Despite the paucity of immunoglobulin deposition in the glomeruli, this form of crescentic glomerulonephritis is correlated with circulating anti-neutrophil cytoplasmic antibodies (ANCA), which are largely specific for two neutrophil constituents, proteinase-3 or myeloperoxidase (MPO). Here, MPO is linked to crescentic glomerulonephritis.