Nephrotic range proteinuria in c-ANCA-positive crescentic glomerulonephritis with linear immune deposits.

The three broad groups of rapidly progressing glomerulonephritis are anti glomerular basement membrane (anti-GBM) disease, renal vasculitis characterized by antineutrophil cytoplasmic antibody positivity, and a heterogeneous group with granular immune deposits. Anti-GBM disease with cytoplasmic antineutrophilic antibodies (c-ANCA) positivity (type III disease) is not known to present with nephrotic syndrome. We report here a rare presentation of nephrotic syndrome in Type III disease. Larger studies are warranted to determine whether the amount and/or type of immune deposits decide the range of proteinuria. These studies are also required to elucidate the impact of immune complex deposition on renal disease in c-ANCA-positive glomerulonephritis and to outline its pathogenetic mechanism.