Surveillance and Modification of Immunosuppression Minimizes BK Virus Nephropathy

Abstract

Background/Aims: Infection of a transplanted kidney with the polyomavirus, BK, is associated with poor allograft survival. Methods: In an attempt to prevent this transplant complication, we studied 144 consecutive transplant recipients for the presence of BK infection with plasma and urine PCR testing at 1, 2, 3, 6 and 12 months. Viruria alone was followed by serial studies. If plasma PCR became positive at >2.6 log copies, mycophenolate was reduced until there was no detectable plasma viral load. Results: Urine PCR was positive in 34 (24%), while plasma PCR turned positive in 22 cases (15%). No patients developed viremia with <6.8 log copies in the urine. Viremia resolved within 3 months or less in 20 of 22 patients after reduction of immunosuppression. Surveillance biopsies at 2 and 6 months revealed no BK nephropathy. Eight patients had acute rejection during reduced immunosuppression; however, all of these reversed with pulse steroids. Patient and graft survival at 1 year was 99 and 98%, respectively. Use of the cell-mediated immunity assay (ImmuKnow®, Columbia, Md., USA) was not useful in identifying infected patients. Conclusion: Active surveillance for BK virus by urine/plasma PCR with prompt reduction in immunosuppression can prevent BK nephropathy.

Evaluation of the immune function assay in pediatric living donor liver transplantation

“…In the present study, low values on the T‐cell immune function assay were associated with susceptibility to infection, although this issue is controversial . In addition, we found a significant difference in the distribution of the ImmuKnow values between the patients with a stable status and those with infection, with the exception of the patients with asymptomatic EBV viremia.…”

Late-Onset BK Viral Nephropathy in a Kidney Transplant Recipient

“…In those and other studies, viremia cleared in 92%e95% of patients, with a mean time to clearance of 54 days [18,19]. In contrast, rejection rates of up to 30% have been reported with reduction in immunosuppression alone, and allograft loss of 35%e50% despite reduction in total immunosuppression [20,21].…”

Antigen-specific T cell responses to BK polyomavirus antigens identify functional anti-viral immunity and may help to guide immunosuppression following renal transplantation

“…As the early diagnosis of BKV reactivation may improve outcomes and reduce complications most renal transplant units have introduced surveillance programmes, with associated protocols for immunosuppression reduction or modulation [41]. BKV screening techniques include cytological evidence of viral replication (decoy cells in the urine) and/or qPCR for viral DNA.…”