September 6, 2016
Last week, we promised to take you through the science that proves that vaccines can and do cause autism. This is the first installment of that promise: the scientific evidence that immune activation is the root cause of autism. The article is reprinted by permission of the author from the website Vaccine Papers. The end of the article lists several possible objections to conclusions drawn here and the responses to those objections with article links backed by solid science. If you have any questions or there is a part of the article you don’t understand, please post them here as comments and they will be addressed.
And what does a vaccination do? It activates the immune system. That’s the point of vaccination. (emphasis in original)
-Dr. Paul Patterson of CalTech: Leading autism and immune activation researcher, 2006
Autism is not an immune-mediated disease. Unlike autoimmune diseases such as multiple sclerosis, there is no evidence of immune activation or inflammatory lesions in the central nervous system of people with autism.
-Dr. Paul Offit: Vaccine promoter, vaccine profiteer, and self-appointed autism pundit, 2009
For decades it has been accepted that the children of women who have an infectious illness (any illness) during pregnancy are much more likely to become autistic or schizophrenic. For many years, this was a well-proven, but mysterious association. Nobody knew why it happened. But it was very clear that something about the infection, or the immune response to it, had a profound, long-term effect on the child’s brain. Infection during pregnancy could cause schizophrenia 20 years later, even though the child appeared perfectly normal.
Before proceeding, it is necessary to provide definitions:
Cytokine: Protein substances that are used in cell signaling, especially by the immune system. Interleukins and interferons are two specific categories of cytokines (there are several others). During infections, the levels of (most) cytokines in the blood and other tissues increase as the immune system is responding. Cytokines control immune function, and also affect the brain. Cytokines can increase or decrease immune activity (“proinflammatory” or “antiinflammatory,” respectively). However, cytokines sometimes can not be categorized as “pro-” or “anti-“, since the effect on inflammation depends on the tissue and cytokine-cytokine interactions. Its complicated.
Neurons: The brain cells that process information by electrical impulses. The ones you are familiar with.
Neuroglia, Glial cells (same thing): Specialized immune cells that live in the brain and spinal cord. Two main types are microglia and astrocytes. In normal, healthy conditions, glial cells are at rest, and simply monitor and help the neurons. Glial cells can become “activated” by infection or toxins. When glial cells are “activated” they look for pathogens like bacteria, release cytokines, and can damage or protect the neurons. Glial cells do not process information. They defend against infection and help repair injury.
Microglial activation: When the immune system cells of the brain (“microglia”) are activated and think there is an infection nearby, or some problem they have to deal with. Microglial/neuroglial activation is immune activation in the brain. Also can be described as “brain inflammation” or “neuroinflammation.”
Purkinje cell: A type of neuron in the cerebellum, a part of the brain. Purkinje cell loss and damage is one of the most consistent observations in autistic autopsied brains. Purkinje cell loss and damage is present in over 90%+ of autism cases. This has been replicated in several studies. Purkinje cells are damaged by immune activation.
The Big Discovery
In 2005, a groundbreaking paper was published by Dr. Vargas of Johns Hopkins University School of Medicine. The Vargas paper has been cited 295 times (on PubMed). It’s a very important paper.
Paper (Vargas): “Neuroglial Activation and Neuroinflammation in the Brain of Patients with Autism”
The study was simple. Brains and spinal fluid from deceased autistic people (ages 5-44) and age-matched controls were analyzed for cytokines and other indicators of chronic inflammation/microglial activation. The findings were dramatic: every autistic brain at every age had very high levels of brain inflammation (elevated cytokines), compared to controls. Vargas et al. stated:
We demonstrate an active neuroinflammatory process in the cerebral cortex, white matter, and notably the cerebellum of autistic patients.
. . . neuroglial reactions . . . are important in the mechanisms associated with neural dysfunction in autism . . . .
. . . the presence of neuroinflammatory changes among the cases we examined suggests that this may be a common pathogenic mechanism in some patients with autism.
(Vargas et al., 2005)
Vargas also observed damage to Purkinje cells in all but one autistic brain, a confirmation of prior reports. This is why the cerebellum is mentioned specifically. The Purkinje cells of the cerebellum were heavily damaged.
Today, the evidence for a chronic inflammation in the autistic brain is overwhelming. For example, in the following excellent study, brains of autistic and matched normal subjects were scanned for markers of microglial activation by positron emission tomography (PET). The autistic brains had widespread microglial activation throughout the brain.
