KDIGO convened a Controversies Conference on Complement-Mediated Kidney Diseases from November 19-21, 2015 in Barcelona, Spain. The two prototypical complement-mediated kidney diseases are C3 glomerulopathy (C3G) and atypical hemolytic uremic syndrome (aHUS). C3G defines a group of untreatable ultra-rare kidney diseases driven by uncontrolled activation of the complement cascade that leads to C3 deposition within the glomerulus. Currently, there is no effective targeted treatment option for C3G and as a consequence a variety of supportive measures are used to delay progression to kidney failure. C3G remains an ideal disease in which to test new complement therapies as these become available. Atypical hemolytic uremic syndrome (aHUS) is also an ultra-rare disease. Until recently, the prognosis for aHUS was poor with the majority of patients developing ESRD within two years of presentation.

The objective of this KDIGO conference was to gather a global panel of multi-disciplinary clinical and scientific expertise to identify key issues relevant to the optimal management of complement-mediated kidney diseases. The goal was to define the renal pathology of C3G and aHUS; describe the clinical phenotype and evaluation of C3G and aHUS; characterize the genetic and acquired drivers of these two diseases; and determine best practice treatment and clinical trial strategies for C3G and aHUS. The conference also aims to summarize outstanding knowledge gaps and propose a research agenda to resolve standing controversial issues. Deliberations from this conference will inform clinicians of the evidence base for present treatment options and help pave the way for future studies in this area.

Drs. Tim Goodship (Newcastle University, United Kingdom) and Richard Smith (University of Iowa, USA) co-chaired this conference.