Don’t blame the peanuts, blame transforming growth hormone for your child’s food and environmental allergies.
When it comes to food allergies, peanuts used to be it. Slowly
however, the kid who gave away his share of peanut butter cups became
the norm. According to the Centers for Disease Control and Prevention
(CDC), food allergies are becoming more common, and in 2007, about
three million children had at least one food or digestive allergy,
including milk allergies, gluten allergies, and nut allergies. At last,
researchers may have found a genetic pathway that controls them all.
Allergies were once thought to be a reaction to a child’s environment or upbringing, but researchers at the Johns Hopkins Children’s Center and the Johns Hopkins Institute of Genetic Medicine have uncovered a genetic glitch that they suspect is the basis for allergic diseases.
focused on patients with Loeys-Dietz syndrome (LDS), a genetic disorder
that also makes patients more likely to develop allergies. They found
that a signaling molecule called transforming growth factor-β (TGFβ)
kick-starts immune responses if it sends signals incorrectly.
affects immune cells called regulatory T cells, which usually help keep
the body from overreacting to safe substances like food and pet dander.
In children with allergies and those with LDS, these T cells actually
do the opposite, causing a greater allergic reaction.
multiple allergies stem from just one misbehaving protein molecule, it
may be possible to find a single, direct fix for childhood allergies.
was interesting to learn that an alteration in a single pathway in
people lead to such diverse allergic phenotypes, including asthma, food
allergy, eczema, and…gastrointestinal disease,” study author Harry
Dietz, M.D., a professor of medicine and genetics at Johns Hopkins, told
However, “more work needs to be done to define the
exact mechanism by which mutations in the TGFβ receptor perturb
immunologic maturation and tolerance,” Dietz said. This study is just
the first step, but it’s akin to finding a map to the ultimate
Finding a Delicate Balance
work in mouse models has suggested that low TGFβ activity can induce a
tendency for loss of immune tolerance,” Dietz said. In this study,
researchers found a connection between allergies and inflammation and a
cellular signature for high TGFβ signaling.
balance of TGFβ signaling in response to food and environmental
allergens is very delicate, and too little or too much can result in an
The study included 58 children with LDS between
the ages of 7 and 20, most of whom had a history of allergies,
displayed irregular TGFβ signaling, and had high levels of traditional
allergic disease markers like white blood cells. Researchers suspect
that their findings in LDS patients can be expanded to included more
allergic diseases in the general population.
“While these studies
instill hope that new therapeutic strategies for allergic disease are on
the horizon, it is essential to determine the best ways to achieve a
productive balance in TGFβ signaling,” Dietz said.
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