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Kidney Week

Abstract: TH-PO626

Exostosin 1-/Exostosin 2-Positive Membranous Lupus Nephritis Is Associated with a Favorable Kidney Prognosis

Session Information

Category: Glomerular Diseases

  • 1402 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Zavala Miranda, Fernanda, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Ciudad de Mexico, Ciudad de México, Mexico
  • Sobrino, Ana María, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Ciudad de Mexico, Ciudad de México, Mexico
  • Pena, Oscar, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Ciudad de Mexico, Ciudad de México, Mexico
  • Pérez Arias, Abril A., Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Ciudad de Mexico, Ciudad de México, Mexico
  • Macedo, Sofia E. Márquez, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Ciudad de Mexico, Ciudad de México, Mexico
  • Juarez Cuevas, Bernardo, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Ciudad de Mexico, Ciudad de México, Mexico
  • Uribe-uribe, Norma O., Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Ciudad de Mexico, Ciudad de México, Mexico
  • Mejia-Vilet, Juan M., Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Ciudad de Mexico, Ciudad de México, Mexico
Background

30-35% of patients with membranous lupus nephritis (MLN) are positive for the exostosin 1/2 (EXT1/2) staining. Previous studies have suggested that positive EXT1/2 stain is associated with better response to therapy, kidney prognosis, and low rates of transition to proliferative nephritis. We evaluated the prevalence of EXT1/2 staining in our cohort of pure MLN and its association with response to therapy and long-term kidney outcomes.

Methods

Retrospective cohort study. From 100 patients with membranous nephropathy we evaluated 53 patients with pure MLN and follow-up >5 years. EXT1/2 was detected by immunohistochemistry. We compared the clinical and histopathological presentation of EXT1/2 positive and negative patients. The kidney outcomes of response to therapy, 40% decline in eGFR, doubling of serum creatinine, and kidney failure were assessed by survival analyses.

Results

Fourteen (26%) MLN patients had positive EXT1/2 staining. Patients with positive EXT1/2 staining were younger and had a higher eGFR at presentation. There were no differences in complete or partial response between both groups (log-rank p=0.118 and p=0.412, respectively). Over a median follow-up of 118 months (IQR 73-172), none of the EXT1/2 positive and 9 of the EXT1/2 negative patients progressed to 40% decline of the eGFR with 5- and 10-year 40% eGFR decline rates of 0% and 0%, and 16% and 26%, respectively (log-rank p=0.046, Figure 1). No differences were observed in progression to doubling of serum creatinine or kidney failure. All patients were alive at the last date of follow-up.

Conclusion

EXT1/2 positive MLN is associated with similar response to therapy than EXT1/2 negative MLN, but better long-term kidney prognosis.

Figura 1. Glomerular EXT1/2 immunohistochemistry (A) and kidney outcome of 40% decline in eGFR according to EXT1/2 staining.