# BK Polyomavirus in Renal Transplantation: Virological Notes for Monitoring and Diagnosis

## TL;DR

This review discusses BK polyomavirus and its impact on kidney transplant patients, focusing on monitoring and diagnosis.

## Contribution

The paper provides a virological perspective on BK polyomavirus in renal transplantation and its management.

## Key findings

- BK polyomavirus can cause renal injury in kidney transplant recipients within the first two years post-transplantation.
- Immunosuppression plays a key role in viral reactivation and must be modulated for effective clinical management.
- Viral and immunological evaluations are essential for optimizing diagnosis and treatment strategies.

## Abstract

Polyomavirus-associated nephropathy was first reported over 50 years ago. However, it still represents a cause of renal injury in kidney transplant recipients, particularly in the first two years post-transplantation, with occurrence rates of 1–10%. The role played by immunosuppression in viral reactivation is well acknowledged, and the modulation of its level is the main strategy for clinical management. Viral and immunological evaluation are fundamental for optimizing its diagnostic and therapeutic pathway. In this review, the main features of BK polyomavirus and associated nephropathy in renal transplant patients are addressed and discussed from a virological point of view; the role of BK polyomavirus in hematopoietic stem cell transplantation and other solid-organ transplant patients is also briefly reported.