Clustering of allergenic pollen on the basis of skin responses of atopic patients by matrix analysis

The responses of 148 atopic patients to some 43 different extracts of allergenic pollen were tested by prick tests. The measure of dissimilarity was introduced and calculated for all pairs of allergens. The investigated allergens were clustered into groups, according to their unbiased greatest similarity, by a matrix-structuring method. Results indicate that subgroups of allergens can be distinguished even within groups of closely related pollen allergens that were believed to be fully cross-reactive. A few cases are demonstrated for various varieties of olives, pecans, date palms, and turf grasses and for some wild chenopods and amaranths. The usefulness of the suggested solution for allergy research and for clinical practice is discussed.