Effect of Brief Incubation with IL-3 on Whole Blood Basophil Histamine Release Tests

Abstract

RATIONALE: Several cytokines, including IL-3, IL-5 and GM-CSF enhance allergen induced histamine release from basophils. This study evaluates the effect of brief pre-treatment of whole blood with IL-3 on the correlation between allergen-induced basophil histamine release tests and allergen skin test results.METHODS: 75 rhinitis patients having a positive clinical history of allergic disease and positive skin tests and/or allergen-specific IgE tests (Phadia UniCAP) were studied. After brief incubation with IL-3 at a final concentration of 5 ng/mL or buffer alone, whole blood samples were placed on glass-fiber coated microtiter well plates (Ref Lab) together with serial dilutions of allergen extracts. The released histamine was detected by o-pthalaldehyde coupling and spectrophotometric detection. Specificity of the test was assessed by parallel experiments with blood samples to which either an irrelevant allergen (negative skin prick test and allergen-specific IgE test) or a relevant allergen (positive skin test and/or allergen-specific IgE test) were added.RESULTS: Histamine released from peripheral blood basophils correlated with the wheal diameter of the skin prick tests (r = 0.715; 95%CI, 0.583 to 0.811; p < 0.001). However, pre-treatment with IL-3 made the correlation even stronger (r = 0.817, 95%CI, 0.724 to 0.880; p < 0.0001). Area under the receiver operating characteristic (ROC) curve was significantly greater after IL-3 pre-treatment of the whole blood basophils (0.993, 95%CI, 0.963 to 0.999) versus without IL-3 pre-treatment (0.818, 0.747 to 0.877; p < 0.0001).CONCLUSIONS: Brief incubation of whole blood basophils with IL-3 improves overall performance of the whole blood basophil histamine release test. RATIONALE: Several cytokines, including IL-3, IL-5 and GM-CSF enhance allergen induced histamine release from basophils. This study evaluates the effect of brief pre-treatment of whole blood with IL-3 on the correlation between allergen-induced basophil histamine release tests and allergen skin test results. METHODS: 75 rhinitis patients having a positive clinical history of allergic disease and positive skin tests and/or allergen-specific IgE tests (Phadia UniCAP) were studied. After brief incubation with IL-3 at a final concentration of 5 ng/mL or buffer alone, whole blood samples were placed on glass-fiber coated microtiter well plates (Ref Lab) together with serial dilutions of allergen extracts. The released histamine was detected by o-pthalaldehyde coupling and spectrophotometric detection. Specificity of the test was assessed by parallel experiments with blood samples to which either an irrelevant allergen (negative skin prick test and allergen-specific IgE test) or a relevant allergen (positive skin test and/or allergen-specific IgE test) were added. RESULTS: Histamine released from peripheral blood basophils correlated with the wheal diameter of the skin prick tests (r = 0.715; 95%CI, 0.583 to 0.811; p < 0.001). However, pre-treatment with IL-3 made the correlation even stronger (r = 0.817, 95%CI, 0.724 to 0.880; p < 0.0001). Area under the receiver operating characteristic (ROC) curve was significantly greater after IL-3 pre-treatment of the whole blood basophils (0.993, 95%CI, 0.963 to 0.999) versus without IL-3 pre-treatment (0.818, 0.747 to 0.877; p < 0.0001). CONCLUSIONS: Brief incubation of whole blood basophils with IL-3 improves overall performance of the whole blood basophil histamine release test.