A prospective study of BK-virus-associated haemorrhagic cystitis in paediatric patients undergoing allogeneic haematopoietic stem cell transplantation

Risk factors for hemorrhagic cystitis in children undergoing hematopoietic stem cell transplantation: a systematic review and meta-analysis

BACKGROUND

The risk factors for hemorrhagic cystitis (HC) in children undergoing hematopoietic stem cell transplantation (HSCT) are unclear. Therefore, we conducted this systematic review and meta-analysis to investigate the risk factors for HC in children undergoing HSCT.

METHODS

We performed this meta-analysis by retrieving studies from PubMed, EMBASE, and the Cochrane Library up to October 10, 2023, and analyzing those that met the inclusion criteria. I2 statistics were used to evaluate heterogeneity.

RESULTS

Twelve studies, including 2,764 patients, were analyzed. Male sex (odds ratio [OR] = 1.52; 95% confidence interval [CI], 1.16-2.00; p = 0.003, I2 = 0%), allogeneic donor (OR = 5.28; 95% CI, 2.60-10.74; p < 0.00001, I2 = 0%), human leukocyte antigen (HLA) mismatched donor (OR = 1.86; 95% CI, 1.00-3.44; p = 0.05, I2 = 31%), unrelated donor (OR = 1.58; 95% CI, 1.10-2.28; p = 0.01, I2 = 1%), myeloablative conditioning (MAC) (OR = 3.17; 95% CI, 1.26-7.97; p = 0.01, I2 = 0%), busulfan (OR = 2.18; 95% CI, 1.33-3.58; p = 0.002, I2 = 0%) or anti-thymoglobulin (OR = 1.65; 95% CI, 1.07-2.54; p = 0.02, I2 = 16%) use, and cytomegalovirus (CMV) reactivation (OR = 2.64; 95% CI, 1.44-4.82; p = 0.002, I2 = 0%) were risk factors for HC in children undergoing HSCT.

CONCLUSIONS

Male sex, allogeneic donor, HLA-mismatched, unrelated donor, MAC, use of busulfan or anti-thymoglobulin, and CMV reactivation are risk factors for HC in children undergoing HSCT.

Immune reconstitution in children after haploidentical haematopoietic stem cell transplantation

INTRODUCTION

Immune reconstitution (IR) kinetics of paediatric patients underwent haploidentical haematopoietic stem cell transplantation (HSCT) with post-transplant cyclophosphamide (PTCy) have not been extensively studied. We compared IR patterns of children receiving HSCT from haploidentical (n = 92) and HLA-matched donors (n = 36), and analysed risk factors for viral infection in these patients.

METHODS

We prospectively measured lymphocyte subset numbers before HSCT and at 1, 3, 6 and 12 months after HSCT. Blood cytomegalovirus (CMV), Epstein-Barr virus, adenovirus, BK virus (BKV) and urine adenovirus and BKV viral loads were measured at designated time points.

RESULTS

The median numbers of total T and T helper cells at 1 month were significantly lower in the haploidentical group compared with the HLA-matched group. Haploidentical HSCT recipients had significantly lower median numbers of several T cell subsets and B cells for 1 year after HSCT. The median NK cell count of the haploidentical group was lower at 1 month. BKV haemorrhagic cystitis, blood CMV and urine adenovirus reactivation were more frequently found in the haploidentical group. Post-haploidentical HSCT patients receiving anti-T lymphocyte globulin (ATG) had significantly lower median numbers of total T cells (at 1 month) and T helper cells (at 6 and 12 months) and higher rate of blood BKV reactivation compared with those without ATG.

CONCLUSION

Paediatric patients who undergo haploidentical HSCT with PTCy are likely to have delayed IR and an increased risk of viral reactivation/infection compared with HLA-matched HSCT. The addition of ATG to PTCy delayed T cell recovery and increased risk of BKV reactivation.

JC polyomavirus: a short review of its biology, its association with progressive multifocal leukoencephalopathy, and the diagnostic value of different methods to manifest its activity or presence

INTRODUCTION

JC polyomavirus is the causative agent of progressive multifocal leukoencephalopathy (PML), a demyelinating disease resulting from the lytic infection of oligodendrocytes that may develop in immunosuppressed individuals: HIV1 infected or individuals under immunosuppressive therapies. Understanding the biology of JCPyV is necessary for a proper patient management, the development of diagnostic tests, and risk stratification.

AREAS COVERED

The review covers different areas of expertise including the genomic characterization of JCPyV strains detected in different body compartments (urine, plasma, and cerebrospinal fluid) of PML patients, viral mutations, molecular diagnostics, viral miRNAs, and disease.

EXPERT OPINION

The implementation of molecular biology techniques improved our understanding of JCPyV biology. Deep sequencing analysis of viral genomes revealed the presence of viral quasispecies in the cerebrospinal fluid of PML patients characterized by noncoding control region rearrangements and VP1 mutations. These neurotropic JCPyV variants present enhanced replication and an altered cell tropism that contribute to PML development. Monitoring these variants may be relevant for the identification of patients at risk of PML. Multiplex realtime PCR targeting both the LTAg and the archetype NCCR could be used to identify them. Failure to amplify NCCR should indicate the presence of a JCPyV prototype speeding up the diagnostic process.

[Clinical study of mesenchymal stem cells from third-party donors in the treatment of refractory late onset hemorrhagic cystitis after allogeneic hematopoietic stem cell transplanation]

Objective: To examine the efficacy and safety of third-party bone marrow-derived mesenchymal stem cells (MSCs) in the treatment of refractory delayed hemorrhagic cystitis (LOHC) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) . Methods: Twenty patients with refractory LOHC received conventional therapy combined with MSCs obtained from third-party donors' bone marrow (BM) . MSCs were given intravenously at a dose of 1 × 10(6) cells/kg once weekly until either the symptoms improved or no changes in LOHC were seen after continuous infusion four times. BK viruria (BKV) -DNA, JC viruria (JCV) -DNA, and CMV-DNA were detected by real-time quantitative PCR before and 8 weeks after the MSCs infusion. Results: ① Of the 20 patients with refractory LOHC, 15 were males, and 5 were females, and the median age was 35 (15-56) years. There were 5 cases of acute lymphoblastic leukemia (ALL) , 9 cases of acute myeloid leukemia (AML) , 5 cases of myelodysplastic syndrome (MDS) , and 1 case of maternal plasma cell like dendritic cell tumor (BPDCN) . There were 4 cases of HLA identical transplantation and 16 cases of HLA incomplete transplantation. ②The median number of MSC infusions for each patient was 3 (range: 2-8) . Seventeen patients achieved complete response, and one had a partial response after treatment. The overall response rate was 90%. Over a median follow-up period of 397.5 days (range 39-937 days) post-transplantations, 13 patients survived, and 7 died. The causes of death included aGVHD (1 case) , infections (5 cases) , and TMA (1 case) . ③The copy numbers of BKV-DNA and CMV-DNA in urine in the 8th week after MSCs infusion were significantly lower than those observed before treatment (11342.1×10(8) copies/L vs 5.2×10(8) copies/L, P=0.016; 3170.0×10(4) copies/L vs 0.2×10(4) copies/L, P=0.006, respectively) , while JCV-DNA did not significantly differ when compared to before treatment (P=0.106) . ④ No adverse reactions related to MSC infusion occurred in any of the 20 patients. Conclusion: Third-party bone marrow-derived MSC has significant efficacy and good safety in the treatment of refractory LOHC after allogeneic HSCT.

