Monitoring the BK virus in liver transplant recipients: a prospective observational study.

ABSTRACT

OBJECTIVES: Because of the controversy regarding the effects of BK virus on nonrenal solid-organ transplant, we detected the BK virus via different methods and its effect on clinical findings, liver and kidney functions, and graft dysfunction in liver transplant recipients. MATERIALS AND METHODS: This prospective cohort study comprised patients over the age of 18, who consecutively received liver transplant from January 1 to December 31, 2011. The patients were examined once, every 2 weeks, for the first 3 months after transplant. Clinical findings were evaluated on each examination; blood and urine samples were collected, BK virus DNA was assessed with real-time polymerase chain reaction, and the presence of decoy cells (which are epithelial cells with large nuclei and large basophilic inclusions) in the urine was investigated. Patients were followed-up for 1 year to see if rejection occurred. RESULTS: Five of 39 patients (12.8%) showed BK viremia; 11 patients (28.2%) showed BK viruria, and 13 (33.3%) showed decoy cells. No statistically significant differences were found between BK virus positive and negative groups, respecting demographic variables, kidney and liver functions, and graft survival. BK virus DNA positivity in blood was the standard, while decoy cell assessment in urine and BK virus polymerase chain reaction test sensitivity in urine was 40%. CONCLUSIONS: No matter the method used to detect BK virus in the urine, the negativity of the tests is more valuable than their positivity. Although no statistically significant difference was found between the groups, we concluded that BK virus is a factor that should be considered when unexplained deterioration in kidney and liver function tests is observed in liver transplant recipients. Prospective studies with larger numbers of patients are warranted.