[Immune complex- and complement-mediated glomerulonephritides]

Glomerulonephritis represents a heterogeneous group of kidney diseases characterized by inflammation of the glomeruli and capable of leading to acute or chronic kidney failure. In addition to the primary glomerulonephritides described elsewhere in this issue, there is a group of diseases in which immune complex deposition or disturbances in complement regulation play a central pathogenic role. Among the most important and clinically relevant forms of these immune complex- and complement-mediated glomerulonephritides are postinfectious glomerulonephritis (PIGN), lupus nephritis (LN), cryoglobulinemic glomerulonephritis, and C3 glomerulopathy (C3G). While PIGN, LN, and cryoglobulinemic glomerulonephritis are characterized by glomerular immune complex deposits, C3 glomerulopathy is primarily based on a dysregulation of the alternative complement pathway. These diseases require specialized treatment in university outpatient clinics in collaboration with nephrology practices. Renal biopsy is a key diagnostic tool, and histologically, a membranoproliferative pattern is frequently observed. This article provides a systematic overview of immune complex- and complement-mediated glomerulonephritis and compares their pathogenesis, clinical presentation, immunoserological profiles, histology, and available therapies.