1 Introduction BK virus, from the Papovaviridae family of viruses, is highly seroprevalent, with an affinity for the renal tubular and transitional epithelial cells of the genitourinary tract after initial infection where it remains latent [1-4]. In its active state, the virus causes BK nephropathy (BKN) in kidney recipients, which can cause graft loss [3]. Unfortunately, BKN is increasingly recognized as a source of renal dysfunction even in non-kidney transplant recipients [3, 5, 6].