|August 2, 1996|
American Academy of Allergy, Asthma and Immunology
611 E. Wells Street
Milwaukee, WI 53202-3889
Contact: Linda Bleimehl
Below are highlights of studies published in the July 1996 issue of the Journal of Allergy and Clinical Immunology, the peer-reviewed, scientific journal of the American Academy of Allergy, Asthma and Immunology (AAAAI). The full text of these studies may be obtained through the AAAAI public relations office.
ARE SOME CATS MORE "ALLERGIC" THAN OTHERS?
MILWAUKEE - Cat dander, a protein found in the saliva and pelt/skin of cats, is the substance that provokes allergy symptoms in allergic patients. Many patients note that certain cats provoke an extreme allergic reaction, while other cats seem to be well tolerated by allergic patients. In a study of five female and five male cats, a group of physicians from France found that male cats produced significantly more allergic protein (Fel d 1) than their female counterparts.
"Recent experiments from our group suggest that Fel d 1 synthesis is controlled by hormones, in particular, testosterone," note the researchers. "The observation that male cats seem to produce more Fel d 1 than female cats strengthens the belief that sebaceous glands produce both sebum and Fel d 1." Additionally, the strong relationship between concentrations of Fel d 1 found in fur and skin washes confirms the role of skin in the synthesis of the major cat allergen, researchers concluded. If these findings are substantiated by other investigators, male felines may definitely need to be barred from the indoor environment of allergy sufferers.
SEVERITY OF ASTHMA RELATED TO DUST MITE EXPOSURE
MILWAUKEE - A recent study indicates that exposure to indoor allergens, particularly to dust mites, can play an important role in both primary sensitization and the later development of asthma. Researchers from England studied a group of 53 asthmatics on which they performed skin tests for several allergens and pulmonary function testing, and collected dust samples from their homes. Sixty percent of the asthmatics had a positive skin test to mite allergen. In this same group, those with demonstrable bronchial hyperresponsiveness were exposed to significantly higher levels of allergens. Of the dust samples collected in various locations of the homes, the researchers found dust mite allergen concentrations to be the highest in beds.
Previous studies have noted when patients with mite-sensitive asthma move to a higher altitude or the mite-free environment of a hospital, their asthma improves. House dust mite avoidance in the home is associated with symptomatic improvement and the reduction in bronchial hyperresponsiveness and medication use. "Our results suggest that in mite-sensitive patients, the level of exposure to mite allergens has a major influence on severity and clinical activity of asthma," the researchers concluded.
TODDLERS WITH RESPIRATORY SYMPTOMS HAVE HIGHER ASTHMA RISK
MILWAUKEE - Children between the ages of three to four years old who have persistent respiratory symptoms such as cough, wheeze, attacks of shortness of breath, and frequent chest colds are 8.5 times more likely to develop asthma than children who don't have respiratory symptoms, according to new study by physicians in Tucson, Arizona.
The researchers who studied over 900 children participating in the Tucson Epidemiologic Study of Airways Obstructive Disease, grouped subjects into three categories: "6-11 months," "1-2 years of age," and "3-4 years of age." Of the children who had no significant respiratory symptoms between 1-and-4 years, only 5 percent were later diagnosed with asthma. In contrast, 35 percent of children who had symptoms at 3-4 years were later diagnosed with asthma. According to the researchers, the results illustrate the natural history of asthma in young children. "Our study shows that wheezing, coughing and frequent chest colds beginning or persisting after the age of 3 years significantly increases the risk of eventual asthma. As indicated in previous studies, we also believe that there may be two different groups of young children with lower respiratory tract symptoms," say researchers.
One of these groups, which is known by names such as "wheezy bronchitis" or "asthmatic bronchitis," is a self-limited illness, which peaks in incidence during the first year of life and then disappears. Asthma, the other illness, peaks in incidence later between 3 and 5 years. These illnesses overlap during the preschool years and are clinically indistinguishable. Viral infections may be responsible for the first type of illness, and children with relatively small airways are most susceptible. The risk of asthma may be related to allergic sensitization, conclude researchers, because it is correlated with skin test reactivity and serum IgE levels.
The AAAAI is the largest national medical organization representing allergists, clinical immunologists, and allied health professionals. Established in 1943, the Academy has more than 5,000 members in the United States, Canada, and 41 other countries.
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EDITOR'S NOTE: These studies were published in the peer-reviewed, scientific journal of the AAAAI, but do not necessarily reflect the policies or opinions of the AAAAI.
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