Paper (Suzuki et al.): “Microglial Activation in Young Adults with Autism Spectrum Disorder”
Above: Positron emission tomography (PET) images of autistic subject and normal control. Colored areas indicate regions of microglial (immune) activation. Colored areas are “inflammatory lesions.” Dr. Paul Offit claims the colored areas in the autistic brain do not exist. Dr. Offit tells this lie because he knows the inflammatory lesions implicate vaccines as a cause of autism. From Suzuki et al.
ASD = Autism Spectrum Disorder.
And for good measure, here is another paper reporting chronic brain inflammation in autism: “Elevated Immune Response in the Brain of Autistic Patients.” There are many papers confirming chronic inflammation in the autistic brain.
These results unequivocally contradict the above statement by Dr. Paul Offit. Dr. Offit was wrong when he wrote the above-quoted statement in 2009, and he is even more wrong today. Autism is an immune-mediated disease. Autistic brains have chronic inflammation and are loaded with inflammatory lesions.
Immune Activation and Brain Development
Dr. Paul Patterson, a biologist at the California Institute of Technology, noticed the Vargas results and other reports of microglial activation in autistics. In view of the studies linking prenatal infections with autism, Dr. Patterson suspected that immune activation during critical stages of brain development causes the chronic neuroinflammation and brain damage of autism.
Dr. Patterson wrote an excellent article in Cal Tech’s technology magazine in 2006, explaining this background, and his initial results. The article is here: “Pregnancy, Immunity, Schizophrenia, and Autism”-Patterson. This article is highly recommended as an introduction to the science.
Dr. Patterson worked with pregnant mice. During pregnancy, the mice were injected with “poly(I:C),” an immune-system stimulant that mimics viruses. When the immune system detects poly(I:C), it becomes activated, because it thinks there is a viral infection happening. But there is no actual infection. Poly(I:C) cannot cause infection. The only effect of poly(I:C) is to activate the immune system.*
Poly(I:C) injection causes increased cytokine levels, fever and sickness behavior. The injected mouse lies in the corner for a few hours, has a fever, sleeps a lot, and generally acts sick (even though they are not actually infected with anything). After several hours, the mouse returns to normal. In the experiments, the pregnant mice received 1-3 injections of poly(I:C). In this way, the developing fetuses are exposed to immune activation and associated high cytokine levels and fever.
The offspring are born, grown to maturity and then tested for behavioral abnormalities and dissected to look for signs of brain damage. These tests were specifically designed to look for autistic traits. The results were dramatic.
The mice exposed to immune activation displayed behavioral abnormalities analogous to human autism. They displayed reduced social interactions, reduced communications with other mice, and repetitive, compulsive behaviors. The Purkinje cells of the cerebellum were damaged, just like in human autism. And male mice were more strongly affected than females, just like human autism.
Also, Dr. Patterson found that immune activation caused permanent changes in brain cytokine levels, into adulthood. The cytokine changes from immune activation were similar to cytokine changes observed in human autism in the Vargas study. The exposed mice had chronic neuroinflammation lasting a lifetime.
Immune Activation Causes Autistic Behavior
Dr. Patterson did many experiments and published several papers. We will now look at one of the most important.
Autism is always diagnosed in humans by its behavioral characteristics. There is no objective or laboratory (e.g. blood) test for autism. The core symptoms of autism are:
1) reduced social interactions;
2) reduced language and communicative ability;
3) repetitive, compulsive behaviors.
These traits can be reliably measured in mice using a variety of behavioral tests which are monitored by computers.
Mice are highly social animals and communicate constantly by ultrasonic vocalizations (USVs). These vocalizations can be measured in number and duration in specific social situations (e.g. isolation, social encounters etc). These are well known and accepted research methods.
Vocalization During Separation
When baby mice are separated from their mother, they vocalize. In this test, mouse pups are separated from mothers, and vocalizations are recorded. Mice exposed to immune activation displayed significantly fewer vocalizations, and spent less time vocalizing. And the vocalizations had abnormal syllables, distinct from normal mice.
Above: Immune activation causes reduced ultrasonic vocalizations (USVs, “mouse speech”) from young mouse pups separated from their mothers. This behavior is analogous to human autism. From Malkova et al.
Vocalization During Social Encounter
In this test, adult male mice are introduced to unfamiliar adult female mice. Male mice exposed to immune activation displayed significantly fewer vocalizations when meeting the unfamiliar female. And once again, the vocalizations had altered syllables, distinct from normal mice. These results show that the reduction in communicative behavior persists into adulthood.
