The Cellular Antigen Stimulation Test (CAST) in diagnosis of allergic and pseudoallergic reactions against hymenoptera venoms

The Cellular Antigen Stimulation Test (CAST) is a new method of in-vitro-di agnosis of allergic reactions. The test based on the prestimulation of bloo d leukocytes with cytokine IL-3 and the exposure to allergens. Mainly basop hiles react by synthesizing sulfido-leukotrienes LTC4 and its metabolites L TD4 and LTE4, which can be detected by ELISA technique. 84 patients with su spected allergy to hymenoptera venoms were investigated by means of the CAS T, CAP and the skin tests. Allergic reactions comprised all severity grades (I - IV ref. H.L. Mueller). The allergolocial work-up included skin test ( up to 1 mu g/ml), the measurement of specific IgE-antibodies by CAP system and Cellular Antigen Stimulation Test. The CAST was carried out with a conc entration of 0,2 mu g/ml bee and wasp venom (Apis mellifera, Vespula spec.) , respectively. A control group of 10 non-allergic CAP-negative individuals was established. Diagnostic accuracy of CAST was evaluated by comparison w ith the skin tests and CAP. With bee venom a sensitivity and specificity of 93/67% was obtained, while wasp venom showed 96/63% sensitivity and specif icity. In our investigations the CAST showed better results in comparison t o CAP results. In some cases pseudoallergic reactions could be detected aft er incubation with C 5a.