Efficacy of Cidofovir in Treatment of BK Virus-Induced Hemorrhagic Cystitis in Allogeneic Hematopoietic Cell Transplant Recipients

BK virus-associated hemorrhagic cystitis (BK-HC) is a common complication after allogeneic hematopoietic stem cell transplantation (allo-HCT), with incidences up to 70%. Cidofovir is an antiviral agent with growing evidence as a therapeutic intervention. To assess the safety profile and efficacy of intravenous and intravesical cidofovir in allo-HCT patients with BK-HC, a retrospective study was undertaken of the allo-HCT cohort who received cidofovir for symptomatic BK-HC (hematuria with BK viruria or viremia) from January 2010 until March 2017 in a single transplant center in Ontario, Canada. The primary outcome measure was a reduction in BK-HC severity (graded from 1 to 4); secondary outcomes included overall survival, BK virus titers, and the onset of acute kidney injury. Twelve allo-HCT patients received cidofovir for BK-HC, with pretreatment clinical severity of 3 (50%) or 4 (50%). Cidofovir was administered via intravenous (33%), intravesical (58%), or both modalities (8%). After a median cumulative dose of 10 mg/kg (range, 1 to 37), mean BK-HC grade decreased significantly by 1.8 (3.5 precidofovir, 1.7 postcidofovir, P < .01). Sixty-six percent of patients had at least partial response to cidofovir, with similar response rates between intravenous (66%) and intravesical (62%) administration. Sixty-seven percent of patients died, and 33% of patients experienced renal toxicity, including 2 patients receiving intravesical therapy. In this retrospective series, there was a significant reduction in BK-HC severity after cidofovir administration; most patients achieved at least partial response after cidofovir administration. Even with intravesical instillation, acute kidney injury remains a potential complication of cidofovir. Although cidofovir may be an efficacious therapy for BK-HC, albeit with potential demonstrated toxicities, further prospective trials are needed.

Reprint of: Virus-Specific T Cells: Broadening Applicability

Virus infection remains an appreciable cause of morbidity and mortality after hematopoietic stem cell transplantation (HSCT). Although pharmacotherapy and/or antibody therapy may help prevent or treat viral disease, these drugs are expensive, toxic, and often ineffective due to primary or secondary resistance. Further, effective treatments are limited for many infections (eg, adenovirus, BK virus), which are increasingly detected after alternative donor transplants. These deficiencies in conventional therapeutics have increased interest in an immunotherapeutic approach to viral disorders, leading to adoptive transfer of virus-specific cytotoxic T lymphocytes (VSTs), which can rapidly reconstitute antiviral immunity post-transplantation without causing graft-versus-host disease. This review will explore how the VST field has improved outcomes for many patients with life-threatening viral infections after HSCT, and how to broaden applicability beyond the "patient-specific" products, as well as extending to other viral diseases even outside the context of HSCT.

Leflunomide for BKvirus: Report of Seven Kidney-Transplanted Children

BACKGROUND

Leflunomide is an immunosuppressive agent commercialized for treatment of rheumatoid arthritis. Because of its immunosuppressive and possible antiviral properties, leflunomide has been evaluated in some case series of BKVAN with favorable results, mostly in adult patients. Leflunomide targeted levels are usually between 50 and 100 mg/L in kidney transplant adult patients. Data in pediatric population are scarce.

OBJECTIVE

To assess the effect of leflunomide on BKvirus in kidney-transplanted children.

METHODS

Therapeutic drug monitoring of leflunomide is routinely performed by measuring its active metabolite, teriflunomide, using a simple HPLC-UV method. Pediatric kidney transplant patients with at least one teriflunomide sample between 2010 and 2017 were retrospectively included in this study. Viremia control was defined as undetectable BK viremia or a decrease of more than 1 log in the viral load from the baseline after two months of treatment. Adverse events were recorded.

RESULTS

A total of 7 patients from 3 centers was included. 6 were only kidney transplant recipients; 1 was a lung-kidney transplant recipient with cystic fibrosis. All patients reported high load BK viremia but none developed BKVAN. For 67% of the patients, complete BK viral clearance was observed during leflunomide treatment with drastic immunosuppressive therapy reduction. Mycophenolate was indeed discontinued in almost all patients. Of note, leflunomide concentrations were significantly higher when viremia was controlled. Only 33% of the observed concentrations were >40 mg/L. The patient with cystic fibrosis had lower concentrations with higher drug doses. No hepatotoxicity was observed in this study and no patient experienced graft rejection. Leflunomide was suspected to cause hemolytic anemia and one patient experienced biological pancreatitis.

CONCLUSION

This study evidenced the wide interindividual variability of the exposure and supported the routine practice of leflunomide with a suggested target level of 30-40 mg/L in pediatric kidney transplanted patient. However, because of the very limited number of patients in our series, further investigations are needed to validate this suggestion.

