Kidney Week

Abstract: SA-PO1146

AT₁R and ETAR Antibodies, Proteinuria, and Renal Dysfunction in Pediatric Kidney Transplantation

Session Information

• Transplantation: Clinical - Rejection, Recurrent Disease, Incompatibility
  November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Transplantation

• 1902 Transplantation: Clinical

Authors

• Elchaki, Rim, Mattel Children's Hospital at UCLA, Los Angeles, California, United States

Rim Elchaki,

• Chen, Lucia, University of California Los Angeles, Los Angeles, California, United States

Lucia Chen,

• Weng, Patricia L., Mattel Children's Hospital at UCLA, Los Angeles, California, United States

Patricia L. Weng,

• Reed, Elaine F., University of California Los Angeles, Los Angeles, California, United States

Elaine F. Reed,

• Tsai, Eileen W., Mattel Children's Hospital at UCLA, Los Angeles, California, United States

Eileen W. Tsai,

• Ettenger, Robert B., Mattel Children's Hospital at UCLA, Los Angeles, California, United States

Robert B. Ettenger,

• Pearl, Meghan, Mattel Children's Hospital at UCLA, Los Angeles, California, United States

Meghan Pearl,

Background

Activating autoantibodies to Angiotensin II Type 1 Receptor (AT₁R) and Endothelin type A receptor (ETAR) are non-HLA antibodies which have been associated with poor kidney allograft outcomes. However, the association of these antibodies with proteinuria and renal dysfunction is unknown. We aimed to determine the association of AT₁R and ETAR antibodies (Ab) with proteinuria and renal allograft function in pediatric kidney recipients (KTRs).

Methods

65 pediatric KTRs were monitored for 2 years after transplantation. ETAR-Ab and AT₁R-Ab (ELISA) were measured at 6 months (m), 12m, and 24m post-transplant and during episodes of rejection. Based on a receiver operating curve analysis, > 10 and >17 units/ml was considered positive for ETAR-Ab and AT₁R-Ab respectively. Renal function (updated Schwartz Equation) and proteinuria were also assessed at the above noted time points. Proteinuria was defined as >1+ (30-100 mg/dl) on urinalysis. Samples were excluded for factors that may result in false positives including high specific gravity >1.030, alkaline PH (>8.5) and gross hematuria (n=3).

Results

AT₁R-Ab and ETAR-Ab were positive in 38 (58%) and 24 (37%) of patients during the first 24m post-transplant respectively. Proteinuria was present in 84 of 323 urinalysis samples (26%) with 44 patients (68%) positive during the first 24m post-transplant. We found that patients with both AT₁R -Ab and proteinuria had greater declines in renal function than patients with either predictor alone (p=0.004, Figure 1a). This relationship was also observed in patients with ETAR-Ab and proteinuria (p =0.018, Figure 1b).

Conclusion

Pediatric KTRs with AT₁R-Ab, ETAR-Ab, and proteinuria have greater declines in kidney function in the first 24m post-transplantation. This association highlights the potential detrimental effects of non-HLA antibodies on the renal allograft in the pediatric population.