Update in the understanding of genetic predisposition to olive pollen sensitization

Olive tree pollen is one of the most important causes of allergy in the Mediterranean countries. Although the importance of this pollen provoking respiratory allergy is well established and documented, during the last decades, olive trees have been widely planted for ornamental purposes originating a new source of urban air pollution. This fact is one important reason why studies on olive pollen allergy are needed, in order to have more information about the prevention and possible modulation of this kind of sensitization. This article summarizes the advances in the study of genetic restrictions implicated in the susceptibility to the sensitization against the major allergen from this pollen: Ole e 1. Asthma and allergies are complex diseases involving genetic as well as environmental factors. The final clinical picture results from the interaction between genetic factors and environmental stimuli, and in addition, variables such as age, concurrent infections, and physiological factors, could promote differences in susceptibility. Despite this complexity, the allergic diseases are considered as an excellent model for the analysis of the genetic basis of the human immune response (1). The principal advantages are that they are common diseases with increasing prevalence and in addition, they have a well-defined clinical picture and the causative allergens may be identified and characterized so the immune response to them can be identified. The allergic reaction appears to require the interaction of environmental factors with a series of steps, which are genetically regulated. Genetic regulation of IgE responses to specific allergens may differ from that of the general atopic response. Probably, genetic associations are more readily detected with reactions to purified major allergens rather than complex allergen sources. The immunogenetic mechanisms underlying heightened IgE responsiveness seen in atopic diseases may be divided into two types: (a) antigen-specific and (b) nonantigen-specific (2–4).