Prevalence of BK virus replication among recipients of solid organ transplants.

BACKGROUND BK virus (BKV) has been implicated as a cause of nephritis and graft loss in 2%-9% of kidney transplant recipients, but the prevalence among recipients of other solid organ transplants (SOTs) has not been well established. Our objective was to determine the prevalence of BKV infection for all types of SOT recipients at our medical center. METHODS A total of 156 consecutive SOT recipients were studied, of whom 49 received kidney transplants, 43 received heart transplants, and 64 received liver transplants. Samples were obtained a median of 559 days (range, 1-9481 days) after transplantation. Nested polymerase chain reaction was performed for detection of BKV DNA in urine and plasma specimens. RESULTS BKV was found in 19% of urine specimens and 6% of plasma specimens. The prevalence of viruria after kidney, heart, and liver transplantation was 26.5%, 25.5%, and 7.8%, respectively. BKV viremia was detected in 12.2% of kidney transplant recipients and 7% of heart transplant recipients. Mean creatinine levels were higher in patients with BKV viruria or viremia (1.9 and 3.5 mg/dL, respectively) than in patients with no BKV replication (1.3 mg/dL). Independent factors related to impaired renal function were renal transplantation (odds ratio [OR], 14.4); BKV replication, including viruria or viremia (OR, 3.3); and mycophenolate use (OR, 2.6). CONCLUSION BKV is common in all types of SOT recipients, particularly those who have received heart or kidney transplants.