Effect of Transient BK Viremia and Viruria on Long-term Renal Allograft Survival and Function

IntroductionThe purpose of this study is to present the five-year survival and function of the renal allograft of recipients who were diagnosed with BK viremia and viruria during the first year after renal transplantation.Patients and MethodsBK virus was studied in 32 new renal allograft recipients, from the first postoperative day until 18 months after the transplantation. Real-time polymerase chain reaction was used to detect and quantitate BK viral load in serum and urine samples.ResultsQualitative analysis with PCR for the DNA of BK virus showed 31 (31/228, 14%) positive serum samples originating from 20 (20/32, 62%) renal allograft recipients and 57 (57/228, 25%) positive urine samples originating from 23 (23/32, 72%) recipients. During the follow up period of 5 years, renal allograft function remained stable (eGFR 18th month: 53.9 ± 23.9 mL/min/1.73 m2 and eGFR 5th year: 52.6 ± 20.6 mL/min/1.73 m2). Comparison of recipients that presented with either BK viremia or viruria with a group that did not present viral reactivation did not reveal a statistically significant difference in eGFR. Furthermore, recipients with significantly high viral load in serum or urine did not present renal allograft dysfunction.ConclusionBK virus is potentially pathogenic in renal allograft recipients. It is certain that there is a reactivation of the virus in a high percentage of transplanted patients mostly in the first year after the surgery, without however a negative effect of the transient viremia and viruria in renal allograft function.