ABSTRACT
BACKGROUND: Double-blind placebo-controlled food challenge (DBPCFC) is currently considered the gold standard for peanut allergy diagnosis. However, this procedure that requires the hospitalization of patients, mostly children, in specialized centers for oral exposure to allergens may cause severe reactions requiring emergency measures. Thus, a simpler and safer diagnosis procedure is needed. The aim of this study was to evaluate the diagnostic performance of a new set of in vitro blood tests for peanut allergy. METHODS: The levels of IgE directed towards peanut extract and recombinant peanut allergens Ara h 1, Ara h 2, Ara h 3, Ara h 6, Ara h 7, and Ara h 8 were measured in 3 groups of patients enrolled at 2 independent centers: patients with proven peanut allergy (n=166); pollen-sensitized subjects without peanut allergy (n=61), and control subjects without allergic disease (n=10). RESULTS: Seventy-nine percent of the pollen-sensitized patients showed IgE binding to peanut, despite their tolerance to peanut. In contrast, combining the results of specific IgE to peanut extract and to recombinant Ara h 2 and Ara h 6 yielded a peanut allergy diagnosis with a 98% sensitivity and an 85% specificity at a positivity threshold of 0.10 kU/l. Use of a threshold of 0.23 kU/l for recombinant Ara h 2 increased specificity (96%) at the cost of sensitivity (93%). CONCLUSION: A simple blood test can be used to diagnose peanut allergy with a high level of precision. However, DBPCFC will remain useful for the few cases where immunological and clinical observations yield conflicting results.
Subject(s)
2S Albumins, Plant/immunology , Antigens, Plant/immunology , Glycoproteins/immunology , Immunoassay/methods , Peanut Hypersensitivity/diagnosis , 2S Albumins, Plant/genetics , Adolescent , Antigens, Plant/genetics , Arachis/genetics , Arachis/immunology , Arachis/metabolism , Child , Child, Preschool , Double-Blind Method , Female , Glycoproteins/genetics , Humans , Immunoglobulin E/blood , Infant , Male , Peanut Hypersensitivity/immunology , Recombinant Proteins/genetics , Recombinant Proteins/immunology , Sensitivity and SpecificityABSTRACT
Correlations between different peripheral blood parameters and harvesting yields of stem cells were analysed in 230 leukaphereses performed on 61 patients. According to multivariate analysis, the number of circulating CD34 positive cells was found to provide the best preleukapheresis parameter for predicting the quality of peripheral blood progenitor cell harvest. A high correlation coefficient and small 95% confidence and prediction intervals would indicate the assay of CD34 positive cells in peripheral blood to be a unique tool essential for monitoring the collection of circulating haematopoietic progenitors.
