Immune Function & Autism

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.

A few studies published on the immune system and autism:

The role of immune dysfunction in the pathophysiology of autism

Autoimmune and gastrointestinal dysfunctions: does a subset of children with autism reveal a broader connection?

Association of family history of autoimmune diseases and autism spectrum disorders.

Plasma cytokine levels in children with autistic disorder and unrelated siblings.

Behavioral Correlates of Maternal Antibody Status Among Children with Autism.

Increased serum levels of anti-ganglioside M1 auto-antibodies in autistic children: relation to the disease severity. 

Detection of autoantibodies to neural cells of the cerebellum in the plasma of subjects with autism spectrumdisorders.

Altered gene expression and function of peripheral blood natural killer cells in children with autism.

Reduced Levels of Immunoglobulin in children with autism correlates with Behavioral Symptoms.

Autoantibodies to cerebellum in children with autism associate with behavior.