Membranous glomerulopathy induced by myeloperoxidase-anti-neutrophil cytoplasmic antibody-related crescentic glomerulonephritis

Abstract

A 68-year-old woman was referred for evaluation of nephrotic-range proteinuria and a course suggesting rapidly progressive glomerulonephritis. Serum anti-neutrophil cytoplasmic antibody against myeloperoxidase (MPO) was 204 U/ml. A renal biopsy specimen revealed necrotizing glomerulonephritis with crescent formation. However, immunofluorescence showed staining with IgG and C3 along capillary walls. IgG positivity included both IgG1 and IgG4. Electron microscopic examination disclosed both paramesangial and subepithelial deposits. This case suggests that rarely, MPO-ANCA-related crescentic glomerulonephritis may present nephrotic-range proteinuria and show immune deposits along capillary walls.