Patients with idiopathic membranous nephropathy at risk for renal failure can be identified in an early stage by measuring urinary low molecular weight proteins and urinary immunoglobulin G (IgG). This study evaluates the possible benefit of early start of immunosuppressive therapy in these high-risk patients.

Inclusion Criteria:

• patients with idiopathic membranous nephropathy
• nephrotic syndrome
• normal renal function (serum creatinine [Screat] < 1.5 mg/dl)
• elevated urinary beta2-microglobulin and IgG

Immunosuppressive therapy consisting of:

• cyclophosphamide 1.5 mg/kg/day for 12 months
• prednisone orally, 0.5 mg/kg on alternate days for 6 months
• i.v. methylprednisolone 1000 mg on days 1,2,3, 60,61,62, 120,121,122

Study Groups:

• early: immediate start of immunosuppressive therapy at the time patient is identified as high-risk
• late: start of therapy after deterioration of renal function (increase of Screat > 25% and Screat > 1.5 mg/dl)

Main Outcome Parameters:

• serum creatinine
• remission of proteinuria
• period of nephrotic proteinuria
• major side effects: hospitalisations, infections

Inclusion Criteria:

• Idiopathic membranous nephropathy
• Serum creatinine < 1.5 mg/dl
• Nephrotic syndrome

Exclusion Criteria:

• Infection
• Instable angina
• Systemic disease
• Pregnancy
• Renal vein thrombosis
• Prior therapy with immunosuppressant agents
• Liver dysfunction
• Use of nonsteroidal anti-inflammatory drugs (NSAIDs)