Long-term outcomes in antineutrophil cytoplasmic autoantibody–positive eosinophilic granulomatosis with polyangiitis patients with renal involvement: a retrospective study of 14 Chinese patients

BACKGROUND: The clinic-pathological features and outcomes of Chinese patients with antineutrophil cytoplasmic autoantibody (ANCA)-positive eosinophilic granulomatosis with polyangiitis (EGPA) and renal involvement have not been studied. METHODS: Fourteen EGPA patients with renal involvement were included. All patients underwent renal biopsy. Clinic-pathological features and outcomes were retrospectively analyzed. RESULTS: The most common initial symptom of EGPA was asthma (57.1 %), followed by hemoptysis (21.4 %), gross hematuria (14.3 %), and arthritis (7.1 %). All patients had positive serum ANCA (anti-MPO in 12, anti-PR3 in 2). Elevated eosinophils (median 15 %, range 10–45 %) were found in all patients. The median serum IgE level was 463 g/L (range 200–1000 g/L). All patients presented with renal dysfunction, with a median SCr of 5.4 mg/dL (range 1.47–11 mg/dL), seven patients (50 %) required initial renal replacement therapy. Thirteen patients showed hematuria and proteinuria (median 1.1 g/24 h, range 0.5–7.8 g/24 h). Renal biopsy showed pauci-immune segmental necrotizing glomerulonephritis with crescents in 13 patients and acute interstitial nephritis in one patient. Twelve patients (85.7 %) showed renal interstitial eosinophil infiltration, among whom three had eosinophilic granuloma. Among seven patients (71.4 %) who required initial dialysis, 5 discontinued dialysis, one died, one received maintenance dialysis after glucocorticoids plus immunosuppressive for induction treatment. Twelve patients were followed up for a median of 43.5 months (range 6–83 months), during follow-up, two patients progressed to end-stage renal disease, nine had chronic kidney disease with eGFR < 60 mL/min, and two patients had normal eGFR. CONCLUSIONS: Renal involvement in ANCA-positive EGPA could be severe and showed varied renal histology. Although intensive immunosuppressive therapy effectively improved the renal function, the long-term renal survival was poor. Early diagnosis and treatment are essential to improve long-term renal survival.