Response to high-dose interferon-alpha after failure of standard therapy in MPGN associated with hepatitis C virus infection.

A 42-year-old man developed mixed cryoglobulinemia secondary to hepatitis C virus (HCV) infection with hypocomplementemia and nephrotic syndrome. His renal biopsy showed membranoproliferative glomerulonephritis type I (MPGN). Despite treatment with interferon-alpha, three million units three times a week for a total of 6 months, the patient continued to have hypocomplementemia, cryoglobulinemia, and nephrosis. After a course of high-dose interferon-alpha treatment consisting of ten million units daily for 2 weeks followed by 10 million units three times per week for an additional 6 weeks, HCV RNA and cryoglobulin testing became negative, complement levels increased to normal levels, and nephrotic syndrome remitted. This case confirms an association between HCV infection and MPGN and suggests a role for high-dose interferon-alpha treatment when conventional interferon therapy fails.