ASN's Mission

ASN leads the fight to prevent, treat, and cure kidney diseases throughout the world by educating health professionals and scientists, advancing research and innovation, communicating new knowledge, and advocating for the highest quality care for patients.

learn more

Contact ASN

1401 H St, NW, Ste 900, Washington, DC 20005

email@asn-online.org

202-640-4660

The Latest on Twitter

Kidney Week

Abstract: PO2086

A Successful Approach for A2 to B Cadaveric Renal Transplantation

Session Information

Category: Transplantation

  • 1902 Transplantation: Clinical

Authors

  • Sogbein, Olusola, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States
  • Kumar, Anand, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States
  • Mujtaba, Muhammad Ahmad, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States
Background

Approximately 20% of blood group A individuals have reduced levels of A-antigen, termed A2, with less immunogenicity toward anti-A1 immunoglobulins. This allows the safe transplant of A2 kidneys into B or AB recipients. In 2014, the Kidney Allocation System was modified to encourage transplant centers to provide A2 kidneys for type B patients to reduce inequities in access. Studies have reported that rates of A2 to B transplants remain underutilized due to high rates of early acute rejection or thrombotic microangiopathy (TMA). We report on outcome metrics of A2 to B transplantation at the University of Texas Medical Branch (UTMB).

Methods

A retrospective, single center analysis of 29 patients who received A2 to B kidney transplants at UTMB between July 2015 and December 2020. We included stable (2 consecutive) anti-A IgG titers ≤ 1:8 for A2 identified individuals. Anti-A titers were monitored quarterly in B waitlisted patients. All A2/A2B to B eligible recipients underwent pre-transplant volume exchange plasmapheresis, followed by 2 additional sessions on post-op days 1 and 3. Thymoglobulin was used for induction and steroids for maintenance immunosuppression.

Results

A major concern in A2 to B transplant is the development of TMA or graft rejection. The incidence of rejection within the first year of all types of renal transplants ranges from 7.9% to 21.4%. We instituted an aggressive plasmapheresis protocol to reduce levels of potential pre-formed IgM anti-A antibodies that may induce graft failure. We report a rate of 3.4% for rejection or TMA within the first year of graft life which is less than previously published reports. This is due to pre- and post-transplant plasmapheresis in combination with intravenous immunoglobulin therapy. We elected not to follow anti-A titer levels post-transplant which did not result in higher rates of graft loss.

Conclusion

Our A2 to B transplant patients had a low rate of rejection and TMA demonstrating the efficacy of our triple maintenance immunosuppression protocol. Anti-A titers need not be followed post-operatively.

RESULTS
OUTCOME 
Cellular or Antibody mediated rejection at 1 year (%)3.45
Thrombotic Microangiopathy at 1 year (%)3.45
Kidney Allograft Survival at 1 year (%)96.55
Patient Survival at 1 year (%)100.00

Table 1