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

Analysis of BK Virus Infection in Children After Hematopoietic Cell Transplantation: A Retrospective Single-center Study

BACKGROUND

BK virus (BKV) is one of the most common causes of hemorrhagic cystitis (HC) in children undergoing hematopoietic stem cell transplantation (HSCT). Viruses can be found in urine and serum of immunocompromised patients.

OBJECTIVE

This study aimed to evaluate the incidence, clinical course, and risk factors for BKV infection in children undergoing HSCT.

METHODS

Retrospectively analyzed children who underwent HSCT at Beijing Children's Hospital, Capital Medical University from June 2020 to June 2022. Data related to the clinical manifestations, engraftment, and prognosis were extracted from medical records. Patients were divided into the case group and the control group, according to the BKV infection or not after HSCT.

RESULTS

A total of 149 patients were enrolled in this study, and 61 (40.9%) patients developed BKV infection after HSCT. Among the 61 patients, BKV load was detected in all patients in urine samples and 22 patients in blood samples. The median value of BKV DNA copies in urine and plasma were 9.50×10 7 (5.37×10 2 to 6.84×10 9 ) copies/mL and 2.97×10 3 (9.96×10 2 to 3.58×10 8 ) copies/mL, respectively. The median time from beginning of the conditioning regimen to BKV infection was 23 (0 to 273) days, and the first positive time of urinary BKV was earlier than that of blood (13.5 d [0.0 to 123.0 d] vs. 30.5 d [7.0 to 165.0 d], P =0.003). Among the patients with BKV infection, 36 (59.0%) patients met the diagnosis of hemorrhagic cystitis (HC), and the incidence was higher than that in the control group ( P <0.001). Similarly, 15 (24.6%) patients developed renal function damage in the case group and the proportion was higher than that in the control group. The median follow-up was 5.67 (0.03 to 24.90) months, and there was no significant difference in 1-year overall survival rate between the case group and the control group (84.2%±5.7% vs. 95.3%±2.3%, P =0.688), but the incidence of TA-TMA/VOD (31.1%) and diffuse alveolar hemorrhage (9.8%) in the case group was higher than that in the control group ( P =0.002 and 0.038, respectively). Multivariate analysis showed that age above 5 years old (OR=9.039, 95% CI: 3.561-24.333, P <0.001) and use of MMF (OR=2.708, 95% CI: 1.041-7.044, P <0.05) were independent risk factors for BKV infection after HSCT.

CONCLUSION

Among children after HSCT, the incidence of BKV infection was high and BKV infection was associated with an increased incidence of TA-TMA/VOD and diffuse alveolar hemorrhage. Patients older than 5 years of age at the time of HSCT and treated with MMF were more likely to develop BKV infection.

An expert consensus on prevention, diagnosis, and management of hemorrhagic cystitis in pediatric hematopoietic cell transplantation, on behalf of the Infectious Disease and Hematopoietic Cell Transplant Working groups of Italian Pediatric Hematology Oncology Association (AIEOP)

The optimal management of hemorrhagic cystitis (HC) in hematopoietic stem cell transplantation (HCT) is debated, both for early onset HC (EOHC) secondary to chemotherapy toxicity and BK Polyomavirus (BKPyV)-related HC, due to the lack of controlled trials, particularly referred to pediatric setting. Actually, clinical practice is mainly based on guidelines of the European Conference on Infections in Leukemia, 6th edition, which considers both adult and pediatric populations but concludes that, despite much progress in understanding the pathogenesis, epidemiology, and risk factors, this complication still represents a disabling unmet clinical need with limited prophylactic and therapeutic options. Additionally, the Guidelines of the American Society of Clinical Oncology define the management of chemotherapeutic toxicity independently from the patients' population. A panel of experts belonging to the Hematopoietic Cell Transplant and Infectious Disease Working Group (WG) of Associazione Italiana di Emato-Oncologia Pediatrica (AIEOP) developed a consensus to define the best practices in prevention, diagnosis, and management of HC in pediatric HCT setting.

Risk factors for mortality in children with hemorrhagic cystitis after hematopoietic transplant

INTRODUCTION

Hemorrhagic cystitis (HC) is a devastating complication of bone marrow (BMT) and stem cell transplant (SCT). Much of the literature has focused on exclusively adult patient populations, with limited evidence regarding risk factors for mortality and morbidity among pediatric HC patients.

