[Case of MPO-ANCA-positive Wegener's granulomatosis with hepatitis C virus infection].

A 77-year-old Japanese man was referred to our hospital because of the progression of renal dysfunction. Two months prior to the admission he had been diagnosed with otitis media. Urinalysis showed proteinuria and microscopic hematuria. Blood examination revealed renal dysfunction, hepatitis C virus (HCV)infection and positive myeloperoxidase (MPO)-ANCA. A chest CT revealed small infiltrates in the right middle lobe. The renal biopsy demonstrated crescentic glomerulonephritis with tubulitis. He was diagnosed as having Wegener's granulomatosis according to the American College of Rheumatology classification criteria. Methylprednisolone pulse therapy followed by oral prednisolone improved all of the otitis media, lung infiltrates and renal function. Recently, a high prevalence of ANCA has been reported in patients with HCV. It has also been reported that the prevalence of HCV infection is high in patients with Wegener's granulomatosis. Therefore, our case points to the clinical significance of HCV infection in ANCA-associated systemic vasculitis including Wegener's granulomatosis.