BK Virus Nephropathy in Renal Transplant Recipients: A Single Centre Experience

Introduction: BK virus nephropathy is an important cause of allograft failure in renal transplant recipients that is linked to highly potent immunosuppressive theraphy. We aimed to exhibit experience of our centre with BK virus nephropathy. Material and method: We retrospectively investigated 11 patients with BK virus nephropathy among 412 patients who received renal transplantation and followed up between 2000 and 2008 in our centre. Results: The mean age of 11 patients (7 male, 4 female) with BK virus nephropathy was 32±13 years. The mean follow up period of living (n=8) and cadaveric (n=3) transplantation was 32±20 months. The mean duration between transplantation and BK virus nephropathy diagnosis was 12±8 months. Diagnosis of BK virus nephropathy was confirmed by biopsy in transplanted kidney in 9 patients. While the mean of basal creatinine was 1.28±0.40 mg/dl, creatinine level of patients during diagnosis was 3.12±1.5 mg/dl. Eight patients were on tacrolimus (FK), mycophenolat mofetil (MMF) and steroid therapy, 2 patients on cyclosporine (CSA), MMF and steroid and the other patient on CSA, sirolimus and steroid as immunosuppressive therapy regimen during diagnosis. In order to reduce immunosuppressive dosage, FK and CSA was discontinued in 7 patients, sirolimus was started in 4 of 7 patients and the dose of MMF was decreased. While cidofovir was given to all patients, intravenous immunoglobulin could be given to only 8 patients. Acute rejection was diagnosed in three patients by allograft biopsy and they were treated by steroid pulse treatment. The follow-up period of patients with BK virus nephropathy was 19±20 months (3-59 months). Eight patients had stable graft function while three patients returned to dialysis at the end of the follow-up period. The mean last creatinine level of the 8 stable patients was 2.4±1.0 mg/dl. Two of 3 patients lost grafts after acute rejection while renal functions turned to basal levels in the other patient. Conclusion: The incidence of BK virus nephropathy was found to be 2.6% in our center. Stabilization could be achieved in the great majority of our patients by reduction of immunosupressive dosage and cidofovir treatment. It is thought that there may be a strong relationship between graft loss and acute rejection.