Allergy : New Thinking

Provocative new  thoughts on allergy have been presented in Nature this issue which makes it a timely reminder of previous commentary and research regarding possible links between autism and allergy.

“Allergies are generally thought to be a detrimental outcome of a mistargeted immune response that evolved to provide immunity to macroparasites. Here we present arguments to suggest that allergic immunity has an important role in host defence against noxious environmental substances, including venoms, haematophagous fluids, environmental xenobiotics and irritants. We argue that appropriately targeted allergic reactions are beneficial, although they can become detrimental when excessive. Furthermore, we suggest that allergic hypersensitivity evolved to elicit anticipatory responses and to promote avoidance of suboptimal environments.”

An editorial summary accompanies the piece here…

Allergy as the flipside of toxin protection

Have we got it wrong about allergy? Allergic reactions tend to be seen as the result of a misfire from an immune system that evolved to repel invasive parasites. In a Perspective this week, Noah Palm, Rachel Rosenstein and Ruslan Medzhitov see things differently. They discuss competing hypotheses about the origin and potentially beneficial aspects of TH2 cytokine-dependent allergic immune responses, with emphasis on the possibility that allergic reactions are excessive or exaggerated responses of a system that serves a necessary function, protecting the body from environmental toxins such as noxious substances, venoms and xenobiotics. The authors propose a model in which type 2 inflammatory responses are heterogeneous depending on the stimulus, and speculate that diverse evolutionary pressures may have selected for this class of immune responses.

The link between autism and allergy is under continuing investigation by researchers at Tufts University School of medicine.

Brief report: “allergic symptoms” in children with Autism Spectrum Disorders. More than meets the eye?

Many children with Autism Spectrum Disorders (ASD) have either family and/or personal history of “allergic symptomatology”, often in the absence of positive skin or RAST tests. These symptoms may suggest mast cell activation by non-allergic triggers. Moreover, children with mastocytosis or mast cell activation syndrome (MCAS), a spectrum of rare diseases characterized by increased number of activated mast cells in many organs, appear to have ASD at a rate tenfold higher (1/10 children) than that of the general population (1/100 children). Mast cell activation by allergic, infectious, environmental and stress-related triggers, especially perinatally, would release pro-inflammatory and neurotoxic molecules. We speculate these could disrupt the gut-blood-brain barriers, thus contributing to brain inflammation and ASD pathogenesis. Increased mast cell responsiveness may define at least a subgroup of ASD subjects, who could benefit from inhibition of mast cell activation.

…and here.

Mast cell activation and autism.

Autism spectrum disorders (ASD) are neurodevelopmental disorders characterized by varying degrees of dysfunctional communication and social interactions, repetitive and stereotypic behaviors, as well as learning and sensory deficits. Despite the impressive rise in the prevalence of autism during the last two decades, there are few if any clues for its pathogenesis, early detection or treatment. Increasing evidence indicates high brain expression of pro-inflammatory cytokines and the presence of circulating antibodies against brain proteins. A number of papers, mostly based on parental reporting on their children’s health problems, suggest that ASD children may present with “allergic-like” problems in the absence of elevated serum IgE and chronic urticaria. These findings suggest non-allergic mast cell activation, probably in response to environmental and stress triggers that could contribute to inflammation. In utero inflammation can lead to preterm labor and has itself been strongly associated with adverse neurodevelopmental outcomes. Premature babies have about four times higher risk of developing ASD and are also more vulnerable to infections, while delayed development of their gut-blood-brain barriers makes exposure to potential neurotoxins likely. Perinatal mast cell activation by infectious, stress-related, environmental or allergic triggers can lead to release of pro-inflammatory and neurotoxic molecules, thus contributing to brain inflammation and ASD pathogenesis, at least in a subgroup of ASD patients. This article is part of a Special Issue entitled: Mast cells in inflammation.

Listening to the stories in the video presented below certainly rings a few bells (alarm?) when I think of the symptomatology – anaphylaxis . lesions , itchiness when hot and faint feeling in sun … our son does not appear to have the pain , wind , diahrrea and other bowel problems that some mastocytosis sufferers

Further Reading of Dr. Theoharides at Tufts University

Hpothesis – Neuro-inflammation, blood-brain barrier, seizures and autism

Autism spectrum disorders and mastocytosis.

“We report that the apparent prevalence of ASD in patients with mastocytosis, a rare disease occurring in 1/4,000 children and characterized by an increased number of hypersensitive mast cells in many organs, is about 1/10 or 10 times higher than the general population”

Mastocytosis Video – Recommended Viewing

Dr. Theoharides at Tufts University

Dr Mariana Castells Harvard Medical School

Dr Norton J Greenberger Clinical Professor of Medicine Harvard Medical School

Dr Cem Akin Assistant Professor University of Michigan

Image: digitalart /



This entry was posted in Allergy, Autism, co-morbid, Environment, Treatment. Bookmark the permalink.

1 Response to Allergy : New Thinking

  1. Pingback: UCP2 – Mast Cells and Autism | asdresearchinitiative

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