Autoantibodies directed against C3 and C5 convertases, termed nephritic factors (C3Nefs and C5Nefs, respectively) since they are associated with rare kidney disorders, stabilize the AP C3 convertase and the AP/CP/lectin pathway (LP) C5 convertases, respectively, thus leading to enhanced C3 and/or C5 cleavage and persistent complement activation [37]. Here, C3 is linked to kidney disorder.