BKV Related Hemorrhagic Cystitis-An Insight into Risk Factors and Later Complications-An Analysis on Behalf of Polish Adult Leukemia Group

Simple Summary

Despite noticeable progress in allogeneic hematopoietic stem cell transplantation, potential viral reactivations are still one of the most challenging complications. The aim of our study was to identify predictive and risk factors associated with the occurrence of the BK virus related hemorrhagic cystitis following hematopoietic stem cell transplantation. Furthermore, we investigated the impact of various factors on the clinical course of patients after hematopoietic stem cell transplantation. We confirmed that >0.75 × 10³ BK virus copies/mL in serum at day +21 after allogeneic hematopoietic stem cell transplantation has a strong predictive ability for hemorrhagic cystitis. Thus, we believe that our findings could be helpful in establishing the predictive validity of the BK viral load measurement in polyomavirus BK-associated hemorrhagic cystitis and survival.

Abstract

BK virus reactivation increases the likelihood of hemorrhagic cystitis (HC) after allogeneic hematopoietic stem cell transplant (HCT). In this study, we aimed to identify predictive and risk factors associated with the increased occurrence of this condition following HCT. On a group of 124 patients aged ≤71 years old (median 40 years) who underwent HCT, we analyzed sex, age, time from diagnosis to transplantation, type of conditioning, donor’s relationship, age, and sex, the impact of immunosuppression with different drugs, and acute and chronic GVHD, BK viremia and viruria as potential factors increasing the risk of BK-related HC after HCT. HC occurred among 24 patients (24/124; 29.2%). A significant correlation was observed between HC incidences after HCT, BK viremia and viruria, and acute GVHD occurrence. Furthermore, the level of BKV DNA in serum at day +21 (>0.75 × 10³) significantly impacted the patients’ survival time. According to our results, the likelihood ratio of BKV-DNA on day +21 in serum is 6.25, indicating that this diagnostic test has the potential to be utilized in a clinical setting. These findings may be used as a voice in the discussion on implementing an optimal preemptive treatment in BKV reactivation after allogeneic HCT.

BK polyomavirus hemorrhagic cystitis in hematopoietic cell transplant recipients

Introduction:

BK polyomavirus-associated hemorrhagic cystitis (BKPyV-HC) is a well-recognized infective complication of hematopoietic cell transplant (HCT) with increased organ dysfunction and mortality. This study was performed to describe the local incidence, risk factors, and outcomes of BKPyV infection.

Methods:

This retrospective case–control study was conducted between 2007 and 2016 from a tertiary hospital in South India. We identified HCT recipients diagnosed with BKPyV-HC and compared them with recipients over the same period who did not develop BK virus infection matched for age, sex, diagnosis, and donor type. We collected data from central electronic medical records and databases maintained in the departments of hematology and virology.

Results:

Over the study period, 1276 transplants were performed, of which 262 patients (20.5%) developed HC and 105 (8.2%) were BKPyV-positive. Grade 3 HC was most commonly (57.1%) seen, and the median time to develop BKPyV-HC was 35 (range 0–858) days. Survival was significantly lower in the cases (42.9% vs. 61%, P < 0.05). On univariate analysis, the protective effect of nonmyeloablative conditioning (P = 0.04), residual disease at the time of transplant in malignant conditions (P = 0.001), lower CD34 dose (P = 0.006), presence of acute graft versus host disease (GVHD, P < 0.001), reactivation of cytomegalovirus infection (P < 0.001), and presence of bacterial urinary tract infection (UTI) (P < 0.001) were significant factors. Multivariate logistic regression confirmed the presence of acute GVHD (P = 0.041), bacterial UTI (P < 0.001), and residual disease (P = 0.009) at HCT as significant risk factors for BKPyV-HC.

Conclusions:

Our study affirms the homogeneity of BKPyV-HC disease in low- and middle-income HCT settings with prior reports and the need for therapeutic strategies to reduce its resultant mortality.

Pretransplant BK Virus-Specific T-Cell-Mediated Immunity and Serotype Specific Antibodies May Have Utility in Identifying Patients at Risk of BK Virus-Associated Haemorrhagic Cystitis after Allogeneic HSCT

BK polyomavirus (BKPyV) persists lifelong in renal and urothelial cells with asymptomatic urinary shedding in healthy individuals. In some immunocompromised persons after transplantation of hematopoietic stem cells (HSCT), the BKPyV high-rate replication is associated with haemorrhagic cystitis (HC). We tested whether the status of BKPyV immunity prior to HSCT could provide evidence for the BKPyV tendency to reactivate. We have shown that measurement of pretransplant anti-BKPyV 1 and 4 IgG levels can be used to evaluate the HC risk. Patients with anti-BKPyV IgG in the range of the 1st-2nd quartile of positive values and with positive clinical risk markers have a significantly increased HC risk, in comparison to the reference group of patients with "non-reactive" anti-BKPyV IgG levels and with low clinical risk (LCR) (p = 0.0009). The predictive value of pretransplant BKPyV-specific IgG was confirmed by determination of genotypes of the shed virus. A positive predictive value was also found for pretransplant T-cell immunity to the BKPyV antigen VP1 because the magnitude of IFN-γ T-cell response inversely correlated with posttransplant DNAuria and with HC. Our novel data suggest that specific T-cells control BKPyV latency before HSCT, and in this way may influence BKPyV reactivation after HSCT. Our study has shown that prediction using a combination of clinical and immunological pretransplant risk factors can help early identification of HSCT recipients at high risk of BKPyV disease.

BK Polyomavirus-Biology, Genomic Variation and Diagnosis

The BK polyomavirus (BKPyV), a representative of the family Polyomaviridae, is widespread in the human population. While the virus does not cause significant clinical symptoms in immunocompetent individuals, it is activated in cases of immune deficiency, both pharmacological and pathological. Infection with the BKPyV is of particular importance in recipients of kidney transplants or HSC transplantation, in which it can lead to the loss of the transplanted kidney or to haemorrhagic cystitis, respectively. Four main genotypes of the virus are distinguished on the basis of molecular differentiation. The most common genotype worldwide is genotype I, with a frequency of about 80%, followed by genotype IV (about 15%), while genotypes II and III are isolated only sporadically. The distribution of the molecular variants of the virus is associated with the region of origin. BKPyV subtype Ia is most common in Africa, Ib-1 in Southeast Asia, and Ib-2 in Europe, while Ic is the most common variant in Northeast Asia. The development of molecular methods has enabled significant improvement not only in BKPyV diagnostics, but in monitoring the effectiveness of treatment as well. Amplification of viral DNA from urine by PCR (Polymerase Chain Reaction) and qPCR Quantitative Polymerase Chain Reaction) is a non-invasive method that can be used to confirm the presence of the genetic material of the virus and to determine the viral load. Sequencing techniques together with bioinformatics tools and databases can be used to determine variants of the virus, analyse their circulation in populations, identify relationships between them, and investigate the directions of evolution of the virus.

