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Maternal antibodies can cause systems of autism in offspring
Maternal antibodies can cause systems of autism in offspring
< * w w w .sciencedaily . com /releases/2008/02/080211172535.htm>
Some Cases Of Autism May Be Traced To The Immune System Of Mothers
During Pregnancy
ScienceDaily (Feb. 12, 2008) ‹ New research from the UC Davis M.I.N.D.
Institute and Center for Children's Environmental Health has found that
antibodies in the blood of mothers of children with autism bind to fetal
brain cells, potentially interrupting healthy brain development. The
study authors also found that the reaction was most common in mothers of
children with the regressive form of autism, which occurs when a period
of typical development is followed by loss of social and/or language
skills. The findings raise the possibility that the transfer of maternal
antibodies during pregnancy is a risk factor for autism and, at some
point, that a prenatal test and treatment could prevent the disorder for
some children.
"While a growing body of research is dedicated to finding distinctions
in the immune systems of children with autism, this is one of the first
studies to identify immunological factors in mothers that could be
linked to autism in the very earliest stages of life," said Judy Van de
Water, senior author of the study and professor of rheumatology, allergy
and clinical immunology. "Our results should lead to more research on
the prenatal environment and the onset of autism. We are also optimistic
that in the future a prenatal test and therapeutic intervention
preventing IgG exposure during pregnancy could protect some children
from ever getting autism."
Van de Water and her team began their research with blood samples from
123 mothers -- 61 whose children have autism and 62 whose children are
typically developing. They isolated IgG antibodies from the samples then
exposed the antibody to fetal brain tissue by western blot analysis,
which detects antibody reactivity to proteins. The outcome revealed a
highly specific reactivity pattern to two fetal brain proteins in seven
of the 61 samples from the autism group, six of which were from mothers
of children who had regressive autism. None of the IgG samples from
mothers in the control group produced this same result.
"We're not entirely sure why the IgG response against fetal brain
proteins was so specific for later onset autism," said Van de Water.
"It's possible that early exposure to maternal antibodies sets in motion
a biological path to autism with the behavioral outcomes not apparent
until much later. It's also possible that an environmental exposure
sometime after birth could be required to set this process in motion. We
are hopeful that this study will help build our understanding of the
foundations of the regressive form of the disorder."
Characteristic features of autism -- social deficits, language
impairments and limited, repetitive behaviors -- are often clear early
in an affected child's life. Other children seem to progress normally
until 12-to-24 months of age, when developmental milestones disappear.
These distinct pathways have led clinicians to identify autism as one of
two types -- early onset or regressive -- potentially with distinct
causes and disease processes.
IgG antibodies are responsible for long-term immune system responses to
infection, but they can also contribute to autoimmune diseases such as
arthritis, multiple sclerosis and lupus. IgG also crosses the placenta
in order to provide key immune system protectants to a growing fetus and
newborn child, which is a key reason why Van de Water decided to
investigate the role of IgG as a potential factor in autism.
Van de Water next wants to know if IgG in women during the time of their
pregnancies produces the same response to fetal brain proteins. Women in
the current study were two-to-five years beyond childbirth. She will now
conduct the same study with women who are pregnant and already have a
child with autism, because such women are much more likely to have
another child with the disorder.
"If women in this next phase of the study give birth to a child
eventually diagnosed with autism, blood analyses from all stages of her
pregnancy will give us a clear picture of the immune system factors that
were in play during gestation and could have altered her child's
neurodevelopment," Van de Water said.
Other key next steps are to identify the specific proteins targeted by
autism-specific maternal antibodies and their role in neurodevelopment
and to determine whether or not exposure to maternal IgG during
pregnancy leads to behavioral or social distinctions in offspring.
Animal model studies are now under way to help answer these questions.
"Our outcome leads autism science in many new and exciting directions,"
said Daniel Braunschweig, pre-doctoral fellow of immunology in the Van
de Water lab, lead author of the current study and recent recipient of
an Autism Speaks mentor fellowship to further pursue this research. "We
now know we should be looking for the clues to the onset and pathology
of autism much earlier than was initially assumed. Future studies should
consider the immune system interactions between mother and child as a
focal point in creating greater understanding of, and eventually finding
effective preventions for, this complex neurodevelopmental disorder."
"This finding is important because it provides important clues about the
potential maternal contributions to autism risk in a subset of children
who may develop autism," said Isaac Pessah, director of the UC Davis
Center for Children's Environmental Health and professor of molecular
biosciences. "We're determined to find out what causes autism. Studies
conducted in the Van de Water lab are giving us valuable insights as to
when and where in the developmental process we should be looking for
those causes."
"We're very interested in understanding the underlying causes of
autism," said Cindy Lawler, scientific program director at the National
Institute of Environmental Health Sciences. "This finding, in
combination with other new research findings coming from NIH-funded
studies, demonstrates the complexity of this disorder and underscores
the importance of understanding how the mother's immune system can
influence early brain development."
The study, "Maternally Derived Antibodies Specific for Fetal Brain
Proteins," is to be published in the March 2008 issue of
Neurotoxicology. It was funded by the National Institutes of
Environmental Health Sciences, the U.S. Environmental Protection Agency
and the M.I.N.D. Institute.
Adapted from materials provided by University of California - Davis -
Health System.