OBJECTIVE

To examine factors associated with all-cause mortality in children with HC after BMT/SCT.

METHODS

The Pediatric Health Information System database was queried for patients with ICD-9/10 codes for hematopoietic transplant and gross hematuria, hematuria unspecified, or cystitis with hematuria. Multivariable logistic regression examined association of medical and surgical interventions frequently employed for hemorrhagic cystitis with mortality and genitourinary morbidity, defined as having received instillation of any bladder medication or having undergone any genitourinary procedure.

RESULTS

A total of 811 patients, mean age of 12.4 years and 62% male, were included. Primary diagnosis included 388 (49%) leukemia/lymphoma, 182 (22%) blood dyscrasia, 99 (12%) solid organ tumor, 27 (3%) metabolic disease, 115 (14%) unknown. Transplant type included 377 (46%) bone marrow, 329 (41%) stem cell, 105, and (13%) unknown. Performing any bladder instillation (p < 0.0001) or any type of GU procedure (p < 0.0001) was significantly associated with mortality. On multivariate analysis, dialysis (OR = 10.7, 95% CI = 5.7-20.2), genitourinary morbidity (OR = 4, 95% CI = 2.2-6.8) and intravenous cidofovir (OR = 2.0, 95% CI = 1.2-3.3) were significantly associated with all cause mortality. Having an underlying diagnosis of blood dyscrasia was protective against mortality (OR = 0.425, CI = 0.205-0.88).

DISCUSSION

In this large retrospective study evaluating factors associated with mortality in children with HC, all cause mortality was found to be 11%. This is probably an underrepresentation of true mortality in this population, as many patients discharged from the hospital likely die outside the hospital at home or hospice care. This study supports the current literature that invasive GU procedures are not associated with increased survival in patients with severe HC. This study is limited by retrospective use of a billing database that has the potential for errors in data entry and missing data. Patients who were discharged from the hospital were not captured by the PHIS which only collects data from inpatient stays.

CONCLUSIONS

Patients with HC who received dialysis, intravenous cidofovir, or underwent GU intervention had significantly higher all-cause mortality. High grade HC is a marker of disease severity and efforts should be made by urologists and oncologists to maximize quality of life and limit futile treatments in this patient population.

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.

BK Polyomavirus Diversity After Hematopoietic Stem Cell Transplantation

BK polyomavirus (BKPyV) infection is common after hematopoietic stem cell transplantation (HSCT) and is associated with the development of hemorrhagic cystitis (HC). The role that BKPyV plays in the pathogenesis of HC is not well characterized. We investigated the impact of BKPyV diversity on the development of HC using a previously established cohort of pediatric HSCT patients. There were 147 urine samples with quantifiable BKPyV at month 1 after HSCT; 137 (93.2%) were amplified using our in-house polymerase chain reaction approach and sent for next-generation sequencing. Subtype Ia was most frequent (61.3%), followed by subtype Ib1 (31.4%). The median viral load of subtype Ia samples was higher than for subtype Ib1 at month 1. Across the protein coding regions, APOBEC-induced mutations and signature patterns associated with HC were identified. This is the largest sequencing study of a single cohort of HSCT patients, providing a vast resource of sequence data for future analyses.

Review of acute kidney injury and progression to chronic kidney disease in pediatric patients undergoing hematopoietic cell transplant

While acute kidney injury (AKI) after hematopoietic cell transplant (HCT) has been well-described in pediatric patients, literature regarding the long term renal consequences of HCT-related AKI, the development of chronic kidney disease (CKD), and CKD care in pediatric patients post-HCT is limited. CKD affects almost 50% of patients after HCT with multifactorial etiology including infection, nephrotoxic medications, transplant-associated thrombotic microangiopathy, graft-versus-host disease, and sinusoidal obstruction syndrome. As renal function declines in CKD, eventually progressing to end stage kidney disease (ESKD), mortality increases and is more than 80% among patients requiring dialysis. Using society guidelines and current literature, this review summarizes definitions and etiologies of and management strategies among patients with AKI and CKD post-HCT with an emphasis on albuminuria, hypertension, nutrition, metabolic acidosis, anemia, and mineral bone disease. The goal of this review is to aid early identification and intervention in patients with renal dysfunction prior to development of ESKD, and to discuss ESKD and renal transplant in these patients post-HCT.

