Autism and The Immune System
The development of autism has long been recognized as having a complex interplay between genes and environment. Many theories with compelling evidence have been put forth regarding the biological basis of autism, including environmental toxicity; gut dysbiosis; cell danger response; hyper-dopamine; assortative mating, and more. However, no single theory carries definitive evidence as being the sole biological basis of autism.
General Immune System:
A great number of articles describe immune and inflammatory imbalances in autistic children, including alterations in antibody levels and high levels of inflammatory cytokines. Perinatal and early childhood infections, vaccinations, and allergies have all been implicated as potential triggers in the development of autism, but these factors are still very controversial at this point.
Atopy (Allergies, Eczema and Asthma):
Numerous reports have shown an increased association between atopic conditions (allergies, eczema, or asthma) early in life and the development of autism and ADHD. Allergy symptoms have been found to be 5 times higher in children with autism than neurotypical children. Studies have also found that eczema and asthma is more prevalent in children with Asperger’s compared to age matched controls (87% vs 7%).
Mast Cell Activation and Autism:
Mast cells are immune cells that are best known for their role in allergies. When mast cells are activated by an external stimulus, such as an allergen, infection, or insect bite, they release various inflammatory mediators and peptides that cause the classic allergic symptoms. These symptoms can range from hives, itching, difficulty breathing, rapid pulse, diarrhea, nausea, and more.
When mast cells are activated, in the case of allergies or eczema, these inflammatory cytokines can also have other undesirable effects, such as disrupting the blood brain barrier. One cytokine that is released from mast cells and found in high concentrations in the brain of children with autism is IL-6. Studies have shown that high levels of serum IL-6 is associated with autistic behaviour. For this reason, mast cells have been implicated as the “immune-gate to the brain” and an important factor contributing to the neuroinflammation found in autism.
It is believed that systemic immune activation from allergies, eczema, and asthma can trigger inflammation within the brain through various inflammatory mediators that are released from mast cells. While allergens are well-known mast cell activators, other environmental exposures and infectious agents can also trigger mast cell activation, including pesticides, heavy metals, bacteria, mould, viruses, and even stress.
Family history and personal history of autoimmunity has been found to be more common in children with autism. One study found that 46% of children with autism had 2 or more family members with autoimmune disease. Another study found that there is a 50% increase of being diagnosed with autism by age 10 among children whose parents had any autoimmune disease. Maternal autoimmunity during pregnancy is a recognized risk factor for the development of autism. Although the exact mechanism is not certain, it is believed that maternal autoimmunity may influence brain development by flooding the fetus with inflammatory cytokines in utero or by altering the child’s own immune response in early development.
There is strong evidence of Immune dysregulation as a driving force in the development of autism and catching it early on is key!
1. Those who have a personal history of autoimmune disease or atopy should do as much as possible before conception to stabilise the immune system!
2. A comprehensive autism intake should include questions regarding family history of autoimmune disorders, atopic conditions, and autism.
3. Mast cell stabilisation and immunomodulation is a key aspect of treatment in many cases of autism.