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BK VIRAL Screening FOLLOWING RENAL TRANSPLANTATION: DEFINING A LOCAL STANDARD
Grant, C.H.¹, Doyle, A²
¹College of Medicine and Veterinary Medicine, University of Edinburgh, Scotland, ²Victoria Hospital Kirkcaldy, NHS Fife
Background: BK virus nephropathy is an emerging and significant cause of graft loss following renal transplantation. A recent study suggested that around 40% of BK viral tubulitiscases result in graft failure within five years of diagnosis. However, there are no defined standardsguiding the needfor serum BK viral screening following renal transplantation or an appropriate time schedule for such a programme. Many centres undertake testing upon identifying graft dysfunction whereas others routinely screen. Furthermore, there is a lack of evidence of managing the results of viraemia or tubulitis. We undertook a retrospective study to assess our local rates of BK virus detection following transplantation to inform a local standard for screening and management.
AIMS: To assess the indication, number and timing of BK viral screening tests undertaken over a three year period following all renal transplants in NHS Fife.
METHODS: A list of all renal transplants undertaken in NHS Fife from January 2011 to December 2013 inclusive was obtained from the ‘proton’ renal electronic patient record. This was compared to a list of all BK viral DNAPCR blood tests conducted for the same period obtained from the microbiology laboratory. Indication for viral screening was identified from the electronic patient record. Transplant biopsies were identified from the renal EPR and lab database
RESULTS: The total number of renal transplants undertaking in NHS Fife during the study period was thirty five.Sixteen of the thirty five patients were tested for BK virus during follow up. Of those sixteen patients the time lapse between transplant and first BK viral screening were as follows: 0-3 months (3), 3-6 months (1), 6-9 months (5), not known (7). The indications were as follows; graft dysfunction (9), random screening (7). Of the nine patients tested for graft dysfunction, only three had viraemia identified and one had graft failure. Of the seven patients tested on screening, four had sustained viraemia without graft dysfunction and one was later investigated for graft dysfunction when biopsy suggested tubulitis.Testing for BK viraemia was mostly undertaken investigating change in graft function which occurred in 25.7%(n9) revealing viraemia in three. BK virus screening in the absence of graft dysfunction was undertaken in 20%(n7) revealing viraemia in four. The remaining 54% (n19) of patients were not tested and had uneventful follow up.
CONCLUSION: In this small cohort of thirty five incident renal transplant recipients, the rate of identified BK nephropathy was 5.7%. Both cases were identified during investigation of graft dysfunction by renal biopsy. However, one of these had been identified by prior screening in the early post transplant period and changes to immunosuppression already made. Although the results indicate a non-uniform and variable approach to BK viral screening following renal transplantation in NHS Fife, all cases of graft dysfunction were appropriately investigated including viral studies and biopsy where appropriate. It is unlikely that clinically significant nephropathy cases have been overlooked by this approach.
RELEVANCE:It is not known whether BK viraemia in the absence of biochemical graft dysfunction poses a subsequent risk of graft problems. One case in the cohort had viraemia identified on screening some weeks before showing graft dysfunction, by which time immunosuppression had already been adjusted.We have shown a significant incidence of BK viraemia in this cohort. We feel that our findings support the routine testing for BK virus following renal transplantation.