PATHOMECHANISMS OF ALLERGIC REACTIONS

The interactions of the immune components of allergic reactions are de scribed using immune complex reactions (type III of the 1963 classific ation of Gell and Coombs) as an example. Considered are the various im munoglobulin classes, the activation of the complement system with the generation of active peptides. the Fc receptors specific for the vari ous immunoglobulin classes, the complement receptors specific for the various peptides and the distribution of these receptors on inflammato ry and other body cells. One should remember that the interaction of t he immune system with an antigen usually leads to the production of an tibodies of several classes, which may all contribute to the formation of immune complexes and to the activation of the complement system, o f complement receptors, and oi Fc receptors. The following conclusions may be drawn for the pathogenesis not only of immune complex reaction s but of allergic reaction in general: A reaction involves not only a single mechanism but is composed of numerous mechanisms interacting wi th one another. The participating cells are stimulated by several stim uli simultaneously. The effects of immune mechanisms are modulated by nonimmune events. In view of their complexity it is not possible to cl assify allergic reactions on the basis of their presumed pathogenesis.