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Master Thesis

Évaluation de l’intérêt du test d’activation des basophiles comme outil de diagnostic de l’allergie à l’arachide et aux protéines de lait de vache

Abstract : Background: determining the threshold dose and the severity of a potential clinical reaction is necessary. The benefit of the BAT in this context was assessed by using a new 6-concentration allergen determination method and its results compared to those obtained during OFC. Objective: this study’s primary objective was to compare basophils activation test (BAT) results based on a 6-concentration allergen calculation method (using R software) and oral food challenge (OFC) results in order to evaluate the BAT as a tool for diagnosis peanut allergy. The secondary goal was to determine BAT expression markers threshold causing reactions in children during OFC in order to replace the OFC by the BAT. Methods: a prospective study was carried out during the child's hospitalisation in a day hospital for OFC. All children were analyzed based on their BAT and OFC results. CDmax, CDsens and area under the curve (AUC) were monitored by flow cytometry after peanut whole extract (f13) or peanut molecular component Ara h 2 stimulation according to the expression of CD63 or CD203c. Results: 55 patients were enrolled in the study and performed OFC and BAT. One BAT non-responder patient were excluded. 3 others patients were also excluded due to activation of basophils during BAT in negative control. Thus 51 peanut BAT were analysed including 31 patients with positive OFC and 20 with negative OFC. We showed that CDsens to f13 or Ara h 2 calculated by our “R” method were closely comparable to those obtained by a method elsewhere published using a Pearson’s correlation with r = 0.82 and r = 0.83, respectively. By using this new method, we showed that CDsens and AUC to f13 or Ara h 2 were significantly increased in patients with positive OFC compared to patients with negative OFC, either for CD63 or CD203 (p < 0.0001). Futhermore, AUC were statistically correlated with threshold dose and the severity of allergic reaction during OFC. We next determined an optimal cutpoint of BAT AUC to f13 or Ara h 2 using CD203c or CD63 and showed that BAT AUC to f13 using CD63 and BAT AUC to Ara h 2 using CD63 seemed to be the more relevant BAT parameters in predicating OFC results. Conclusion : basophil reactivity was associated with OFC results, the threshold of allergic reactions and with clinical grade during OFC. BAT thus shows its interest and performance in the diagnosis of peanut allergy. It also makes it possible to assess the clinical severity of consuming a certain amount of peanut without going through OFC, when BAT is positive. AUC seems to be the best markers for predicting threshold dose during OFC for peanut-allergic patients, as well as to differentiate allergic patients from only sensitized patients. Peanut BAT would therefore be an excellent alternative to OFC, considerably decreasing the number of potentially dangerous OFC for children.
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Master Thesis
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https://dumas.ccsd.cnrs.fr/dumas-03642496
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Submitted on : Friday, April 15, 2022 - 10:31:13 AM
Last modification on : Friday, May 6, 2022 - 3:39:01 AM

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Marine Godignon. Évaluation de l’intérêt du test d’activation des basophiles comme outil de diagnostic de l’allergie à l’arachide et aux protéines de lait de vache. Médecine humaine et pathologie. 2019. ⟨dumas-03642496⟩

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