Abstract:

Objective To investigate the roles of FK506,urea,creatinine（Cr） and mononuclear cell count in the judgment of renal transplant recipients with positive urinary BK virus（BKV） DNA. Methods Urinary BKV DNA were determined in 197 renal transplant recipients,which the cases ≥2.0×10³ copies/mL were enrolled in positive group,and which the cases <2.0×10³ copies/mL were enrolled in negative group. The differences of FK506,urea,Cr,the percentage of lymphocyte（LYMPH%） and the absolute value of lymphocyte（LYMPH#）,the percentage of monocyte（MO%） and the absolute value of monocyte（MO#） between the 2 groups were evaluated. A total of 21 patients with negative to positive urinary BKV DNA within 3 to 6 months after transplantation were enrolled for matching comparison. The efficiency of determining positive urinary BKV DNA by each indicator was evaluated by receiver operating characteristic（ROC） curve,and the correlation between each indicator and urinary BKV DNA load was evaluated by Pearson or Spearman analysis. The indicators with significant difference were compared in 21 recipients with the first change of urinary BKV DNA from negative to positive. Results The levels of FK506,urea and Cr in BKV positive group were higher than those in BKV negative group（P<0.05）. LYMPH%,LYMPH#,MO% and MO# showed no statistical significance between the 2 groups（P>0.05）. Urinary BKV DNA load was positively correlated with FK506（r=0.466,P<0.001）,and there was no correlation with urea（r=0.157） and Cr（r=0.156）（P>0.05）. ROC curve analysis showed that the areas under curves（AUC）of FK506,urea and Cr for the positive determination of urinary BKV DNA were 0.685,0.581 and 0.606,respectively. The optimal cut-off values were 7.05 ng/mL,7.20 mmol/L and 100.5 μmol/L,respectively. The sensitivities were 58.3%,71.4% and 83.3%,and the specificities were 74.3%,46.0% and 38.1%,respectively. FK506 was increased in the 21 recipients when they firstly experienced urinary BKV DNA conversion from negative to positive（P<0.001）,and urea and Cr had no statistical significance（P>0.05）. Conclusions FK506 is valuable in the judgment of renal transplant recipients with positive urinary BKV DNA.

Key words: FK506, Renal function index, Mononuclear cell count, BK virus, Renal transplantation