Anorexia nervosa, autoimmunity and the hygiene hypothesis

Area of Science:

• Immunology
• Neuroscience
• Psychiatry

Background:

• Anorexia nervosa (AN) is increasingly prevalent, particularly in females, with epidemiological patterns suggesting environmental influences.
• Existing research indicates the presence of auto-antibodies to regulatory peptides in AN patients, potentially linked to microbial antigens.

Purpose of the Study:

• To investigate the hypothesis that anorexia nervosa is an autoimmune disorder resulting from microbial exposure.
• To explore the role of auto-antibodies and their correlation with disease psychopathology.

Main Methods:

• Serological analysis for IgG, IgA, and IgM auto-antibodies against regulatory peptides and hypothalamic neurons.
• Comparison of auto-antibody levels in AN patients, bulimia nervosa patients, and healthy controls.
• Epidemiological data analysis, including incidence, demographics, and seasonal birth variations.

Main Results:

• Auto-antibodies to appetite and mood regulatory peptides, showing homology with microbial sequences, are present in AN patients.
• Auto-antibodies to alpha-melanocyte stimulating hormone (αMSH) correlate with AN psychopathology.
• Similar auto-antibodies are found in bulimia nervosa patients and controls, necessitating further investigation.

Conclusions:

• Epidemiological and serological findings support the autoimmune hypothesis for AN, aligning with the hygiene hypothesis.
• Further research, including large case-control studies and MHC gene polymorphism assessment, is warranted.
• Pooled immunoglobulin therapy may be a viable treatment option for severe, life-threatening AN cases.