Richard A. Lafayette, Ellie Kelepouris

Immunoglobulin A (IgA) nephropathy is the most common form of primary glomerulonephritis and has clinical associations with a wide range of inflammatory and infectious diseases. There is a substantial variation in clinical course and outcomes, with many patients not diagnosed until they present with sequelae, which may include gross hematuria, hypertension, renal insufficiency, and/or significant proteinuria. Treatment options are currently limited and directed mainly toward control of these sequelae and have limited ability to reduce the incidence of end-stage renal disease or treat the primary IgA defect. Growing knowledge about the pathogenesis of IgA nephropathy and research into its genetic basis are helping to elucidate the course of this widely variable disease. IgA accumulation in the kidneys is thought to be the result of a number of different pathways in a "multi-hit" process that includes an initial traumatic trigger (often infection related) and subsequent memory responses that are amplified in those with a genetic predisposition to the disease and lead to an inflammatory response in susceptible individuals. Genome-wide association studies are providing new insights into the genetic variance of this autoimmune disease and are yielding information that may address both its causes and consequences. Key Messages: New treatment approaches are urgently required for the management of patients with IgA nephropathy. Novel interventions based around its inflammatory nature and "multi-hit" pathogenesis are being investigated to potentially limit disease progression.