Evaluation of the risk factors for BK virus-associated hemorrhagic cystitis in pediatric bone marrow transplantation patients: Does post-transplantation cyclophosphamide increase the frequency?

BACKGROUND

BKV-HC is one of the most significant complications of HSCT. This retrospective study aimed to determine the frequency of BKV-HC in pediatric patients undergoing HSCT, detect the associated risk factors for the development of BKV-HC, and explore the effects of post-transplantation Cy use.

METHODS

Three hundred twenty-seven patients (girls: 121, boys: 206) were analyzed according to sex, conditioning regimen, transplantation type, donor relatedness, stem cell source, the presence and grade of aGVHD, CMV co-existence, and Cy use.

RESULTS

Multivariate analysis confirmed the prognostic importance of age (OR: 4.865), TBI use, the presence of aGVHD (OR: 2.794), CMV coinfection (OR: 2.261), and Cy use (OR: 27.353). A statistically significant difference was found between the mean BKV-HC follow-up times compared with post-transplantation Cy intake (p < .001). The BKV-HC rate increased as the number of risk factors of the patient increased.

CONCLUSION

BKV-HC is an essential complication of HSCT primarily associated with Cy use, the presence of aGVHD, and donor relatedness. The present study shows that the use of Cy in the post-transplantation period further increases BKV-HC risk in pediatric patients, regardless of dose.

Endovesical instillation of Cidofovir in the treatment of BK polyomavirus hemorrhagic cystitis after allogeneic hematopoietic cell transplantation

BACKGROUND

Hemorrhagic cystitis (HC) with BK polyomavirus (BKPyV) is a common complication after allogeneic hematopoietic cell transplantation (alloHCT) that may lead to severe discomfort for the patient and significant morbidity (urinary obstruction, increased transfusion requirements and prolonged hospitalization). So far, there is no clear consensus on how to manage this complication.

PATIENTS AND METHODS

Here, we report a single-center case series of 9 patients (4 children and 5 adults) treated with cidofovir endovesical (EV) instillation(s) for BKPyV-HC after alloHCT. EV Cidofovir was administered at a dose of 5 mg/kg, for 1 to 3 instillations (with a minimum delay between 2 successive doses of 5 days).

RESULTS

Eight out of the 9 treated patients with EV Cidofovir achieved a complete resolution of HC after 1-3 instillation(s), without recurrence of symptomatic infection within the next 3 months. Only 1 adult patient did not improve after treatment and developed severe morbidity (emphysematous cystitis).

CONCLUSION

Although this single-center case series of EV cidofovir for BKPyV HC after alloHCT shows encouraging results, only large prospective studies will definitively establish the effectiveness of this therapy.

Pediatric Vulvovaginal Graft-Versus-Host Disease: A Retrospective Cohort Study and Literature Review

STUDY OBJECTIVE

To assess genital symptomatology, characterize the findings of genital examination, and describe the incidence and treatment of vulvovaginal graft-versus-host disease (vvGvHD) in girls and adolescents after allogeneic hematopoietic stem cell transplantation (HSCT).

DESIGN

Retrospective cohort.

SETTING

Metropolitan-area children's hospital.

PARTICIPANTS

Female allogeneic HSCT recipients ages 0 to 22 years.

MAIN OUTCOME MEASURES

Genital symptoms, genital examination, diagnosis, and treatment of vvGvHD.

RESULTS

A total of 57 participants were included in the analysis. The median age at the time of HSCT was 10 years (range 4 months-23 years). Most (n = 40, 71%) underwent transplant for a nonmalignant condition, most commonly sickle cell anemia (n = 19, 33%). The median time of onset of GvHD post HSCT was 62 days (IQR = 42 to 151 days). The most common initial site of GvHD was skin (n = 21, 64%), followed by GI tract (n = 10, 30%). Three patients (5%) were diagnosed with vvGvHD. The time of onset of vvGvHD post HSCT ranged from 62 to 1565 days. One patient (33%) was asymptomatic at the time of diagnosis. There was no difference in diagnosis of vvGvHD when race (P = 0.15), age at allogeneic HSCT (P = 0.64), nonmalignant vs malignant indication (P = 0.21), source of stem cells (P = 0.25), partial vs full human leukocyte antigens (HLA) donor match (P = 0.34), and GvHD prophylaxis regimen (P = 0.18) were compared. None had isolated vvGvHD. Vulvovaginal GvHD was preceded by skin GvHD in 1 patient, was preceded by lung GvHD in 1 patient, and occurred concurrently with skin GvHD in the third patient.

