[Measurement of levels of specific IgE by the Efficient New Enzymatic Allergy (ENEA) System II (CIS bio)].

Abstract

The diagnosis of IgE dependant food allergy relies on the demonstration of specific IgE by prick tests or in vitro tests. The ENEA System II (CIS bio international) is a new automatic assay analyser of specific IgE, that uses allergens coupled to a solid phase and a urease marked anti-IgE antibody. This study aims to compare the performance of the ENEA System II to that of Pharmacia CAP System for the assay of food specific IgE (milk, eggs, peanuts) by means of unit tests and multitests. Sixty three patients were included: 10 non atopic controls, 19 egg-allergic patients, 10 patients allergic to cow's milk, and 24 patients allergic to peanuts. The food allergy was proved by means of a double blind oral, labial or bronchial challenge and/or effective avoidance of the food. For both systems, the specificity of unit tests was 100%. Sensitivity was 60% and 100% with both systems, using milk and peanuts respectively. However, using eggs, it was only 74% with ENEA System II versus 95% with Pharmacia CAP System. The intra-trial variation coefficients were comparable. In contrast, inter-trial variation coefficient was very high for the ENEA System II (20.3% versus 7.3%). The multitest named "children's food" showed an important inter-set variability. In conclusion, the ENEA System II is a rapid automatic tester whose performance has to be improved. The actual thermostatically control of the system was shown to achieve quality assay. The conservation of the solid phase, recently perfected, is expected to suppress the inter-set variability.