Polyomaviruses BK- And JC-DNA quantitation in kidney allograft biopsies

BackgroundPolyomavirus-associated nephropathy (PVAN) is one of the most common viral disease affecting renal allograft, with BK being the most frequent causal agent and JCV being considered responsible in <3% of the cases.ObjectivesTo quantify polyomaviruses BK and JC load by real-time TaqMan PCR in tissue specimens (renal and ureteral) from kidney transplant recipients.Study design and methodsOne-hundred-thirty-eight specimens (125 kidneys, 13 ureters) obtained from 109 patients were evaluated by quantitative real-time PCR for the detection of BKV- and JCV-DNA. Demographic, virological, and histopathological data were collected.ResultsBKV-DNA was positive in 32 of 109 patients (29.6%) and JCV-DNA in 20 of 109 patients (18.3%). The highest BK viral loads (>104 genome equivalents/cell) were found in two renal samples with histopathologically confirmed PVAN; while JC viral load was >104 genome equivalents/cell in one ureteral sample.ConclusionsAlthough quantitation of viral DNA on renal allograft biopsies could be complementary to histopathological evaluation and the highest viral load are detectable in renal specimens with PVAN, the identification of a diagnostic cut-off should require further studies.