578 Comparison of the Modified Autologous Serum Skin Test and the Cd63 Basophil Activation Test in Chronic Urticaria

BACKGROUND: The modified CD63 basophil activation test in the diagnosis of chronic autoimmun urticaria was first described in 2004 by Szegedi et al. We demonstrated that the strongly sensitized basophils of atopic donors can be successfully used without the addition of IL-3 for the in vitro evaluation of autoimmun urticaria. Positive correlation was found between the basophil CD63 expression test and the autolog serum skin test (ASST), and between the CD63 test and the gold standard histamine release assay. METHODS: We examined 50 patients with chronic ordinary urticaria and with the help of a validated questionnaire urticaria score index was calculated. ASST with the patient's own diluted (1:10, 1:100) and undiluted sera, and CD63 basophil activation test on atopic donor basophils were performed. Pearson's exact test was used to analyze the correlation between the results of the CD63 assay and the urticaria score index. RESULTS: Based on our results ASST performed with diluted sera of chronic urticaria patients did not show correlation with the results of the CD63 assay. A significant correlation was found between the CD63 assay and the score index representing severity of disease. CONCLUSIONS: ASST with diluted sera of chronic urticaria patients does not have any additional information on the diagnosis of autoimmun urticaria. In the CD63 basophil activation assay the degree of the CD63 cell surface expression can give information on the severity of the clinical signs.