Monoclonal gammopathy associated with crescentic glomerulonephritis and antimyeloperoxidase antibodies

A 68-year-old male patient suffering from dizziness, gait instability, deafness, and visual loss showed proteinuria, hematuria, reduced creatinine clearance, and a monoclonal IgA lambda component. Renal biopsy revealed crescentic glomerulonephritis. Serum antibodies against myeloperoxidase were identified. These antibodies were IgG, not related to the IgA monoclonal component. This clinical description adds new information to the spectrum of diseases associated with glomerulonephritis and antimyeloperoxidase antibodies and illustrates that a monoclonal component cannot be directly implicated in the pathogenesis of a vasculitic process associated with antineutrophil cytoplasm antibodies.