[Cellular and humoral bases of allergic reactions].

The inflammatory symptoms of allergic reactions are caused by complex interactions of mediator substances. They are either split from humoral precursor molecules by proteolytic enzymes or released from various cells. Mediators may cause the allergic symptoms directly or act on other mediators and mediator systems. New activities may be generated by mediator cooperation. Mediator systems can be activated by immunological antigen-specific and nonimmunological nonspecific mechanisms. In a given reaction both types of induction mechanisms are involved. It is not possible to relate a certain allergic symptom to a certain mediator or a set of mediators.