Recurrent allograft C3 glomerulonephritis and unsuccessful eculizumab treatment.

There is a great lack of efficient treatments for membranoproliferative glomerulonephritis (MPGN) and recently emerged complement therapies have been proposed to be useful. We report a patient with a complement-mediated MPGN having recurrencies in kidney allografts and an unsuccessful treatment with complement inhibitor, eculizumab (anti-C5 monoclonal antibody). Nephritic factor (C3Nef), an autoantibody against C3bBb, in the patient serum activated C3 but not C5 showing that major damage was mediated by C3 activation with clearly less involvement of C5 explaining unresponsiveness to eculizumab. Analyzing C3Nef-mediated C3 and C5 activation separately could help in choosing the right patients for eculizumab therapy.