Outcomes of renal transplant recipients with BK virus infection and BK virus surveillance in the Auckland region from 2006 to 2012

AIM: To evaluate incidence, risk factors and treatment outcome of BK polyomavirus nephropathy (BKVN) in a cohort of renal transplant recipients in the Auckland region without a formal BK polyomavirus (BKV) surveillance programme. METHODS: A cohort of 226 patients who received their renal transplants from 2006 to 2012 was retrospectively reviewed. RESULTS: Seventy-six recipients (33.6%) had a BK viral load (BKVL) test and 9 patients (3.9%) developed BKVN. Cold ischaemia time (HR = 1.18, 95%CI: 1.04-1.35) was found to be a risk factor for BKVN. Four recipients with BKVN had complete resolution of their BKV infection; 1 recipient had BKVL less than 625 copies/mL; 3 recipients had BKVL more than 1000 copies/mL and 1 had graft failure from BKVN. BKVN has a negative impact on graft function [median estimated glomerular filtration rate (eGFR) 22.5 (IQR 18.5-53.0) mL/min per 1.73 m(2), P = 0.015), but no statistically significant difference (P = 0.374) in renal allograft function was found among negative BK viraemia group [median eGFR 60.0 (IQR 48.5-74.2) mL/min per 1.73 m(2)), positive BK viraemia without BKVN group [median eGFR 55.0 (IQR 47.0-76.0) mL/min per 1.73 m(2)] and unknown BKV status group [median eGFR 54.0 (IQR 43.8-71.0) mL/min per 1.73 m(2)]. The incidence and treatment outcomes of BKVN were similar to some centres with BKV surveillance programmes. CONCLUSION: Recipients with BVKN have poorer graft function. Although active surveillance for BKV has been shown to be effective in reducing incidence of BKVN, it should be tailored specifically to that transplant centre based on its epidemiology and outcomes of BKVN, particularly in centres with limited resources.