Crescentic glomerulonephritis and elevated antimyeloperoxidase antibody in a patient with Churg-Strauss syndrome

A 45-year-old man with a long history of bronchial asthma was admitted to the National Cardiovascular Center with complaints of severe pain, swelling, and ecchymoses of the lower extremities. A diagnosis of Churg-Strauss syndrome was made because of marked eosinophilia, vasculitis, and a history of asthma. Urinalysis revealed severe proteinuria and microscopic hematuria. A renal biopsy demonstrated extensively crescentic glomerulonephritis. The antineutrophil cytoplasmic antibody against myeloperoxidase (MPO-ANCA) level, determined by enzyme-linked immunosorbent assay (ELISA), was 494 ELISA units. Under treatment with prednisolone, the symptoms and eosinophilia improved within 3 days. The MPO-ANCA level decreased to its lowest value, and renal function was ameliorated within 3 months. The patient has been followed regularly on an ambulatory basis with a regimen of prednisolone.