ABSTRACT
The nature of the cellular and molecular events that result in the acquisition of skin sensitization is relatively well characterized (7). In contrast, the events leading to sensitization of the respiratory tract by chemicals are not completely understood and remain controversial. It is known that skin and respiratory allergy to chemicals share some general similarities in the complex cascade of chemical and biological events leading to sensitization. However, it is also known that there are differences, especially concerning the immune response. Not all compounds provoking a specifi c immune response have the potential to cause hypersensitivity of the respiratory tract. A large number of skin sensitizers, for example, are believed to have no respiratory sensitizing effect (8). Why chemical allergens actually behave differently? Why is that some chemical allergens preferentially cause skin sensitization and ACD, whereas others are associated selectively with respiratory allergy?
