Vasoactive Mediators in Contact Sensitivity

The function of vasoactive substances, especially of histamine, in the development of allergic reactions has been extensively studied and their role in anaphylactic reactions convincingly established [1]. Initially, their role in delayed hypersensitivity was also presumed and investigated [23]. However, the failure of antihistaminic drugs to influence the manifestation of cell-mediated immune reactions [10] and the discovery of lymphokines as putative mediators of this type of hypersensitivity [6] diverted the attention of scientists to the latter substances.