Adjuvant Ciprofloxacin for Persistent BK Polyomavirus Infection in Kidney Transplant Recipients

Background. BK virus (BKV) infection is a common complication following kidney transplantation. Immunosuppression reduction is the cornerstone of treatment while adjuvant drugs have been tried in small uncontrolled studies. We sought to examine our center’s experience with the use of ciprofloxacin in patients with persistent BKV infection. Methods. Retrospective evaluation of the effect of a 30-day ciprofloxacin course (250？mg twice daily) on BKV infection in kidney transplant recipients who had been diagnosed with BK viruria ≥106 copies/mL and viremia ≥500 copies/mL and in whom the infection did not resolve after immunosuppression reduction and/or treatment with other adjuvant agents. BKV in plasma and urine was evaluated after 3 months following treatment with ciprofloxacin. Results. Nine kidney transplant recipients received ciprofloxacin at a median of 130 days following the initial reduction in immunosuppression. Three patients showed complete viral clearance and another 3 had a ≥50% decrease in plasma viral load. No serious adverse events secondary to ciprofloxacin were reported and no grafts were lost due to BKV up to 1 year after treatment. Conclusion. Ciprofloxacin may be a useful therapy for persistent BKV infection despite conventional treatment. Randomized trials are required to evaluate the potential benefit of this adjuvant therapy. 1. Introduction BK polyomavirus (BKV) is a common pathogen of kidney transplant recipients, which can result in impaired graft function and inferior graft survival [1]. Approximately 30%, 11–13%, and 8% of kidney transplant recipients develop BK viruria, viremia, and BK virus associated nephropathy (BKVAN), respectively [1–3]. Graft loss rates have been reported to be as high as 30–50% following a diagnosis of BKVAN [1, 4], although more recent data indicate that with early diagnosis of BK viremia or viruria using regular screening, the majority of patients respond favorably [5]. However, BKV infection continues to have a major impact on graft function with nearly 25% of infected patients showing a sustained increase in serum creatinine of at least 50% compared to that observed at the time of diagnosis [6]. Several donor and recipient risk factors for the development of BKV infection have been identified and of these, a high burden of immunosuppression appears to be the most important [7]. A strategy of immunosuppression reduction is therefore considered the cornerstone of treatment for BKV infection [8], although a uniform standardized protocol has not yet been established [2, 9]. The inability to clear this