Diagnostic de l’IgE-réactivité par analyse des composants moléculaires (test ISAC)

Abstract

Specific IgE-reactivities have first been implemented by the use of allergenic extracts then purified or recombinant major allergens. The frequent cross-reactivity (CR) due to vegetal and insect carbohydrate determinants has been suppressed by the use of bacteria originated recombinant allergens. CR linked to homology of amino acid sequences leads to classification of allergens, either species specific or cross-reactive ones. The micro array technology (ISAC) makes a component-resolved diagnosis possible by the analysis of 103 allergens. The assessment of this technique may be applied to different pathologies. Negative tests in eight cases of idiopathic anaphylaxis are reported. The ISAC microassay applied to atopic dermatitis shows different polysensitization profiles in 22 children compared to adults. The extensive association of aeroallergen and food allergen sensitizations is a hallmark of eosinophilic esophagitis. Another indication is to set a patient-taylored immunotherapy to pollens and mites. Present restrictions are the CR without clinical relevance (PR-10 family and tropomyosins), the poor performance of certain allergens (wheat allergens, Ana c 2, Ana o 3), the absence of allergens from the following allergenic sources: mustard, lupine, lentils, almond, walnut, buckwheat. In the near future, ISAC could be applied to epidemiological studies and to the follow-up of immunotherapies studied by specific IgG4s. Present prospects are to conduct thorough investigations about the efficiency of the currently available allergens, and to develop computerized algorithms taking into account clinical profiles and patterns of sensitization to improve the diagnosis of clinically relevant sensitization and to achieve the prediction of persistence and severity.