The cut-off value of BK virus DNA load in urine or plasma for diagnosis of BKVN in renal transplantation recipients / 中华器官移植杂志

ABSTRACT

Objective To compare the applied value of BK virus DNA load detection in urine and plasma for diagnosis BK virus nephropathy (BKVN) in renal transplantation recipients.Method In 88 renal transplantation recipients receiving renal allograft from February 2011 to January 2012 in our institute,BK virus DNA load in urine and plasma was detected by using real-time PCR,and renal biopsy was performed on the recipients with gradual deterioration of the graft function or the loads of BKV replication being very high.The diagnosis of BKVN was confirmed by using immunohistochemistry.Results Of 88 recipients,there were 35 cases (39.8％) of viruria,18 cases (20.5％) of viremia and 5 cases (5.7％) of BKVN.The median BKV DNA load in both urine and plasma in BKVN recipients was significantly higher than in non-BKVN recipients (P＜0.05).The viruria sensitivity and specificity for BKVN were 100％ and 57.3％ (P =0.03),and the viremia sensitivity and specificity for BKVN was 100％ and 82.9％ (P =0.0002),respectively.We regraded viral load ≧ 105 copies/mL in plasma or ≥107 copies/mL in urine as the best discriminant cut-off value to predict the disease and to identify patients at risk of developing BKVAN.The positive cut-off value of urine's positive predictive value (PPV+) was 26.3％ and negative predictive vaule (PPV-) was 95.7％,and the positive cut-off value of plasma's positive predictive value (PPV +) was 83.3％ and negative predictive vaule (PPV-) was 98.8％.Conclusion The viral load ≥105 copies/mL in plasma can be used as the best discriminant cut-off value to predict the disease and to identify patients at risk of developing BKVAN,but the cut-off value of urine should be only used for screening BKV infection.