House CallJun/Jul 2012 Issue

Research Roundup: Taste of Gluten, Hives, Celiac Screenings, and More!

First Taste of Gluten

For years, experts have recommended introducing gluten to infants at risk for celiac disease, such as those with parents or siblings with the condition, between 4 and 6 months of age. Now researchers at the University of Maryland Center for Celiac Research say there may be a benefit to delayed exposure, waiting until at least 12 months of age.

The new finding comes from a pilot study published in March in PLoS ONE, which looked at the intestines of 26 at-risk infants to find out how the introduction of gluten—early versus late—might play a role in the development of celiac disease.

Compared to those infants who weren’t exposed to gluten until 12 months, those exposed earlier, beginning at 6 months, developed celiac disease more frequently (by 24 months). One child was diagnosed with celiac at 24 months while a second developed type 1 diabetes, an associated autoimmune disorder, at 22 months.

“The introduction of gluten in an immature gastrointestinal microbiota [bacterial environment] could trigger or accelerate the development of autoimmunity,” write the researchers. Through stool sample analyses, the team discovered that the bacterial composition of the intestines of infants at risk for celiac didn’t mature at the same rate as other previously studied infants without a genetic susceptibility to celiac.

Results suggest that the microbial environment as a whole may be important to the onset of celiac and possibly other autoimmune disorders, Alessio Fasano, MD, co-lead author of the study, explained in a press release. A multicenter study with a larger number of infants is now underway.

The Meaning of Hives

When no cause can be found for chronic urticaria (hives), it could be autoimmune in nature, say researchers from Tel Aviv University in Israel. Investigators there recently undertook one of the largest studies to date on chronic urticaria (CU), confirming previous reports of a strong association between CU and multiple autoimmune disorders.

Individuals with CU were 17 times more likely than those without it to have been diagnosed with an autoimmune disorder, such as thyroid disease, celiac disease, rheumatoid arthritis or lupus. The high rate of autoimmune disorders lends support to the idea that CU is a member of this group of diseases, say researchers.

The study, published ahead-of-print in February in the Journal of Allergy and Clinical Immunology, provides a framework for better understanding CU, as well as helping to increase awareness of the potential for co-existing autoimmune disorders in individuals with CU.

First Born and Food Allergies

Researchers in Japan have found older siblings are more likely to have food allergies than younger ones. Led by Takashi Kusunoki, MD, PhD, a team from the Shiga Medical Center for Children and Kyoto University surveyed the parents of more than 13,000 school-aged children in Kyoto City, Japan. They observed that 4 percent of first-born children, 3.4 percent of second-born and just 2.6 percent of third or later born tots had a food allergy.

Older children expose younger ones to more germs, which may help protect them from food allergy. But the researchers also point out that the rate of food allergy in children in infancy—before age one—was lower in younger siblings, too, hinting that allergic status may be programmed early in life, possibly in the womb. Multiple pregnancies may cause changes to the mother’s immune system, which may in turn affect the fetus, say researchers. The study was published online in February in Pediatric Allergy and Immunology.

Screening Relatives for Celiac

Celiac experts have long recommended screening first-degree relatives for celiac disease. A study published in late 2011 in Medical Archives aims to drive home this message. In the study, researchers from the University Center at Tuzla in Bosnia and Herzegovina asked 75 parents and siblings of children newly diagnosed with celiac disease to take part in a screening initiative. Although none of the family members reported symptoms suggestive of celiac, 20 percent tested positive to at least one of the tests in the celiac panel. (Confirmatory biopsies were offered but in most cases they were declined.)

Researchers say their results are on par with other studies and demonstrate how screening can help identify a significant number of individuals with asymptomatic forms of celiac disease. The researchers also call attention to two specific study participants found to have positive test results. The first was a mother with a several year history of infertility. After adopting a gluten-free diet, she became pregnant, underscoring the importance of screening to help prevent serious complications of undiagnosed (untreated) celiac disease, such as infertility. The second case was that of an 8-year-old brother who happened to have been tested several years earlier. At that time, results were negative. But when he was screened as part of the research study, results were positive. Testing should be repeated every two to three years, the researchers write.

Tummy Troubles and Autism

Parents frequently describe gastrointestinal disturbances in children with autism. Such problems can impact a child’s quality of life as well as responses to treatments. Now a study published online in January in Autism Research finds parents aren’t over-reporting the presence of gastrointestinal troubles.

Researchers from Vanderbilt University and Zilkha Neurogenetic Institute at the University of Southern California found very high agreement—greater than 90 percent—between parent report of GI symptoms on study questionnaires and independent clinical evaluation by pediatric gastroenterologists. Parent-physician agreement on the specific type of GI disorder was somewhat lower (constipation was the most common diagnosis), but researchers say that’s to be expected since few parents are also GI experts. Over 120 children and their parents participated in the study. A third had autism and GI disturbances, another third had autism only, and the final group included typically developing children with GI symptoms.

Separately, a small study published online in January in mBio, reveals that over half of 23 children with autism and gastrointestinal disturbances had high levels of the bacterium Sutterella in the walls of their intestines. None of the nine children in the study without autism had the bacterium, despite also reporting gastrointestinal troubles.

The findings are notable because they were obtained via biopsy rather than stool samples; previous investigations into a link between microbes in the gut and autism have relied on stool samples. Little is known about Sutterella, including what role it may play in autism, the microbiota (the bacteria normally present in the body), infections and inflammation. Additional work with Sutterella is planned by the research team from the Center for Infection and Immunity at Columbia University’s Mailman School of Public Health.

Medical writer Christine Boyd lives in Baltimore.

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