55-year-old patient receiving cadaveric transplant. Induction: daclizumab-tacrolimus-MMF-steroids. Maintenance: tacrolimus-MMF-steroids. Creatinine 1 and 1.2 mg/dl; creatinine clearance: 96 ml, without proteinuria. Nine months post-transplant, he presented viruria (107 copies/ml) for BKV, without renal dysfunction, with negative viremia. High viruria persisted with negative viraemia, which was positive at month 12 (> 104 copies/ml), the biopsy showed interstitial nephritis, tubular nuclear alterations linked to BKV. Immunosuppressive medication was rotated to sirolimus 2 mg/day and cipro-floxacin 500 mg/day (10 days) was added. Renal function remained stable, with a clearance of 86 ml, no proteinuria and a decrease in viral load in urine and blood. At present, the patient retained his kidney and did not require dialysis.

