BK virus infection in kidney transplantation: a case for early intervention

The prognosis for renal allograft survival in a patient with BK virus-associated nephropathy is distressing because nearly 50% of affected grafts are lost. With these statistics in mind, attempting clinical intervention before BK virus disease develops seems appropriate. Noninvasive screening tools such as tests to detect decoy cells in urine can enable diagnosis of BK viral infection in its early stages. Although it is not entirely clear which patients with BK infection will have BK disease develop, it may be possible to intervene in this early warning period to prevent the further development of BK virus-associated nephropathy. We present a case of a 50-year-old man in whom asymptomatic BK viruria developed 6 weeks after he received a non-HLA matched kidney from a deceased donor. This BK viruria was accompanied, subsequently, by an unexplained increase in serum creatinine level 2 months after transplantation. Following a change in his immunosuppressive regimen as therapy for presumed renal allograft dysfunction associated with BK viral infection, the decoy cells in his urine disappeared and his creatinine levels stabilized.