Monitoring of BK virus in liver transplant recipients

Aim: The role of BK Virus (BKV) in renal and bone marrow transplant recipients has already been defined. Because of unclear situation of BKV in non renal solid organ transplant recipients, we planned to determine the incidence and effects of BKV in liver transplant recipients. Primarily, we aimed to study BKV by three different methods (including polymerase chain reaction (PCR) assays of plasma and urine and decoy cell screening) in first three month after transplantation and evaluate the relationship between BKV with hepatic-renal functions and graft failure in liver transplant recipients. The second aim of this study was defining the importance of BKV DNA PCR in routine practice. Materials and Methods: From January 1 to December 31, 2011 at the Liver Transplantation Unite of General Surgery Department of our center, all liver transplant recipients (?18 years) were enrolled in this prospective study. The patients were visited bi weekly in first three months post transplantation and urine and plasma samples were collected for detection of BKV DNA using a real time quantitative PCR assay and decoy cell screening. Clinical data were also collected. Results: Thirty nine liver transplant recipients were enrolled in this single center prospective study. BK viremia was detected in 5 patients (12.8 %) and BK viruria was detected in 11 patients (28.2 %). Decoy cells were positive in 13 patients (33.3%). We did not observe any difference about demographic data, renal-hepatic functions and graft survival between with and without BKV groups. In our study, urine BKV DNA PCR and decoy cell screening assays have low sensitivity and low positive predictive value compared with the blood BKV DNA PCR. But negative predictive values were 89.2% and 88.4% respectively. Conclusions: According to results of our study, negative results of these two tests are more important than positive results. These tests (urine BKV PCR and decoy cell screening) may be useful for routine practice, but positive results of the tests should be confirmed by blood BKV PCR. Based on the results of our study and similar studies, despite there is no statistical significance, BKV is a factor that should be consider in this group of patients, if there is renal and hepatic dysfunction due to unknown reasons. More prospective multicenter studies are needed to define the role of BKV at rejection in liver transplant population. Keywords: Polyomavirus, BK Virus, BKV, PCR, Decoy, Liver transplantation