Background and Aim:ABO-incompatible kidney transplantation (ABOiKT) recipients may have an increased risk of BK virus allograft nephropathy (BKVAN), a major cause of renal dysfunction and allograft loss. We investigated BK viremia and BKVAN in ABOiKT recipients compared to ABO compatible kidney transplantation (ABOcKT) recipients.

Methods: This study analyzed a total of 1111 kidney transplant recipients between January 2012 and December 2015 (n= 217 ABOiKT and n= 894 ABOcKT) at Asan Medical Center. High viremia was defined as serum BK viral load with peak ≥ 10,000copies/㎖ more than once after transplantation and low viremia was defined as serum BK viral load with peak < 10,000 copies/㎖. BKVAN was confirmed by biopsy.

Results: The incidence of high viremia was 12.0% ( n= 26/217) in ABOiKT and 8.4% (n= 75/894) in ABOcKT (p= 0.067). BKVAN was diagnosed in 4.6% (n= 10/217) ABOiKT recipients and 1.6% (n = 14/894) ABOcKT recipients (p= 0.015). In ABOiKT, graft survival was not significantly different among the groups according to degree of BK viral loads (p= 0.092), but graft functions of patients with high viremia were worse than that of patients with aviremia, especially at 6 months and 12 months [62.6 mL/min/1.73 m² versus (vs) 79.2 mL/min/1.73 m², p= 0.020 and 65.4 mL/min/1.73 m²vs 81.4 mL/min/1.73 m², p= 0.006, respectively]. Among patients with high viremia, 38.5% (10/26) patients in ABOiKT were diagnosed BKVAN compared with only 18.7% (14/75) patients in ABOcKT (p= 0.041). BKV was first detected within 6 months after transplantation in both groups (p=0.304). In patients with high viremia, graft functions of ABOiKT patients were worse than that of ABOcKT patients at 6 months after transplantation. Approximately 80% of patients used tacrolimus as a maintenance immunosuppressant and there were no differences in through levels of tacrolimus during one year. There was no significant difference in the incidence of graft failure, but graft failure was caused by BKVAN in ABOiKT with high viremia and by acute rejection in ABOcKT with high viremia. However, there was no significant difference in graft survival between ABOiKT and ABOcKT.

Conclusions: ABOiKT recipients have a greater risk for BK viremia and BK allograft nephropathy compared to ABOcKT. In ABOiKT, high BK viremia was associated with worse graft function although it did not affect graft survival.

CITATION INFORMATION: Yoon J., Baek C., Park S-.K., Kim H. Clinical Outcomes of Patients with BK Viremia in ABO-Incompatible Kidney Transplantation and Comparison with ABO-Compatible Kidney Transplantation Am J Transplant. 2017;17 (suppl 3).

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