Membranous glomerulonephritis

Thickening of the capillary basement membrane because of immune complex deposition is the main feature of this disease. In the majority of patients the antigenic component of the complex is unknown.

Associations include SLE (where the antigen is host DNA), malignancy of the bowel and bronchus (tumour-derived antigen), penicillamine therapy and hepatitis B infection. Plasmodium malariae is a common cause in the tropics. A strong association with HLA-DR3 has been found.

This condition occurs mainly in adults, predominantly in males. Patients present with proteinuria or frank nephrotic syndrome. Approximately one-third of patients develop end-stage renal failure within 10-20 years of diagnosis. Younger patients, females and those with asymptomatic proteinuria of modest degree at the time of presentation do best. Spontaneous remission occurs in about one-third of patients, particularly females.

Uncertainty exists as to the place of corticosteroid and immunosuppressive treatment with, for example, chlorambucil, cyclophosphamide or azathioprine in the treatment of membranous glomerulonephritis.

Interpretation of controlled trial data in unselected patients with the condition has proved difficult owing to the fact that a significant proportion of patients are destined to do well without specific treatment. There is an increasingly strong consensus (supported by meta-analysis of trial data) that patients with a poor prognosis (those with heavy proteinuria and progressive renal impairment) do benefit from such treatment.