More on Maternal Immune Systems and Maternal Antibodies: A cause of autism?
February 27, 2008 by Kristina Chew, PhD
Filed under Health
Genetic and environmental factors are frequently cited as causes for autism (and, just to be upfront about it, the genetic studies best explain why my son is autistic). Three recent studies suggest that immunological factors ought also to be considered.
Earlier this month, two studies conducted by researchers at the University of California-Davis M.I.N.D. Institute suggested links between autism and mothers’ immune systems. According to one study, some cases of “regressive autism” (in which a child seems to be developing normally and then loses skills and becomes autistic, in contrast to “early onset autism”) may be connected to the immune systems of mothers during pregnancy; researchers hope to further study IgG antibodies as a potential factor for autism (IgG antibodies are responsible for long-term immune system responses to infection and can also contribute to autoimmune diseases such as arthritis, multiple sclerosis and lupus). Another study found that an interaction between fetal brain cells and antibodies in mothers’ blood could be linked to “stereotypies” such as flapping, toe-walking, spinning, and other repetitive behaviors often noted in autistic children.
A third study reported in the February 25th Science Daily has found that mothers of some autistic children may have produced antibodies during pregnancy that affected their fetus’ brain tissue. The antibodies crossed the placenta and may have caused changes that led to autism:
Mostly anecdotal past evidence of immune system involvement has emerged from unusual antibody levels in some autistic children and from postmortem brain tissue studies showing immune abnormalities in areas of the brain. Antibodies are proteins the body makes in response to viruses and bacteria or sometimes mistakenly against its own tissues. Yet, the majority of children with autism have no clinical evidence of autoimmune diseases, which prompted researchers to wonder whether the antibodies transferred from mother to child during pregnancy could interfere with the fetal brain directly.
To test their hypothesis, the research team used a technique called immunoblotting (or Western blot technology), in which antibodies derived from blood samples are exposed to adult and fetal brain tissue to check whether the antibodies recognize and react against specific brain proteins.
Comparing the antibody-brain interaction in samples obtained from 100 mothers of autistic children and 100 mothers of children without autism, researchers found either stronger reactivity or more areas of reactivity between antibodies and brain proteins in about 40 percent of the samples obtained from the mothers of autistic children. Further, the presence of maternal antibodies was associated with so-called developmental regression in children, increasingly immature behaviors that are a hallmark of autism.
While the findings suggest an association between autism and the presence of fetal brain antibodies, the investigators say further studies are needed to confirm that particular antibodies do indeed cross the placenta and cause damage to the fetal brain.
“The mere fact that a pregnant woman has antibodies against the fetal brain doesn’t mean she will have an autistic child,” [Harvey] Singer [M.D., director of pediatric neurology at Johns Hopkins Children's Center] says.
The new study will be published in the February issue of the Journal of Neuroimmunology.
Since these studies connecting maternal antibodies to autism are focused on the immune system of mothers, it will be interesting to see if there is a greater focus on how a mother’s health might affect her fetus and its development, and what this might have to do with autism.
I do worry that this line of research will place more emphasis on unreasonable restrictions on pregnant women (or women hoping to become pregnant). I have long wondered if the increasing age of parents these days has some link to these issues – whether the eggs and sperm themselves have a shelf-life of sorts, or whether the increased risk of autoimmune disorder or other problems as we age increases the risk that some of these differences will be an issue.
As a society, we are engaged in a huge experiment that few recognize as such: we have delayed the age at which people have children substantially, and in a very short period of time. There could be all kinds of repercussions that we have no idea about. I’m just concerned that it will all be considered the mother’s fault – because afterall, isn’t everything?
I don’t know that I think it has as much to do with maternal age (as badmommy mentions above) but, perhpas, with family history of autimmune dysfunction. Then again, might it, in some cases, have as much to do with what happens to a child’s immune ystem in the early days of life –particularly children such as my son who spent a very long time in the hospital and were very ill/compromised. There are so many other factrs that may never be evaluated and/or considered—the way our food cahin/production has changed over the generations, the way our bodies have resonded to the changes, the environment, etc…I do not believe there is one specific, identifiable cause for autism that will be found.
