A larger study of food-related IgG confirms the possible new epidemiological approach to non-IgE-mediated reactions and suggests five great food clusters

摘要

BackgroundStudies in mouse models show 2 pathways of systemicanaphylaxis: the classic one mediated by IgE, FcεRI, mastcells and histamine and platelet-activating factor (PAF)and the alternative way mediated by total IgG, FcgRIII,macrophages, and PAF. The importance of the latter inhumans is still uncertain, but human IgG, IgG receptors,macrophages, mediators and their receptors have appropriateproperties to support this pathway if enough IgGand antigens are present [1]. Food specific IgG valuesmight reflect the exposure to food clusters in individualdiet habits [2]. This suggests new perspectives in understandingnon-IgE-related reactions. The aim of this perspectivestudy was to assess the robustness of foodantigen cluster analysis [3] on a larger cohort of subjects.MethodsSpecific total IgG antibodies against 44 common food antigenswere measured in sera of 11488 Italian patients(76.1% females; age 46.7 ± 14.2 years). We used an unsupervisedhierarchical clustering algorithm to explore varyingdegrees of similarity among food antigens. Thealgorithm initially has 44 clusters (one for each antigen)and then gradually groups them together according totheir similarities. The algorithm stops when all food antigensbelong to the same cluster [4].ResultsFive great food clusters have been identified. The firstone consists of highly Nickel-containing foods such astomato, kiwi fruit, peanut, almond and buckwheat.Within this group it is possible to identify the secondcluster including wheat and related grains such as kamut,spelt and barley. The third cluster contains dairy products(cow and goat milk as well as parmesan, mozzarellaand ricotta cheese). The fourth one includes yeasts suchas Candida albicans and Saccharomyces cerevisiae andcontains also porcini and champignon mushrooms. Thiscluster is probably connected with fermented foods. Thelast cluster, less detailed, probably contains foods with ahigher concentration of natural salicylates: products suchas honey, tea, courgettes, oranges and so on.ConclusionThese larger data allow an innovative nutritionalapproach to the diagnosis and therapy of non-IgEmediatedfood reactivities. This provides immunologicalevidence to food cluster nutritional approach to individualpatients affected by food hypersensitivities.