RT Journal Article
SR Electronic
T1 Urinary Biomarkers in Relapsing Antineutrophil Cytoplasmic Antibody-associated Vasculitis
JF The Journal of Rheumatology
JO J Rheumatol
FD The Journal of Rheumatology
SP 674
OP 683
DO 10.3899/jrheum.120879
VO 40
IS 5
A1 Jason G. Lieberthal
A1 David Cuthbertson
A1 Simon Carette
A1 Gary S. Hoffman
A1 Nader A. Khalidi
A1 Curry L. Koening
A1 Carol A. Langford
A1 Kathleen Maksimowicz-McKinnon
A1 Philip Seo
A1 Ulrich Specks
A1 Steven R. Ytterberg
A1 Peter A. Merkel
A1 Paul A. Monach
A1 the Vasculitis Clinical Research Consortium
YR 2013
UL http://www.jrheum.org/content/40/5/674.abstract
AB Objective. Glomerulonephritis (GN) is common in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), but tools for early detection of renal involvement are imperfect. We investigated 4 urinary proteins as markers of active renal AAV: alpha-1 acid glycoprotein (AGP), kidney injury molecule-1 (KIM-1), monocyte chemoattractant protein-1 (MCP-1), and neutrophil gelatinase-associated lipocalin (NGAL). Methods. Patients with active renal AAV (n = 20), active nonrenal AAV (n = 16), and AAV in longterm remission (n = 14) were identified within a longitudinal cohort. Urinary biomarker concentrations (by ELISA) were normalized for urine creatinine. Marker levels during active AAV were compared to baseline remission levels (from 1–4 visits) for each patient. Areas under receiver-operating characteristic curves (AUC), sensitivities, specificities, and likelihood ratios (LR) comparing disease states were calculated. Results. Baseline biomarker levels varied among patients. All 4 markers increased during renal flares (p < 0.05). MCP-1 discriminated best between active renal disease and remission: a 1.3-fold increase in MCP-1 had 94% sensitivity and 89% specificity for active renal disease (AUC = 0.93, positive LR 8.5, negative LR 0.07). Increased MCP-1 also characterized 50% of apparently nonrenal flares. Change in AGP, KIM-1, or NGAL showed more modest ability to distinguish active renal disease from remission (AUC 0.71–0.75). Hematuria was noted in 83% of active renal episodes, but also 43% of nonrenal flares and 25% of remission samples. Conclusion. Either urinary MCP-1 is not specific for GN in AAV, or it identifies early GN not detected by standard assessment and thus has potential to improve care. A followup study with kidney biopsy as the gold standard is needed.