Allergens are those antigens responsible for clinical allergic diseases. These are usually proteins or glycoproteins capable of inducing the synthesis of IgE antibodies, sensitizing the potentially allergic subject83. Upon re-exposure to the same allergen, the previously sensitized patient exhibits the signs and symptoms of allergy, as the allergen reacts with cell-bound IgE tissue antibodies and the cells generate inflammatory mediators. Therefore, it is imperative that the circumstances of allergic disease are linked to allergen exposure, as allergens represent important etiological factors in the pathogenesis of allergy84. The Allergen Nomenclature Committee of the International Union of Immunological Societies (IUIS) has developed a unified nomenclature system for purified allergens85. They are designated phenotypically by the first three letters of the genus followed by a space, the first letter of the species, another space and finally an Arabic numeral; occasionally it is necessary to add an additional letter to the genus or species designation. Allergens can be further classified based on the nature or manner in which the patient is exposed into inhalants, ingestives, contactants, and injectants. The allergens responsible for allergic respiratory diseases, including allergic asthma and allergic rhinitis, are mainly inhalants. These aeroallergens, which can be present outside (pollen, products of animal origin such as skin and fur excrements, algae) or inside (mold, products of animal origin, dust) are responsible for the majority of allergic diseases. Foods and other ingestions, including medications, are also important, especially for allergic gastrointestinal and skin diseases. The contacts are mainly responsible for...... middle of paper ......eptidase99 and the carbohydrate-rich protein (Api m 10), a component of unknown function100. Phospholipase A2 (Api m 1) and hyaluronidase (Api m 2) appear to be the major sensitizing allergens in bee venom93,101 and the peptide components melittin (Api m 4) and Api m 6 are considered minor allergens99,102. In recent years, designated genes could be assigned to the acid phosphatase Api m 3103, the DPPIV enzyme Api m 596 as well as the carbohydrate-rich protein (Api m 10)100, the recombinantly produced allergens characterized for their allergenic properties . Other proteins, including peptidases, esterases, and proteases, some of which are listed in databases, are currently being evaluated for their allergenic potential (unpublished data). Considering the complex composition of insect venoms, however, it is likely that additional allergens are present in bee venom.