BK virus infection in renal transplant recipients: an overview

Although BK virus (BKV) was discovered in 1971, it took almost three decades for this virus to be routinely considered as a possibility among a plethora of causes of renal dysfunction in a kidney transplant recipient. BKV infection, an early complication of renal transplant, often presents within the first year after transplantation. It presents as an asymptomatic gradual rise in creatinine with tubulointerstitial nephritis that mimics acute rejection and poses a diagnostic and therapeutic dilemma. More frequent diagnosis of BKV infection over the past 2 decades is a consequence of more potent immunosuppression (aimed to prevent acute rejection episodes and, thereby, improving allograft survival). Untreated BKV infections cause renal allograft dysfunction and subsequently allograft loss. A routine screening protocol for early recognition of asymptomatic BKV infection has been reported to result in better allograft outcomes. This review is aimed to discuss the most recent evidence addressing the virology, pathogenesis, clinical features, diagnostic tools, screening protocols, treatment strategy, and short-term and long-term renal allograft survival concerning BKV infection.