Discovery and characterization of novel trans-spliced products of human polyoma JC virus late transcripts from PML patients

Although the human neurotropic polyomavirus, JC virus (JCV), was isolated almost a half century ago, understanding the molecular mechanisms governing its biology remains highly elusive. JCV infects oligodendrocytes and astrocytes in the central nervous system (CNS) and causes a rare fatal brain disease known as progressive multifocal leukoencephalopathy (PML) in immunocompromised individuals including AIDS. It has a small circular DNA genome (∼5 kb) and generates two primary transcripts from its early and late coding regions, producing several predicted alternatively spliced products mainly by cis-splicing. Here, we report the discovery and characterization of two novel open reading frames (ORF1 and ORF2) associated with JCV late transcripts, generated by an unusual splicing process called trans-splicing. These ORFs result from (i) the trans-splicing of two different lengths of the 5'-short coding region of VP1 between the coding regions of agnoprotein and VP2 after replacing the intron located between these two coding regions and (ii) frame-shifts occurring within the VP2 coding sequences terminated by a stop codon. ORF1 and ORF2 are capable of encoding 58 and 72 aa long proteins respectively and are expressed in infected cells and PML patients. Each ORF protein shares a common coding region with VP1 and has a unique coding sequence of their own. When the expression of the unique coding regions of ORFs is blocked by a stop codon insertion in the viral background, the mutant virus replicates less efficiently when compared to wild-type, suggesting that the newly discovered ORFs play critical roles in the JCV life cycle.

Graft loss among renal-transplant recipients with early reduction of immunosuppression for BK viremia

AIM

To review the incidence of graft loss and acute rejection among renal transplant recipients with early reduction of immunosuppression for BK viremia.

METHODS

We performed a retrospective analysis of consecutive de-novo kidney-only transplants from January 2009 to December 2012 to evaluate the incidence of Polyoma-virus associated nephropathy (PyVAN). Recipient plasma was screened for BKV DNA via quantitative polymerase chain reaction (PCR) at months 1, 3, 6, 9 and 12 post-transplant and on worsening graft function. Immunosuppression was reduced at ≥ 3-log copies/mL. Those with viremia of ≥ 4-log copies/mL (presumptive PyVAN) underwent renal transplant biopsy. Presumptive PyVAN (PP) and definitive PyVAN (DP; biopsy-proven) were treated by immunosuppression reduction (IR) only.

RESULTS

Among 319 kidney transplant recipients, the median age was 53 years (range 19-83), 65.8% were male, and 58.9% were white. Biopsy-proven acute rejection was found in 18.5% within 0-168 wk. Death-censored graft loss occurred in 5.3% (n = 17) and graft loss attributable to PyVAN was 0.6% (n = 2). Forty-seven patients were diagnosed with PP (14.7%) and 18 (5.6%) with DP. Graft loss among participants with PyVAN (8.5%) and those without (4.8%) was not significantly different. Deceased donor kidney transplantation (OR = 2.3, 95%CI = 1.1-4.6) and AR (OR = 2.3, 95%CI = 1.2-4.7) were associated with PyVAN in the multivariate analysis. BK viremia between 3 and 4-log copies/mL occurred in 27 patients, all of whom underwent IR. Of these, 16 (59%) never developed PyVAN while 11 (41%) developed PyVAN (4 DP, 7 PP) within a range of 11-39 wk.

CONCLUSION

Instituting an early reduction of immunosuppression, in the absence of adjunctive antivirals, is effective at preventing PyVAN and may be associated with a lower incidence of graft-loss without a reciprocal increase in the incidence of acute rejection.

Virus-Specific T Cells: Broadening Applicability

Virus infection remains an appreciable cause of morbidity and mortality after hematopoietic stem cell transplantation (HSCT). Although pharmacotherapy and/or antibody therapy may help prevent or treat viral disease, these drugs are expensive, toxic, and often ineffective due to primary or secondary resistance. Further, effective treatments are limited for many infections (eg, adenovirus, BK virus), which are increasingly detected after alternative donor transplants. These deficiencies in conventional therapeutics have increased interest in an immunotherapeutic approach to viral disorders, leading to adoptive transfer of virus-specific cytotoxic T lymphocytes (VSTs), which can rapidly reconstitute antiviral immunity post-transplantation without causing graft-versus-host disease. This review will explore how the VST field has improved outcomes for many patients with life-threatening viral infections after HSCT, and how to broaden applicability beyond the "patient-specific" products, as well as extending to other viral diseases even outside the context of HSCT.

