Oral Presentation Joint Annual Scientific Meeting of the Nutrition Society of NZ and the Nutrition Society of Australia

CD63 upregulation on basophils is not a predictor of salicylate sensitivity (204)

Sreepurna Malakar 1 , Peter Gibson 1 , Jane Muir 1
  1. Department of Gastroenterology, Central Clinical School, Monash University, Melbourne, Victoria, Australia

Background/Aims: About 2.5% of the general population show pseudoallergic reactions to salicylates (including aspirin). Patients with aspirin-exacerbated respiratory disease (AERD) show symptomatic improvement on low salicylate diet. Aspirin sensitivity is detected through oral provocation test - contraindicated in anaphylactoid reaction. Food salicylate sensitivity is detected through highly restrictive and lengthy ‘elimination and rechallenge diet’ raising compliance issues. More recently, an in vitro assay, the basophil activation test (BAT), is reported to detect pseudoallergic reactions with high sensitivity and specificity. However, the results remain controversial. The aim of this study was to examine the ability of BAT to differentiate known salicylate sensitivity from healthy controls (HC).

Methods: Peripheral blood of 10 AERD patients (2 males, 8 females), 10 HC (3 males, 7 females) was stimulated in vitro with aspirin (5, 2.5, 1.25, 0.6, 0.3, 0.15, 0.07 mg/ml). Flow cytometry was used to detect activated basophils (IgE+/CD63+). Stimulation index (SI) and percentage activation (% act) were used to determine basophil activation. Receiver-operator characteristics (ROC) were determined.

Results: Mean SI in AERD was similar to HC for all concentrations (p-values ranged from 0.178 (0.6mg/ml) to 0.800 (0.07 mg/ml), independent sample t-tests)). Likewise, % act did not differ between the groups (p-values ranged from 0.869 (2.5mg/ml) to 0.498 (5mg/ml)). No cut-off values were able to discriminate the two subject groups (area-under-the-curve for ROC analyses <0.5 for all).

Conclusions: BAT using CD63 is unable to predict salicylate sensitivity. It may not be an useful diagnostic test for non-IgE mediated pseudoallergic reactions.

Funding source(s): Gastroenterology department