A Prospective Viral Monitoring Study After Pediatric Allogeneic Hematopoietic Stem Cell Transplantation for Malignant and Nonmalignant Diseases

Allogeneic hematopoietic stem cell transplantation (HSCT) is the treatment of choice for many high-risk pediatric hematological malignant diseases (MD) and several nonmalignant diseases (NMD), including primary immune deficiencies. Infections must be managed to obtain better outcomes after HSCT. In this prospective observational study, viral monitoring was performed on 74 pediatric patients with MD and NMD who underwent HSCT. The incidence, risk factors, and impact of common opportunistic viral infections occurring within the first 100 days following HSCT were assessed. The viral pathogens included human herpesviruses, BK polyomavirus (BKV), adenovirus, parvovirus B19, and hepatitis B virus. In total, 52 (70%) patients had viral DNAemia, and 53% and 41% of patients developed human herpesvirus 6 (HHV-6) and cytomegalovirus (CMV) DNAemia, respectively. The risk factors were as follows: negative CMV serology for any viral infections; age ≥ 2 years and negative CMV serology for HHV-6; age ≥5 years and female sex for BKV. The risk of viral infection did not significantly differ between MD and NMD, and no risk factor was identified for viral disease, likely because of the small sample numbers. However, despite the absence of symptoms, CMV DNAemia was found to increase the risk of mortality. The findings of the current study could improve the risk stratification and the management of pediatric HSCT recipients.

BK Virus Epidemiology, Risk Factors, and Clinical Outcomes: An Analysis of Hematopoietic Stem Cell Transplant Patients at Texas Children's Hospital

BACKGROUND

BK virus-associated hemorrhagic cystitis (BKV-HC) is a serious complication after hematopoietic stem cell transplantation (HSCT).

METHODS

A retrospective review was performed to determine the frequency of BKV-HC and identify risk factors and renal morbidity associated with BKV-HC in pediatric HSCT recipients at our institution.

RESULTS

A total of 314 pediatric recipients underwent allogeneic HSCT for either malignant (173, 55.1%) or nonmalignant disorders (141, 44.9%) from January 1, 2011, to December 31, 2015, with a minimum follow-up of 5 years post-HSCT. Severe BKV-HC (grades 3 and 4) was prevalent in 46 out of 67 (68.7%) recipients. Timing to presentation of severe BKV-HC (grades 3 and 4) occurred at a median of 37 days (26, 74; IQ1, IQ3) post-HSCT, with the duration of macroscopic hematuria lasting a median of 37.5 days (18, 71; IQ1, IQ3). In the first 60 days post-HSCT, peak acute kidney injury (AKI) stages 2 and 3 were seen more frequently in HSCT recipients who developed BKV-HC than those without (P = .004). Similarly, during post-HSCT days 61 to 100, peak AKI stage 3 was also more frequently seen in HSCT recipients who already developed BKV-HC prior to or during this time period than those without BKV-HC (P = .0002). Recipients who developed BKV-HC within 1 year of HSCT had more frequent mild to moderate chronic kidney disease (CKD stages 2-3) than those without BKV-HC (P = .002 and .007, respectively). On multivariate analysis, BKV-HC was associated with all-cause mortality (hazard ratio [HR]: 2.22; 95% confidence interval [CI]: 1.35-3.65). The following clinical variables were associated with time to development of HC on multivariate analysis: age (subdistribution HR [sHR] 1.11; 95% CI: 1.06-1.16) and myeloabalative conditioning regimen (sHR 4.2; 95% CI: 2.12-8.34).

CONCLUSIONS

Pediatric HSCT patients with BKV-HC experience significant morbidity and mortality. Renal morbidity, including AKI and CKD, is associated with BKV-HC.

Risk factors of BK viral hemorrhagic cystitis in allogenic hematopoietic stem cell transplantation

Reactivation of BK virus (BKV) can occur during intensive immunosuppression such as in allogenic hematopoietic stem cell transplant (AHSCT) recipients for whom a systematic PCR urine test for BKV will be positive in 50% to 100% of patients. Only 5% to 40% will develop BKV hemorrhagic cystitis (HC). Thus, BKV PCR testing is useful to confirm a diagnosis of BKV-HC but not to predict its occurrence. The aim of this retrospective study was to ascertain the risk factors of developing BKV HC, mostly in patients receiving posttransplant cyclophosphamide. The study looked at data from Grenoble Alpes University Hospital included in the national retrospective register ProMISe, administered by the "Société Francophone de Greffe de Moelle et de Thérapie Cellulaire". Urine BKV PCR was performed when patients presented grade ≥ 2 hematuria with clinical symptoms of cystitis. BKV-HC was defined as an association of clinical symptoms of cystitis, grade ≥ 2 hematuria and BKV viruria > 7 log₁₀ copies/ml. From January 2014 to January 2018, 168 AHSCTs were considered for analysis, of which 43 (25.6%) developed BKV-HC and 44.9% of the subgroup that received posttransplant cyclophosphamide. After logistic regression, the risk factors associated with BKV-HC were reduced to posttransplantation exposure to cyclophosphamide (OR 4.25, [1.66; 10.87], P = .02), age < 40 y (OR 3.85 [1.51; 9.80], P = .005) and corticosteroid therapy (OR 3.86, [1.59; 9.36], P = .003). Exposure to cyclophosphamide, younger age (<40) and corticosteroid therapy are potential risk factors for BKV-HC.

Non-permissive human conventional CD1c+ dendritic cells enable trans-infection of human primary renal tubular epithelial cells and protect BK polyomavirus from neutralization

The BK polyomavirus (BKPyV) is a ubiquitous human virus that persists in the renourinary epithelium. Immunosuppression can lead to BKPyV reactivation in the first year post-transplantation in kidney transplant recipients (KTRs) and hematopoietic stem cell transplant recipients. In KTRs, persistent DNAemia has been correlated to the occurrence of polyomavirus-associated nephropathy (PVAN) that can lead to graft loss if not properly controlled. Based on recent observations that conventional dendritic cells (cDCs) specifically infiltrate PVAN lesions, we hypothesized that those cells could play a role in BKPyV infection. We first demonstrated that monocyte-derived dendritic cells (MDDCs), an in vitro model for mDCs, captured BKPyV particles through an unconventional GRAF-1 endocytic pathway. Neither BKPyV particles nor BKPyV-infected cells were shown to activate MDDCs. Endocytosed virions were efficiently transmitted to permissive cells and protected from the antibody-mediated neutralization. Finally, we demonstrated that freshly isolated CD1c⁺ mDCs from the blood and kidney parenchyma behaved similarly to MDDCs thus extending our results to cells of clinical relevance. This study sheds light on a potential unprecedented CD1c⁺ mDC involvement in the BKPyV infection as a promoter of viral spreading.

Dr Sylvia Gardner first discovered the BK polyomavirus (BKPyV) in the urine of a kidney-transplant recipient in 1970. In the 1990’s, the widespread use of potent immunosuppressive drugs such as tacrolimus, sirolimus or mycophenolate mofetil led to the emergence of BKPyV nephropathy. Recently, various studies reported a specific influx of myeloid dendritic cells (mDCs) in the renal tissue of kidney-transplant patients who were diagnosed with a BKPyV nephropathy. MDCs are immune cells both residing in tissues and migrating to other organs or compartments like the blood when changes in their environment occur. Their main functions are the detection of danger signals such as pathogens or tumors and the processing of antigens to prime naïve specific effectors of the adaptive immune response. Although anti-BKPyV cellular immune responses have been investigated in post-transplant recipients as well as healthy individuals, supporting an active role of mDCs little is known about how mDCs and BKPyV interact with each other. Our study provides the basis to understand the role played by mDCs in virus capture through an unprecedented endocytic mechanism and possibly in viral protection from neutralization by specific antibodies. Moreover, we showed that mDCs are unable to sense BKPyV particles or BKPyV-infected dying cells as a danger signal, supporting the view that other DC subsets might act as the true antigen presenting cells that promote the adaptive immune response against BKPyV infection.