I don’t think there are any links between microchimerism or antibodies trasfering and age of eggs etc. I read an article on this type of issue in scientific american where immune cells from a mother can cross the placenta and get involved in various problems. The article even addressed how in some situations the presence of the mothers cells can be highly beneficial. Such as providing immunity against diseases that normally wouldn’t be covered by the child’s immune system, or say people with autoimmune diabetes, after doing autopsies the only pancreas cells left were made from the mothers cells, not the persons. This may just be dealing with antibodies instead of the full cells like in microchimerism, but the basic principle is the same… in many cases child mother biological interactions of this type can be good just as often or more often than bad and we don’t have any real test for when when the good will happen vs the bad. All sorts of bad things could happen but many of these are already guarded against which is why this stuff doesn’t happen to every child. Eventually we might get some tests to help predict negative interactions between the child’s immune system and the mothers (children’s immune systems can pass to mothers and cause problems to) but we are nowhere near that point. We’re just figuring out a lot of this stuff works.
You are right the age of first and later childbirths is biologically important. I seem to remember they found important links between age of first birth and breast cancer. But all mommy’s fault? That’s a difficult assertion to make, especially since whether a child would be recognized by mom’s cells as foreign tissue to be attacked has at least as much to do with daddy’s tissue as with mommy. After all the thing that really makes a difference for this kind of thing is how similar the mother’s immune system is to the child’s. And we have no idea what triggers a change from mothers cells being helpful to attacking other than the most different the immune systems the better.
See more on related issues:
http://www.sciam.com/article.cfm?id=your-cells-are-my-cells
Thanks for that link—this is quite off the subject, but there was a theory in ancient Greek medicine that the woman was a “greenhouse” for the male’s seed; that the woman was just, as it were, a container, for the fetus to grow in. (This theory is described in the Greek tragedian Aeschylus’ Eumenides and also in some of the Hippocratic texts—-as in Hippocrates, the ancient doctor.) And who says that cultural attitudes don’t influence science, or what kinds of ideas are entertained…..
I’ve mentioned it before, but I’ll mention it again: It would not surprise me one bit if autoimmunity in families were found to ride side-by-side with autism spectrum disorders.
Also, on a potentially related note, of my three children, I developed pre-eclampsia/toxemia (immune-related disorder) with two and didn’t with one. Guess which children are on the spectrum or showing signs?
My family is enrolled in an autism registry and I remember being asked to participate in a study out of somewhere in Texas, last year or perhaps late 2006, that wanted us to list any members of the family, on both sides and of several generations, that had any kind of autoimmune disorder. So this is something a lot of people are working on, I think.
Oxidative stress (which is identical with low NO) does cause immune system deviation and so does tend to cause autoimmune sensitization. That is a “feature”, when a part of an organ is compromised, it becomes hypoxic and exhibits oxidative stress. That dysfunctional piece of tissue needs to be cleared by the immune system.
Emily, that exactly fits with my low NO hypothesis of ASDs. Preeclampsia is a low NO state.
Daedalus, you tout this low NO thing everywhere, and I’m now curious: could your hypothesis account for what I will, for complete lack of a better term, call adult-onset autism? I can’t be the only one who has shifted, around age 20, from being on the “quirky” side of NT to fitting diagnostic criteria for Asperger’s. This has coincided with a sudden increase in migraines and otitis media.
I know that correlation is nothing. It has also coincided with increased awareness of autism on my part, so perhaps I am more comfortable with myself.
This reminds me of the hypothesis that gay men are often boys with older brothers because their mothers produce antibodies that attack the fetus in some way. I don’t think I buy that line of reasoning, either, but it’s interesting.
I don’t agree that age has ANYTHING to do with anything (mentioned in earlier comments). I was 21 when I had my son , who was diagnosed with Autism at around 3 years old.
I am confused though. are they saying that mothers who did possibly play a part in their imuune systems maybe playing a part in an Autistic child, …will these mothers more than likely have some type of problems theirself? such as lups, MS, or arthritis?? wouldn’t that be a very good pssibility?
I am worried now.
Because my mother always seemed very healthy, but in her 40’s she was told she has a rare form of Lukemia. She also has rhumetoid arthritis.
I also feel that I may have a little bit of the Asphergers syndrome. lol.
I am pretty sure. I have always been extremley terified of being around new people, in front of a crowd, or looking someone in the eye when talking, and lots more.
I’m just scared now about possibly developing Lupus, or MS, or arthritis…or Lukemia. or if they are saying this about the mothers, couldn’t a child develope these illneses easier? (a child with autism)