Drug allergy and hypersensitivity. Risk factors.

Drug allergies are heterogeneous, multifactorial disorders that always involve an exaggerated immune-mediated reaction. Proposed models of immunologic mechanisms (mainly based on Gell and Coombs' classification) cannot fully explain the pathophysiology of these reactions. Epidemiologic studies show that female gender, concomitant infections (HIV herpesvirus, etc.) and illnesses (systemic lupus erythematosus) are all significant risk factors. Genetic predisposition is under investigation in our laboratory. Most genetic studies concern HLA haplotype associations or polymorphisms in genes that encode drug-metabolising enzymes. An ongoing study by our group points to a role of polymorphisms within the IL-10 promoter and in the IL-4Ra gene in immediate reactions to beta-lactams.