Mice were tested in the “three chamber social test.” A mouse under test can enter two rooms: one contains an inanimate object (like wood block or rock), and one contains an unfamiliar mouse. Normal mice are social and prefer to spend time with the unfamiliar mouse. Mice exposed to immune activation prefer to spend time with the inanimate object. Once again, this behavior is analogous to human autism. Here are the results:
Repetitive, Compulsive Behavior
Mice were tested for repetitive/compulsive behavior, with the well-known “marble burying test.” In this test, a mouse is placed alone in a cage with dozens of marbles. Mice like to bury things, and all mice will bury at least a few marbles. But some mice are obsessive about burying marbles and will tend to bury them all. This behavior is analogous to the repetitive, compulsive behavior common in human autism. Here are the results:
Above: Immune activation causes a dramatic increase in repetitive and compulsive behavior. This behavior is analogous to human autism. From Malkova et al.
Immune Activation: Non-Behavioral Effects
Human autism is defined by its behavioral abnormalities. But autism is strongly associated with several physiological abnormalities, including:
1) Missing and damaged Purkinje cells.
2) Mitochondrial dysfunction — Energy production by mitochondria is impaired in autism;
3) Long term brain inflammation (chronically elevated cytokines in the brain) — This was reported by Vargas and others (above).
4) Microbiome disruption (dysbiosis) — Dysbiosis is an abnormal composition of bacteria in the gut. Abnormal bacteria in the gut cause chronic inflammation in the gut and other tissues, including the nervous system.
Immune activation in animals produces all these features. This is powerful evidence that immune activation is the true cause of autism.
Purkinje Cell Damage
As noted above, Purkinje cells are almost always found to be damaged and/or missing in autism. Dr. Patterson found that immune activation (from poly(I:C)) caused a 20% reduction in Purkinje cells, which is comparable to the reduction seen in human autism. Dr. Patterson states:
Our finding of a localized deficit in Purkinje cells strikingly resembles that seen in autism both in location and magnitude, with a 25% reduction in Purkinje cell linear density reported in autism . . . and 20% [poly(I:C)] reductions reported here. (emphasis added)
Paper (Shi et al.): “Activation of the Maternal Immune System Alters Cerebellar Development in the Offspring”
Below are images of mouse cerebellum, showing the reduced number of Purkinje cells in mice exposed to immune activation (from influenza infection, not poly(I:C)). The Purkinje cells are the red dots at the surface of the cerebellum folds. Dr. Patterson reported that only specific “lobules” (numbered I, II, III, IV, V etc) of the cerebellum showed reduced Purkinje cell numbers, which is also just like human autism.
Above: Photographs of cerebellum from normal control mouse (L), and mouse exposed to immune activation (R).
Immune activation caused a significant reduction in the number of Purkinje cells (red dots). From Shi et al.
A single immune activation event from poly(I:C) causes a significant reduction in number of Purkinje cells. The same is observed in human autism.
Above: Immune activation causes reduction in number of Purkinje cells in some lobes of the cerebellum. From Shi et al.
The mitochondria are the energy-producing units inside cells. All cells have them. The mitochondria use a 4-stage process for producing energy. An enzyme “complex” is responsible for each stage (So there are four complexes: I, II, III and IV).
The following study (by a different research group at UC Davis) shows that immune activation (with poly(I:C) during gestation, like the above studies) causes permanent mitochondrial dysfunction. Specifically, immune activation causes reduced oxygen use by mitochondria and reduced complex I activity.
Paper (Giulivi et al.): “Gestational Exposure to a Viral Mimetic Poly(I:C) Results in Long-Lasting Changes in Mitochondrial Function by Leucocytes in the Adult Offspring”
Left: Immune activation causes reduction in oxygen use, a sign of mitochondrial dysfunction.
Right: Patterns of mitochondrial activity indicate a reduction in complex I activity due to immune activation. The same is observed in human autism. From Guilivi et al.
This result is very similar to human autism. Mitochondrial dysfunction (in brain and white blood cells) is well-proven in autism. And in human autism, complex I is damaged (along with complex IV). These papers, for example, describe mitochondrial dysfunction in autism:
“Mitochondrial Dysfunction in Autism,”
“Mitochondrial Abnormalities in Temporal Lobe of Autistic Brain.”
Chronic Brain Inflammation
In another paper, published in 2012, Dr. Patterson’s group reported that maternal immune activation caused long-term inflammatory changes in brain levels of cytokines, compared to unexposed controls. In this experiment, exposed mice and unexposed controls were dissected at different ages (0, 7, 14, 30, and 60 weeks of age), and the cytokine levels in different brain regions were measured. The paper states:
Most important, maternal immune activation induces striking, long-lasting changes in cytokine levels in the brains of offspring . . . .
Remarkably, many of the cytokines altered in the maternal immune activation brains and serum are similar to those found to be altered in autistic spectrum disorder and schizophrenia.
