Five great food clusters of specific IgG for 44 common food antigens. A new approach to the epidemiology of food allergy

摘要

BackgroundStudies with mouse models demonstrate 2 pathways ofsystemic anaphylaxis: a classic pathway mediated by IgE,FcεRI, mast cells, histamine, and platelet-activating factor(PAF) and an alternative pathway mediated by total IgG,FcgRIII, macrophages, and PAF. The former requiringfewer antigens and antibodies than the latter. The importanceof the alternative pathway in humans is uncertain,but human IgG, IgG receptors, macrophages, mediators,and their receptors have appropriate properties to supportthis pathway if enough IgG and antigens are present [1].MethodsSpecific IgG antibodies for 44 common food antigens inserum were measured in 5010 Italian patients (3795females and 1215 males; age 44.67± 13.94 years). We usean unsupervised linkage procedure to identify clustersamong the 44 products. This agglomerative hierarchicalalgorithm intially has as many groups as variables, andthen groups are gradually fused together in function oftheir similarities. The algorithm stops when all productsbelong to a single cluster. We use the sample covarianceas similarity matrix between the variables, and a completelinkage method to measure distances between groups.This notion of distance guarantees that all the productsin a cluster are within a maximum distance of each other.ResultsWe identified five great food clusters. The first groupcontains dairy products starting from goat and cow milkas well as Parmesan cheese, mozzarella and ricottacheese. The second group consists in foods with higherconcentration of nickel salts such as tomatoes, spinach,oat, buckwheat and so on. Within this group it is possibleto identify the third cluster about wheat and relatedgrains such as kamut. The fourth group is about yeastssuch as Aspergillus fumigatus and Saccharomyces cerevisiaeand contains also porcini mushrooms and champignonmushrooms. This cluster is probably connectedwith fermented foods. In the last group appear foodswith the higher concentration of natural salicylates: productssuch as honey, tea, courgette, orange and so on.ConclusionThe identification of these five great food clusters isprobably connected with different diet habits. Once theimportance of the anaphylaxis alternative pathway inhumans subjects is clarified, this knowledge will be usefulin diagnosis and therapy of non-IgE-mediated allergicforms.Disclosure of interestNone declared.