Use of Bortezomib in the Treatment of C3 Glomerulonephritis Refractory to Eculizumab and Rituximab

C3 glomerulopathy (C3G) is a chronic kidney disease defined by the predominance of C3 deposition in the renal glomeruli.1 C3G is caused by dysregulation of the alternative pathway of complement activation. The majority of C3G is caused by acquired factors—circulating Igs that stabilize the formation of the alternative pathway C3 convertase, C3bBb, which are referred to as C3 nephritic factor (C3NeF).2 In a smaller subset of C3G, autoantibodies that bind to and interfere with factor H, a protein that competes with factor B for C3 binding and acts as a cofactor for factor I, are present.