Paper (Garay et al.): “MIA Causes Cytokine Changes throughout Development” (Note: P0, P7, P14, P30, P60 refer to the age, in weeks, of mice when dissected)
These results explain the original findings of Vargas et al. described at the beginning of this article. Vargas reported elevated inflammatory cytokines in human autistic brains, and this experiment shows that immune activation causes similar increases in inflammatory cytokines. Immune activation during early brain development is likely the cause of life-long brain inflammation observed by Vargas and Suzuki (and others).
Microbiome Disruption (Dysbiosis)
A 2013 paper by the Patterson group (Hsiao et al.) reported that maternal immune activation caused abnormal microbiota (dysbiosis) in mice. Immune activation during early development caused long-term dysbiosis. In the study, the dysbiosis was permanent, lasting into adulthood. However it was treatable with probiotic (beneficial) bacteria delivered orally. The Hsaio paper states:
Subsets of ASD individuals display dysbiosis of the gut microbiota, and some exhibit increased intestinal permeability. Here we demonstrate gut barrier defects and microbiota alterations in a mouse model displaying features of ASD, maternal immune activation (MIA).
. . . these findings support a gut-microbiome-brain connection in ASD . . .
(ASD = Autism spectrum disorder)
The “microbiota” is the mixture of bacteria living in the gut. The microbiota can be healthy or diseased, depending on what bacteria are present. Immune activation causes an overgrowth of disease-causing (inflammatory) bacteria.
The Hsaio paper also reported that the probiotic bacteria Bacteroides fragilis (a human bacteria with strong anti-inflammatory effects), given orally to the mice, alleviated the damage. For example, B. Fragilis normalized gut permeability, normalized the microbiotia, and (in some measurements), completely normalized behavioral abnormalities. This is powerful evidence that autistic behaviors are caused by inflammation originating in the gut. Many parents of autistic children report that diets, probiotics and supplements targeting the microbiota can improve autism.
Full Paper (Hsaio 2013): “The Microbiota Modulates Gut Physiology and Behavioral Abnormalities Associated with Autism”
Above: Immune activation adversely affected the microbiota (dysbiosis). Dysbiosis is common in human autism. From Hsaio et al., 2013.
Above: Oral treatment with the beneficial gut bacteria Bacteroides fragilis reduced or eliminated autistic behavior. B. fragilis also normalized the microbiota and improved gut permeability (see paper for these results). From Hsaio et al., 2013.
Above: The Hsaio paper provides a pretty illustration explaining how immune-activation-induced dysbiosis damages the gut barrier and negatively affects the brain and behavior. This mechanism is similar to the hypothesis proposed by Dr. Andrew Wakefield in 1998. From Hsaio et al., 2013.
Immune activation in mice during early stages of brain development causes autistic behavior and causes many physiological characteristics observed in human autism. This obviously implicates immune activation as the fundamental cause of human autism. This is further reinforced by the studies showing an association between maternal infection and autism in the child. The evidence that immune activation causes autism in humans is diverse, consistent, and compelling.
Part 2 in this article series explains the specific immune signal that causes autism: http://vaccinepapers.org/part-2-interleukin-6-autism/.
Vaccine advocates make several objections to linking vaccines with immune activation experiments. The objections are addressed in the following articles:
Objection 1: “The mechanism for what is happening is not clear, and so cannot be linked to vaccines.”
Answer: The damage is caused by the cytokine interleukin-6 (and interleukin-17a). See Part 2: http://vaccinepapers.org/part-2-interleukin-6-autism/
Objection 2: “These are mouse experiments. Since autism is defined by behavior, a mouse model of autism is dubious.”
Answer: Immune activation experiments have been replicated in monkeys, with the same results: See part 3: http://vaccinepapers.org/part3-monkey-experiments/
Objection 3: “The studies are of maternal immune activation. Vaccines are given postnatally, without any maternal involvement.”
Answer: Both mouse and human brains can be damaged postnatally. No maternal involvement is necessary, since the brain-damaging cytokines can be produced by the infant brain: See part 4: http://vaccinepapers.org/postnatal-immune-activation/
Objection 4: “Vaccines do not cause strong enough immune activation to damage the brain. A vaccine cannot cause a surge of cytokines in the brain.”
Answer: Vaccine adverse reactions can cause very large cytokine expression in the brain, including expression of IL-6, a proven cause of autism. Aluminum (present in most vaccines) also stimulates IL-6 expression in the brain: See Part 5: http://vaccinepapers.org/vaccine-reactions-aluminum-il-6/
Also, aluminum adjuvant from vaccines travels into the brain: http://vaccinepapers.org/al-adjuvant-nanoparticles-can-travel-brain/
Click here for a list of papers mentioned in this article.