CONCLUSIONS

Pediatric vvGvHD can occur within the first 100 days after transplant and can be asymptomatic. Routine gynecologic evaluation post allogeneic HSCT in children and adolescents should include a thorough review of vulvovaginal symptoms and a gynecologic exam for the detection and treatment of vvGvHD.

A Nomogram for Predicting BK Virus Activation in Kidney Transplantation Recipients Using Clinical Risk Factors

BK virus is a common opportunistic viral infection that could cause BK virus-associated nephropathy in renal transplant recipients. Thus, we retrospectively analyzed clinical and laboratory data associated with a higher risk of BK virus activation from 195 renal transplant recipients by the multivariate logistic regression analysis and performed the external validation. Results showed that patients with BK virus active infection were associated with a deceased donor, had lower direct bilirubin levels, a higher proportion of albumin in serum protein electrophoresis, and lower red blood cells and neutrophil counts. The multivariate logistic regression analyses revealed that the living donor, direct bilirubin, and neutrophil counts were significantly associated with BK virus activation. The logistic regression model displayed a modest discriminability with the area under the receiver operating characteristic curve of 0.689 (95% CI: 0.607–0.771; P < 0.01) and also demonstrated a good performance in the external validation dataset (the area under the receiver operating characteristic curve was 0.699, 95% CI: 0.5899–0.8081). The novel predictive nomogram achieved a good prediction of BK virus activation in kidney transplant recipients.

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-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.

Post-allogeneic hematopoietic stem cell transplantation viral reactivations and viremias: a focused review on human herpesvirus-6, BK virus and adenovirus

Human cytomegalovirus and Epstein-Barr virus have been recognized as potential drivers of morbidity and mortality of patients undergoing allogeneic stem cell transplantation for years. Specific protocols for monitoring, prophylaxis and pre-emptive therapy are in place in many transplant settings. In this review, we focus on the next three most frequent viruses, human herpesvirus-6, BK virus and adenovirus, causing reactivation and/or viremia after allogeneic transplant, which are increasingly detected in patients in the post-transplant period owing to emerging techniques of molecular biology, recipients' characteristics, treatment modalities used for conditioning and factors related donors or stem cell source. Given the less frequent detection of an illness related to these viruses, there are often no specific protocols in place for the management of affected patients. While some patients develop significant morbidity (generally older), others may not need therapy at all (generally younger or children). Furthermore, some of the antiviral therapies used are potentially toxic. With the addition of increased risk of secondary infections, risk of graft failure or increased risk of graft-versus-host disease as well as the relationship with other post-transplant complications, the outcomes of patients with these viremias remain unsatisfactory and even long-term survivors experience increased morbidity.

Virus-specific T-cell therapy to treat BK polyomavirus infection in bone marrow and solid organ transplant recipients

BK polyomavirus (BKPyV) infection is a major complication of hematopoietic stem cell transplant (HSCT) and solid organ transplant (SOT). Treatment options are limited, poorly effective, and have significant toxicities. Cellular therapy using T cells directed against BKPyV is an emerging therapy, and we report efficacy in controlling BKPyV-associated disease in highly immunocompromised patients. Virus-specific T cells (VSTs) against BKPyV were manufactured using either blood from the patient's stem cell donor (donor-derived VSTs) or from unrelated donors (third-party VSTs). VSTs were used to treat BKPyV in 38 HSCT recipients and 3 SOT recipients between June 2017 and December 2019. Overall response rate was 86% in patients treated for BK viremia, 100% in patients treated for hemorrhagic cystitis, and 87% in patients treated for both BK viremia and hemorrhagic cystitis. No infusional toxicity, de novo graft-versus-host disease, or rejection of the organ occurred attributable to the VST infusion. BKPyV-specific immune responses were demonstrated by interferon-γ production by peripheral blood mononuclear cells postinfusion in response to BKPyV antigens. VSTs are a safe and potentially effective strategy to treat BKPyV and associated symptoms in recipients of HSCT and SOT. Cellular therapy should be considered for all patients with BKPyV and underlying immune suppression at risk of complications. This trial was registered at www.clinicaltrials.gov as #NCT02532452.