Need to cite this story in your essay, paper, or report? Use one of the
following formats:
APA
MLA
New research suggests that the transfer of maternal antibodies during
pregnancy is a risk factor for autism and, at some point, that a
prenatal test and treatment could prevent the disorder for some
children. (Credit: iStockphoto/Olivier Lantzendörffer)
< * w w w .sciencedaily . com /releases/2008/02/080211172535.htm>
Some Cases Of Autism May Be Traced To The Immune System Of Mothers
During Pregnancy
ScienceDaily (Feb. 12, 2008) ‹ New research from the UC Davis M.I.N.D.
Institute and Center for Children's Environmental Health has found that
antibodies in the blood of mothers of children with autism bind to fetal
brain cells, potentially interrupting healthy brain development. The
study authors also found that the reaction was most common in mothers of
children with the regressive form of autism, which occurs when a period
of typical development is followed by loss of social and/or language
skills. The findings raise the possibility that the transfer of maternal
antibodies during pregnancy is a risk factor for autism and, at some
point, that a prenatal test and treatment could prevent the disorder for
some children.
"While a growing body of research is dedicated to finding distinctions
in the immune systems of children with autism, this is one of the first
studies to identify immunological factors in mothers that could be
linked to autism in the very earliest stages of life," said Judy Van de
Water, senior author of the study and professor of rheumatology, allergy
and clinical immunology. "Our results should lead to more research on
the prenatal environment and the onset of autism. We are also optimistic
that in the future a prenatal test and therapeutic intervention
preventing IgG exposure during pregnancy could protect some children
from ever getting autism."
Van de Water and her team began their research with blood samples from
123 mothers -- 61 whose children have autism and 62 whose children are
typically developing. They isolated IgG antibodies from the samples then
exposed the antibody to fetal brain tissue by western blot analysis,
which detects antibody reactivity to proteins. The outcome revealed a
highly specific reactivity pattern to two fetal brain proteins in seven
of the 61 samples from the autism group, six of which were from mothers
of children who had regressive autism. None of the IgG samples from
mothers in the control group produced this same result.
"We're not entirely sure why the IgG response against fetal brain
proteins was so specific for later onset autism," said Van de Water.
"It's possible that early exposure to maternal antibodies sets in motion
a biological path to autism with the behavioral outcomes not apparent
until much later. It's also possible that an environmental exposure
sometime after birth could be required to set this process in motion. We
are hopeful that this study will help build our understanding of the
foundations of the regressive form of the disorder."
Characteristic features of autism -- social deficits, language
impairments and limited, repetitive behaviors -- are often clear early
in an affected child's life. Other children seem to progress normally
until 12-to-24 months of age, when developmental milestones disappear.
These distinct pathways have led clinicians to identify autism as one of
two types -- early onset or regressive -- potentially with distinct
causes and disease processes.
IgG antibodies are responsible for long-term immune system responses to
infection, but they can also contribute to autoimmune diseases such as
arthritis, multiple sclerosis and lupus. IgG also crosses the placenta
in order to provide key immune system protectants to a growing fetus and
newborn child, which is a key reason why Van de Water decided to
investigate the role of IgG as a potential factor in autism.
Van de Water next wants to know if IgG in women during the time of their
pregnancies produces the same response to fetal brain proteins. Women in
the current study were two-to-five years beyond childbirth. She will now
conduct the same study with women who are pregnant and already have a
child with autism, because such women are much more likely to have
another child with the disorder.
"If women in this next phase of the study give birth to a child
eventually diagnosed with autism, blood analyses from all stages of her
pregnancy will give us a clear picture of the immune system factors that
were in play during gestation and could have altered her child's
neurodevelopment," Van de Water said.
Other key next steps are to identify the specific proteins targeted by
autism-specific maternal antibodies and their role in neurodevelopment
and to determine whether or not exposure to maternal IgG during
pregnancy leads to behavioral or social distinctions in offspring.
Animal model studies are now under way to help answer these questions.
"Our outcome leads autism science in many new and exciting directions,"
said Daniel Braunschweig, pre-doctoral fellow of immunology in the Van
de Water lab, lead author of the current study and recent recipient of
an Autism Speaks mentor fellowship to further pursue this research. "We
now know we should be looking for the clues to the onset and pathology
of autism much earlier than was initially assumed. Future studies should
consider the immune system interactions between mother and child as a
focal point in creating greater understanding of, and eventually finding
effective preventions for, this complex neurodevelopmental disorder."
"This finding is important because it provides important clues about the
potential maternal contributions to autism risk in a subset of children
who may develop autism," said Isaac Pessah, director of the UC Davis
Center for Children's Environmental Health and professor of molecular
biosciences. "We're determined to find out what causes autism. Studies
conducted in the Van de Water lab are giving us valuable insights as to
when and where in the developmental process we should be looking for
those causes."
"We're very interested in understanding the underlying causes of
autism," said Cindy Lawler, scientific program director at the National
Institute of Environmental Health Sciences. "This finding, in
combination with other new research findings coming from NIH-funded
studies, demonstrates the complexity of this disorder and underscores
the importance of understanding how the mother's immune system can
influence early brain development."
The study, "Maternally Derived Antibodies Specific for Fetal Brain
Proteins," is to be published in the March 2008 issue of
Neurotoxicology. It was funded by the National Institutes of
Environmental Health Sciences, the U.S. Environmental Protection Agency
and the M.I.N.D. Institute.
Adapted from materials provided by University of California - Davis -
Health System.
Need to cite this story in your essay, paper, or report? Use one of the
following formats:
APA
MLA
New research suggests that the transfer of maternal antibodies during
pregnancy is a risk factor for autism and, at some point, that a
prenatal test and treatment could prevent the disorder for some
children. (Credit: iStockphoto/Olivier Lantzendörffer)
