Prevalence and risk factors of polyomavirus BK replication in simultaneous pancreas/kidney transplant recipients from a single transplant center.

BACKGROUND: BK virus (BKV) replication is considered as a marker of risk for polyomavirus BK-associated nephropathy (PVAN). We evaluated the occurrence and risk factors for BKV DNA positivity following simultaneous pancreas/kidney transplantation (SPK). METHODS: Point prevalence of BK viruria and viremia was assessed in 183 SPK recipients. Real-time polymerase chain reaction was used with a detection threshold of 10(3) copies/mL. High-level BKV positivity was defined as viruria and/or viremia >10(7) and >10(4) copies/mL, respectively. BKV-positive patients were retested after 4-13 months and underwent an additional six-month clinical follow-up. RESULTS: Urine and serum BKV positivity was detected in 28 (17.3% of available samples) and 7 (3.8%) patients, with high-level viruria and viremia occurring in 6 (3.7%) and 3 (1.6%) patients, respectively. PVAN was biopsy-confirmed in 1 and suspected as a cause of progressive renal failure in another SPK recipient. Patients with single low-level viruria did not progress to high-level positivity or PVAN at follow-up. In multivariate analysis, pre-transplant diabetes duration and delayed graft function were independently associated with BKV positivity. CONCLUSIONS: Point prevalence of high-level BKV positivity and PVAN was low in SPK recipients from a single center. Diabetes duration and delayed graft function were independent risk factors for BKV replication.

Kidney retransplantation following graft loss to polyoma virus-associated nephropathy: an effective treatment option in simultaneous pancreas and kidney transplant recipients.

Polyomavirus-associated nephropathy (PVAN) has emerged as an important cause of graft loss following kidney transplantation. Experience with kidney retransplantation (reKT) in PVAN is very limited, especially in the setting of uninterrupted immunosuppression protecting the still functioning pancreatic graft after simultaneous pancreas/kidney transplantation (SPK). We present a review of five cases of reKT in four SPK recipients with Type 1 diabetes mellitus from a single centre (a second reKT was performed in one patient following first reKT failure due PVAN recurrence). Pre-emptive nephrectomy of the failed graft was performed in three of the cases and all kidney grafts for reKT were harvested from cadaveric donors. All patients are dialysis- and insulin-independent at 30 (9-55), median (range), months following last reKT with maintenance immunosuppression consisting of tacrolimus/sirolimus in three and cyclosporine A/mycophenolate mofetil in one patient. In conclusion, reKT represents an effective treatment option in SPK patients with kidney failure on account of PVAN. Use of interventions designed to reduce active viral replication, including pre-emptive nephrectomy of the failed graft, should be considered before reKT.