Clinico-pathological features and outcomes of patients with propylthiouracil-associated ANCA vasculitis with renal involvement.

OBJECTIVE: To retrospectively investigate clinico-pathological features and outcomes of patients with renal involvement in propylthiouracil (PTU)-associated antineutrophil cytoplasmic autoantibody (ANCA) vasculitis (PTU-AAV).
METHODS: Clinico-pathological features and outcomes of 12 patients (female 11, average age 32.4 ± 13.8 years) who developed AAV after treatment with PTU were collected and analyzed. ANCA was detected by both immunofluorescence (IF) and enzyme linked immunosorbent assay (ELISA). All patients had renal biopsy.
RESULTS: Twelve patients received PTU for 2-264 months (median 42 months) when PTUAAV was diagnosed. All patients had positive serum P-ANCA, 11 of them were MPO-ANCA, 1 was MPO and PR3-ANCA double positive. All patients presented with hematuria and proteinuria, 5 of them had gross hematuria, urine protein was 1.9 ± 1.6 g/24 h, 7 of 12 (58.3%) patients had renal dysfunction, among them 3 needed initial renal replacement therapy. Renal biopsy showed pauci-immune segmental necrotizing crescentic glomerulonephritis in ten patients, segmental necrotizing glomerulonephritis superimposed on membranous nephropathy in two patients. All patients withdrew PTU and received steroid and immunosuppressive therapy. After a median follow-up of 42 months (range 21-86), 3 patients developed to ESRD, 7 patients entered complete renal remission. Serum ANCA turned negative only in 2 patients, 10 patients had persistent positive serum ANCA. Three patients relapsed with the elevation of serum ANCA level.
CONCLUSION: Renal damage of PTU-AAV could be pauci-immune necrotizing crescentic glomerulonephritis, and necrotizing glomerulonephritis coexisted with membranous nephropathy. Most patients had persistent positive serum ANCA and had a risk of relapse and progression to ESRD even after PTU withdrawal and immunosuppressive therapy.