Arthritis & Rheumatism, Volume 60,
October 2009 Abstract Supplement

The 2009 ACR/ARHP Annual Scientific Meeting
Philadelphia October 16-21, 2009.


Angiopoietin-2 as a Biomarker in ANCA-Associated Vasculitis

Monach1,  Paul A., Kumpers2,  Philipp, Cuthbertson3,  David, Carette4,  Simon, Hoffman5,  Gary S., Khalidi6,  Nader A., Langford5,  Carol A.

BU, Boston, MA
Medical School Hannover, Germany
University of South Florida, FL
Toronto Western Hospital, Toronto
Cleveland Clinic, Cleveland, OH
Hamilton
Johns Hopkins University, Baltimore, MD
Mayo Clinic, Rochester, MN
Boston University, Boston, MA

Purpose:

To explore angiopoietin-2 (Ang-2) as a biomarker of active ANCA-associated vasculitis (AAV). Ang-2 is an inducible mediator of endothelial activation and vascular permeability. We have shown that circulating levels of Ang-2 are elevated in AAV prior to treatment and drop to normal levels after treatment. The present study was conducted to i) confirm the association of elevated Ang-2 with AAV at different levels of clinical disease activity and ii) evaluate changes in Ang-2 over time in patients transitioning between clinical remission and mildly-active disease.

Methods:

108 plasma samples from 59 patients with Wegener's granulomatosis or microscopic polyangiitis were selected from a repository linked to comprehensive longitudinal clinical data. Disease activity at each visit was assessed using BVAS, BVAS/WG, and physician global assessment (PGA). Ang-2 was measured by ELISA. Generalized linear models (GLM) were used to study the association of Ang-2 levels with activity measures while controlling for subject-specific effects.

Results:

Active AAV, using any index, was associated with higher levels of Ang-2. This association was driven by subjects with highly active disease (Figure): mean Ang-2 levels were 2.99, 1.43, 1.42, and 1.49 ng/ml (normal = 1.0 ± 0.7 ng/ml) in high, moderate, low, or absent (remission) disease activity (p=0.0002). Among subjects with multiple assessments, most of whom transitioned between low activity and remission, Ang-2 levels tended to be stable relative to baseline (Figure).

Conclusion:

Ang-2 levels are associated with highly-active AAV but not partially-treated or smoldering AAV. Assessing the value of Ang-2 as a predictor of relapse will require more study of longitudinal cohorts.

To cite this abstract, please use the following information:
Monach, Paul A., Kumpers, Philipp, Cuthbertson, David, Carette, Simon, Hoffman, Gary S., Khalidi, Nader A., et al; Angiopoietin-2 as a Biomarker in ANCA-Associated Vasculitis [abstract]. Arthritis Rheum 2009;60 Suppl 10 :1834
DOI: 10.1002/art.26908

Abstract Supplement

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