive correlation between antibody concentrations and severity of the disease. But people with bulimia showed a negative correlation between antibody concentrations and symptom severity. There was no correlation between antibody amounts and psychological test results in the healthy volunteers. The researchers report their findings in the Oct. 11 Proceedings of the National Academy of Sciences.--C.B.