Process whereby the immune system reacts against the body’s own tissues. Autoimmunity may produce or be caused by AUTOIMMUNE DISEASES.
NLM Medical Subject Headings
U.S. National Library of Medicine, 2021
“Background: Encephalitis, the inflammation of the brain, may be caused by an infection or an autoimmune reaction.”
“Conclusion: Gut microbiota disruption was observed in encephalitis patients, which manifested as pathogen dominance and health-promoting commensal depletion. Disease severity and brain damage may have associations with the gut microbiota or its metabolites.”
Excerpts:
“Herein, we will discuss the accumulating literature for ASD, giving special attention to the relevant aspects of factors that may be related to the neuroimmune interface in the development of ASD, including changes in neuroplasticity.”
Commentary on the article:
“The authors rightly highlight the newest challenging frontier of autism research: the neuroimmune axis alterations. These alterations are first evident in the cells early responsible for immune responses, as they are the precursors for macrophages, dendritic, and microglial cells: monocytes or peripheral blood mononuclear cells (PBMCs). These cells show strong dysfunctions in ASD children and are committed to a pro-inflammatory state, which in turn result in long-term immune alterations (4). In ASDs, altered PBMCs are responsible for elevated pro-inflammatory cytokine production. The up-regulation of inflammatory cytokines is also reflected in brain centers of autistic patients (5): the consequences are the induction of blood–brain barrier (the immunological interface between peripheral immune system and central nervous system) disruption. Changes in BBB permeability directly influence neural plasticity, connectivity and function, triggering impairments in social interaction, communication, and behavior (3). Immunological abnormalities also influence the gastrointestinal system and the microglial innate immune cells of the central nervous system (6). The authors also discuss the role of autoimmunity in the pathogenesis of autism. Familial or virus/bacteria-infected autoimmunity could be a risk factor for autism. Even if the exact cellular and molecular pathways responsible for the induction of neuroimmune alterations are still to be further clarify, a complex interaction among epigenetic and environmental risk factors (7) could trigger the neuroimmune abnormalities, such as abnormal neuron and glia responses.”
Excerpts:
“The likelihood of the child having ASD more than doubled among children with food allergy compared with those without food allergy; children with respiratory and skin allergy were also significantly more likely to have ASD, but at a lesser magnitude. While no sex difference was found for food allergy, boys with ASD were significantly more likely than girls with ASD to have respiratory and skin allergy.”
” It may be that GI dysfunction, seizures, and sleep disorder, in addition to food, respiratory, and skin allergies, are medical comorbidities that characterize the immune-mediated subtype of ASD.”
“In the Discussion section of their article, Xu and colleagues review other aspects of immune dysfunction reported in ASD, including abnormalities in peripheral immunoglobulins, imbalance of T-cell subsets, and increased levels of proinflammatory cytokines in postmortem brains of patients with ASD. Considering the significant association between food, respiratory, and skin allergy in children with ASD reported by Xu and colleagues, in conjunction with numerous studies documenting aspects of immune dysfunction in patients with ASD and specific animal models of ASD, evidence continues to mount that an immune-mediated subtype of ASD should continue to be pursued and defined.”
CONCLUSIONS AND RELEVANCE In a nationally representative sample of US children, a significant and positive association of common allergic conditions, in particular food allergy, with ASD was found. Further investigation is warranted to elucidate the causality and underlying mechanism
Abstract
There are similarities between the immune response following immunization with aluminum adjuvants and the immune response elicited by some helminthic parasites, including stimulation of immunoglobulin E (IgE) and eosinophilia. Immunization with aluminum adjuvants, as with helminth infection, induces a Th2 type cell mediated immune response, including eosinophilia, but does not induce an environment conducive to the induction of regulatory mechanisms. Helminths play a role in what is known as the hygiene hypothesis, which proposes that decreased exposure to microbes during a critical time in early life has resulted in the increased prevalence and morbidity of asthma and atopic disorders over the past few decades, especially in Western countries. In addition, gut and lung microbiome composition and their interaction with the immune system plays an important role in a properly regulated immune system. Disturbances in microbiome composition are a risk factor for asthma and allergies. We propose that immunization with aluminum adjuvants in general is not favorable for induction of regulatory mechanisms and, in the context of the hygiene hypothesis and microbiome theory, can be viewed as an amplifying factor and significant contributing risk factor for allergic diseases, especially in a genetically susceptible subpopulation.
Excerpts:
“NDD, a derived diagnostic measure, was defined as having one or more of the following three closely-related diagnoses: a learning disability, Attention Deficient Hyperactivity Disorder, and Autism Spectrum Disorder.”
“Vaccinated children were significantly more likely than the unvaccinated to have been diagnosed with the following… ASD (4.7% vs. 1.0%, p = 0.013; OR 4.2, 95% CI: 1.2, 14.5),”
“In conclusion, vaccinated homeschool children were found to have a higher rate of allergies and NDD than unvaccinated homeschool children.”
INTERPRETATION:
Our findings suggest that predisposition to autoimmunity, and immune/inflammatory activation, may be associated with autistic regression.
Excerpt:
“Our results support previous observations that children with autism have elevated prevalence of specific immune-related comorbidities.”
Abstract
A role for immunological involvement in autism spectrum disorder (ASD) has long been hypothesized. This review includes four sections describing (1) evidence for a relationship between familial autoimmune disorders and ASD; (2) results from post-mortem and neuroimaging studies that investigated aspects of neuroinflammation in ASD; (3) findings from animal model work in ASD involving inflammatory processes; and (4) outcomes from trials of anti-inflammatory/immune-modulating drugs in ASD that have appeared in the literature. Following each section, ideas are provided for future research, suggesting paths forward in the continuing effort to define the role of immune factors and inflammation in the pathophysiology of a subtype of ASD
Abstract
The autism spectrum disorders (ASD) are a group of related neurodevelopmental disorders that have been increasing in incidence since the 1980s. Despite a considerable amount of data being collected from cases, a central mechanism has not been offered. A careful review of ASD cases discloses a number of events that adhere to an immunoexcitotoxic mechanism. This mechanism explains the link between excessive vaccination, use of aluminum and ethylmercury as vaccine adjuvants, food allergies, gut dysbiosis, and abnormal formation of the developing brain. It has now been shown that chronic microglial activation is present in autistic brains from age 5 years to age 44 years. A considerable amount of evidence, both experimental and clinical, indicates that repeated microglial activation can initiate priming of the microglia and that subsequent stimulation can produce an exaggerated microglial response that can be prolonged. It is also known that one phenotypic form of microglia activation can result in an outpouring of neurotoxic levels of the excitotoxins, glutamate and quinolinic acid. Studies have shown that careful control of brain glutamate levels is essential to brain pathway development and that excesses can result in arrest of neural migration, as well as dendritic and synaptic loss. It has also been shown that certain cytokines, such as TNF-alpha, can, via its receptor, interact with glutamate receptors to enhance the neurotoxic reaction. To describe this interaction I have coined the term immunoexcitotoxicity, which is described in this article.
