The importance of hapten–protein complex formation in the development of drug allergy

Drug-specific T cells have been isolated from different patients with allergy. Formation of hapten-protein complexes, their processing and antigen presentation have been implicated in the development of drug allergy to p-phenylenediamine, sulfonamides and β-lactams. However, evidence also supports the pi mechanism of immune activation wherein drugs interact directly with immune receptors. Thus, multiple mechanisms of immune activation may occur for the same drug.