Uppsala, June 13, 2011
Precise assessment of patients with allergy to bee and wasp venoms helps allergists to identify the optimal venom immunotherapy (VIT) in each case. Molecular Allergology with recombinant allergen components facilitate the process by making it easier to differentiate between “true” allergies and cross reactivity.
This information was disclosed at the European Academy of Allergy and Clinical Immunology (EAACI) held in Istanbul 11 – 15 June, 2011.
- 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.
Stings from insects of the Hymenoptera order, such as bees and wasps, can cause severe distress to individuals with venom allergy. Studies have shown that optimal venom immunotherapy (VIT) improves the safety and well-being of patients by providing effective protection against future anaphylactic reactions. Indications for VIT are based on documented true sensitization and allergic reactions to venoms from the respective offending insect. The correct venom(s) to be used in treatment are selected in each case in accordance with the patient’s reaction to true venom allergens.
In traditional clinical tests using complete natural venom extracts for the detection of bee or wasp venom sensitization, many patients with allergy to bee and wasp result positive for venom from both insects, although they show clinical reactions only to one type of substance. In most cases, such double positivity is due to specific IgE antibodies directed towards Cross-reactive Carbohydrate Determinants (CCDs). The reason for this cross-reaction is that CCDs with identical structures are present on several venom allergens from bee as well as from wasp. The IgE reaction to CCDs is detected in the traditional test as double positivity for both venoms, but these findings have rarely clinical relevance.
It is possible to eliminate the problem of double positivity by testing with CCD-free recombinant allergen components. Tests using such components provide more detailed information than usual tests but they can also discriminate whether double positivity is caused by true sensitization or is merely the result of CCD-dependent cross-reactivity between venoms.
The test can thus discriminate between bee and wasp venom sensitization also in cases of double-positivity to the complete venom extracts
Molecular diagnostics with ImmunoCAP allergen components, for instance, include testing with components such as rApi m 1 (marker for honey bee), rVes v 1, rVes v 5/rPol d 5 (markers for wasps) and CCD, the marker of cross-reactivity between several venom allergen components.
Speakers at the EAACI meeting concluded that both complete venom extracts and recombinant components are necessary for a precise patient assessment in venom allergy.
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