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Kidney Week

Abstract: PO2589

What Is the Safe Anti-A2 Titer for a Successful A2-Incompatible Kidney Transplantation?

Session Information

Category: Transplantation

  • 1902 Transplantation: Clinical

Authors

  • Al Azzi, Yorg, Montefiore Medical Center, Bronx, New York, United States
  • Loarte Campos, Pablo, Montefiore Medical Center, Bronx, New York, United States
  • Nair, Gayatri Devi, Montefiore Medical Center, Bronx, New York, United States
  • Ajaimy, Maria, Montefiore Medical Center, Bronx, New York, United States
  • Liriano-Ward, Luz E., Montefiore Medical Center, Bronx, New York, United States
  • Pynadath, Cindy T., Montefiore Medical Center, Bronx, New York, United States
  • Nandigam, Purna Bindu, Montefiore Medical Center, Bronx, New York, United States
  • Akalin, Enver, Montefiore Medical Center, Bronx, New York, United States
Background

The new kidney allocation system implemented in December 2014 allowed for use of A2/A2B donors to B recipients. However there is no mandate by UNOS regarding what anti-A2 titers are acceptable. We aimed to investigate the safety of kidney transplant in patients with anti-A2 titers equal or less than 1/16.

Methods

We performed 41 A2-incompatible kidney transplants at our institution if pre transplant anti-A2 titers are equal or less than 1/16. All patients received anti-thymocyte globulin induction. Patients with donor-specific-anti HLA-antibodies (DSA) received intravenous immunoglobulins 500 mg/kg for 3 doses.

Results

Of the 41 recipients, 85% were male, 48% African-American, with a median age of 53 (20-73) years. There were 38 deceased donor renal transplants and 3 living related. Median donor age was 42 (16-65) and median KDPI was 52 (2-86). Twenty-one patients had PRA 0% and 8 had pre transplant DSA. Pretransplant anti-A2 titers were 1/2 in 16, 1/4 in 9, 1/8 in 6, and 1/16 in 5 and too weak to titer in 5 recipients. During a median follow-up of 33 months (6-57) patient and graft survival were 100% and 90.2% respectively. Twelve patients underwent a clinically indicated kidney biopsy at a median 28 days post transplant (6-390). There was one case of acute T cell mediated rejection type IIA, and one chronic antibody-mediated rejection which was due to non-compliance leading to graft loss. Interestingly C4d positivity was seen in 9 biopsies, of which 8 did not have any findings of antibody mediated rejection and no microvascular inflammation. Median serum creatinine level at last follow up was 1.3 mg/dL (0.6-3.2) and only 3 patients had spot urine protein/creatinine more than 1 g/day.

Conclusion

A2-incompatible transplantation appears to be safe in patients with anti-A2 titers equal or less than 1/16 with or without DSAs and excellent short-term kidney allograft outcomes. C4d positivity is frequent in allograft biopsies without acute rejection suggesting accommodation to the allograft.