Management of BK virus-associated haemorrhagic cystitis in allogeneic stem cell transplant recipients

BK virus (BKV)-related haemorrhagic cystitis (HC) is an important cause of morbidity following allogeneic haematopoietic stem cell transplantation (HSCT). The various risk factors include high-level BKV viruria and/or viremia, myeloablative conditioning, acute graft versus host disease (GVHD), cytomegalovirus viremia, and unrelated or HLA-mismatched donor. The presence of high plasma BK viral load and cytopenias have been implicated as important predictors for protracted disease course. These patients frequently require hospitalisation which may extend for several weeks. Supportive measures in the form of analgesics, intravenous hydration, bladder irrigation, and transfusion support remain the mainstay of management. Various drugs have been used with limited success in this setting. These include antiviral drugs, fluoroquinolones, leflunomide, growth factors, clotting factors, estrogens, and prostaglandins. The role of adoptive cellular immunotherapy has also been explored but lacks clinical validation. The strategies aimed at expediting urothelial repair like hyperbaric oxygen therapy (HBOT), intravesical fibrin glue and platelet-rich plasma (PRP) are emerging. Some patients with severe disease do require surgical intervention to relieve urinary obstruction. The frequent co-occurrence of acute GVHD and CMV disease further complicates the management in such patients. There is an unmet need for effective and evidence-based options for the prevention and management of this disease. Due to lack of robust data supported by randomised trials, the acceptability of the available guidelines to simplify the treatment is expected to be low. Despite the availability of various treatment options, the management of BKV-related HC in day-to-day practice continues to be a challenge. The aim of this article is to put forward an up-to-date review of the preventive and therapeutic strategies for BKV-related HC.

BK virus encephalitis and end-stage renal disease in a child with hematopoietic stem cell transplantation

BK virus encephalitis after HSCT is uncommon. Several reports of native kidney BKVN in patients with HSCT, hematologic malignancies, human immunodeficiency virus infection, and non-renal solid organ transplantation have been described. However, an uncommon combination of BK encephalitis and ESRD of native kidneys secondary to BK virus in a child with HSCT has not been described. We report a 10-year-old boy who presented with a gradually rising serum creatinine during treatment for severe autoimmune hemolytic anemia, which he developed 9 months after receiving an allogeneic HSCT for aplastic anemia. There was no proteinuria or hematuria present. Serum BK virus load was 5 × 10⁶  copies/mL. A renal biopsy showed evidence of BKVN. He developed fever, seizures, and confusion, and the (CSF) showed significant presence of the BK virus (1 × 10⁶  copies/mL) along with biochemical evidence of viral encephalitis. Cerebrospinal fluid cultures were negative. Despite significant clinical symptoms and presence of BK virus in CSF, the magnetic resonance brain imaging findings were minimal. With reduction of immunosuppression, there was resolution of BK encephalitis but BKVN remained resistant to multiple anti-BK virus agents, including leflunomide and cidofovir. He eventually became dialysis-dependent and, 6 years later, received a renal transplant from his mother. This case illustrates that BK virus in severely immunocompromised HSCT recipient may lead to BK encephalitis and BKVN of native kidneys, even without hemorrhagic cystitis, leading to ESRD. Knowledge of such is important for appropriate timely evaluation and management.

Prospective Analysis of Hemorrhagic Cystitis and BK Viremia in Allogeneic Hematopoietic Stem Cell Transplantation

Objective

BK virus (BKV) infection has been shown to be related to hemorrhagic cystitis (HC) in allogeneic hematopoietic stem cell transplantation (allo-HSCT). There are conflicting data regarding the association between BKV titers in plasma and clinical disease as well as the risk factors for BKV-related HC. Our aim is to study the risk factors and relationship with plasma BK viral load for development of HC in a prospective analysis.

Materials and Methods

We prospectively evaluated 59 patients who received allo-HSCT between 2014 and 2016 by quantitative BK virus polymerase chain reaction (PCR) (Altona Diagnostics, Germany) from blood samples at days 0, 30, 60, and 90 after allo-HSCT. The patients were monitored for signs and symptoms of HC.

Results

HC was diagnosed in 22 patients (37%) at a mean of 100 days (range: 0-367 days). In multivariate analysis, the usage of cyclophosphamide (sub-distribution hazard ratio [sdHR]: 7.82, confidence interval [CI]: 1.375-39.645, p=0.02), reactivated CMV (sdHR: 6.105, CI: 1.614-23.094, p=0.008), and positive BKV viremia (sdHR: 2.15, CI: 1.456-22.065, p=0.01) significantly increased the risk of developing HC. Patients with higher viral loads at day 30 and day 60 were diagnosed with more severe HC (p<0.001). Median BK viral loads of >101.5 copies/mL at day 0 (sensitivity 0.727, specificity 0.875), >98.5 copies/mL at day 30 (sensitivity 0.909, specificity 0.875), and >90.0 copies/mL at day 60 (sensitivity 0.909, specificity 0.875) were indicative of HC.

Conclusion

Our study showed that administration of cyclophosphamide, CMV reactivation, and BK virus positivity were associated with HC. Plasma BK virus PCR titers at days 0, 30, and 60 after transplant were sensitive tools for predicting clinically proven HC.

BK virus infection in allogeneic hematopoietic cell transplantation: An update on pathogenesis, immune responses, diagnosis and treatments

In hematopoietic cell transplantation (HCT) patients, BK polyomavirus (BKPyV) infection results in significant morbidity mainly due to hemorrhagic cystitis (HC). Despite increased knowledge acquired over recent decades, no treatment has shown effectiveness in the management of organ damage in HCT allografts. This review summarizes the current knowledge on BKPyV, from the virus constitution to the pathophysiology and immune-related mechanisms. We next focus on BKPyV-induced HC in HCT to discuss the benefit of monitoring BKPyV viruria and viremia in the management of patients. At last, we review currently used therapeutics, along with future promising therapies to propose clinical and practical guidelines and further interesting research areas.

Impacts and Challenges of Advanced Diagnostic Assays for Transplant Infectious Diseases

The advanced technologies described in this chapter should allow for full inventories to be made of bacterial genes, their time- and place-dependent expression, and the resulting proteins as well as their outcome metabolites. The evolution of these molecular technologies will continue, not only in the microbial pathogens but also in the context of host-pathogen interactions targeting human genomics and transcriptomics. Their performance characteristics and limitations must be clearly understood by both laboratory personnel and clinicians to ensure proper utilization and interpretation.

ECIL guidelines for the prevention, diagnosis and treatment of BK polyomavirus-associated haemorrhagic cystitis in haematopoietic stem cell transplant recipients

Objectives

To define guidelines for BK polyomavirus (BKPyV)-associated haemorrhagic cystitis (BKPyV-HC) after paediatric and adult HSCT.

Methods

Review of English literature and evidence-based recommendations by expert consensus.

