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Abstract: PO1418

Urine and Plasma Complement Ba Levels During Flares of Nephritis in Patients with ANCA-Associated Vasculitis

Session Information

Category: Glomerular Diseases

  • 1202 Glomerular Diseases: Immunology and Inflammation

Authors

  • Almaani, Salem, The Ohio State University Wexner Medical Center, Columbus, Ohio, United States
  • Song, Huijuan, The Ohio State University Wexner Medical Center, Columbus, Ohio, United States
  • Suthanthira, Meshora, The Ohio State University Wexner Medical Center, Columbus, Ohio, United States
  • Toy, Christopher, Colorado State University System, Denver, Colorado, United States
  • Fussner, Lynn A., The Ohio State University Wexner Medical Center, Columbus, Ohio, United States
  • Meara, Alexa Simon, The Ohio State University Wexner Medical Center, Columbus, Ohio, United States
  • Nagaraja, Haikady N., The Ohio State University Wexner Medical Center, Columbus, Ohio, United States
  • Khalidi, Nader A., McMaster University, Hamilton, Ontario, Canada
  • Pagnoux, Christian, Mount Sinai Hospital, Toronto, Ontario, Canada
  • Warrington, Kenneth, Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States
  • Monach, Paul, Brigham and Women's Hospital, Boston, Massachusetts, United States
  • Merkel, Peter A., University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States
  • Rovin, Brad H., The Ohio State University Wexner Medical Center, Columbus, Ohio, United States
  • Birmingham, Daniel J., The Ohio State University Wexner Medical Center, Columbus, Ohio, United States

Group or Team Name

  • Vasculitis Clinical Research Foundation
Background

The alternative complement pathway has been implicated in the pathogenesis of ANCA-associated vasculitis (AAV), however it is not clear whether activation of complement occurs systemically or in affected organs such as the kidney. This study measured levels of urinary and plasma complement fragment Ba (uBa and pBa respectively) at multiple timepoints in patients with AAV.

Methods

Ba was measured by ELISA in serial samples of urine (uBa) and plasma (pBa) from 20 AAV patients who developed a renal flare, 20 who developed a non-renal flare, and 20 in long-term remission. Changes in Ba levels were modeled using linear mixed effect models.

Results

Cohort characteristics are given in Figure.1. uBa levels increased at renal flare , but did not increase at non-renal flare , and remained stable in long-term remission (Figure 2a). pBa levels were stable over time in all groups (Figure 2b). uBa correlated with renal AAV activity measured as the renal component of the BVAS score (R2= 0.33, p<0.01), but did not correlate with the overall BVAS score during renal flare (R2= 0.13, p=0.12) or non-renal flare (R2= 0.10, p=0.22).

Conclusion

Urine, but not plasma, Ba levels increase at the time of a flare of renal disease in AAV, suggesting intra-renal alternative complement pathway activation. uBa has the potential for use as a surveillance biomarker of renal vasculitis.

Funding

  • Other NIH Support