BK virus replication in renal transplant recipients: Analysis of potential risk factors may contribute in reactivation

BACKGROUND

Considering the increasing problem of BK virus infection during post renal transplant surveillance, it is necessary to distinguish the main risk factors leading to reactivation of latent BK virus. Up to now, some probable risk factors have been investigated in some studies, but the results have been confusing and contradictory.

OBJECTIVES

The goal of the present study was to determine the frequency and potential risk factors that may play a role in BK polyomavirus reactivation and nephropathy.

STUDY DESIGN

In this cross-sectional study, 110 patients, who underwent consecutive transplantation between 2010 and 2013, were enrolled without preliminary screening. Urine and blood samples were taken, and quantitative Real-time PCR assay was used to detect and measure the viral load. Demographic and clinical characteristics of the patients who had BK viremia and/or viruria were documented.

RESULTS

Among 110 cases of renal transplant recipients, BK viruria and viremia were found in 54 (49%) and 22 people (20%) respectively. The pre-transplant durations of dialysis among patients with BK viruia were found longer in comparison to BK negative patients. Treatment with Tacrolimus (p=0.03) was found to be a risk factor for development of BK viruria. In patients with viruria and viremia the median creatinine levels were 1.45mg/dl and 1.35mg/dl respectively, which were higher than those in the patients with negative results for BK viruria (p=0.002) and viremia (p=0.02). Also, treatment with Cyclosporine could significantly increase the incidence of BK virus shedding in both urine and blood among patients who received it (p=0.01). Significant relation between reactivation of BK virus and other factors such as age, sex, acute rejection and diabetes was not found.

CONCLUSION

Based on our findings, the main potential risk factors for shedding of BK virus into urine in renal transplant recipients were prolonged pre-transplant dialysis and Tacrolimus regimen. Cyclosporine regimens could be considered as risk factor for both BK viruria and viremia. A significant correlation between BK virus replication and elevated creatinine level was seen among our patients.

CMV and BKPyV Infections in Renal Transplant Recipients Receiving an mTOR Inhibitor-Based Regimen Versus a CNI-Based Regimen: A Systematic Review and Meta-Analysis of Randomized, Controlled Trials

BACKGROUND AND OBJECTIVES

The objective of this meta-analysis is to compare the incidences of cytomegalovirus and BK polyoma virus infections in renal transplant recipients receiving a mammalian target of rapamycin inhibitor (mTOR)-based regimen compared with a calcineurin inhibitor-based regimen.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a comprehensive search for randomized, controlled trials up to January of 2016 addressing our objective. Other outcomes included acute rejection, graft loss, serious adverse events, proteinuria, wound-healing complications, and eGFR. Two review authors selected eligible studies, abstracted data, and assessed risk of bias. We assessed quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation methodology.

RESULTS

We included 28 randomized, controlled trials with 6211 participants classified into comparison 1: mTOR inhibitor versus calcineurin inhibitor and comparison 2: mTOR inhibitor plus reduced dose of calcineurin inhibitor versus regular dose of calcineurin inhibitor. Results showed decreased incidence of cytomegalovirus infection in mTOR inhibitor-based group in both comparison 1 (risk ratio, 0.54; 95% confidence interval, 0.41 to 0.72), with high quality of evidence, and comparison 2 (risk ratio, 0.43; 95% confidence interval, 0.24 to 0.80), with moderate quality of evidence. The available evidence neither confirmed nor ruled out a reduction of BK polyoma virus infection in mTOR inhibitor-based group in both comparisons. Secondary outcomes revealed more serious adverse events and acute rejections in mTOR inhibitor-based group in comparison 1 and no difference in comparison 2. There was no difference in graft loss in both comparisons. eGFR was higher in the mTOR inhibitor-based group in comparison 1 (mean difference =4.07 ml/min per 1.73 m2; 95% confidence interval, 1.34 to 6.80) and similar to the calcineurin inhibitor-based group in comparison 2. More proteinuria and wound-healing complications occurred in the mTOR inhibitor-based groups.

CONCLUSIONS

We found moderate- to high-quality evidence of reduced risk of cytomegalovirus infection in renal transplant recipients in the mTOR inhibitor-based compared with the calcineurin inhibitor-based regimen. Our review also suggested that a combination of a mTOR inhibitor and a reduced dose of calcineurin inhibitor may be associated with similar eGFR and rates of acute rejections and serious adverse events compared with a standard calcineurin inhibitor-based regimen at the expense of higher incidence of proteinuria and wound-healing complications.

