779:
Novel Markers in the Basophil Activation Test may Improve its Clinical Relevance as a Diagnostic Tool
Monday, March 5, 2018
South Hall A2 (Convention Center)
Ursula R. Janikowski, M.S., Jenna R. Bergerson, MD MPH, Paul J. Bryce, PhD, Anne Marie Singh, MD
RATIONALE: The basophil activation test (BAT) has been used experimentally to detect IgE mediated responses, but is not widely used as a clinical diagnostic tool in pediatric food allergy. We hypothesized the use of novel activation markers may increase specificity in the BAT, or correlate to the severity of symptoms.

METHODS: Fifteen children with and without food allergy were recruited from Lurie Children’s Hospital. Peripheral blood was collected from each patient and was stained for BAT testing before being run by flow cytometry. Activated basophils were measured by CD63 expression. Clinical histories were obtained by a board-certified allergist, and were scored for severity of food allergy symptoms. Cell-surface marker activation was compared between children with and without food allergy using the Kruskal-Wallis test, while the one-way ANOVA was used to compare percent marker activation to severity score. The interaction between antigen stimulation dose and symptom severity on BAT marker expression was calculated using a two-way ANOVA test.

RESULTS: CD63, CD82 and CD164 demonstrated increased expression in activated basophils upon antigen stimulation in food allergic children and not in control children (p<0.05 for each marker). CD63 upregulation on basophils correlated to stimulation dose (p=0.0002), but not clinical severity (p=0.41092). Similar results were seen for CD82 (p<0.0001; p=0.1297) and CD164 (p=0.0001; p=0.1135). Interestingly, CD151 correlated with both stimulation dose (p=0.0010) and clinical severity (p=0.0176).

CONCLUSIONS: Novel markers may improve the clinical relevance of the BAT test and provide a way to predict severity of food allergy symptoms in children.