The Development of Autoimmune Membrano-Proliferative Glomerulonephritis (Type II) In a Female Patient with Serological Combined Autoantibodies against Complement 3b and Factor B: Case Report

Background: Most of membranoproliferative glomerulonephritis (MPGN) raise from the abnormalities in alternative complement pathways. Case presentation: A 3-year-old girl manifested hematuria (HU), proteinuria (PU), and hypocomplementemia (HC) without a known cause; the first renal biopsy indicated MPGN that resembled type I MPGN. After treatment with Methylprednisolone and Cyclophosphamide (CTx), the nephritic syndrome (HU plus PU) withdrew but often relapsed. At the age of 7 years, the clinical situation suddenly worsened, PU and the activity of the urinary sediment increased, and the glomerular filtration rate rapidly decreased; simultaneously, auto-antibodies against Complement 3b (C3b) and Factor B were detected with high titers. The second renal biopsy exhibited a typical glomerular injury of type II MPGN with diffuse cellular crescents; the patient was treated with methylprednisolone plus plasmapheresis and Rituximab, but the renal failure still proceeded. She started peritoneal dialysis at the age of 9 years and received renal transplantation at the age of 11 years; after transplantation, she was given routine immunosuppression plus plasmapheresis and Rituximab (anti-CD 20 globulin), and presented clinical remission except for persistent HC. The nephritic syndrome relapsed at the age of 13 years, and the third renal biopsy confirmed a recurrence of type II MPGN; thereafter, Eculizumab (anti-C5 monoclonal antibody) was administered, which significantly ameliorated the clinical condition. Conclusion: The pathological appearance of type II MPGN may be variable but not completely irrelevant according to the clinical conditions at the time of biopsy