The ideal immune system will:
- Recognize all foreign organisms (bacteria, viruses, parasites, fungi, worms).
- Efficiently and rapidly destroy invaders.
- Prevent a second infection with the same microbe (have a good memory).
- Never cause damage to self.
Things that can go wrong:
- Immune deficiency/dysfunction: defective or ineffective response.
- Hypersensitivity: Over-reaction to innocuous foreign material, out of proportion to potential damage (allergy).
- Autoimmunity: Inappropriate reaction towards self, loss of self-recognition.
- Inflammation: Too-vigorous attack against invaders with “bystander” damage to normal tissue.
Dysregulation of immunity in people with autism can lead to any of these four problems.
There is a tendency towards a positive family history of autoimmunity in families – Rheumatoid Arthritis, Thyroiditis – with an ASD child. Many, many types of autoantibodies (against “self” tissues) have been found in ASD children but the significance of the many types of anti-brain antibodies is not yet clear. Several studies find that some ASD children have low immunoglobulins (IgG, IgM, IgA), and/or low T cell numbers, altered cytokine profiles, and/or low-normal functioning and/or low NK cells; a subset of children have true immunodeficiency. Some children have low serum IgA, predisposing them to respiratory and GI infections.
Antibodies are divided up into classes:
- IgA: Mucosal surfaces – if this is low, it predisposes to respiratory and GI infections as well as autoimmunity; it is sometimes low in ASD children
- IgM: Rapid response bloodstream antibody made at the beginning of an infection; can be high or low in ASD
- IgG: Slower but longer lasting bloodstream antibody; can be high or low in ASD
- IgE: Allergy; can be high or normal in ASD
Conclusion #1: A child on the autism spectrum with recurrent infections deserves an immune evaluation for immunodeficiency.
Conclusion #2: A child on the autism spectrum with eczema, chronic nasal symptoms, asthma, significant GI symptoms, or recurrent respiratory infections deserves an allergy evaluation for IgE inhalant and food allergies.