Results

BKPyV-HC occurs in 8%-25% of paediatric and 7%-54% of adult recipients undergoing allogeneic HSCT. Diagnosis requires the triad of cystitis, macro-haematuria and high urine BKPyV loads >7 log10 copies/mL, and exclusion of other relevant aetiologies. BKPyV viraemia is frequent and may serve as a more specific semiquantitative follow-up marker. No randomized controlled trials are available to inform antiviral prophylaxis or treatment. However, hyper-hydration and/or bladder irrigation showed limited prophylactic value. Fluoroquinolones are not effective for prophylaxis or treatment, but rather increase antibiotic resistance. Hyperbaric oxygen or fibrin glue is marginally effective based on small case series from correspondingly equipped centres. Although cidofovir has been reported to improve and/or reduce BKPyV viraemia or viruria, the current data do not support its regular use.

Conclusions

BKPyV-HC remains a disabling unmet clinical need in HSCT that requires novel approaches supported by proper clinical trials.

Successful induction of therapeutic urinary concentration by intravenous ganciclovir and oral valganciclovir with remission of adenoviral hemorrhagic cystitis after cord blood transplantation

AdV11-HC is one of the major complications after allogeneic HSCT in Japan. We previously reported that the intravenous infusion of ganciclovir was effective against AdV11-HC in a post-transplant patient. We here report a case of a 10-year-old boy who underwent cord blood transplantation for the treatment of relapsed lymphoblastic lymphoma. He developed AdV11-HC with an elevated AdV load in his urine and blood on day 14 after HSCT. He was immediately treated with intravenous ganciclovir; he rapidly achieved a remission of AdV11-HC with a decreased AdV load in his urine and blood. He remained in remission of AdV11-HC, even after we switched ganciclovir to oral valganciclovir on day 63. A pharmacokinetics study of his urine revealed that therapeutic concentrations of ganciclovir could be achieved by both intravenous ganciclovir and oral valganciclovir. These findings suggested that both intravenous ganciclovir and oral valganciclovir could be promising alternatives for the treatment of AdV11-HC in post-transplant patients.

High incidence of BK virus-associated hemorrhagic cystitis in children after second or third allogeneic hematopoietic stem cell transplantation

BKV-HC is a serious complication of allogeneic HSCT. To characterize the incidence, risk factors, and clinical outcomes of post-HSCT BKV-HC, we retrospectively analyzed 112 patients who underwent one or more allogeneic HSCTs at our hospital between 2001 and 2017. Twenty underwent second or third HSCT thereafter. Ten patients developed BKV-HC at a median of 30 days after HSCT. The 100-day cumulative incidences of grade 0-4 and grade 2-4 BKV-HC were 7.8% and 6.2%, respectively. HSCTs performed in 2011-2017 associated with significantly higher 100-day cumulative incidence of grade 2-4 BKV-HC (14.0%) than HSCTs performed in 2001-2010 (1.3%, P = 0.004). On multivariate analysis, second or third HSCT was the only independent significant risk factor for development of grade 2-4 BKV-HC (P = 0.015). Serial PCR monitoring of urine and blood BKV load did not predict BKV-HC. The recent increase in the incidence of BKV-HC may reflect recent innovations in transplant technologies that facilitate second or third HSCT, which are known to cause prolonged immune deficiency. If safe and effective treatment or prophylaxis becomes available, it could be used to target the high-risk patients for BKV-HC.

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.

Treatment of late-onset hemorrhagic cystitis after allogeneic hematopoietic stem cell transplantation: the role of corticosteroids

We aimed to evaluate the treatments, particularly the role of corticosteroids, in patients with late-onset hemorrhagic cystitis (LOHC) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). One hundred and sixty-three consecutive patients who underwent non-T-cell-depleted allo-HSCT and met the criterion of LOHC after allo-HSCT were enrolled in this study. The median time from allo-HSCT to the occurrence of LOHC was 29 (range, 4–155) days. Pathogens identified in blood and/or urine samples from 143 patients were mostly viruses. All of the patients with LOHC received intravenous fluid hydration, alkalization, and forced diuresis, of which 2 patients achieved complete remission (CR) after these treatments. The remaining 161 patients received anti-infection therapies and 71 achieved CR after the therapies. Corticosteroids were additionally applied to 83 out of 90 patients who did not achieve CR after anti-infection therapies, and 88.0% (n = 73) of them showed a grade 3 to 4 LOHC at the beginning of corticosteroid therapy. Thirty-five patients showed an immediate response (CR or downgraded at least one grade) within 1 week after the beginning of the corticosteroid therapy. Sixty-four patients (77.1%) achieved CR after corticosteroid therapy, and the median period from the beginning of corticosteroid therapy to CR was 17 days. Thus, we observed that viruses were the most common pathogens in LOHC after allo-HSCT and that anti-infection therapies were critical. For patients not showing a satisfactory response to anti-infection therapies, additional corticosteroid therapy may help to achieve CR.

Nosocomial BK Polyomavirus Infection Causing Hemorrhagic Cystitis Among Patients With Hematological Malignancies After Hematopoietic Stem Cell Transplantation

BK polyomavirus (BKPyV) is recognized as a pathogen that causes diseases such as hemorrhagic cystitis and nephritis after allogeneic hematopoietic stem cell transplantation (HSCT) or renal transplantation. BKPyV-associated disease is thought to occur through reactivation under immunosuppression. However, the possibility of its nosocomial transmission and the clinical significance of such transmission have not been elucidated. During a 6-month period, nine adult patients (median age: 47 years) who had hematological disorders and who were treated with HSCT (n = 7) or chemotherapy (n = 2) in a single hematology department developed hemorrhagic cystitis due to BKPyV infection. The polymerase chain reaction products of BKPyV DNA obtained from each patient were sequenced. Of the nine patients, six had subtype I, 2 had subtype IV, and 1 had subtype II or III. In the alignment of sequences, four and two of the six subtype I strains were completely homologous (100%). These results strongly suggest that BKPyV has the potential to cause nosocomial infection within a medical facility, especially among recipients of HSCT. Further studies are clearly warranted to elucidate the route(s) of BKPyV transmission in order to establish optimal infection control.

The Association of Combined GSTM1 and CYP2C9 Genotype Status with the Occurrence of Hemorrhagic Cystitis in Pediatric Patients Receiving Myeloablative Conditioning Regimen Prior to Allogeneic Hematopoietic Stem Cell Transplantation

Hemorrhagic cystitis (HC) is one of the complications of busulfan-cyclophosphamide (BU-CY) conditioning regimen during allogeneic hematopoietic stem cell transplantation (HSCT) in children. Identifying children at high risk of developing HC in a HSCT setting could facilitate the evaluation and implementation of effective prophylactic measures. In this retrospective analysis genotyping of selected candidate gene variants was performed in 72 children and plasma Sulfolane (Su, water soluble metabolite of BU) levels were measured in 39 children following treatment with BU-CY regimen. The cytotoxic effects of Su and acrolein (Ac, water soluble metabolite of CY) were tested on human urothelial cells (HUCs). The effect of Su was also tested on cytochrome P 450 (CYP) function in HepaRG hepatic cells. Cumulative incidences of HC before day 30 post HSCT were estimated using Kaplan–Meier curves and log-rank test was used to compare the difference between groups in a univariate analysis. Multivariate Cox regression was used to estimate hazard ratios with 95% confidence intervals (CIs). Multivariate analysis included co-variables that were significantly associated with HC in a univariate analysis. Cumulative incidence of HC was 15.3%. In the univariate analysis, HC incidence was significantly (p < 0.05) higher in children older than 10 years (28.6 vs. 6.8%) or in children with higher Su levels (>40 vs. <11%) or in carriers of both functional GSTM1 and CYP2C9 (33.3 vs. 6.3%) compared to the other group. In a multivariate analysis, combined GSTM1 and CYP2C9 genotype status was associated with HC occurrence with a hazards ratio of 4.8 (95% CI: 1.3–18.4; p = 0.02). Ac was found to be toxic to HUC cells at lower concentrations (33 μM), Su was not toxic to HUC cells at concentrations below 1 mM and did not affect CYP function in HepaRG cells. Our observations suggest that pre-emptive genotyping of CYP2C9 and GSTM1 may aid in selection of more effective prophylaxis to reduce HC development in pediatric patients undergoing allogeneic HSCT.

