Background: BK virus-associated nephropathy (BKVAN) is an important risk factor that results in an allograft loss in kidney transplant recipients (KTRs). The short-term prognosis of patients with BKVAN is good; however, the long-term prognosis is uncertain. We evaluated the long-term prognosis and prognostic factors of graft failure in KTRs with BKVAN.

Methods: We retrospectively analyzed the medical records of 583 patients performed kidney transplantation between 2001 and 2014.

Results: Among them, the number of patients with positive urinary decoy cells was 258 patients, and 15 of 258 patients were diagnosed to BKVAN by allograft biopsies. Median time from KT to BKVAN diagnosis was 5.9 months (interquartile range (IQR), 4.4 – 8.7), and the follow-up duration after BKVAN diagnosis was 58.5 months (IQR, 32.2 – 123.4). Among the KTRs with BKVAN, KTRs with biopsy-proven acute rejection and graft failure were 10 patients, respectively. Median time from BKVAN diagnosis to graft failure was 36.2 months (IQR, 9.7 – 65.5). The cause of graft failure, less than 1 year after diagnosis of BKVAN, was a patient death with a functioning graft (2 patients) and the cause of graft failure, 1 year or more after diagnosis of BKVAN was uncontrolled rejection (8 patients). Death-censored graft survival rate of KTRs with BKVAN was significantly lower than that of KTRs without BKVAN (P < 0.001). Patient survival rate of KTRs with BKVAN was also significantly lower than that of KTRs without BKVAN (P < 0.001). The death-censored graft survival rate of KTRs with BKVAN accompanying acute rejection was significantly worst in comparison with KTRs with BKVAN without acute rejection or without BKVAN regardless of acute rejection (P < 0.001). The proportion of combined acute rejection and trough levels of tacrolimus at diagnosis of BKVAN were independent prognostic factors of graft failure in KTRs with BKVAN.

Conclusions: The long-term prognosis of BKVAN was poor because of graft failure due to inadequate rejection treatment for acute rejection accompanying with BKVAN and patient death due to infection by over-immunosuppression after anti-rejection treatment. We should carefully monitor the status of immunosuppression in KTRs with the risk factors of BKVAN.

CITATION INFORMATION: Park W., Yeo S., Kang S., Park H., Jin K., Park S., Choe M., Han S. Long-Term Prognosis of BK Virus Associated Nephropathy in Kidney Transplant Recipients Am J Transplant. 2017;17 (suppl 3).

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