The impact of recipient BKV shedding before transplant on BKV viruria, DNAemia, and nephropathy post-transplant: A prospective study

We previously demonstrated that detectable BKV replication in donor urine pretransplant was significantly associated with post-transplant recipient BKV viremia. In this 4-year prospective study, we assessed whether recipient BKV replication pretransplant was associated with post-transplant viremia/BKV nephropathy. We studied 220 primary adult and pediatric organ transplant recipients for 490 person-years and 2100 clinical visits. BKV viruria was detectable in 28 (16%), 26 adults and two children; and viremia in none pretransplant. Post-transplant viruria occurred in all recipients with pretransplant BKV viruria, significantly more than in recipients without pretransplant viruria on univariate (P<.005) and multivariate analysis including type of organ transplanted and immunosuppression type (P .008). Time to post-transplant viruria was significantly shorter in recipients with pretransplant viruria (P .01). By univariate and multivariate analysis, BKV viruria in recipients pretransplant did not impact post-transplant BKV viremia (P=.97 and .97, respectively) even when stratified by type of organ transplant (kidney P=.6; liver P=.5). The peak serum and urine BKV PCR post-transplant were not significantly different in patients with pretransplant BKV viruria and no one developed BK nephropathy. In conclusion, recipient BKV viruria prior to transplant predicts post-transplant viruria but not viremia or BKV nephropathy.

BK Virus-associated Hemorrhagic Cystitis in Patients with Allogeneic Hematopoietic Cell Transplantation: Report of Three Cases

BK viras is a human polyoma viras. It is acquired in early childhood and remains life-long latent in the genitourinary system. BK virus replication is more common in receiving immunosuppressive therapy receiving patients and transplant patients. BK virus could cause hemorrhagic cystitis in patients with allogeneic stem cell transplantation. Hemorrhagic cystitis is a serious complication of hematopoietic stem cell transplantation. Hemorrhagic cystitis could cause morbidity and long stay in the hospital. Diagnosis is more frequently determined by the presence of BK virus DNA detected with quantitative or real-time PCR testing in serum or plasma and less often in urine. The reduction of immunosuppression is effective in the treatment of BK virus infection. There are also several agents with anti-BK virus activity. Cidofovir is an active agent against a variety of DNA viruses including poliomyoma viruses and it is a cytosine nucleotide analogue. Intravenous immunoglobulin IgG (IVIG) also includes antibodies against BK and JC (John Cunningham) viruses. Hereby, we report three cases of hemorrhagic cystitis. Hemorrhagic cystitis developed in all these three cases of allogeneic stem cell transplantation due to acute myeloid leukemia (AML). BK virus were detected as the cause of hemorrhagic cystitis in these patients. Irrigation of the bladder was performed. Then levofloxacin 1 x750 mg intravenous and IVIG 0.5 gr/kg were started. But the hematuria did not decreased. In the first case, treatment with leflunomide was started, but patient died due to refractory AML and severe graft-versus-host disease after 4th day of leflunamide and levofloxacin treatments. Cidofovir treatment and the reduction of immunosuppressive treatment decreased the BK virus load and resulted symptomatic improvement in the second case. Initiation of cidofovir was planned in the third case. Administration of cidofovir together with the reduction of immunosuppression in the treatment of hemorrhagic cystitis associated with BK virus in allogeneic stem cell transplant recipients could be a good option.

Variability in assessing for BK viremia: whole blood is not reliable and plasma is not above reproach - a retrospective analysis

Polyomavirus nephropathy (PVN) is a major complication of kidney transplantation. Most reports describe polyomavirus viremia either precedes or is detectable at the time of diagnosis of PVN. This association is the basis of current screening recommendations. We retrospectively reviewed the PCR results of blood and urine samples from 29 kidney transplant recipients with biopsy-proven PVN. Biopsies were performed for a rise in serum creatinine or persistent high-level BK viruria. All biopsies showed polyoma virus large T-antigen expression in tubular epithelium using immunohistochemistry. All had viruria preceding or at the time of biopsy (range, 5.2 × 10⁴ to >25 × 10⁶ BKV DNA copies/ml). Twenty (69%) had viremia ranging from 2.5 × 10³ to 4.3 × 10⁶ copies/ml at the time of the biopsy. Via blood BK PCR assay, nine (31%) had no BK viremia detected either preceding or at the time of the biopsy. In five recipients where sufficient specimen permitted, additional plasma BK assessment revealed positive detection of viremia. A comparative analysis of assays from two centres was performed with spiked samples. BK DNA may not be detected in the blood of some kidney transplant recipients with histologically confirmed PVN. This may reflect limitation of whole blood as opposed to plasma-based BK DNA assessment.

BK viruria and viremia in children with systemic lupus erythematosus

BACKGROUND

BK virus (BKV) is a ubiquitous polyoma virus that lies dormant in the genitourinary tract once acquired in early childhood. In states of cellular immunodeficiency, the virus can reactivate to cause hemorrhagic cystitis and nephritis. Children with systemic lupus erythematosus (SLE) have an increased risk of developing infectious complications secondary to their immunocompromised state from the administration of several immuno-modulatory drugs. Currently, there are no data regarding the prevalence of BK viruria or viremia in children with SLE.

