Real-time Pcr to detect polyomavirus BK-,JC- and SV40-Dna in renal and ureteral specimens from transplant recipients

INTRODUCTION AND AIMS: Polyomavirus-associated nephropathy (PVAN) is one of the most common viral diseases affecting renal allograft, with BK being the most frequent causal agent. JCV is considered responsible in <3% of the cases, while the role of SV40 is still unknown. Objectives. To quantify polyomaviruses (BK, JC and SV40) load by real-time TaqMan PCR in tissue specimens (renal and ureteral) from kidney transplant recipients. METHODS: One-hundred-thirty-eight specimens (125 kidneys, 13 ureters) obtained from 109 patients were evaluated by quantitative real-time PCR for the detection of BK, JC, and SV40-DNA. Demographic, virological, and histopathological data were collected. RESULTS: BKV-DNA was positive in 32 of 109 patients (29.6%); JCV-DNA in 20 of 109 patients (18.3%); and SV40-DNA in 11 of 109 patients (10.1%). BK viral load was >4 x 106genome equivalents/g of extracted DNA in two renal samples with histopathologically confirmed PVAN; JC viral load was >4 x 106genome equivalents/g in one ureteral sample from a patient with ureteral stenosis, while SV40 load was low in all the cases. SV-40 was detected only in concomitance with BK and/or JC. CONCLUSIONS: A complete and early diagnosis of polyomavirus-associated nephropathy seems to require the integration of multiple techniques. Our data confirm the renotropism of polyomaviruses BK and JC, as well as SV40. SV-40 was detected also in patients who did not receive the contaminated polio vaccine, confirming the occurrence of new infections due to unknown modes of transmission.