Membranoproliferative glomerulonephritis

The key histological features of membranoproliferative glomerulonephritis (MPGN) are mesangial hypercellularity, endocapillary proliferation, and capillary wall remodelling. There are two main types: (1) immune complex-mediated disease—caused by chronic infection causing persistent antigenaemia (notably hepatitis C), autoimmune disease, or monoclonal immunoglobulin production by plasma cell dyscrasia, and a few ‘idiopathic’ cases; and (2) complement-mediated disease—caused by dysregulation of the alternative pathway of complement, including by C3 nephritic factor (C3Nef), an autoantibody that stabilizes the alternative pathway C3 convertase. Clinical presentation is varied, including nephrotic syndrome, episodic visible haematuria, hypertension/rapidly progressive glomerulonephritis, asymptomatic nonvisible haematuria, and chronic kidney disease. Treatment depends on the underlying disease. All patients should receive appropriate conservative measures (blood pressure control, angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker). Underlying infection or monoclonal gammopathy should be treated, when possible, in those with immune complex-mediated MPGN. Eculizumab may have a role in treatment of some patients with complement-mediated MPGN. Steroids and cyclophosphamide or mycophenolate mofetil are used in patients with severe idiopathic MPGN.