METHODS

We conducted a prospective cohort study involving children with SLE of 18 years and younger. We obtained urine and blood samples at baseline and every 3 months up to 1 year for BK virus detection by real-time, quantitative polymerase chain reaction analysis. A comprehensive review of demographic information, clinical characteristics and medication history was also obtained.

RESULTS

Thirty-two pediatric patients (26 females and 6 males) with SLE were enrolled. Median age at the time of SLE diagnosis and enrollment into study was 13.6 years and 16.0 years old, respectively. The prevalence at enrollment was 3.1% (1/32) for BK viruria and 6.2% (2/32) for BK viremia. During the study period, 3 patients had viruria, 5 had viremia and 4 had both viruria and viremia. Of the 12 patients with BKV reactivation, only one was positive for microscopic hematuria, all others were asymptomatic. A total of nine of 97(9.2%) urine samples and 10 of 96(10.4%) blood samples were positive for BK virus. The most commonly utilized biologics in this cohort group were Rituximab (90.6%), Abatacept (12.5%), and Belimumab (9.3%). The type of medication exposure and clinical characteristics did not statistically differ between the groups that did or did not have BK viruria and/or viremia.

CONCLUSIONS

Our study suggests that pediatric patients with SLE have BK viremia and/or viruria at a higher rate than the general healthy population, although the significance of the reactivation and viral level is unclear. The influence of immune-modulatory drugs on BKV reactivation is still uncertain. To understand the interplay amongst BK virus, immunosuppression and dysregulated immune system in children with SLE, ongoing research in a larger population is still warranted, which may help establish proper surveillance, diagnosis and treatment for BKV infection.

The Frequency and Associated Factors for BK Virus Infection in a Center Performing Mainly Living Kidney Transplantations

PURPOSE

BK virus (BKV) nephropathy has increasingly become an important cause of morbidity in renal transplant recipients. We evaluated the frequency and associated factors for BKV infection in a center performing mainly living donor transplantations over a long time period.

METHODS

One hundred consecutive renal transplant patients were included. Quarterly visits were planned to examine urine for decoy cells and to measure the BKV DNA in the blood and urine. Renal biopsy was performed in case of deteriorated allograft function. Serological examinations for BKV immunoglobulin G (IgG) were performed in donors.

RESULTS

Throughout the entire follow-up period, the rates of viruria, viremia, and the positivity of decoy cells were 12%, 6%, and 13%, respectively. The negative and positive predictive values of decoy cells were 93.1% and 69.2%, respectively, for viruria, and 99.2% and 45.5%, respectively, for viremia. Biopsy-proven BKV nephropathy was observed in 1 patient. The BKV IgG was positive in all living donors. Viruria and viremia were associated with deceased donor transplantation, acute rejection, and pulse steroid therapy. In addition, viremia was associated with antithymocyte globulin therapy and a short duration of the posttransplant period.

CONCLUSIONS

The frequency of BKV infection was lower in our transplant unit compared to previous reports. Reduced doses of immunosuppression seem to be the main factor that may explain the reduced frequency. However, an active screening strategy is still of importance for this patient group.

Stability of BK polyomavirus IgG seroreactivity and its correlation with preceding viremia

BACKGROUND

Recently we showed that the level of BK polyomavirus (BKPyV) IgG seroreactivity in kidney donors predicted viremia and BKPyV-associated nephropathy in kidney transplant recipients (KTRs). This observation could be explained by assuming a direct association between BKPyV seroreactivity and the amount of persistent infectious virus in the renal allograft.

OBJECTIVES

Since the renal BKPyV reservoir is probably sowed by viremia during primary BKPyV infection, we systematically analysed the dynamics of BKPyV IgG seroreactivity in relation to preceding BKPyV viremia in KTRs and healthy individuals.

STUDY DESIGN

A cohort of 85 KTRs consisting of BKPyV viremic and nonviremic subjects was analysed for BKPyV IgG seroreactivity at five fixed time points until one year after transplantation. A cohort of 87 healthy blood donors (HBDs) was used as controls.

RESULTS

Baseline BKPyV seropositivity was high in both KTRs and HBDs, and the baseline mean BKPyV IgG level comparable. BKPyV IgG levels in nonviremic KTRs and HBDs remained stable during follow-up, while a considerable increase was observed in viremic KTRs (p=0.015). The increase of BKPyV seroreactivity in viremic KTRs was associated with the duration and peak level of BKPyV viremia.

CONCLUSIONS

BKPyV IgG seroreactivity was stable over time in immunocompetent subjects, which enables the use of this potential pretransplantation biomarker in kidney donors. The observed dose-dependent relationship of BKPyV IgG seroreactivity with preceding BKPyV replication is in agreement with the assumption that BKPyV seroreactivity reflects past BKPyV activity and correlates with the amount of latent BKPyV residing within a kidney allograft.