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.

The Natural History of BK Polyomavirus and the Host Immune Response After Stem Cell Transplantation

BACKGROUND

BK polyomavirus (BKPyV) is associated with symptomatic hemorrhagic cystitis after hematopoietic cell transplantation (HCT). Little is known about the host immune response, effectiveness of antiviral treatment, or impact of asymptomatic replication on long-term kidney function.

METHODS

In children and young adults undergoing allogeneic HCT, we quantified BKPyV viruria and viremia (pre-HCT and at Months 1-4, 8, 12, and 24 post-HCT) and tested associations of peak viremia ≥10 000 or viruria ≥109 copies/mL with estimated kidney function (glomerular filtration rate, eGFR) and overall survival at 2 years posttransplant. We examined the factors associated with viral clearance by Month 4, including BKPyV-specific T cells by enzyme-linked immune absorbent spot at Month 3 and cidofovir use.

RESULTS

We prospectively enrolled 193 participants (median age 10 years) and found that 18% had viremia ≥10 000 copies/mL and 45% had viruria ≥109 copies/mL in the first 3 months post-HCT. Among the 147 participants without cystitis (asymptomatic), 58 (40%) had any viremia. In the entire cohort and asymptomatic subset, having viremia ≥10 000 copies/mL was associated with a lower creatinine/cystatin C eGFR at 2 years post-HCT. Viremia ≥10 000 copies/mL was associated with a higher risk of death (adjusted hazard ratio, 2.2; 95% confidence interval, 1.1-4.2). Clearing viremia was associated with detectable BKPyV-specific T cells and having viremia <10 000 copies/mL, but not cidofovir exposure.

CONCLUSIONS

Screening for BKPyV viremia after HCT identifies asymptomatic patients at risk for kidney disease and reduced survival. These data suggest potential changes to clinical practice, including prospective monitoring for BKPyV viremia to test virus-specific T cells to prevent or treat BKPyV replication.

Incidence of BKV in the urine and blood samples of pediatric patients undergoing HSCT

The aims were to investigate the incidence of BKV infection and the presence of HC in pediatric patients undergoing HSCT. Twenty-four children patients (M/F: 17/7) undergoing HSCT in a single center over a period of 1 year were included in the study. The presence of BKV DNA was determined by quantitative real-time PCR in plasma and urine samples at the following times: before transplantation, twice a week until engraftment time, and weekly for + 100 days. The mean age of the patients was 7.79 ± 5.03 years, the mean follow-up time was 95.6 ± 25.9 days, and the average number of samples per patient was 15.8 ± 3.2. BKV DNA was detected in at least one urine sample in 91.6% (n: 22) and at least one plasma sample in 75% (n:18) of the patients. The median time to the first BKV DNA positivity in urine and plasma samples was 11 (range: 1-80) and 32 days (range: 2-79), respectively. The median value of BKV DNA copies in urine and plasma were 1.7 × 10⁶ (range: 2.8 × 10¹ -1.2 × 10¹⁴ ) and 1.9 × 10³ copies/mL (range: 3-2.1 × 10⁶ ), respectively. Thirteen patients (54.2%) had hematuria with BKV viruria; 8 (33.3%) patients had viremia. The median value of the BKV DNA copies in urine and plasma was 4.4 × 10⁷ (range: 65-1 × 10¹¹ ) and 2.9 × 10³ (range: 7-7.8 × 10⁴ ) copies/mL in these patients. Two (15.4%) of the 13 patients with BKV viruria and hematuria were diagnosed with BKV-related HC. BKV DNA viral load monitoring of urine and plasma in pediatric HSCT patients with a high risk for viral infections is valuable for understanding the development of BKV-related HC.

