Complement activation and C3 glomerulopathy

Abstract

The classical roles of the complement (C) system are known to contribute in part to innate host immunity. In addition, bridging roles of the C system to adaptive immunity were found in the late 21st Century. Since anti-C agents such as C1-inhibitor and anti-C5 antibodies have started to be used in clinical practice during recent decades, the C system has become more familiar to clinicians. Analyses of aspects of the C system are now starting to clarify pathological mechanisms related to the C system and anti-C agents are under development. In the field of nephrology, unexpected C activation has been associated with the incidence, development and/or progression of glomerular and interstitial injuries. Moreover, atypical hematolytic uremic syndrome and C3 nephropathy were referred to as C-associated diseases. However, issues associated with C3 glomerulopathy, its pathogenesis, etiology and therapeutic approaches remain unclear. This mini-review provides a short summary and discussion of renal pathogeneses associated with the C system and its dysregulation, with particular focus on recent insights into C3 glomerulopathy.