Immune complex type crescentic glomerulonephritis accompanied with perinuclear anti-neutrophil cytoplasmic antibodies

A 70-year-old male developed rapidly progressive glomerulonephritis syndrome with serum perinuclear anti-neutrophil cytoplasmic antibodies (P-ANCA). A renal biopsy showed diffuse crescentic glomerulonephritis. Immunofluorescence microscopy revealed 2+ granular staining of IgG over the mesangial area and along glomerular capillary walls. Electron microscopy showed scattered deposits in the paramesangial area. These morphologic findings were consistent with those of immune complex type crescentic glomerulonephritis (IC-CGN). Serum C3, C4, and CH50 were within normal limits, and circulating immune complexes were not detected by C1q-binding assay, but both P-ANCA and anti-myeloperoxidase antibodies were positive. A possible relation of P-ANCA to IC-CGN is discussed.