OBJECTIVE: To analyze the characteristics of BK polymavirus (BKV) infection and the optimal time window for intervention in kidney transplant recipients (KTRs). METHODS: We retrospectively analyzed the clinical data and treatment regimens in 226 KTRs in our center between January, 2013 and January, 2018. Among the recipients, 157 had a urine BKV load ≥1.0×10 copy/mL after transplantation, and 69 had a urine BKV load below 1.0×10 copy/mL (control group). RESULTS: Among the 157 KTRs, 60 (38.2%) recipients were positive for urine BKV, 66 (42.0%) had BKV viruria, and 31(19.7%) had BKV viremia. The incidence of positive urine occult blood was significantly higher in BKV-positive recipients than in the control group ( < 0.05). The change of urine BKV load was linearly related to that of Tacrolimus trough blood level (=0.351, < 0.05). In urine BKV positive group, the average estimated glomerular filtration rate (eGFR) was below the baseline level (60 mL·min·1.73 m) upon diagnosis of BKV infection reactivation, and recovered the normal level after intervention. In patients with BKV viruria and viremia, the average eGFR failed to return to the baseline level in spite of improvement of the renal function after intervention. CONCLUSIONS Positive urine occult blood after transplantation may be associated with BKV infection reactivation in some of the KTRs. BKV infection is sensitive to changes of plasma concentration of immunosuppressive agents. Early intervention of BKV replication in KTRs with appropriate dose reduction for immunosuppression can help to control virus replication and stabilize the allograft function.
BK Virus ; physiology ; Humans ; Kidney Transplantation ; Polyomavirus Infections ; virology ; Retrospective Studies ; Transplant Recipients ; Tumor Virus Infections ; virology ; Viral Load ; Virus Replication

OBJECTIVETo explore the clinical diagnosis of BK virus (BKV) infection in renal transplant recipients.

METHODSUrine and peripheral blood samples were taken from 234 renal transplant recipients for BKV detection with cytological test and real-time PCR.

RESULTSThe occurrence rate of urine decoy cells, BKV viruria and viremia in these patients was 33.3 %, 33.3% and 16.2%, respectively, and the median level of urine decoy cells was 6/10 HPF, with the median level of urine and peripheral blood BKV of 7.62 x 10(3) copy/ml and 7.61 x 10(3) copy/ml, respectively. The positivity rate of BKV in the urine samples were significantly higher than that in peripheral blood samples (P=0.000). The amount of decoy cells was related to BKV load in the urine samples (gamma=0.59, P=0.000), but the BKV load in the urine samples was not related to that in peripheral blood samples (P=0.14).

CONCLUSIONRenal transplantation is associated with increased BKV shedding, indicating the necessity of BKV monitoring in renal transplant recipients with urine cytology, which is convenient and sensitive and indicates renal histological changes indirectly. Urine and peripheral blood BKV DNA detection is of value in identifying BKV activation to prevent irreversible graft damage of BKV-associated nephropathy.

Adolescent ; Adult ; Aged ; BK Virus ; genetics ; isolation & purification ; physiology ; Child ; Child, Preschool ; Female ; Humans ; Kidney Transplantation ; adverse effects ; Male ; Middle Aged ; Polyomavirus Infections ; diagnosis ; virology ; Young Adult

BK virus (BKV) is a subtype of papovaviridae. The latent and asymptomatic infection of BKV is common among healthy people. The incidence of BKV re-activation in renal transplant recipients ranges 10%-68%. About 1%-7% of renal transplant recipients will suffer from BKV-associated nephropathy (BKVAN), and half of them will experience graft failure. This paper summarizes the re-activation mechanism of BKV as well as the risk factors, pathology, diagnosis, and treatment of BKVAN.
BK Virus ; physiology ; Humans ; Kidney ; pathology ; virology ; Kidney Transplantation ; Polyomavirus Infections ; diagnosis ; pathology ; therapy ; Postoperative Complications ; diagnosis ; pathology ; therapy ; virology ; Risk Factors ; Tumor Virus Infections ; diagnosis ; pathology ; therapy ; Virus Activation

BK virus-associated nephropathy (BKVAN) is one of the major causes of allograft dysfunction in kidney transplant (KT) patients. We compared BKVAN combined with acute rejection (BKVAN/AR) with BKVAN alone in KT patients. We retrospectively analyzed biopsy-proven BKVAN in KT patients from 2000 to 2011 at Seoul National University Hospital. Among 414 biopsies from 951 patients, biopsy-proven BKVAN was found in 14 patients. Nine patients had BKVAN alone, while 5 patients had both BKVAN and acute cellular rejection. BKVAN in the BKVAN alone group was detected later than in BKVAN/AR group (21.77 vs 6.39 months after transplantation, P=0.03). Serum creatinine at diagnosis was similar (2.09 vs 2.00 mg/dL). Histological grade was more advanced in the BKVAN/AR group (P=0.034). Serum load of BKV, dose of immunosuppressants, and tacrolimus level showed a higher tendency in the BKVAN alone group; however it was not statistically significant. After anti-rejection therapy, immunosuppression was reduced in the BKVAN/AR group. Renal functional deterioration over 1 yr after BKVAN diagnosis was similar between the two groups (P=0.665). These findings suggest that the prognosis of BKVAN/AR after anti-rejection therapy followed by anti-BKV therapy might be similar to that of BKVAN alone after anti-BKV therapy.
Acute Disease ; Adult ; Antiviral Agents/therapeutic use ; BK Virus/*physiology ; Creatinine/blood ; Female ; *Graft Rejection/diagnosis/virology ; Humans ; Immunosuppressive Agents/administration & dosage ; Kidney/*virology ; Kidney Diseases/pathology/surgery/*virology ; *Kidney Transplantation ; Male ; Middle Aged ; Polyomavirus Infections/drug therapy/*etiology/pathology ; Retrospective Studies ; Tacrolimus/administration & dosage ; Time Factors ; Transplantation, Homologous/adverse effects ; Tumor Virus Infections/drug therapy/*etiology/pathology