GENETIC AND ENVIRONMENTAL-FACTORS IN THE CHANGING INCIDENCE OF ALLERGY

Several studies have indicated that the incidence and prevalence of al lergic diseases are increasing. Such data should not be regarded as me re statistical curiosities, but should be analysed to provide informat ion on the factors contributing to allergy and its changing epidemiolo gy Extensive evidence has been accumulated that allergic diseases are polyfactorial. Data reported in the literature and particularly twin s tudies have also suggested polyfactorial control of individual allergy variables, such as total serum levels IgE and IgG4, specificity of an tibody response, mediator release from inflammatory cells and target o rgan response. Markers of genetic susceptibility may identify individu als at risk for allergy, while identification of the environmental fac tors influencing the phenotypic expression of allergy can be useful in evaluating the cost-benefit ratio of taking preventive measures in su ch individuals.