Mise au point d'un dosage automatisé des IgE spécifiques des allergènes des pollens de cyprès et de genévrier par VIDAS Stallergy

Study objective

Cypress pollen is a significant cause of allergies in the Mediterranean area. In order to improve the in vitro diagnosis to cypress sensitization, we used a Juniperus ashei extract to develop a new semi-quantitative test for the measurement of IgE specific to juniper and cypress pollen allergens based on the VIDAS automated system.

Methods

The VIDAS Stallergy^® assay combines a two-step enzyme immunoassay sandwich method with a final fluorescence detection. The reagent comprises the Solid Phase Receptacle (SPR) coated with a J. ashei extract, which serves as a solid phase as well as a pipetting device during the assay and a strip that contains all the ready-to-use reagents.

Results

The precision study shows coefficients of variation lower than 1.7% for intra-assay variability and between 1.6 and 9.5 for inter assays variability. Correlation with the CAP system^® method shows an 80.7% agreement to the nearest class (N = 57). For 65% of sera class results are similar with the two techniques, and for 33% of sera, class results are higher with the VIDAS method. Test specificity is confirmed by VIDAS inhibition experiments. A sensitivity study performed using 82 clinically recognized cypress allergic patients shows that 97.6% of the patients are detected with the VIDAS Stallergy^® Juniper reagent.

Conclusion

The Juniper Stallergy^® test allows to measure specific IgEs to cypress pollen, with a sensitivity of detection at least similar to the CAP system^® method.