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 Infections in Pediatric Patients with Hematopoietic Stem Cell Transplantation

Aim: BK virus (BKV)-associated hemorrhagic cystitis (HC) is a common complication in patients after hematopoietic stem cell transplantation (HSCT). The aim of this study was to investigate the incidence of BKV infection in pediatric patients receiving HSCT. Material and Methods: Total of 51 patients aged between 16 months and 16 years old and followed up between October 2015 and September 2017 were included in the study. The patients were monitored by quantitative real-time polymerase chain reaction (Anatolia Geneworks, Turkey) test for the detection of BKV DNA in urine and blood. Results: Of patients, 46 received allogeneic HSCT and 5 autologous HSCT. BKV DNA positivity was detected in urine and/or blood of total 27 (52.9%) patients in whom 26 (56.5%) of 46 patients with allogeneic transplantation, and 1 (20.0%) of 5 patients with autologous transplantation. BKV viral load in urine >107 copies/ml required for preemptive treatment was detected in 12 (26.1%) of 46 patients received allogeneic HSCT. The development of HC was prevented in 9 (75.0%) of the 12 patients given preemptive treatment, while 3 (25.0%) cases developed HC and cured by treatment. BKV viruria was detected >109 copies/ml in two weeks before the onset of HC and was accepted as a prognostic indicator for predictive diagnosis of HC. BKV viremia was found >104 copies/ml in 1 patient within two weeks before the onset of cystitis. Conclusion: Screening for BKV infection, especially BKV viruria in HSCT patients, is recommended for the predictive diagnosis of HC in patients at high risk.

Development and validation of a risk assessment tool for BKPyV Replication in allogeneic stem cell transplant recipients

BACKGROUND

BK polymavirus (BKPyV), a member of the family Polyomaviridae, is associated with increased morbidity and mortality in allogeneic stem cell transplant recipients.

METHODS

In our previous retrospective study of 2477 stem cell transplant patients, BKPyV replication independently predicted chronic kidney disease and poor survival. In this study, using the same cohort, we derived and validated a risk grading system to identify patients at risk of BKPyV replication after transplantation in a user-friendly modality. We used 3 baseline variables (conditioning regimen, HLA match status, and underlying cancer diagnosis) that significantly predicted BKPyV replication in our initial study in a subdistribution hazard model with death as a competing risk. We also developed a nomogram of the hazard model as a visual aid. The AUC of the ROC of the risk-score-only model was 0.65. We further stratified the patients on the basis of risk score into low-, moderate-, and high-risk groups.

RESULTS

The total risk score was significantly associated with BKPyV replication (P < .0001). At 30 days after transplantation, the low-risk (score ≤ 0) patients had a 9% chance of developing symptomatic BKPyV replication, while the high-risk (score ≥ 8) of the population had 56% of developing BKPyV replication. We validated the risk score using a separate cohort of 1478 patients. The AUC of the ROC of the risk-score-only model was 0.59. Both the total risk score and 3-level risk variable were significantly associated with BKPyV replication in this cohort (P < .0001).

CONCLUSIONS

This grading system for the risk of symptomatic BKPyV replication may help in early monitoring and intervention to prevent BKPyV-associated morbidity, mortality, and kidney function decline.

Beyond Cytomegalovirus and Epstein-Barr Virus: a Review of Viruses Composing the Blood Virome of Solid Organ Transplant and Hematopoietic Stem Cell Transplant Recipients

Viral primary infections and reactivations are common complications in patients after solid organ transplantation (SOT) and hematopoietic stem cell transplantation (HSCT) and are associated with high morbidity and mortality. Among these patients, viral infections are frequently associated with viremia. Beyond the usual well-known viruses that are part of the routine clinical management of transplant recipients, numerous other viral signatures or genomes can be identified in the blood of these patients. The identification of novel viral species and variants by metagenomic next-generation sequencing has opened up a new field of investigation and new paradigms. Thus, there is a need to thoroughly describe the state of knowledge in this field with a review of all viral infections that should be scrutinized in high-risk populations. Here, we review the eukaryotic DNA and RNA viruses identified in blood, plasma, or serum samples of pediatric and adult SOT/HSCT recipients and the prevalence of their detection, with a particular focus on recently identified viruses and those for which their potential association with disease remains to be investigated, such as members of the Polyomaviridae, Anelloviridae, Flaviviridae, and Astroviridae families. Current knowledge of the clinical significance of these viral infections with associated viremia among transplant recipients is also discussed. To ensure a comprehensive description in these two populations, individuals described as healthy (mostly blood donors) are considered for comparative purposes. The list of viruses that should be on the clinicians' radar is certainly incomplete and will expand, but the challenge is to identify those of possible clinical significance.

A case-control study to assess the role of polyomavirus in transplant complications: Where do we stand?

PURPOSE

The study's aim was to assess whether polyomavirus DNAemia screening was associated with different outcomes in patients with positive viremia compared with negative viremia.

