The Clinicopathologic Spectrum of Rapidly Progressive Glomerulonephritis Based on Glomerular Immune Deposition and Antineutrophil Cytoplasmic Antibody.

Rapidly progressive glomerulonephritis presents crescentic glomerulonephritis (CrGN) pathologically. Immune complex (IC)-mediated CrGN is characterized by glomerular IC deposits, whereas pauci-immune CrGN is characterized by presence of antineutrophil cytoplasmic antibody (ANCA) and absence of glomerular IC deposits. CrGN cases presenting both IC deposits and ANCA were common. We retrospectively investigated 91patients with rapidly progressive glomerulonephritis, including 36 patients with idiopathic IC-mediated CrGN and 55 patients with pauci-immune CrGN. On the basis of ANCA and IC deposits, there were 42 patients with ANCA alone (ANCA+IC-), 6 patients with IC deposits alone (ANCA-IC+), 30 patients with both ANCA and IC deposits (ANCA+IC+), and 13 patients with neither ANCA nor IC deposits. The patients with IC-mediated CrGN had more proteinuria, lower estimated glomerular filtration rate (eGFR), higher percentage of cellular crescent formation, and a worse renal outcome compared with those with pauci-immune CrGN. The ANCA+IC+ CrGN patients had lower eGFR level, higher percentage of crescent formation and a tendency of more proteinuria, and worse renal outcome compared with ANCA+IC- CrGN patients, but had no significant differences on the above characteristics compared with ANCA-IC+ CrGN patients. Within a median 7.1 months, 22 patients developed end-stage renal disease. Cox regression revealed the factors including lower eGFR level, more proteinuria, lower platelet level, higher glomerular global sclerosis rate, and glomerular IgG deposits were the independent factors for worse renal outcome. In conclusion, the clinicopathologic spectrum of ANCA+IC+ CrGN was similar with IC-mediated CrGN and glomerular IgG deposition was one of the independent factors for worse renal outcome.