Sequential development of anti-GBM nephritis and ANCA-associated pauci-immune glomerulonephritis

The medical history is presented of a 23-year-old man experiencing three ep isodes of pulmonary-renal syndrome. On the first occasion, a diagnosis of a nti-glomerular basement membrane (GEM) disease (with linear deposition of i mmunoglobulin G [IgG] along the GEM) was made, whereas anti-neutrophil cyto plasmic autoantibodies were also present in serum. On the third occasion, 5 years later, p-ANCA-associated vasculitis (with pauci-immune crescentic gl omerulonephritis) was diagnosed, whereas anti-GEM antibodies were absent. T he current literature on ANCA-positive anti-GEM disease is briefly reviewed . A substantial proportion (20% to 30%) of patients with histologically and serologically proven anti-GEM nephritis display the presence of ANCA as we ll. In this group of patients with dual antibodies, clinical and histologic al findings suggest that ANCA are not merely epiphenomena, but are of patho genetic importance and might be responsible for an initial vasculitic insul t to the kidney with resultant secondary anti-GEM nephritis. The clinical c ourse in our patient lends further support to this concept. Histological de monstration of anti-GEM nephritis followed by ANCA-associated pauci-immune glomerulonephritis in a single patient has not been reported before. (C) 19 99 by the National Kidney Foundation, Inc.