Neues und Relevantes zur Medikamentenallergie

Abstract

During the evolution, the immune system has been well prepared to handle protein antigens, but the interplay with xenobiotics was minimal and restricted to some substances in plants in low concentrations. The generation of millions of new molecules and their use in rather large amounts thus poses a rather unexpected new challenge to the human immune system, which can cause rather surprising reactions by the specific and unspecific immune system, which partly contradict the existing immunological dogmata. In this short review 4 topics are shortly presented: a) the rather frequent observation that certain i.v. applied drugs like neuromuscular blocking agents as well as radiocontrast media can cause anaphylactic reactions at the first encounter - which nevertheless appears to be IgE-mediated. For neuromuscular blocking agents the prior use of e.g. pholcodin, a cough sirup containing a tertiary amino group, may have been sensitizing; the crossreactive compound for a possible sensitization to radio-contrast media is unknown. b) The subclassification of Type IV reactions according to Gell and Coombs into IVa, IVb, IVc and IVd types: these reactions differ due to distinct functions of involved T cells, which recruit different inflammatory effector cells. This better explains the clinically often rather distinct clinical pictures elicited by drugs. c) The p-i concept, which implies a pharmacological interaction of drugs with immune receptors, has been established using drug specific T cell clones and explains the generalized reaction to drugs. And last, d) the transfer of these new concepts to a better diagnostic of drug allergies using new in vitro tests.