Clinical Characteristic and Outcomes of BK Virus Infection in Kidney Transplant Recipients Managed Using a Systematic Surveillance and Treatment Strategy

Background: BK virus (BKV)–associated nephropathy is a significant complication of kidney transplantation that progresses to graft dysfunction and graft loss. The aim of this study was to know the infection rate and progression of BKV according to our strategy. Materials and Methods: This study included 302 patients who received kidney transplantation between August 2010 and October 2012. Patients were divided into 4 groups: no BK infection, BK viruria only, low BK viremia, and high BK viremia. Results: In this study, 57 patients had BK viremia (18.9%), and 18 patients had BK nephropathy (5.9%) during a 2-year follow-up period. Age, sex, cytomegalovirus (CMV) viremia, existence of donor-specific antibodies, type of transplantation, and delayed graft function were not significantly different. Disappearance of BKV infection was better in the viruria and low viremia groups than in the high viremia group (P = .001), and duration of BK infection was longer in the high viremia group than the low viremia group (P = .002). Conclusion: All diagnosed cases of BKV nephropathy were in the high BK viremia group. For BK viruria and viremia, early detection of BK infection together with early intervention by reduced immunosuppressant is a useful strategy to maintain allograft function. Long-term follow up is required to identify the risk factors for BK infection and graft survival after kidney transplantation.