Allergy epidemiology in the St. Louis, Missouri, area: II grasses.

3219 patients for seven species of grass pollen extracts and mixtures of these grasses in the St. Louis, Missouri, metropolitan area exhibited specific levels of allergenicity to different grasses, as well as a degree of cross-reactivity among all species tested. Adult patient reactions to these extracts generally were similar to those of the pediatric patients tested. Mixed grass pollen preparations proved to be inadequate as a gauge of patient allergenicity to individual species. Intersection of the prick skin testing method and the intracutaneous technique was found at specific concentrations. For the first time phylogenetic and taxonomic conclusions regarding the grass family are supported by immunological data.