ABSTRACT
Objective To analyze the risk factors of high-level BK viruria after renal transplantation and the significance in preventing BK virus-associated nephropathy (BKVAN). Methods Clinical data of 262 renal transplant recipients with regular follow-up data were retrospectively analyzed. According to the DNA load of BK virus, all recipients were divided into the high-level BK viruria group (n=35) and non-high-level BK viruria group (n=227). The incidence of high-level BK viruria after renal transplantation was summarized. The risk factors of high-level BK viruria after renal transplantation were analyzed by univariate analysis and multivariate analysis. Survival curve was delineated by Kaplan-Meier method, and survival analysis of recipients was performed. Results Among 262 renal transplant recipients, 35 cases developed high-level BK viruria with an incidence of 13.4%. The median time of occurrence of high-level BK viruria was 181 (126, 315) d. The incidence was the highest within 6 months after renal transplantation, gradually decreased from 6 months to 2 years, and then increased after 2 years. Univariate analysis showed that the history of antithymocyte globulin (ATG) treatment, acute rejection (AR), donation type and delayed graft function (DGF) were the risk factors of high-level BK viruria after renal transplantation (all P < 0.05). Multivariate Cox regression analysis demonstrated that donation after brain death followed by cardiac death (DBCD), AR and DGF were the independent risk factors of high-level BK viruria after renal transplantation. The 1-, 3- and 5-year survival rates of recipients with ATG treatment history, AR, DGF and donation type of DBCD were significantly lower than those with non-ATG treatment history, non-AR, non-DGF and other donation types [donation after brain death (DBD), donation after cardiac death (DCD) and living organ donation] respectively (all P < 0.05). Conclusions DBCD, AR and DGF are the independent risk factors of high-level BK viruria after renal transplantation. Strengthening the postoperative monitoring of these recipients and delivering early intervention may effectively prevent BKVAN.
ABSTRACT
Objective To investigate the relationship between the metabolic rate of tacrolimus (FK506) and BK virus infection early after renal transplantation. Methods Eighty recipients undergoing allogenic renal transplantation in Institute of Organ Transplantation of the 309thHospital of Chinese People's Liberation Army were recruited in this study. The polymorphism of cytochrome P450 (CYP) 3A5 gene was detected in 80 recipients. All patients were divided into fast metabolism group ( CYP3A5*1/*3 and CYP3A5*1/*1 genotypes, n=38) and slow metabolism group ( CYP3A5*3/*3 genotype, n=42) based on the gene detection results. The distribution of CYP3A5 genotypes in 80 recipients was analyzed. The metabolic rate [concentration/dose ratio (C/D value)] of FK506 was statistically compared between two groups. The incidence of BK virus infection events [BK viruria, BK viremia and BK virus nephropathy(BKVN)] within postoperative 6 months were compared between two groups. Results Among 80 recipients, 5 cases (6%) were detected with CYP3A5*1/*1 genotype, 33 (41%) with CYP3A5*1/*3 genotype, and 42 (53%) with CYP3A5*3/*3 genotype. Among the 160 alleles in 80 recipients, 117 CYP3A5*3 allele were identified, suggesting that the mutation rate of CYP3A5*3 allele was 73.1%. In the fast metabolism group, the C/D values at postoperative 1, 3, and 6 months were significantly lower than those in the slow metabolism group (all P<0.01). The incidence rates of BK viruria in the fast and slow metabolism groups were 37% and 29%, 18% and 2% for BK viremia, and 3% and 0 for BKVN, respectively. In the fast metabolism group, the incidence of BK virenia was significantly higher than that in the slow metabolism group (P=0.02). The incidence of BK viruria and BKVN did not significantly differ between two groups (both P>0.05). Conclusions According to the CYP3A5 genotyping outcomes, the recipients with a high metabolic rate of FK506 have a high risk of BK viremia early after renal transplantation.
ABSTRACT
Objective To analyze the impairment of renal allograft function in renal transplant recipients caused by BK virus infection after renal transplantation. Methods Clinical data of 210 recipients who underwent allogenic renal transplantation and received BK virus monitoring regularly were analyzed retrospectively. The incidence of BK viruria, viremia and BK virus nephropathy (BKVN) after renal transplantation was summarized. The effect of BK virus infection on renal allograft function and prognosis of renal allograft function after the removement of BK virus were analyzed. Results Among the 210 recipients, there were 46 cases with pure viruria, 46 cases with viremia complicated with viruria and 7 cases with BKVN confirmed by pathological biopsy. The level of serum creatinine (Scr) in the recipients with viremia after renal transplantation was linearly related to BK viral load in urine and blood (r=0.594, 0.672, both P<0.01). The level of Scr increased significantly when BK viral load in blood of the recipients with viremia was found positive for the first time, and increased continuously after viremia sustained. And the level of Scr decreased slightly when blood viral load turned to negative after treatment, but still significantly higher than before virus infection. All the above differences were statistically significant (all P<0.05). Compared with the basic level, there was no significant difference in the level of Scr of recipients with pure viruria during positive viruria (all P>0.05). Conclusions It will impair the renal allograft function when BK viremia occurs after renal transplantation, and it is necessary to monitor viral infection regularly. Once the blood BK virus is found positive, it shall be implemented immediately to reduce the intensity of immunosuppression as the preferred clinical intervention.