Incidence, risk factors and the effect of polyomavirus infection in hematopoietic stem cell transplant recipients

Objective The effect of polyomavirus infection in HSCT recipients is poorly understood. Methods We evaluated 38 HSCT recipients. Polyomavirus was detected by nested qualitative polymerase chain reaction (PCR) assays of urine. The risk factors for BK virus and JC virus were analysed. The kidney and liver functions of infected and uninfected patients were compared. Results BK virus, JC virus, and simian virus 40 were detected in 21%, 42%, and 0% of HSCT recipients respectively. HCMV infection was found to be an independent risk factor for JC virus infection (odds ratio (OR): 8.528), while transplants with mismatched HLA are more susceptible to BK virus infection (OR: 12.000). Liver function of JC virus-infected subjects was worse than that of uninfected subjects. Conclusion We must be vigilant for opportunistic polyomavirus infections in HSCT recipients, especially those with HCMV co-infection or a mismatched HLA transplant. When unexplained liver function deterioration is observed, JC virus infection should be considered.

BKV-specific T cells in the treatment of severe refractory haemorrhagic cystitis after HLA-haploidentical haematopoietic cell transplantation

BACKGROUND

Haemorrhagic cystitis caused by BK virus (BKV) is a known complication of allogeneic haematopoietic cell transplantation (HCT) and is relatively common following HLA-haploidentical transplantation. Adoptive immunotransfer of virus-specific T cells from the donor is a promising therapeutic approach, although production of these cells is challenging, particularly when dealing with low-frequency T cells such as BKV-specific T cells.

CASE REPORT

Here, we present a patient who, following haploidentical HCT, developed severe BKV haemorrhagic cystitis, resistant to standard therapy. He responded well to adoptive transfer of donor cells enriched in BKV-specific T cells using the new second-generation CliniMACS Prodigy and the Cytokine Capture System from Miltenyi Biotec. Treatment led to full resolution of both the symptoms and viraemia without unwanted complications.

CONCLUSION

Our observations suggest that use of products enriched with BKV-specific T cells generated using this system is safe and efficient in HLA-haploidentical HCT where BKV cystitis can be a serious complication.

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

BKV infection and nephropathy complicate pediatric HTx, but the incidence and time course of the disease are unknown. We assessed the incidence of BKV infection and its association with kidney dysfunction in pediatric HTx recipients. A single center prospective study compared pediatric (<18 years) HTx recipients, with and without BKV infection, who received an allograft between September 2013 and December 2014. Screening of urine for BKV was performed prior to transplant, and at week 1, and at months 3, 6, 9, 12, and 15 months post-transplantation. Serum for BKV DNA was assayed if BK viruria was present. Statistics included Fisher's exact test and Student's t test. Twelve patients were enrolled. Two patients were removed per parent request. Two (20%) had BK viruria and one (10%) had BK viremia. No patients developed BKVN. BK viruria was present within 2 months following transplantation. There were no identifiable risk factors for BKV infection and no statistically significant difference in renal function between the groups; however, there was a trend toward worsening renal function in those with BKV infection. BKV infection can occur early following heart transplantation. Screening for BK viruria should be considered in HTx recipients.

A Simple and Reliable Strategy for BK Virus Subtyping and Subgrouping

BK virus (BKV)-associated diseases in transplant recipients are an emerging issue. However, identification of the various BK virus subtypes/subgroups is a long and delicate process on the basis of currently available data. Therefore, we wanted to define a simple and effective one-step strategy for characterizing all BK virus strains from the VP1 gene sequence. Based on the analysis of 199 available complete DNA VP1 sequences, phylogenetic trees, alignments, and isolated polymorphisms were used to define an effective strategy for distinguishing the 12 different BK virus subtypes/subgroups. Based on the 12 subtypes identified from the 199 complete BKV VP1 sequences (1,089 bp), 60 mutations that can be used to differentiate these various subtypes/subgroups were identified. Some genomic areas were more variable and comprised mutational hot spots. From a subregion of only 100 bp in the VP1 region (1977 through 2076), we therefore constructed an algorithm that enabled rapid determination of all BKV subtypes/subgroups with 99% agreement (197/199) relative to the complete VP1 sequence. We called this domain of the BK viral genome the BK typing and grouping region (BKTGR). Finally, we validated our viral subtype identification process in a population of 100 transplant recipients with 100% efficiency. The new simpler method of BKV subtyping/subgrouping reported here constitutes a useful tool for future studies that will help us to more clearly understand the impact of BKV subtypes/subgroups on diagnosis, infection, and BK virus-associated diseases.

