Diagnosis of venom allergy by flow cytometry. Correlation with clinical history, skin tests, specific IgE, histamine and leukotriene C4 release

Background Potent allergens such as hymenoptera venoms are capable of induc ing severe and life threatening clinical reactions. Percentage of false neg ative results obtained by the usual diagnostical methods is comprised betwe en 10 and 25% Objective Evaluation of the sensitivity and the specificity of cellular tes ts and particularly evaluation of a new flow cytometric method. Methods Forty-five allergic patients having experienced a local, a systemic reaction or an anaphylactic shock and 10 controls having undergone hymenop tera stings without clinical reactions were selected on the basis of the cl inical history, skin tests and specific IgE. Three cellular tests were perf ormed on the same cell suspensions and in the presence of 2 ng/mL of rIL3: histamine release (RIA), leukotriene C4 release (ELISA) and basophil activa tion test (flow cytometry after double anti-IgE FITC, anti-CD63 PE labellin g). Results As compared to the clinical history, sensitivities of skin tests, s pecific IgE, flow cytometry, histamine release and leukotriene release were , respectively; 85%, 88%, 100%, 89% and 100%. Flow cytometric analysis of b asophil activation showed a significant decrease of the mean fluorescence d ensity and number of IgE positive cells and a significant increase of the n umber of CD63 positive cells. The 10 controls tested by flow cytometry were negative. Conclusion As compared to the clinical history and to the other parameters tested here, flow cytometry showed a high sensitivity and a high specificit y. The excellent correlation observed between this method and the other cel lular tests such as histamine and leukotriene release are in favour of the specificity of flow cytomery and in favour of the use of this method for ve nom allergy diagnosis.