Article summary:

(1) Children carrying functional alleles in GSTM1 and CYP2C9 are at high risk for developing hemorrhagic cystitis following treatment with busulfan and cyclophosphamide based conditioning regimen.

(2) Identification of children at high risk for developing hemorrhagic cystitis in an allogeneic HSCT setting will enable us to evaluate and implement optimal strategies for its prevention.

Trial registration: This study is a part of the trail “clinicaltrials.gov identifier: NCT01257854.”

BK nephropathy in the native kidneys of patients with organ transplants: Clinical spectrum of BK infection

Nephropathy secondary to BK virus, a member of the Papoviridae family of viruses, has been recognized for some time as an important cause of allograft dysfunction in renal transplant recipients. In recent times, BK nephropathy (BKN) of the native kidneys has being increasingly recognized as a cause of chronic kidney disease in patients with solid organ transplants, bone marrow transplants and in patients with other clinical entities associated with immunosuppression. In such patients renal dysfunction is often attributed to other factors including nephrotoxicity of medications used to prevent rejection of the transplanted organs. Renal biopsy is required for the diagnosis of BKN. Quantitation of the BK viral load in blood and urine are surrogate diagnostic methods. The treatment of BKN is based on reduction of the immunosuppressive medications. Several compounds have shown antiviral activity, but have not consistently shown to have beneficial effects in BKN. In addition to BKN, BK viral infection can cause severe urinary bladder cystitis, ureteritis and urinary tract obstruction as well as manifestations in other organ systems including the central nervous system, the respiratory system, the gastrointestinal system and the hematopoietic system. BK viral infection has also been implicated in tumorigenesis. The spectrum of clinical manifestations from BK infection and infection from other members of the Papoviridae family is widening. Prevention and treatment of BK infection and infections from other Papovaviruses are subjects of intense research.

Polyomaviruses BK, JC, KI, WU, MC, and TS in children with allogeneic hematopoietic stem cell transplantation

Timely and reliable detection of viruses is of key importance in early diagnosis of infection(s) following allogeneic HSCT. Among the immunocompetent, infections with BKPyV and JCPyV are mostly subclinical, while post-HSCT, the former may cause HC and the latter PML. The epidemiology and clinical impact of the newly identified KIPyV, WUPyV, MCPyV, and TSPyV in this context remain to be defined. To assess the incidence and clinical impact of BKPyV, JCPyV, KIPyV, WUPyV, MCPyV, and TSPyV infections, we performed longitudinal molecular surveillance for DNAemias of these HPyVs among 53 pediatric HSCT recipients. Surveillance pre-HSCT and for three months post-HSCT revealed BKPyV DNAemia in 20 (38%) patients. Our data demonstrate frequent BKPyV DNAemia among pediatric patients with HSCT and the confinement of clinical symptoms to high copy numbers alone. MCPyV and JCPyV viremias occurred at low and TSPyV viremia at very low prevalences. KIPyV or WUPyV viremias were not demonstrable in this group of immunocompromised patients.

Successful treatment with intravesical cidofovir for virus-associated hemorrhagic cystitis after allogeneic hematopoietic stem cell transplantation: A case report and a review of the literature

Virus-associated hemorrhagic cystitis (VAHC) is a formidable complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). The standard management of severe VAHC after allo-HSCT has not been established. Intravenous administration of cidofovir (CDV), an acyclic nucleoside analogue with broad-spectrum activity against DNA viruses, has been reported to be effective for VAHC, but it can cause severe renal toxicity. Here we report four cases who achieved clinical responses with intravesical instillation of CDV for severe VAHC after allo-HSCT. Median age was 57 years (40-63), and all were male. The underlying diseases were hematological malignancies. Three had received bone marrow transplantation, and one received cord blood transplantation twice. Conditioning regimen was myeloablative for one, and reduced-intensity for three. The viral types were BK virus and/or adenovirus. Two patients had received CDV intravenously prior to the intravesical therapy. A dose of intravesical CDV was 2-5 mg/kg. In all cases, symptoms of cystitis improved dramatically within a few days without showing any systemic adverse effects. The virological response was observed in two cases. This local therapy was effective even in the cases refractory to the intravenous CDV and a case with severe renal failure. Along with the review of literature, we propose that the intravesical instillation of CDV can be a therapeutic option for severe VAHC after allo-HSCT.

Risk factors for hemorrhagic cystitis in pediatric allogeneic hematopoietic stem cell transplant recipients

BACKGROUND

Hemorrhagic cystitis (HC) results in significant morbidity among hematopoietic stem cell transplant (HSCT) recipients. Several potential causes for HC have been postulated, including viral infection, but definitive evidence is lacking, particularly in pediatric HSCT patients.

METHODS

Ninety pediatric HSCT recipients were prospectively tested on a weekly basis for adenovirus (ADV) and BK virus (BKV) by quantitative real-time polymerase chain reaction in blood and urine samples. Results were correlated with the occurrence of grade II-IV HC. The odds ratio (OR) of HC (95% confidence interval) for BKV ≥1 × 10(9) copies/mL of urine was 7.39 (1.52, 35.99), with a P-value of 0.013. Those with acute graft-versus-host disease (aGVHD) also had higher odds of developing HC, with an OR of 5.34. Given a 20% prevalence rate of HC, positive and negative predictive values of 29% and 95% were seen with a cutoff of 10(9) copies/mL.

RESULTS

BK viremia did not reach significance as a risk factor for development of HC (P = 0.06). Only 8 patients showed ADV viruria and 7 showed ADV viremia; all had low viral loads and 4 had no evidence of HC.

CONCLUSION

HC in pediatric HSCT is correlated most strongly to elevated urinary viral load of BKV and to aGVHD, but less strongly to BK viremia.

Simultaneous BK Polyomavirus (BKPyV)-associated nephropathy and hemorrhagic cystitis after living donor kidney transplantation

BK polyomavirus (BKPyV) commonly reactivates after kidney transplantation, and can cause polyomavirus-associated nephropathy (PyVAN), whereas after allogeneic stem cell transplantation the most frequent manifestation of BKPyV is polyomavirus-associated hemorrhagic cystitis (PyVHC). Despite high-level BKPyV replication in both, the pathogenesis and manifestation of both BKPyV entities appears to differ substantially. We describe an unusual case of simultaneous PyVAN and PyVHC presenting with acute symptoms in a BKPyV-IgG positive recipient eight months after kidney transplantation from a haploidentical living donor, who was BKPyV-IgG negative. Symptoms of cystitis and viremia subsided rapidly after reduction of immunosuppression.

