JC viraemia in kidney transplant recipients: to act or not to act?

Human polyomaviruses have entered the domain of clinical decision-making in renal transplantation and this has coincided with the use of more potent immunosuppressive regimens. BK polyomavirus has predominated, resulting in nephropathy and ureteral strictures with the potential for graft loss [1]. JCV is a type of human polyomavirus, named with the initials of the patient from whom the virus was first isolated. JC polyomavirus is known to cause progressive multifocal leukoencephalopathy (PML) which has been reported in the renal transplant population [2]. Polymerase chain reaction (PCR) screening for BK polyomavirus in the early post-transplant period is routinely performed worldwide but is not known to occur for JC polyomavirus.