A historical study of American patients with anti-neutrophil cytoplasmic antibody negative pauci-immune glomerulonephritis.

Abstract

Anti-neutrophil cytoplasmic antibodies (ANCA) play an important role in the pathogenesis of ANCA-associated vasculitis. The lack of ANCA antibodies may indicate a variation in clinical presentation and outcomes of this disease. We identified 74 adult patients between 1995 and 2009 with the diagnosis of pauci-immune glomerulonephritis. Demographics, histological features, and treatment outcomes were compared between ANCA-positive and ANCA-negative patients. These factors were correlated with renal function at presentation and follow-up. Of the 74 patients, 57 were ANCA-positive, and 17 were ANCA-negative. Demographics and mean Birmingham Vasculitis Activity Score were similar between ANCA-negative and ANCA-positive patients at presentation. Renal function was significantly worse at presentation in the ANCA-negative patients (eGFR 16.59 vs. 31.89ml/min/1.73m(2), p = 0.03). Patients in the ANCA-negative group had a significantly higher interstitial fibrosis score compared to the ANCA-positive group (2.1 vs.1.6, p = 0.04). The median time to remission was shorter in the ANCA-negative patients (51 vs. 78days, p = 0.01). Long-term renal function and 1-year patient and renal survival were similar between ANCA-negative and ANCA-positive patients. Baseline eGFR, percentage of normal glomeruli, glomerular sclerosis, and tubulointerstitial scarring predicted eGFR at 1year in both groups similarly. This is the first historical review of American patients with pauci-immune glomerulonephritis, comparing patients with ANCA-negative and ANCA-positive serology. Although ANCA-negative patients present with lower eGFR and more interstitial fibrosis, 1-year and long-term outcomes in both groups are similar.