BK polyomavirus infection in pediatric heart transplant recipients: a prospective study

Symptomatic BK virus cystitis in non-renal transplant recipients

BACKGROUND

BK virus is implicated most commonly in causing BK virus-associated nephropathy in renal transplant recipients. However, on rare occasions, it can also produce symptomatic cystitis in other solid organ transplant recipients.

METHODS

Retrospective review of 2,149 non-renal solid organ transplant recipients over a 6-year period to evaluate patients for cases of symptomatic BK virus cystitis.

RESULTS

Three patients (two heart transplant recipients and one lung transplant recipient) are reported herein with symptomatic BK virus cystitis. These patients responded to reduced immunosuppressive medication with a reduction in viral load in two instances, and the third patient appeared to have an apparent response to prolonged levofloxacin treatment.

CONCLUSIONS

A high index of suspicion should be exercised in non-renal solid organ transplant recipients (particularly heart and lung transplant recipients) who have symptoms consistent with cystitis but have a negative urine bacterial culture.

BK Virus: A Cause for Concern in Thoracic Transplantation?

Human BK polyomavirus (BKV) infection is poorly documented in heart and lung transplant patients. BK viruria and viremia have been estimated to affect 19% and 5% of heart transplant recipients, respectively. Data are limited, especially for lung transplantation, but the proportion of patients progressing from BK viruria to viremia or BKV-related nephropathy (BKVN) appears lower than in kidney transplantation. Nevertheless, a number of cases of BKVN have been reported in heart and lung transplant patients, typically with late diagnosis and generally poor outcomes. Risk factors for BKV infection or BKVN in this setting are unclear but may include cytomegalovirus infection and anti-rejection treatment. The relative infrequency of BKVN or other BK-related complications means that routine BKV surveillance in thoracic transplantation is not warranted, but a diagnostic workup for BKV infection may be justified for progressive renal dysfunction with no readily-identifiable cause; after anti-rejection therapy; and for renal dysfunction in patients with cytomegalovirus infection or hypogammaglobulinemia. Treatment strategies in heart or lung transplant recipients rely on protocols developed in kidney transplantation, with reductions in immunosuppression tailored to match the higher risk status of thoracic transplant patients.

BK virus as a mediator of graft dysfunction following kidney transplantation

PURPOSE OF REVIEW

BK virus is a significant risk factor for kidney allograft dysfunction and loss among renal transplant recipients. Currently, there is no proven effective treatment except for the reduction of immunosuppression. In this review, we discuss diagnostic challenges and current treatment options for BK in kidney transplant recipients.

RECENT FINDINGS

Antiviral and antibiotic therapies have been employed for BK viraemia with variable efficacy. In addition, novel therapeutic regimens such as adoptive transfer of targeted T cells have been described as possible treatment options for recipients with BK nephropathy. BK can also be seen in the native kidneys of pancreas, heart, lung and liver transplant recipients, suggesting that BK screening measures should be employed to other solid organ transplant recipients.

SUMMARY

Early screening for BK combined with reduction of immunosuppression remains the mainstay of treatment for BK viraemia. New therapeutic advances demonstrate promise in vitro; however, the in-vivo efficacy will be demonstrated by future studies.