Pathogenesis of immunoglobulin A nephropathy

Purpose of review In this article, we review recent findings on the pathogenesis and genetics of immunoglobulin A (IgA) nephropathy. Recent findings During the past 2 years, the understanding of the pathogenesis of IgA nephropathy has evolved as a result of progress in technology and new tools that have been developed. Since 1968, when IgA nephropathy was described as an IgA-IgG immune-complex disease, the knowledge base expanded to allow definition of IgA nephropathy as an autoimmune disease with a multihit pathogenetic process. Specifically, galactose-deficient immunoglobulin A1 (IgA1) is recognized by unique autoantibodies, resulting in the formation of pathogenic immune complexes that ultimately deposit in the glomerular mesangium and induce renal injury. New approaches using high-resolution mass spectrometry have provided unique insight at the molecular level into IgA1 O-glycosylation. Cutting-edge genome-wide association studies revealed multiple disease-associated risk loci and have mapped their geographic and racial distribution. Summary Recent studies of molecular and genetic defects operating in IgA nephropathy can define new biomarkers specific for the disease that can be developed into clinical assays to aid in the diagnosis, assessment of prognosis, and monitoring of disease progression. Moreover, disease-specific targets are being discovered that may lead to development of new approaches for treatment.