Development of a BK virus real-time quantitative assay using the bioMérieux analyte-specific reagents in plasma specimens

OBJECTIVES

Viral load testing for BK virus (BKV) has become the standard of care for diagnosing BKV infection and monitoring therapy in kidney transplant patients. However, there are currently no US Food and Drug Administration-approved assays and no standardization among available tests.

METHODS

This study evaluated the performance of the analyte-specific reagent (ASR) BKV primers r-gene and probe r-gene reagents (bioMérieux, Marcy l'Étoile, France) soon to become available on the US market for accuracy, linearity, precision, analytical sensitivity, specificity, and correlation with the Qiagen (Germantown, MD) BKV ASR test using commercial material and patient plasma samples.

RESULTS

The assay was linear from 204 to 3.92 million (2.31-6.6 log10) DNA copies/mL (coefficient of determination: R(2) =0.999). A dilution series demonstrated limits of detection and quantitation of 2.14 log10 and 2.30 log10 copies/mL (95% hit rate detection), respectively. Interrun precision was highly reproducible, with coefficients of variance ranging from 2.2% to 6.0%. A comparison of 34 matched samples showed a good agreement (R(2) = 0.87) between the bioMérieux BKV laboratory test and the Qiagen BKV ASR assay results, with an average negative bias (-0.28 log10 copies/mL).

CONCLUSIONS

The laboratory-developed test with bioMérieux BKV reagents is a reliable and sensitive assay for BKV DNA quantitation compared with the Qiagen ASR test.

A Prospective Study on the Predictive Value of Plasma BK Virus-DNA Load for Hemorrhagic Cystitis in Pediatric Patients After Stem Cell Transplantation

BACKGROUND

In hematopoietic stem cell transplantation (HSCT), late hemorrhagic cystitis (HC) has been associated with BK virus (BKV) infection. We assessed the value of plasma BKV load in predicting HC.

METHODS

Plasma and urine BKV-DNA load were assessed prospectively in 107 pediatric patients.

RESULTS

Twenty patients developed grade II and III HC, with 100-day cumulative incidence of 18.8%. At diagnosis of HC, the median load of BKV DNA was 2.3 × 10(3) copies/mL. A plasma BKV-DNA load of 10(3) copies/mL had a sensitivity of 100% and a specificity of 86% with a negative predictive value (NPV) of 100% and a positive predictive value (PPV) of 39% for HC. A urine BKV-DNA load of >10(7) copies/mL had a sensitivity of 86% and a specificity of 60% with a NPV of 98% and a PPV of 14% for HC. A BKV load of 10(3) copies/mL on plasma was significantly associated with HC in multivariate analysis (hazard ratio [HR], 6.1; P = .0006). Patients with HC had a significantly higher risk of mortality than patients who did not have HC (HR, 2.6; P = .018).

CONCLUSIONS

The above values were used to monitor plasma BKV-DNA load, and they provided a better prediction of patients at risk of HC than urine BKV-DNA load.

BK virus-associated hemorrhagic cystitis after pediatric stem cell transplantation

Hemorrhagic cystitis is a common stem cell transplantation-related complication. The incidence of early-onset hemorrhagic cystitis, which is related to the pretransplant conditioning regimen, has decreased with the concomitant use of mesna and hyperhydration. However, late-onset hemorrhagic cystitis, which is usually caused by the BK virus, continues to develop. Although the BK virus is the most common pathogenic microorganism of poststem cell transplantation late-onset hemorrhagic cystitis, pediatricians outside the hemato-oncology and nephrology specialties tend to be unfamiliar with hemorrhagic cystitis and the BK virus. Moreover, no standard guidelines for the early diagnosis and treatment of BK virus-associated hemorrhagic cystitis after stem cell transplantation have been established. Here, we briefly introduce poststem cell transplantation BK virus-associated hemorrhagic cystitis.

Effective treatment of severe BK virus-associated hemorrhagic cystitis with leflunomide in children after hematopoietic stem cell transplantation: a pilot study

Leflunomide, an immunosuppressant with antiviral activity, was used to treat 5 children with severe BK virus-associated hemorrhagic cystitis after hematopoietic stem cell transplantation. Without severe side effects, BK viral loads in blood and urine decreased significantly after leflunomide treatment. Compared with 7 historical controls, duration of BK virus-associated hemorrhagic cystitis was significantly shorter in patients receiving leflunomide therapy (P < 0.01).

The risk of polyomavirus BK-associated hemorrhagic cystitis after allogeneic hematopoietic SCT is associated with myeloablative conditioning, CMV viremia and severe acute GVHD

Hemorrhagic cystitis (HC) is a common complication after allogeneic hematopoietic SCT (allo-HSCT). Several risk factors have been suggested including BU-containing myeloablative conditioning, unrelated donors and GVHD, but these have not been consistently reported. We conducted a retrospective study including 339 allo-HSCT recipients between 2009 and 2012. Of 339 patients, 79 (23.3%) developed HC with 2-year cumulative incidence of 24.0% (95% confidence interval, 19.4-28.9). The median onset time was 45 days (range, 16-430) after allo-HSCT. Sixty-two patients (84%) out of 74 evaluated for urine BK virus PCR testing showed a positive result (mean 2.0 × 10(10) copies of DNA per mL). In univariate analysis, myeloablative conditioning, HLA-mismatched donor, CMV viremia and acute GVHD (aGVHD) grade 3-4 were significantly associated with the risk of HC. Multivariate analysis confirmed all associating factors identified in univariate analysis except for HLA-mismatched donor: myeloablative conditioning (hazard ratio (HR) 2.63, P=0.003), CMV viremia (HR 1.88, P=0.014) and aGVHD grade 3-4 (HR 1.71, P=0.029). HC did not affect OS or non-relapse mortality. Symptomatic HC is a frequent complication following allo-HSCT, with a 2-year cumulative incidence of 24.0%. Three clinical factors associated with HC were identified including myeloablative conditioning, CMV viremia and severe aGVHD.

BK Virus and Its Role in Hematopoietic Stem Cell Transplantation: Evolution of a Pathogen

We reviewed the literature regarding disease induced by BK virus (BKV) in the hematopoietic stem cell transplant (HSCT) population, particularly hemorrhagic cystitis (HC) and nephritis. The association between BKV and HC has been reported over the past four decades. BKV has been clinically implicated and widely accepted as an etiologic agent of HC and nephritis in HSCT and nephropathy in renal transplant patients. We discuss the potential benefit of early initiation of therapy in patients who fail supportive care alone as well as the different treatment strategies for HC induced by BKV. Treatments that have been used such as cidofovir and leflunomide are accompanied by risks, and the benefits are not as concrete as with other viral illness in the HSCT population.

