BK virus nephropathy in simultaneous pancreas kidney transplant: a potentially preventable cause of kidney allograft loss.

More than half of the simultaneous pancreas kidney transplant (SPK) patients afflicted with BK virus nephropathy (BKVN) lose their kidney allograft. Fear of pancreatic rejection limits the ability to reduce immunosuppression; this may result in inadequate treatment of BKVN. This single-center retrospective review included 138 SPK patients who underwent periodic BKV screening and were managed with IS reduction alone as a treatment of choice for BKVN. All patients underwent rabbit anti-thymocyte globulin (rATG) induction and were maintained on tacrolimus/sirolimus or mycophenolate. The incidence of BKVN was 4.4%. BKVN was diagnosed at a median of 11 months; mean serum creatinine 2.1 mg/dL and the geometric mean BK serum viral load at diagnosis 1,758,000 DNA copies/mL. Median time to BKV clearance was 5.6 months; there was 96% reduction in the mycophenolate dose, 100% reduction in sirolimus, and 40% reduction in the tacrolimus blood level at BKVN clearance. No BKVN-related kidney failure was noted, and patients retained excellent kidney and pancreatic allograft function till last follow-up (43 months). BKVN in SPK is a potentially preventable cause of end-stage kidney disease, and IS reduction alone is an acceptable treatment modality in SPK without a higher risk of kidney/pancreas allograft loss as long as close monitoring can be ensured.