Complement-mediated renal diseases after kidney transplantation - current diagnostic and therapeutic options in de novo and recurrent diseases

Figure 3 Disease mechanisms in C3 glomerulopathy, based on genetic defects identified in family studies. A: Physiological regulation of C3 activation to C3b via the alternative pathway is mediated by complement factor H (CFH) (Cfh). Competitive inhibition of CFH by CFHR proteins is termed CFH deregulation; B: Homozygous deficiency or dysfunction of CFH results in excessive C3 activation; C: Hyper-functional C3 produces excessive C3 activation despite normal CFH activity; D: Abnormal CFHR proteins enhance CFH deregulation, leading to excessive C3 activation. Adapted from Barbour et al[11].