Relationship of BK polyoma virus (BKV) in the urine with hemorrhagic cystitis and renal function in recipients of T Cell-depleted peripheral blood and cord blood stem cell transplantations

Hematopoietic stem cell transplant (HSCT) recipients are at significant risk for BK virus (BKV) reactivation, hemorrhagic cystitis (HC), and renal dysfunction. We prospectively monitored 98 patients who had received HSCT by serial BKV PCR in the urine through day (D) +100 to analyze the relationship between BK viruria and HC, serum creatinine (Cr), and creatinine clearance (CrCl) through D +180 or death. Patients, median age 52 years (range, 20 to 73), received T cell-depleted (50%) or cord blood allografts (21%). Median pre-HSCT BKV IgG titers were 1:10,240. Incremental increase in BKV IgG titers correlated with developing BK viruria ≥ 10(7) copies/mL. By D +100, 53 (54%) patients had BK viruria. BKV load in the urine increased at engraftment and persisted throughout D +100. HC developed in 10 patients (10%); 7 of 10 with BK viruria. In competing risk analyses, BK viruria ≥ 10(7) copies/mL, older age, cytomegalovirus reactivation, and foscarnet use were risk factors for HC. Cr and CrCl at 2, 3, and 6 months after HSCT were similar between patients with and without BK viruria.

High burden of BK virus-associated hemorrhagic cystitis in patients undergoing allogeneic hematopoietic stem cell transplantation

BK virus (BKV) reactivation has been increasingly associated with the occurrence of late-onset hemorrhagic cystitis (HC) after allogeneic hematopoietic SCT (allo-HSCT) resulting in morbidity and sometimes mortality. We investigated the incidence, risk factors and outcome of BKV-HC in 323 consecutive adult patients undergoing allo-HSCT over a 5-year period. BK viremia values for HC staging were evaluated, as well as the medico-economic impact of the complication. Forty-three patients developed BKV-HC. In univariate analysis, young age (P=0.028), unrelated donor (P=0.0178), stem cell source (P=0.0001), HLA mismatching (P=0.0022) and BU in conditioning regimen (P=0.01) were associated with a higher risk of developing BKV-HC. In multivariate analysis, patients receiving cord blood units (CBUs) (P=0.0005) and peripheral blood stem cells (P=0.011) represented high-risk subgroups for developing BKV-HC. BK viremia was directly correlated to HC severity (P=0.011) with a 3 to 6-log peak being likely associated with grades 3 or 4 HC. No correlation was found between BKV-HC and acute graft versus host disease or mortality rate. Patients with BKV-HC required a significantly longer duration of hospitalization (P<0.0001), more RBC (P=0.0003) and platelet transfusions (P<0.0001). Over the 5-year study period, the financial cost of the complication was evaluated at \[euro]2 376 076 ($3 088 899). Strategies to prevent the occurrence of late-onset BKV-HC after allo-HSCT are urgently needed, especially in CBU and peripheral blood stem cell recipients. BK viremia correlates with the severity of the disease. Prospective studies are required to test prophylactic approaches.

Cytomegalovirus is a potential risk factor for late-onset hemorrhagic cystitis following allogeneic hematopoietic stem cell transplantation

Late-onset hemorrhagic cystitis (LOHC) is a common complication following allogeneic hematopoietic stem cell transplantation (allo-HSCT) and is primarily associated with viral infection. We prospectively quantified cytomegalovirus (CMV), BK virus (BKV), and adenovirus in urine and plasma using Q-RT-PCR in 50 consecutive patients to define the relationship between virus and LOHC. Of the 50 patients, 21 developed LOHC at a median of 29 days (range 4-64 days), with a cumulative incidence of 42% (±7.1%). The cumulative incidence of LOHC on day 100 in patients with and without CMV viremia (prior to or at the onset of LOHC) were 56.3% (±8.9%) and 16.7% (±9.1%) (P = 0.018), respectively, and it was 59.3% (±9.8%) and 21.7% (±8.8%) in patients with and without CMV viruria (prior to or at the onset of LOHC) (P = 0.021), respectively. The cumulative incidence of LOHC was also higher in patients with a plasma BKV load increased ≥3 log10 or with a urine BKV load increased ≥4 log10 than those without the increase (P < 0.001). Only one patient with LOHC was tested positive for ADV. Both the univariate and multivariate analyses showed that CMV viremia (HR = 3.461, 95% CI: 1.005-11.922, P = 0.049) and a plasma BKV load that was increased ≥3 log10 (HR = 10.705, 95%CI: 2.469-46.420, P = 0.002) were independent risk factors for the development of LOHC. We conclude that both CMV viremia and an increase of plasma BKV are independent risk factors for LOHC. And the role of CMV viremia was firstly demonstrated.

Kidney and bladder outcomes in children with hemorrhagic cystitis and BK virus infection after allogeneic hematopoietic stem cell transplantation

BK virus (BKV) infection is associated with hemorrhagic cystitis (HC) in hematopoietic stem cell transplantation (HSCT) recipients and nephropathy after kidney transplantation. We assessed the association between BKV and kidney and bladder complications in children developing HC by retrospectively reviewing 221 consecutive pediatric allogeneic HSCT recipients at the Children's Hospital of Philadelphia from 2005 to 2011. We included all patients with BKV PCR testing performed for clinical indication from day 0 until 1 year post-HSCT (N = 68). We assessed the association of any BKV infection (urine and/or blood) or peak BK viremia ≥ 10,000 copies/mL (high viremia) with severe HC (defined as grade IV-bladder catheterization or surgical intervention); the need for dialysis; serum creatinine-estimated glomerular filtration rate at the time of BKV testing, day 100, and day 365; and death. Children with high viremia more likely developed severe HC compared with those with peak viremia < 10,000 copies/mL (21% versus 2%; P = .02). BKV infection of the blood or urine was not associated with the need for dialysis, change in estimated glomerular filtration rate, or mortality. BKV infection is common after pediatric allogeneic HSCT, and plasma testing in those with HC may predict patients who will develop severe bladder injury.

Treatment of BK virus-associated hemorrhagic cystitis in pediatric hematopoietic stem cell transplant recipients with cidofovir: a single-center experience

BACKGROUND

BK virus (BKV)-associated hemorrhagic cystitis (BKV-HC) is a severe complication after hematopoietic stem cell transplantation (HSCT). Cidofovir (CDV) has emerged as an effective agent for the treatment of BKV nephropathy, but its use for BKV-HC in pediatric HSCT recipients has not yet been established as a standard therapy.

PATIENT AND METHODS

We retrospectively investigated the efficacy and safety of CDV therapy for patients with BKV-HC at a single institution and analyzed the clinical management outcomes.

RESULTS

From April 2009 to July 2011, 12 patients developed BKV-HC at a median of 37 days after transplant (range 15-59 days). The cumulative incidence was 9% and the median peak of the urine BKV load was 2.5 × 10(10) copies/mL (range 1.4 × 10(9) -1.2 × 10(11) copies/mL). Eleven patients received intravenous CDV (5 mg/kg/dose, with probenecid), whereas 1 patient received CDV (5 mg/kg/dose, without probenecid) intravesically. The median duration of therapy was 25 days (range 9-73 days), and a median of 2 doses was given (range 1-4). A reduction of ≥ 1 log in the BKV load was found in 11 patients, while 1 patient did not have any significant change in BKV load. Clinical improvement was observed in all cases, and no HC-related death was observed. CDV-related toxicity occurred in 1 patient (8%) and spontaneously resolved.

CONCLUSIONS

CDV appears to be an effective and safe treatment for BKV-HC in pediatric HSCT recipients, but prospective trials are warranted to support its use.