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Title: AAAAI: Allergen-Specific IgE Test Confirms Increase in Allergy Frequency and Severity
URL: http://www.pslgroup.com/dg/24B7CE.htm
Doctor's Guide
March 22, 2005


By Paula Moyer

SAN ANTONIO, TX -- March 22, 2005 -- A new test that identifies allergen-specific immunoglobulin E (IgE) in blood samples gives quantifiable evidence that allergies are increasing in both frequency and severity, according to findings presented here at the 61st annual meeting of the American Academy of Allergy, Asthma, and Immunology.

The test provides a more accurate and noninvasive way of identifying allergens than either skin tests or the conventional blood assay, radioallergosorbent test (RAST), said investigator P. Brock Williams, MD, associate clinical professor, department of allergy and immunology, University of Cincinnati Medical School, Cincinnati, Ohio, United States.

These benefits could help physicians as they counsel allergic patients on appropriate therapies and avoidance measures, Dr. Williams said.

"Diagnosing allergies has been … susceptible to bias until now," he said. However, the study used the new test to provide quantitative data showing that the incidence of allergies is, in fact, increasing in industrialised society, he explained.

The new test -- known as ImmunoCAP -- measures allergen-specific IgE levels in blood. Unlike skin tests, any antihistamines the patient may be taking do not affect the test's accuracy, according to company literature. The manufacturer also claims that the new test is more accurate than RAST, which is known to be less sensitive than skin tests.

Dr. Williams wanted to determine the truth of numerous reports that suggested the incidence of allergies was increasing in industrialised societies. The concern was whether the reported increase was due to improved reporting methods, growing patient awareness, or use of better tests, or whether the increase was real and attributable to environmental or lifestyle changes.

In a previous study that focused on the genetics of asthma, he had recruited families with at least one parent who had reversible airway disease. The family members were tested with the new system for IgE specific to several common allergens; however, the study focused on dust mite allergen. The cohort consisted of 666 parents with 797 children, for a total database of 1,458.

Among these participants, 302 (45.3%) of the parents and 479 (60.1%) of their sons and daughters had mite-specific IgE, which was defined a positive test as more than 0.35 KU/L.

When Dr. William quantified the mite-specific IgE levels in the parents versus the children, he found that sensitized parents had an average mite-specific IgE level of 14.8 KU/L, while the sensitized children had an average level of 51.7 KU/L.

Further, 10% of parents had mite-specific IgE that exceeded 100 KU/L, compared to 42% of the children.

The findings show large, objectively measurable increases in mite-specific IgE levels between parents and their offspring, Dr. Williams said. Therefore, the findings lend credence to the theory that the incidence of allergies, as well as their severity, is increasing, he concluded.

The study was funded by Pharma Diagnostics, which manufactures ImmunoCAP.


[Presentation title: Differences in Mite Specific IgE Between Asthmatic Parents and Their Offspring are Large. Abstract 676]

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