Detection of polyomavirus microRNA-5p expression in saliva shortly after kidney transplantation.

MicroRNAs (miRNAs) of polyomavirus (PyV) are present in several biological fluids and are suggested to be relevant viral factors for monitoring its persistence. To evaluate the effect of an immunosuppressive regimen on the status of PyV-miRNA-5p in the oral cavity. The JCPyV, BKPyV, MCPyV miRNA-5p were investigated in paired saliva and plasma samples obtained from 23 patients before and shortly after renal-transplantation by using real-time RT-PCR. Overall, within a short-time after transplantation, patients exhibited decreased numbers of leukocyte and lymphocyte as well as low levels of creatinine. During the clinical management of the patients, a significant amount of saliva samples were positive for JCPyV and BKPyV miRNA-5p (range: 26%-91%) compared to paired plasma samples (range: 9%-35%). Among the two polyomaviruses showing positive expression of miRNA-5p, BKPyV presented the highest positivity in saliva (91%) and MCPyV-miRNA-5p was constantly negative in both saliva and plasma samples. Compared to the time before transplantation, a significant reduction in the expression of JCPyV-miRNA-5p was observed in saliva samples obtained after transplantation. Altogether, these data suggest that additional investigations of polyomavirus miRNA-5p in saliva should be performed shortly after renal-transplantation to evaluate the potential role in early viral reactivation.