Validation of the 2010 histopathological classification of ANCA-associated glomerulonephritis in a Japanese single-center cohort

Objectives. To validate the 2010 histopathological classification system of anti-neutrophil cytoplasmic antibodies (ANCA)-associated glomerulonephritis (GN) in a Japanese single-center cohort. Methods. We retrospectively studied 54 patients (28 renally limited pauci-immune GN, 25 microscopic polyangiitis, and one Churg-Strauss syndrome). Results. There were 17 patients with focal GN, eight patients with crescentic GN, 19 patients with mixed GN, and 10 patients with sclerotic GN. Detailed information regarding treatment was available in 39 patients. All these patients were treated with steroids with or without immunosuppressive agents. Hemodialysis was introduced in two patients with crescentic GN and three patients with sclerotic GN. During the follow-up period, 27 of 54 patients died. The major cause of death was pneumonia. Significant differences were observed in estimated glomerular filtration rate among patients with focal, crescentic, mixed, and sclerotic GN at entry and 1- and 5-year follow-up. Patients with focal GN had preserved renal function and favorable outcome. Conclusions. Our validation study suggests that the 2010 histopathological classification of ANCA-associated GN might aid in prognostication of patients at the time of diagnosis and in therapy selection.