METHODS

Case-control retrospective study of patients with polyomavirus DNAemia (viremia > 1000 copies/mL) matched 1:1 with controls. Control group consists of the patient who received a transplant immediately before or after each identified case and did have nil viremia.

FINDING

Ultimately, 120 cases of BK polyomavirus (BKPyV) were detected and matched with 130 controls. Of these, 54 were adult kidney transplant recipients (KTRs), 43 were pediatric KTRs, and 23 were undergoing hemato-oncologic therapy, of which 20 were undergoing hematopoietic stem cell transplantation. The odds ratio (OR) for overall risk of poorer outcomes in cases versus controls was 16.07 (95% CI: 5.55-46.54). The unfavorable outcome of switching the immunosuppressive drug (ISD) (14/40,35%) was no different from that of those treated with reduced ISD doses (31/71, 43.6%, P = .250). Acute rejection or graft-versus-host disease, previous transplant, and intensity of immunosuppression (4 ISDs plus induction or conditioning) were risk factors for BKPyV-DNAemia (OR: 13.96, 95% CI: 11.25-15.18, P < .001; OR: 6.14, 95% CI: 3.91-8.80, P < .001; OR: 5.53, 95% CI: 3.37-7.30, P < .001, respectively).

CONCLUSIONS

Despite viremia screening, dose reduction, and change in therapeutic protocol, patients with positive BKPyV-DNAemia present poorer outcomes and unfavorable results.

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.

Viral infections and immune reconstitution interaction after pediatric allogenic hematopoietic stem cell transplantation

Background: Viral infections are a major cause of morbidity and mortality after hematopoietic stem cell transplantation (HSCT). Although immune suppression plays a central role, the literature shows conflicting results on interplay between post-transplant immune reconstitution (IR) and viral infections. Methods: We prospectively studied viral infections and IR in 30 pediatric patients undergoing allogenic HSCT, with a follow-up time of 24 months. In total, 1337 blood (CMV, EBV, HHV-6, ADV and BKV) and urine (BKV and JCV) virus samples were analyzed. IR including B-cells (CD19+), T cells (CD3+, CD4+, CD8+) and NK-cells were measured. Clinical outcomes included overall survival (OS), non-relapse mortality (NRM), graft-versus-host disease (GVHD) and occurrence of blood culture positive bacterial infections. Results: We found BKV reactivation to be most frequent, 47% of the children had viremia and 77% viruria. The frequencies of CMV, HHV-6 and adeno viremia were 37%, 37% and 6%, respectively. Viremias beyond 3 months post-HSCT were uncommon. Factors such as GVHD, use of steroids, EBV and CMV infections and pre-transplant irradiation affected IR. No specific viral infection or IR related factor was associated to OS or NRM. Conclusions: Viral infections and IR interact in a bi-directional manner. Accordingly, close follow-up of both IR and viral loads is warranted.

Infections with DNA Viruses, Adenovirus, Polyomaviruses, and Parvovirus B19 in Hematopoietic Stem Cell Transplant Recipients and Patients with Hematologic Malignancies

Infections due to adenovirus, polyomaviruses (BK and JC viruses), and parvovirus B19 may not be as common as infections due to other DNA viruses, such as cytomegalovirus in patients with hematological malignancies and the recipients of hematopoietic stem cell transplantation. However, these infections may result in life-threatening diseases that significantly impact patients' recovery, morbidity, and mortality. Treating physicians should be aware of the diseases associated with these viruses, the patient populations at increased risk for complications due to these infections, and the available diagnostic and therapeutic approaches.

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.

Infectious complications after hematopoietic stem cell transplantation: current status and future perspectives in Korea

Hematopoietic stem cell transplantation (HSCT) is a treatment for hematologic malignancies, immune deficiencies, or genetic diseases, ect. Recently, the number of HSCTs performed in Korea has increased and the outcomes have improved. However, infectious complications account for most of the morbidity and mortality after HSCT. Post-HSCT infectious complications are usually classified according to the time after HSCT: pre-engraftment, immediate post-engraftment, and late post-engraftment period. In addition, the types and risk factors of infectious complications differ according to the stem cell source, donor type, conditioning intensity, region, prophylaxis strategy, and comorbidities, such as graft-versushost disease and invasive fungal infection. In this review, we summarize infectious complications after HSCT, focusing on the Korean perspectives.

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.

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.

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.