BK virus-hemorrhagic cystitis following allogeneic stem cell transplantation: Clinical characteristics and utility of leflunomide treatment

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.

Decreased lymphocyte count before conditioning is associated with BK virus-associated hemorrhagic cystitis after allogeneic hematopoietic stem cell transplantation

BACKGROUND

BK virus-associated hemorrhagic cystitis (BKV-HC) is a serious complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). It can cause morbidity and may increase treatment-related mortality. Previous studies showed that the occurrence of BKV-HC was related to various factors. However, there are still many controversial factors. It is not clear whether BKV-HC will affect the long-term prognosis of patients.

OBJECTIVE

We aimed to identify risk factors for BKV-HC after allo-HSCT and evaluate the effect of BKV-HC on overall survival (OS) and progression- free survival (PFS) of patients.

STUDY DESIGN

We retrospectively analyzed the clinical data of 93 patients who underwent allo-HSCT. Univariate and multivariate analysis were used to identify risk factors for BKV-HC. The Kaplan-Meier method was used to estimate OS and PFS. A difference was considered statistically significant if P < 0.05.

RESULTS

A total of 24 patients developed BKV-HC. The median occurrence time of BKV-HC was 30 (range:8-89) days after transplantation, and the median duration was 25.5 (range:6-50) days. Multivariate logistic regression analysis indicated that peripheral blood lymphocyte count <1 × 10⁹/L before conditioning (OR = 4.705, P = 0.007) and haploidentical transplantation (OR = 13.161, P = 0.018) were independent risk factors for BKV-HC. The 3-year OS rate was 85.9% (95%CI:62.1%-95.2%) in the BKV-HC group and 73.1% (95%CI: 58.2%-88.0%) in the non-BKV-HC group. There was no significant difference between the two groups (P = 0.516). The 3-year PFS rate was 76.3% (95%CI: 57.9%-94.7%) in the BKV-HC group and 58.1% (95%CI: 39.5%-76.7%) in the non-BKV-HC group. There was no significant difference in the two groups (P = 0.459). The severity of BKV-HC was not related to the OS and PFS of the patients (P value was 0.816 and 0.501, respectively).

CONCLUSION

Haploidentical transplantation and decreased peripheral blood lymphocyte count before conditioning increased the risk of BKV-HC after allo-HSCT. The occurrence of BKV-HC after allo-HSCT and the severity of which did not affect OS and PFS of the patients.

Antivirals against human polyomaviruses: Leaving no stone unturned

Human polyomaviruses (HPyVs) encompass more than 10 species infecting 30%-90% of the human population without significant illness. Proven HPyV diseases with documented histopathology affect primarily immunocompromised hosts with manifestations in brain, skin and renourinary tract such as polyomavirus-associated nephropathy (PyVAN), polyomavirus-associated haemorrhagic cystitis (PyVHC), polyomavirus-associated urothelial cancer (PyVUC), progressive multifocal leukoencephalopathy (PML), Merkel cell carcinoma (MCC), Trichodysplasia spinulosa (TS) and pruritic hyperproliferative keratinopathy. Although virus-specific immune control is the eventual goal of therapy and lasting cure, antiviral treatments are urgently needed in order to reduce or prevent HPyV diseases and thereby bridging the time needed to establish virus-specific immunity. However, the small dsDNA genome of only 5 kb of the non-enveloped HPyVs only encodes 5-7 viral proteins. Thus, HPyV replication relies heavily on host cell factors, thereby limiting both, number and type of specific virus-encoded antiviral targets. Lack of cost-effective high-throughput screening systems and relevant small animal models complicates the preclinical development. Current clinical studies are limited by small case numbers, poorly efficacious compounds and absence of proper randomized trial design. Here, we review preclinical and clinical studies that evaluated small molecules with presumed antiviral activity against HPyVs and provide an outlook regarding potential new antiviral strategies.

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.

Treatment protocols for BK virus associated hemorrhagic cystitis after hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) represents a vital curative choice for many disease. However its outcome can be hampered by a variety of transplant associated complications. Hemorrhagic cystitis (HC) considered as one of the major difficulties after HSCT. HC symptoms comprise hematuria, dysuria, burning during urination, urinary frequency, urgency and incontinency, abdominal or suprapubic pain, urinary obstruction, and renal or bladder damage. There are a lot of causes for HC development. BK virus reactivation is one of the major causes of HC after HSCT. There is still no standard and approved treatment protocol for BK virus associated HC (BKV-HC). Treatment of HC is according to the local standard operating procedures, depending on the cause and severity. In this study we will review the current treatments available for this disease. We have divided the therapeutic procedures into 5 categories including conservative therapy, complimentary options, surgical procedures, pharmacological treatments and adoptive cell therapy. We believe that comparing the advantages and disadvantages of different therapies make it easier to choose the best treatment protocol. In addition, we had a greater focus on adoptive cell therapy, because it is a relatively new introduced method and might be a logical alternative to conventional treatments for refractory patients. In total, no definitive recommendation is possible for current available treatments because these procedures have only been utilized sporadically in a limit number of patients. Furthermore, a number of treatment options are only experimental and definitely need more effort.

Pathogenicity of BK virus on the urinary system

Introduction

The polyomaviruses are omnipresent in nature. The major sites of BK virus appearance are the kidney tubular epithelial cells and urinary bladder surface transitional cells.

Material and methods

A literature search according to PRISMA guidelines within the Medline database was conducted in July 2019 for articles presenting data about BK virus in urologic aspect without setting time limits, using the terms ‘BK virus’ in conjunction with transplantation, nephropathy, stenosis, cancer, bladder, prostate, kidney.

Results

The BK virus usually stays latent, however, its replication may become active in various clinical situations of impaired immunocompetence such as solid organ transplantation, bone marrow transplantation, AIDS, pregnancy, multiple sclerosis, administration of chemotherapy or biologic therapy. BK virus is associated with two main complications after transplantation: polyomavirus-associated nephropathy in kidney transplant patients and polyomavirus-associated hemorrhagic cystitis in allogeneic hematopoietic stem cell transplant patients.

Conclusions

The aim of this article was to present available data on urologic aspects of BK virus infection, its detection methods and available treatment.