Polyomavirus-associated nephropathy in simultaneous kidney-pancreas transplant recipients: a single-center experience

With the introduction of more potent immunosuppressive agents, rejection rates have decreased markedly in simultaneous pancreas-kidney transplant (SPK) recipients. However, with more intense immunosuppression, opportunistic infections such as polyoma virus have been more frequent. The purpose of this article is to outline the clinical course of SPK patients who developed documented polyoma infection in the transplanted kidney.

A retrospective review of 146 consecutive SPK recipients from 1996 to 2002 was performed. Induction and maintenance immunosuppression, surgical complications, rejection episodes, and opportunistic infections were reviewed. Patients who developed biopsy-proven polyoma virus infection in the renal allograft were identified.

Nine patients (6%) were identified who developed polyoma. All had received induction therapy with either OKT3 (5 mg/d for 10.5 days) or thymoglobulin (5.7 mg/kg). Patients without polyoma had received similar induction. Maintenance immunosuppression included Prograf/MMF in six patients, CsA/MMF in two, and CsA/azathioprine in one. Time to diagnosis was an average of 359.3 days (range 136 to 836) after transplantation. Two patients had undergone treatment for kidney rejection prior to the diagnosis of polyoma. Immunosuppression was decreased in all patients when polyoma was identified, and more recently Cidofovir has been administered. Despite these interventions, five of the nine lost kidney function (creatinine > 5.0 or resumption of dialysis). However, none of the nine developed pancreatic abnormalities as demonstrated by normal blood glucose and amylase and no requirement for exogenous insulin. Two patients underwent LRRT more than 1 year after polyoma diagnosis; both have normal kidney function (Cr < 1.5 mg/dL) at 4 years of follow-up. Polyoma virus was the leading cause of renal loss in this cohort of patients.

Polyoma is a serious concern for SPK transplant recipients. The pancreas, however, is spared from clinical evidence of infection, and no rejection was noted when immunosuppression was decreased. These graft losses appear to be a penalty of more potent immunosuppression, and a better treatment strategy is needed to prevent renal graft loss when polyoma is diagnosed. Retransplantation can be considered based on our limited experience.