Drug-induced lupus: Traditional and new concepts.

Drug-induced lupus (DIL) includes a spectrum of drug-induced reactions often characterised by a clinical phenotype similar to that of idiopathic systemic lupus eruthematosus (SLE) but usually lacking major SLE complications. Different drugs may be associated with distinct clinical and serological profiles, and early recognition is crucial. Drugs traditionally associated with DIL include procainamide, hydralazine, quinidine and others, but strong associations with newer agents, such as TNF α (TNFα) inhibitors, are increasingly recognised. The pathogenic mechanisms explaining how drugs that have heterogeneous chemical structure and function lead to autoimmunity are only partially understood. However, it is likely that traditional DIL-associated agents can boost innate immune responses, particularly neutrophil responses, with neutrophil extracellular trap (NET) formation and exposure of autoantigens. Research in the field of DIL is evolving and may provide interesting models for the study of autoimmunity.