A kidney transplant recipient with renal medullary viral cytopathic changes

We present a case of JC polyomavirus (JCV)-associated nephropathy (PyVAN) in an asymptomatic deceased-donor kidney transplant recipient. Despite the presence of viral cytopathic effect in the kidney biopsy and positive BK polyomavirus (BKV) in situ hybridization (ISH), BKV real-time polymerase chain reaction (PCR) results of plasma and urine were negative. JCV ISH was performed and was found to be positive. JCV real-time PCR on urine, plasma, and the kidney biopsy tissue was positive. Reduction in immunosuppression resulted in resolution of JCV viremia. This case highlights that JC-PyVAN is a distinct clinical entity and is likely to have a better clinical outcome than BK-PyVAN. Concurrent infection with BKV and JCV may occur, but may be difficult to confirm due to the potential for cross-reactivity between BKV and JCV ISH stains.

Poor immune reconstitution is associated with symptomatic BK polyomavirus viruria in allogeneic stem cell transplant recipients

BACKGROUND

BK polyomavirus (BKPyV) infections are known indicators of immune suppression in hematopoietic stem cell transplant (HSCT) recipients; they can lead to hemorrhagic cystitis, ureteral stenosis, renal dysfunction, and prolonged hospital stays. In this study, we determined transplant-associated variables and immune parameters that can predict for the risk of BKPyV viruria. We hypothesized that BKPyV infection is a marker of poor immune recovery.

METHODS

We analyzed all engrafted patients undergoing first allogeneic HSCT at MD Anderson Cancer Center in Houston between January 2004 and December 2012. We evaluated their immune parameters and their transplant-associated factors. BKPyV positivity was defined as BKPyV detection in urine by polymerase chain reaction testing. Cox proportional hazards model, as well as competing risk analysis method using subdistribution hazard models with death as competing risk, were applied to assess risk of BKPyV viruria.

RESULTS

We identified a total of 2477 patients with a median age of 52 years. BKPyV viruria was manifest in 25% (n=629) of the patients. The median time from transplantation to BKPyV viruria development was 42 days among the patients who had BKPyV viruria. On multivariate analysis, tumor type, acute GVHD, chronic GVHD, myeloablative conditioning regimen, cord blood as the graft source, CD3⁺ , CD4⁺ , CD8⁺ , CD56⁺ , NK counts, and low platelet count were shown to be significantly associated with BKPyV infection. These finding were further confirmed when models incorporating the competing risk of death yielded similar findings.

CONCLUSION

In this study, we report significant associations between BKPyV reactivation following allogeneic HSCT and suppressed immune variables. In addition, this study provides valuable information on the immune status of HSCT recipients as a predictor of BKPyV infections that may in turn help us formulate plans for more effective prevention and treatment of this infection.

Ureteral stent placement and immediate graft function are associated with increased risk of BK viremia in the first year after kidney transplantation

Ureteral stent (UrSt) placement has been shown to be a significant independent risk factor for BK viruria, viremia, and BK virus nephropathy. We assessed whether this observation could be validated at our high volume kidney transplant center that has had a strong historical focus on BK virus nephropathy detection. We performed a retrospective case-control study of adults receiving a kidney-only transplant and followed for 1 year between 2004 and 2011 with uniform immunosuppression and use of blood BK virus PCR screening protocol. Among 1147 patients, 443 (38.6%) received a UrSt and 17.2% with a UrSt had BK viremia versus 13.5% without stent (odds ratio 1.33; 95% CI: 1.00-1.78). We confirmed a previously reported association between immediate graft function (IGF) and higher rate of BK viremia (15.7% vs. 5.9% in patients without IGF). On multivariable competing risks Cox regression in patients with IGF, UrSt (adjusted hazard ratio [aHR] 1.35; 95% CI: 1.04-1.75) and African American race (aHR 1.47; 95% CI: 1.04-2.09) significantly increased the risk for BK viremia. In the largest sample size to date, we confirmed that UrSt placement during kidney transplant surgery is a risk factor for BK viremia within the first year post-transplant and that IGF is associated with BK viremia.

Incidence of BK polyomavirus infection after kidney transplantation is independent of type of immunosuppressive therapy

BACKGROUND

BK polyomavirus (BKV) infection and BKV nephropathy (BKVN) are risk factors for allograft function and survival.

METHODS

We retrospectively analyzed BK viremia and BKVN in 348 patients who received a kidney transplantation donated after brain death (n=232) or living donation (n=116) between 2008 and 2013. A total of 266 patients were treated with standard immunosuppression consisting of basiliximab induction, calcineurin inhibitor (CNI), and mycophenolic acid (MPA, n=219) or everolimus (n=47); 82 patients received more intense immunosuppression with lymphocyte depletion, CNI and MPA (n=38) or everolimus (n=44).

