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Allergies in Young Children: Effects of Exposure to Multiple Air Pollutants During Prenatal and Early Life
Dec10

Allergies in Young Children: Effects of Exposure to Multiple Air Pollutants During Prenatal and Early Life

By Roberta Attanasio The frequency of allergies in children keeps rising rapidly worldwide, but it’s not clear why. However, it is acknowledged that developing even one type of allergy early in life is almost like turning on a switch—it can start children on a path to more. “The progression of skin allergies to asthma and allergic rhinitis is called the allergic or atopic march. Atopic dermatitis is an itchy, inflammatory skin allergy that, before 1960, affected fewer than 3% of children; by the 2000s it had increased to around 20%. A child with atopic dermatitis is more likely to develop other allergic conditions or symptoms. For example, about 70% of people with severe atopic dermatitis have asthma, whereas in those without atopic dermatitis, only about 8% have asthma—a nearly 9-fold difference.” According to the American Academy of Allergy, Asthma & Immunology, atopy refers to the genetic tendency to develop allergic diseases such as allergic rhinitis, asthma and atopic dermatitis (eczema). Atopy is typically associated with heightened immune responses, more specifically with excessive IgE production in response to common allergens, especially inhaled allergens and food allergens. Photo by Glenn Carstens-Peters on Unsplash Atopicn diseases (eczema, asthma and rhinoconjunctivitis) are clinical syndromes each defined by a group of symptoms and signs. Not all children with atopy will have atopic disease or develop symptoms after exposure to an allergen. Both genetic and environmental factors determine the development of atopic disease. Now, results from a new study show that there is a significant association between multiple prenatal and early life exposures to indoor pollutants and the degree of allergic sensitivity in 2 year old children. Now, results from a new study show that there is a significant association between multiple prenatal and early life exposures to indoor pollutants and the degree of allergic sensitivity in 2 year old children. For the study, researchers followed 108 mother-child pairs from birth to 2 years of age. They obtained data on the exposure to air fresheners, candles, mold, cats, dogs, carpet and environmental tobacco smoke during the prenatal, 6-month, 1-year, and 2-year timepoints. Then, they performed a skin prick test on both the mother and the 2-year-old child. A skin prick test, also called a puncture or scratch test, checks for immediate allergic reactions to as many as 40 different substances at once. This test is usually done to identify allergies to pollen, mold, pet dander, dust mites and foods. In adults, the test is usually done on the forearm, whereas children may be tested on the upper back. The researchers found that exposure to candles during the prenatal window, cats during the 6 month window, and environmental tobacco smoke at 2 years significantly increased the risk of a positive...

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Environmental Toxins and Damage to the Immune System: Transgenerational Effects
Dec05

Environmental Toxins and Damage to the Immune System: Transgenerational Effects

By Roberta Attanasio The hypothesis of the Developmental Origins of Health and Disease (DOHaD), also called “Barker’s hypothesis”, was formulated a few decades ago and stimulated interest in the fetal origins of adult disorders. Subsequent research by Mohan Manikkam and Michael Skinner helped establish the principle of transgenerational toxicity by showing that the effects of toxic chemicals can extend even to the third generation of offspring. Photo by Liv Bruce on Unsplash Indeed, it is now clear that early life development is a critical and unique window of vulnerability during which environmental exposures influence cellular programming in ways that shape health and disease later in life. While most research on the transgenerational effects of environmental chemicals focuses on the reproductive, nervous, or endocrine systems, results from a recently published study show that environmental toxins may also impair the immune system. Paige Lawrence, senior author of the study, said in a press release: “The old adage ‘you are what you eat’ is a touchstone for many aspects of human health. But in terms of the body’s ability to fights off infections, this study suggests that, to a certain extent, you may also be what your great-grandmother ate.” To carry out the study, researchers exposed pregnant mice to dioxin, a common by-product of industrial production and waste incineration which is also found in some consumer products. Thus, dioxins are environmental pollutants. They belong to the so-called “dirty dozen”—a group of dangerous chemicals known as persistent organic pollutants (POPs). Dioxins are of concern because of their highly toxic potential. In the environment, dioxins tend to accumulate in the food chain. The higher an animal is in the food chain, the higher the concentration of dioxins. Therefore, dioxins are found in greater concentrations in animal-based food products. Once dioxins enter the body, they last a long time because of their chemical stability and their ability to be absorbed by fat tissue, where they are then stored. Their half-life in the body is estimated to be 7 to 11 years.  After exposing pregnant mothers to dioxin, they assessed the production and function of cytotoxic T cells in the offspring. To do so, they infected the mice with influenza A virus, and found that exposure of the pregnant mothers to dioxin resulted in an impaired cytotoxic T cell response of the offspring against the influenza A virus. The impaired cytotoxic T cell response was observed not only in the offspring of the mice whose mothers where exposed to dioxin, but also in subsequent generations, up to the rodent equivalent of great-grandchildren.   Lawrence said: “When you are infected or receive a flu vaccine, the immune system ramps up production of...

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