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Abstract: SA-PO416

Soluble CD163 Differentiates Active Vasculitis and Lupus Nephritis from Inactive Disease

Session Information

Category: Glomerular Diseases

  • 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Amador, Daniel Alberto, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico, Mexico
  • Mejia-Vilet, Juan M., Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico, Mexico
  • Cruz, Cristinoc, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico, Mexico
  • Correa-Rotter, Ricardo, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico, Mexico
  • Nino-Cruz, Jose Antonio, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico, Mexico
Background

Urine soluble CD163 (sCD163) is an enzymatically cleaved form of CD163 that has been described to discriminate active from inactive renal ANCA-associated vasculitis (rAAV) with 71-87% sensitivity and >97% specificity. sCD163 has also been reported to be elevated in active lupus nephritis (aLN).

Methods

The aim of the study was to evaluate urine sCD163 in patients with rAAV (n=20), systemically-active AAV without renal vasculitis (sAAV, n=5), inactive AAV (iAAV, n=4), aLN (n=10), clinically-inactive LN (iLN,n=5), and living-kidney donors (KD,n=5). To explore other diseases that may increase urine sCD163 we also evaluated patients with tubulointerstitial nephritis including tuberculous TIN (n=3) and IgG4 TIN (n=2).

Results

Median BVAS score was 19 (14-23), 7 (5-18) and 0(0-0) in rAAV, sAAV and iAAV respectively. Renal BVAS was 12 (10-12) in rAAV and 0 in both sAAV and iAAV. aLN patients had a median NIH activity score of 11 (10-12) and chronicity score of 4 (3-5). Median urine sCD163 titers were 3.5ng/mg (1.8-20.0) in rAAV, 0.4ng/mg (0.03-1.1) in sAAV, and 0.2ng/mg (0.1-0.3) in iAAV (Figure 1A). The AUC was 0.919 to differentiate rAAV from non-renal AAV (p<0.001). With a cutoff>1.75ng/mg the sensitivity was 80% and specificity 100%. Median urine sCD163 was 66.3ng/mg (52.0-182.0) in aLN compared to 1.0ng/mg (0.3-3.8) in iLN with 100% sensitivity and specificity to differentiate between both groups (Figure 1B). Tuberculous TIN and IgG4 TIN had urine sCD163 values >3.0ng/mg.

Conclusion

Urine sCD163 is a good biomarker to differentiate both active renal AAV and active LN from inactive disease. Nevertheless, urine sCD163 titers were highest in aLN. This molecule can be also elevated in other diseases such as granulomatous and IgG4 TIN. Its use as biomarker should be further explored in longitudinal cohorts.