BK virus-induced renal allograft nephropathy.

Karel Krejci,Tomas Tichy,Jana Bednarikova,Kamil Zamboch,Josef Zadrazil

doi:10.5507/bp.2018.018

Abstract

BK virus nephropathy (BKVN) is a serious opportunistic infection threatening renal function especially during the first year after transplantation. Its incidence is now on the rise and is closely related to the level of the recipient's immune system inhibition. This is more intensive with current trends in transplantation medicine, where more potent immunosuppressive protocols are used and more aggressive antirejection therapy is applied. In the absence of BK virus (BKV) specific therapy and limited treatment options for advanced BKVN, active screening of BKV replication and subsequent preemptive adjustment of immunosuppression are essential measures to prevent BKVN. However, it remains unclear how to modify immunosuppressive protocols as well as how to address initial stages of BKV replication. This comprehensive review summarizes the currently applied and not completely uniform procedures for the detection, prophylaxis and therapy of BKV replication and BKVN. The pitfalls brought by reduced immunosuppression, as a typical response to a significant viral replication or a developed BKVN, are also mentioned, particularly in the form of graft rejection. The paper also outlines the authors' experiences, and lists currently ongoing studies on the subject. The perspectives of new, especially immune-based, procedures in the treatment of complications associated with BKV infections are highlighted. Different views on the management of patients indicated for kidney re-transplantation whose previous graft failed because of BKVN are also discussed.

Highlights

EPIDEMIOLOGY AND PATHOGENESIS OF BK virus (BKV) nephropathy (BKVN)As the number of prognostically risky renal transplantations increase, especially retransplantations performed in patients with previous repeated or severe rejections, more intensive immunosuppressive protocols must be chosen
The number of Haufen bodies (HB) correlated strongly with 1 to 3 BKV nephropathy (BKVN) histological stages. These findings suggest that HB capture in urine could be a sufficiently sensitive and specific non-invasive method of detecting BKVN in renal transplantations[66]
BKVN is a serious complication endangering the function of the kidney graft especially during the first year after transplantation and should be considered whenever renal function deteriorates

Summary

INTRODUCTION

As the number of prognostically risky renal transplantations increase, especially retransplantations performed in patients with previous repeated or severe rejections, more intensive immunosuppressive protocols must be chosen. This is so in the absence of a clear biopsy finding In this situation, BKVN diagnosis appears to be likely if urinary DC excretion persists with simultaneous detection of significant BKV replication in plasma (DNA PCR-BKV >104 copies/mL) even in the absence of graft dysfunction. In one study investigating the 4-year graft survival in patients with significant BKV viraemia and/or histologically verified BKVN detected in the first year after renal transplantation, no significant differences were seen in the treatment associated with the reduction of immunosuppressive therapy and concomitant leflunomide use, when compared to the group without BKV viraemia[84]. Overall this therapy was well tolerated by patients and quantitatively reduced the BKV viral load, but with some patients experiencing dose-limiting gastrointestinal toxicity

Alternative methods in immunosuppressive therapy adjustments

Findings

CONCLUSION