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There has been a notable rise of BK virus among kidney transplant recipients. Single-center reports have identified risk factors for development of BK virus. However, there has not been an assessment of risk factors and incidence of this complication at a national level. This study utilized newly collected follow-up information from the national SRTR database to investigate incidence, risk factors and outcomes for solitary kidney transplant recipients associated with treatment for BK virus (TBKV) from 2004 to 2006. Logistic and Cox models were utilized to assess risk factors and evaluate graft survival associated with TBKV. Incidence of TBKV was 1.6% at 6 months and 2.6% at 1 year following transplantation. Patients with and without TBKV at 6 months had 79% and 90% 3-year overall graft survival respectively. Risk factors included advanced donor age, pediatric, African American and male recipients, human leukocyte antigen-mismatching and tacrolimus and thymoglobulin induction as baseline immunosuppression. Acute rejection episodes were more frequent prior to and following TBKV. TBKV is a common and rising incidence, varies based on transplant characteristics and should be included as a safety endpoint in studies investigating immunosuppressive protocols. Careful monitoring and further understanding of disease etiology and treatment strategies are needed.

Although there might be a limited impact of HLA matching on acute rejection and graft survival, many patients might be negatively impacted from poor HLA matching of their first kidney transplant when needing a second transplant. This might be particularly important in patients with a long life expectancy because of the high likelihood of needing a second transplant during their lifetime.

The placement of ureteral stent (UrSt) at kidney transplantation reduces major urological complications but increases the risk for developing nephropathy from the BK virus. It is unclear whether UrSt placement increases nephropathy risk by increasing risk of precursor viral replication or by other mechanisms. We retrospectively investigated whether UrSt placement increased the risk for developing BK Viremia (BKVM) in adult and pediatric kidney transplants performed at the University of Florida between July 1, 2007, and December 31, 2010. In this period all recipients underwent prospective BKV PCR monitoring and were maintained on similar immunosuppression. Stent placement or not was based on surgeon preference. In 621 transplants, UrSt were placed in 295 (47.5%). BKVM was seen in 22% versus 16% without UrSt (P = 0.05). In multivariate analyses, adjusting for multiple transplant covariates, only UrSt placement remained significantly associated with BKVM (P = 0.04). UrSt placement significantly increased the risk for BKVM. Routine UrSt placement needs to be revaluated, since benefits may be negated by the need for more BK PCR testing and potential for graft survival-affecting nephritis.