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Avoiding Pets May Not Prevent Allergies

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October 22nd, 2003, 11:33 AM
American Academy of Allergy, Asthma and Immunology

Avoiding Pets May Not Prevent Allergies, From the Journal of Allergy and Clinical Immunology

-- Exposure to high levels of cat allergen as a child may prevent the development of allergies, according to a study published in the October 2003 Journal of Allergy and Clinical Immunology (JACI). The JACI is the peer-reviewed journal of the American Academy of Allergy, Asthma & Immunology (AAAAI).
Researchers found that avoiding having cats or dogs as pets may not protect against the development of allergies. Eva Ronmark, PhD, and colleagues from the Obstructive Lung Disease in Northern Sweden Study Group and the University of Virginia at Charlottesville studied 2,454 children in Northern Sweden, ages 7 to 8 years. The children were skin tested originally in 1996 and again in 2000. In addition, parents completed questionnaires each year asking about risk factors.

The study found that, despite cat being the most common allergens of sensitization, keeping these animals at home was not related to an increased risk for the development of sensitization between age 7 and age 11. Children who continually owned cats or dogs had a lower incidence of developing allergies to the animal compared to new pet owners and to those who had only been exposed earlier in life. Among the children allergic to cats, 80% had never kept a cat at home.

Researchers found that persistent exposure to high levels of cat and dog allergen appears to be protective against the development of an allergy among both boys and girls.

The fact that allergy symptoms increase when a person who is allergic is exposed to the allergen has resulted in the assumption that avoiding cats and other pets at home protects against the development of an allergy to the animal. The current findings from the October JACI study go against traditional thinking that increased exposure to cats and dogs results in more severe symptoms.

Breast feeding may decrease risk of asthma

Cytokines present in breast milk may decrease an infant's risk of developing asthma, according to a study published in the October 2003 Journal of Allergy and Clinical Immunology (JACI).

Wendy H. Oddy, PhD, from the University of Western Australia and colleagues investigated the relationship between the level of the cytokine TGF-B1 in breast milk and wheeze in infancy to determine whether breast milk has a protective effect against developing asthma symptoms.

It has recently been shown that breast milk contains cytokines, the most abundant of which is TGF-B1. It is believed that TGF-B1 has a potent immunosuppressive action that may prevent sensitization to food allergens. Researchers also believe that TGF-B1 enhances infant lung development and helps to reduce susceptibility to respiratory infections.

In the study, data on breast feeding and infant wheeze were collected from birth to 1 year from 243 mothers participating in the Infant Immune Study in Tucson, Arizona. Researchers showed that the dose of TGF-B1 received from breast milk is significantly associated with infant wheeze, suggesting that at least some of the protective effect of breast feeding against wheeze might be attributable to the presence of this cytokine in the milk.

Previous studies have shown that breast feeding infants for at least four months provided them protection from developing asthma. However, the current study is the first to study the effects of a cytokine in breast milk on the health of an infant.

Urine test may diagnose asthma in infants

Urine tests may help with the diagnosis of asthma in infants, according to a study published in the October 2003 Journal of Allergy and Clinical Immunology (JACI).

In the study, researchers from the North West Lung Centre in Manchester, England, studied the eosinphilic protein X (EPX) levels in the urine of 903 three-year old children. EPX plays a role in the airway inflammation seen in asthma and is the only eosinphile that can be accurately measured in urine.

The study found that EPX levels were significantly higher in children with wheezing as well as in children with chronic cough. Researchers conclude that measuring EPX levels in urine could be a useful additional test when making the decision to start asthma treatment on a young child with chronic cough or wheezing.

The AAAAI is the largest professional medical specialty organization in the United States representing allergists, asthma specialists, clinical immunologists, allied health professionals and others with a special interest in the research and treatment of allergic disease. Allergy/immunology specialists are pediatric or internal medicine physicians who have elected an additional two years of training to become specialized in the treatment of asthma, allergy and immunologic disease. Established in 1943, the Academy has nearly 6,000 members in the United States, Canada and 60 other countries. The Academy serves as an advocate to the public by providing educational information through its Web site at www.aaaai.org or the toll-free physician referral and information line at 1-800-822-2762.




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Source: American Academy of Allergy, Asthma and Immunology