New molecular diagnostic test precisely identifies insect venom allergy

Bees, wasps and bumble bees pose a real health threat to individuals with venom allergy. One sting from these insects may cause potentially life-threatening anaphylactic reactions in people with these conditions. Physicians specializing in allergies need adequate tools for finding individuals that must be protected in advance against insect venoms. A new diagnostic test involving special allerg encomponents now makes it easier for specialists to identify optimal anti-venom therapy for the individual patients. The treatment secures long-term protection against anaphylactic reactions following insect stings.

This information was disclosed at the European Academy of Allergy and Clinical Immunology (EAACI), a meeting held in Istanbul 11 - 15 June, 2011.    

One of the presentations at the EAACI concluded that adequate treatment of venom allergy require precise assessment of the allergic reaction and the secure identification of the allergy-causing substances (allergens) involved. Such information is best gathered through molecular allergology diagnostic tests helping allergy specialists to decide on the right treatment for each individual patient.  

- Making the right decision can be crucial and life saving in cases of insect venom allergy, says professor, dr Thilo Jakob, allergist at the University Medical Center in Freiburg, Germany.

New allergen components diagnostic tests pinpoint the cause of allergy

One problem in diagnostic testing against venom allergy is that traditional diagnostic tests sometimes lack the precision needed to suggest the optimal treatment for the patient.

In conventional diagnostic tests using complete natural venom extracts for the detection of allergic reactions to bee or wasp venom, many patients result positive for allergy to substances from both insects, although they show clinical reactions to venom from only one kind. In most cases, such double positivity is due to specific antibodies, called IgE, directed towards certain molecular structures (called cross-reactive carbohydrate determinants or CCDs) present on several venom allergens from bee as well as from wasp. The IgE reaction to CCDs is detected in the conventional test as double positivity for both venoms, but these findings have rarely clinical relevance.

Today, it is possible to eliminate the problem of double positivity by testing with specially prepared "recombinant" allergen components completely free from the CCD structures. Tests using such components provide the same information as traditional diagnostic tests but can also determine whether double positivity is caused by "true" allergy to venom of one kind or the other, or whether the reaction observed is merely the result of CCD-dependent cross-reactivity.    

This new Molecular Allergology diagnostics can thus discriminate between real and "fake" reactions to bee and wasp venoms thus helping allergists to find the right and effective treatment for their patients. Studies have shown that the optimal treatment of venom allergy is venom immunotherapy (VIT) involving the patient's immune system by causing it to tolerate the allergens in insect venoms. Such "hyposensitization" has the potential to improve the safety and well-being of patients by providing effective protection against future anaphylactic reactions in the event of new insect stings.

Source: European Academy of Allergy and Clinical Immunology