Combined C3b and Factor B Autoantibodies and MPGN Type II

Abstract

Membranoproliferative glomerulonephritis (MPGN) type II (MPGN II), also called dense-deposit disease, is a rare glomerular disease that often progresses to end-stage renal disease.¹ MPGN II is associated with complement because of systemic C3 activation and deposition of C3 cleavage products along the glomerular basement membrane.² Genetic causes include mutations in the genes encoding for complement factor H and C3, which result in deregulation of the C3 convertase.³ In addition, autoantibodies, such as C3 nephritic factor, which stabilize C3 convertase and induce a permanent activation of complement, have been identified in 50 to 80% of patients with MPGN II.⁴ Single cases of patients with autoantibodies to factor B and factor H have also been described. There is currently no effective treatment for patients with MPGN II, and the prognosis for survival after kidney transplantation is poor.