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

To retrospectively investigate clinico-pathological features and outcomes of patients with renal involvement in propylthiouracil (PTU)-associated antineutrophil cytoplasmic autoantibody (ANCA) vasculitis (PTU-AAV). 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. 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. 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 withdrawl and immunosuppressive therapy.