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June/July 2008 Issue
The Autism Puzzle - Understanding Autism Diagnosis
Goodbye Allergy Shots?
If you’ve been wishing for an alternative to allergy shots to treat your child’s allergic asthma, researchers from the University of Genoa in Italy have good news. A review of nine studies that included more than 400 patients between the ages of 3 and 18 found that children with allergic asthma might benefit from oral administration in the form of tablets or drops. Sublingual immunotherapy (SLIT) was found in the researchers’ review to lessen the symptoms of asthma and medication use.
Although much research exists on injection immunotherapy for allergies and asthma —and SLIT for allergic rhinitis—research on SLIT and its efficacy in treating asthma in kids is less abundant, say study authors. They found that, in addition to having fewer symptoms and needing less rescue medicines, kids receiving SLIT had only mild adverse effects that resolved on their own.
SLIT is routinely used in Europe; several clinical trials are now underway in the United States, the authors write. They call for additional research to determine the best doses and regimens. Their review appeared in the journal CHEST.
Focus on the Breath
If researchers at the University of Colorado at Boulder have anything to say about it, diagnosing diseases such as diabetes, cancer or asthma by analyzing a person’s breath won’t be just a bunch of hot air.
In a study published in Optics Express, scientists from the University of Colorado Boulder and the National Institute of Standards and Technology explain how they use laser light to analyze breath samples.
Certain molecules in exhaled breath can be markers for disease; detecting them may give doctors valuable diagnostic clues. For instance, excess amounts of a substance called methylamine may signal liver and kidney disease; high amounts of acetone may indicate diabetes; high nitric oxide levels can be used to diagnose asthma, according to Jun Ye, the physics professor who led the work. Detecting several molecules simultaneously can give highly reliable information. A patient is more likely to have asthma, for example, when carbonyl sulfide, carbon monoxide and hydrogen peroxide are detected along with nitric oxide.
Using the breath to look for markers of disease isn’t new. But approaches have been limited in detecting a range of rare markers or in detecting such small amounts of molecules, according to Ye. He had volunteers exhale into a space between two curved mirrors. He and his colleagues then directed laser light pulses into the space. Different molecules absorb light differently, and as the lasers ricocheted around the space, researchers were able to tell which molecules were present, and in what quantity, by how much light they absorbed.
The team is working on an enhanced laser system this year and hopes to be ready to work with doctors on clinical trials soon.
Allergies and IBS
About 15 percent of the population suffers from irritable bowel syndrome, or IBS, a painful gastrointestinal disorder. Atopic diseases, such as allergic rhinitis, eczema, asthma and food allergies affect about 20 percent of the population. Earlier research has hinted that exposure to allergens may trigger symptoms of IBS in patients with atopic disease, but no studies have yet looked at the frequency.
Researchers at Rush University Medical Center recently undertook a study of 125 adults to see whether there is a link. They found that among patients with IBS, 80 percent reported seasonal allergies (vs. 61 percent of patients without IBS); 51 percent reported allergic eczema (vs. 18 percent of those without IBS). Patients with seasonal allergic rhinitis were more than twice as likely to have IBS, and patients with allergic eczema were more than three times as likely to have the disease.
The findings suggest a “previously unappreciated” link between atopic disorders and IBS, and the researchers have proposed a subgroup of patients with what they’re calling “atopic IBS.” The distinction is important, they note, to further study how IBS develops, as well as find more effective therapies to prevent and manage it.
The research was published in the Annals of Allergy, Asthma & Immunology.
Possible Piece to Autism Puzzle
New research is adding to the evolving understanding of autism. The causes of the disorder, which affects about one in every 150 children in the United States, are still unknown, although genetic, metabolic and environmental factors are all suspected to play a role.
At Johns Hopkins University School of Medicine, research suggests that the mothers of some autistic children may have made antibodies against their fetuses’ brain tissue during pregnancy. Those antibodies may then have crossed the placenta and caused changes in the brain that led to autism.
The investigators took antibodies in blood samples from mothers of children with autism and mothers of children without autism and exposed the antibodies to fetal brain tissue to see if the antibodies recognized and reacted against certain proteins in the fetal brain. A comparison showed either stronger reactivity or more areas of reactivity between maternal antibodies and fetal brain proteins in about 40 percent of the samples from moms of autistic kids. In addition, the presence of maternal antibodies was associated with the regressive type of autism, in which children lose previously acquired communication and social skills.
The maternal antibodies may be another factor or trigger in kids already predisposed, according to lead investigator Harvey Singer, M.D., director of pediatric neurology at Hopkins Children’s Center.
Similar research conducted at the University of California at Davis also suggests that certain maternal antibodies may react with fetal brain tissue and lead to regressive autism.
“We’re not entirely sure why the [antibodies’] response against fetal brain proteins was so specific for later onset autism,” said Judy Van de Water, senior study author and professor of rheumatology, allergy and clinical immunology, in a press release. “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.”
Building on Van de Water’s work, another group at UC Davis exposed eight monkeys to human antibodies during pregnancy. Half the monkeys received antibodies from mothers of kids with autism; the other half received antibodies from moms of neurotypical children. Researchers found mild social alterations in all four monkeys who had received antibodies from the mothers of autistic children, and all four engaged in distinct, repetitive behaviors much like those seen in autism.
“The major significance of this study is that it links exposure to abnormal immune system factors during pregnancy with specific behavioral outcomes in offpsring,” said David Amaral, research director of the M.I.N.D. Institute at UC Davis and senior author of the study.
Although the research suggests a link between certain maternal antibodies and development of autism in some children, further study is needed. This, and future research may lead to a more complete understanding of how and why the disease develops and, eventually, tests and therapies to predict and prevent it.