Prevalence of WU and KI polyomaviruses in plasma, urine, and respiratory samples from renal transplant patients.

WU and KI polyomaviruses (WUPyV, KIPyV) have been detected in respiratory, blood, stool, and lymphoid tissue, but not in urine samples. PCR based detection revealed higher frequency in immunocompromised individuals. In this study the prevalence of WUPyV and KIPyV was analyzed in respiratory, urine, and blood samples from renal transplant patients compared with healthy individuals. WUPyV and KIPyV were detected by nested PCR. The PCR products were sequenced and viral DNA loads were determined by quantitative real-time PCR. WUPyV and KIPyV were found in plasma (3.6%; 7/195), urine (14%; 7/50), and respiratory samples (10%; 9/90) of renal transplant patients, but not in plasma (0/200) and urine (0/36) specimens from healthy blood donors. WUPyV and KIPyV were detected mainly early after renal transplantation and the viral loads were low. A higher prevalence of WUPyV was found in plasma and urine samples, KIPyV was found more frequently in respiratory samples from renal transplant patients. It is hypothesized that immunosuppression due to the transplantation may result in reactivation of these viruses or may establish greater susceptibility to infection with KIPyV and WUPyV.