Aha good timing...... The study refers to thw US- here mercury containing vaccines are still given routinely.
Almost everyone in dh's family has an autoimmune condition of some sort....
June 9, 2004
THE NATION
Study Finds Genetic Link Between Autism, Vaccines
A preservative once common in inoculations affected only one strain
of lab mice, possibly explaining the mixed results of past studies.
By Thomas H. Maugh II, Times Staff Writer
The mercury preservative used in some vaccines can cause behavioral
abnormalities in newborn mice characteristic of autism, but only in
mice with a specific genetic susceptibility, Columbia University
researchers report today.
The findings challenge the results of several large studies on
autism and bolster the fears of parents who have long believed their
children were harmed by the vaccines.
The fact that the preservative, called thimerosal, had an effect on
only one strain of mice could explain why researchers had found it
so difficult to prove or disprove a link to autism.
"The exciting thing is that this gives us a way forward in
understanding why we have not seen more conclusive findings on
either side of the fence, and how we need to design studies to pick
up gene-environment interactions," said Ellen Silbergeld of the
Johns Hopkins School of Public Health, who was not involved in the
study.
"I believe this has enormous implications for public health," said
Dr. Julio Licinio of UCLA, editor of the journal Molecular
Psychiatry, where the report is appearing.
"Showing that genetic background impacts on the outcome of
thimerosal exposure is a major breakthrough."
He added that the study clearly showed that there was a link between
vaccines and autism "for some groups and not for others."
An Institute of Medicine report released last month concluded that
there was no evidence to support a link and suggested that
researchers study other possible causes.
Dr. Steven Goodman of the Johns Hopkins School of Medicine, a member
of the commission that prepared the report, said those on the
commission were aware of the research.
"It's a tantalizing little piece of evidence that requires a lot
more work" to overturn the "tremendous amount of human work that
doesn't find a clue of a connection," he said.
The researchers have not yet identified the human analog of the
mouse gene or genes that confer susceptibility to the effects of
thimerosal, so it is not clear what proportion of children could be
at risk from vaccinations containing the preservative.
What they do know is that the genes are involved in the immune
system and that they make the mice more vulnerable to autoimmune
diseases. Researchers already know that as many as a third of
families with an autistic child have a history of autoimmune
problems.
The researchers do not believe that all cases of autism - or even a
majority of them - are caused by vaccines, said Dr. Mady Hornig of
Columbia, the lead author. "Autism is a constellation of syndromes
that almost certainly has many different causes," she said.
But the link to thimerosal may help explain recent increases in the
incidence of the disorder, she said.
Thimerosal, which contains ethyl mercury, has long been used as a
preservative in vaccines. Critics contend it became a problem in the
1970s, when the number of vaccines given to children increased
sharply.
Since 1999, it has been removed from most of the vaccines routinely
recommended for infants and children. It is still used in injectable
influenza vaccine, though some thimerosal-free flu vaccine is
expected to be available this year.
Autism is a severe developmental disorder in which children seem
isolated from the world around them.
There is a broad spectrum of symptoms, but the disorder is marked by
poor language skills and an inability to handle social relations.
No cure exists, but many problems can be alleviated with intensive
behavioral therapy.
Between 1975 and 1985, studies showed the U.S. rate of autism to be
about four cases per 10,000. Between 1985 and 1995, the numbers
tripled to 12 per 10,000. But researchers now think the actual rate
may be much higher, on the order of 20 cases per 10,000.
Several epidemiological studies have failed to find a link between
vaccines and the increase in autism, and laboratory studies in mice
and other animals have also failed to show a connection.
But researchers may have simply looked at the wrong animals, said
Dr. W. Ian Lipkin, in whose laboratory the new work was carried out.
Hornig and her colleagues studied four strains of mice, including
one strain - called SJL/L - in which mercury had previously been
shown to stimulate autoimmune disorders.
Newborn mice of each strain were injected with either thimerosal or
a thimerosal-vaccine combination at ages corresponding to those when
human infants are typically immunized.
The doses of mercury were also comparable to those used in humans.
The three strains of mice with no autoimmune susceptibility showed
no effects from either type of inoculation.
But virtually all of the SJL/L mice developed a variety of problems,
including delayed growth, abnormal response to novel environments,
decreased exploration of their environments, abnormalities in brain
architecture and increased brain size.
All of those are typical of children with autism, Hornig said.
"This is clearly showing that there is an interaction of genes with
the environment," said Dr. Daniel H. Geschwind of UCLA, who had been
looking for genetic causes of autism and was not involved with the
Columbia study. "The strain difference is . quite fascinating. This
will clearly rev the debate [about vaccines] up again."
The researchers are now following up on these findings by trying to
determine what other genes, if any, may be involved in the mercury
susceptibility.
They are also working with researchers at Brigham Young University
to try to find families with a genetic defect comparable to that
observed in the SJL/L mice to determine whether they have a higher
risk of autism.
END ARTICLE