RESULTS

BK viremia occurred in 33 (9.5%) patients in the first year and in 7 (2.0%) recipients in the second year after transplantation. BKVN occurred in 4 (1.1%) patients in the first year. Donor and recipient age, diabetes, previous transplantation, and type of transplantation (donated after brain death vs living donation) were not risk factors (P>.05). BK incidence did not differ depending on induction or maintenance immunosuppression.

CONCLUSION

Incidence of BK viremia is independent of recipient characteristics, type of transplantation as well as induction and maintenance immunosuppression.

BK polyomavirus encephalitis in a patient with thrombotic microangiopathy after an allogeneic hematopoietic stem cell transplant

To date, only one case of BK polyomavirus (BKPyV) encephalitis combined with transplant-associated thrombotic microangiopathy has been reported in an hematopoietic stem cell transplantation (HCT) recipient. We report the case of an HCT recipient who developed thrombotic microangiopathy and subsequent BKPyV encephalitis. She died despite treatment with cidofovir, ciprofloxacin, and intravenous immunoglobulin without improvement in mental status. Early suspicion of BKPyV encephalitis in an HCT recipient presenting with altered mental status and hemorrhagic cystitis is important.

Outcomes of renal transplant recipients with BK virus infection and BK virus surveillance in the Auckland region from 2006 to 2012

AIM

To evaluate incidence, risk factors and treatment outcome of BK polyomavirus nephropathy (BKVN) in a cohort of renal transplant recipients in the Auckland region without a formal BK polyomavirus (BKV) surveillance programme.

METHODS

A cohort of 226 patients who received their renal transplants from 2006 to 2012 was retrospectively reviewed.

RESULTS

Seventy-six recipients (33.6%) had a BK viral load (BKVL) test and 9 patients (3.9%) developed BKVN. Cold ischaemia time (HR = 1.18, 95%CI: 1.04-1.35) was found to be a risk factor for BKVN. Four recipients with BKVN had complete resolution of their BKV infection; 1 recipient had BKVL less than 625 copies/mL; 3 recipients had BKVL more than 1000 copies/mL and 1 had graft failure from BKVN. BKVN has a negative impact on graft function [median estimated glomerular filtration rate (eGFR) 22.5 (IQR 18.5-53.0) mL/min per 1.73 m², P = 0.015), but no statistically significant difference (P = 0.374) in renal allograft function was found among negative BK viraemia group [median eGFR 60.0 (IQR 48.5-74.2) mL/min per 1.73 m²), positive BK viraemia without BKVN group [median eGFR 55.0 (IQR 47.0-76.0) mL/min per 1.73 m²] and unknown BKV status group [median eGFR 54.0 (IQR 43.8-71.0) mL/min per 1.73 m²]. The incidence and treatment outcomes of BKVN were similar to some centres with BKV surveillance programmes.

CONCLUSION

Recipients with BVKN have poorer graft function. Although active surveillance for BKV has been shown to be effective in reducing incidence of BKVN, it should be tailored specifically to that transplant centre based on its epidemiology and outcomes of BKVN, particularly in centres with limited resources.

High-dose steroid therapy in BK viremia adversely affected the long-term graft function after kidney transplantation

BACKGROUND

Although high-dose steroid therapy has been attempted for the management of clinically suspected allograft rejection, before testing for BK viral activity or acute cellular rejection accompanied by BK polyomavirus nephropathy, its long-term outcome remains unknown. We investigated the impact of high-dose steroids on BK viral activity and long-term graft outcomes in patients with BK viremia.

METHODS

The study population comprised 144 kidney transplant recipients with BK viremia. They were divided into 2 groups based on the amount of steroids administered: low-dose group (<2 g, n=123) or high-dose group (≥2 g, n=21).

RESULTS

The baseline serum BK viral loads were 5.4±1.1 log cp/mL in the low-dose group and 6.0±1.3 in the high-dose group (P=.054). These changed to 5.2±1.3 and 6.1±1.4, 1 month after steroid treatment (P=.03) and 4.9±1.3 and 5.9±1.4 at 2 months (P=.033), respectively. From 3 months to 1 year, the serum BK viral titers were not different between groups. Kaplan-Meier analyses demonstrated that the rates of the decline of graft function and graft failure were higher in the high-dose group (P=.02 and P=.04, respectively). High-dose steroids (P=.012, hazard ratio [HR] 5.04, 95% confidence interval [CI] 1.42-17.85) and log serum BK viral load at 2 months after steroid treatment (P=.042, HR 1.52, 95% CI 1.02-2.28) were independent risk factors for the decline of graft function.

CONCLUSION

High-dose steroids induced BK viral activation and subsequently resulted in poor long-term graft function and early graft failure in patients with BK viremia.