Prevalence and Distribution of BK virus Subtypes in Renal Transplant Recipients Referred to Golestan Hospital in Ahvaz, Iran

The effect of BK polyomavirus large T antigen on CD4 and CD8 T cells in kidney transplant recipients

Human BK polyomavirus (BKPyV) can affect the machinery of the host cell to induce optimal viral replication or transform them into tumor cells. Reactivation of BKPyV happens due to immunosuppression therapies following renal transplantation which might result in BK polyomavirus nephropathy (BKPyVAN) and allograft loss. The first protein that expresses after entering into host cells and has an important role in pathogenicity is the Large T antigen (LT-Ag). In this review tries to study the molecular and cellular inter-regulatory counteractions especially between CD4 and CD8 T cells, and BKPyV LT-Ag may have role in nephropathy after renal transplantation.

Higher Viral Load of Polyomavirus Type BK but not JC among Renal Transplant Recipients in Comparison to Donors

Background & Objective:

Polyomaviruses types BK and JC and Cytomegalovirus (CMV) have been shown to be related to kidney transplantation complications. This study aimed to assess the prevalence of these viruses in patients receiving kidney transplantation.

Methods:

This cross-sectional study was performed on 40 kidney transplant recipients and 44 donors. Urine samples were used for the extraction of viral DNA. The prevalence of JC and BK viruses and their viral loads were determined by real-time polymerase chain reaction.

Results:

JC and BK viruses were identified in 31% and 92.3% of all subjects, respectively. The frequency of JC and BK cases was not statistically different between the recipient and donor groups (P>0.05). All patients in the donor group and 96.8% of the recipients were positive for CMV IgG antibody. The mean viral load of BK in donors and recipients was 4.5×10¹⁰ and 3.3×10¹¹ copies, respectively. The mean viral load of JC was 8.6×10⁷ copies in donors and 2.9×10⁸ copies in recipients. The distribution of BKV was significantly higher in recipients than donors (P=0.001), while no difference was observed between the two studied groups for JCV.

Conclusion:

This study showed a relatively high prevalence of BK and JC viruria in both renal transplant donors and recipients. The viral load for BKV, but not JCV, was higher in recipients than in donors.

Prevalence of Human Polyomavirus BK Virus in Prostate Cancer Patients and Benign Prostatic Hyperplasia: A Cross-sectional Study on Prostate Patients Referred to Imam Khomeini Hospital in Ahvaz Between 2015 and 2017

Background: Human polyomavirus BK virus (BKV) belongs to the Polyomaviridae family and seems to be a drastic virus in prostate cancer (PCa) etiology. BK virus induces oncogenesis via the expression of large tumor antigen (LTAg) and small tumor antigen (stAg). Also, BKV infection seems to play an essential role in prostate cancer development. Objectives: In this study was aimed to study the prevalence of BKV in benign and cancerous prostate tissues. Methods: In this study, 100 formalin-fixed paraffin-embedded tissues of PCa specimens and benign prostatic hyperplasia (BPH) were collected. The DNA was extracted from tissue samples, and the BKV DNA was investigated using a semi-nested polymerase chain reaction (PCR). The MEGA 6.0 software was used for phylogenetic analysis to assemble the viral genome. A phylogenetic tree was constructed by neighbor-joining analysis with 1,000 replicates of the bootstrap resampling test. Results: The BKV DNA was found in 66% (33/50) of patients with PCa and 36% (18/50) of patients with benign prostatic hyperplasia (BPH) (P = 0.003). The frequency of BKV DNA in different classes of Gleason score (5 - 10) was not significant (0.094). The distribution of BKV DNA among different age groups was not significant (P = 0.086). Conclusions: High frequency of BKV infection was detected in patients with PCa compared to patients with BPH (P = 0.003), and the coexistence of BKV DNA was confirmed in 51% (51/100) of tissue samples, which were confirmed to be subtype 1 of BKV infection.

CC and CXC chemokines play key roles in the development of polyomaviruses related pathological conditions

It has been reported that polyomaviruses are the microbes which can be a cause of several human pathological conditions including cancers, nephropathy, progressive multifocal leukoencephalopathy and gynaecological disease. Although investigators proposed some mechanisms used by the viruses to induce the disorders, the roles played by chemokines in the pathogenesis of polyomaviruses infections are yet to be clarified. This review article investigated recent studies regarding the roles played by chemokines in the pathogenesis of the polyomaviruses infections. The research in the literature revealed that CXC chemokines, including CXCL1, CXCL5, CXCL8, CXCL9, CXCL10, CXCL11, CXCL12 and CXCL16, significantly participate in the pathogenesis of polyomaviruses. CC chemokines, such as CCL2, CCL5 and CCL20 also participate in the induction of the pathological conditions. Therefore, it appears that CXC chemokines may be considered as the strategic factors involved in the pathogenesis of polyomaviruses.

Viruria of Human BK Virus and John Cunningham Virus among Renal Transplant Recipients and Healthy Control in Southeast of Caspian Sea

BACKGROUND

Members of the Polyomaviridae family, BK virus (BKV), and John Cunningham virus (JCV) are linked to polyomavirus-associated nephropathy-associated transplant rejection in immunodeficient patients.

OBJECTIVE

The aim of the study was to evaluate the prevalence of BKV and JCV in immunocompetent individuals in the north of Iran.

METHODS

Ninety-one urine samples were obtained from renal transplant recipients with a mean age of 39.78 ± 11.19 years. A healthy control group of 65 volunteers with an average age of 40.32 ± 10.7 years also contributed. After DNA extraction, positive cases were detected through PCR. Genotyping was done by alignment and phylogenetic tree construction of the VP1 region against all known JCV and BKV genotypes.

RESULTS

The prevalence of BKV and JCV was 15.38 and 19.78%, respectively. JCV was detected in 7.69% of the control group. The prevalence of the BKV between the case and control groups was significant (p < 0.0001). There was no significant association between BKV and JCV and duration of dialysis (p > 0.05). Overall, 62.16% of JCV cases were genotype I. Besides, genotype II was dominant within patients with BKV-positive patients.

DISCUSSION

The results obtained here show a relatively lower prevalence of BKV and JCV in immunocompromised renal transplant receivers and healthy control than those reported from other areas in Iran. JCV genotyping was evaluated for the first time in Iran. Genotype I for JCV and genotype II for BKV were dominant genotypes in the north of Iran.

Survey of BK Virus in Renal Transplant Recipients in Iran: A Systematic Review and Meta-Analysis

INTRODUCTION

BK virus (BKV) infection in renal transplant (RT) recipients can cause hemorrhagic cystitis, transient renal dysfunction, and BKV nephropathy (BKVN). The prevalence and significance of BKV in RT recipients remain to be clarified in the Iranian population. The purpose of this review is to summarize the overall prevalence of BKV infection in RT recipients from previously published studies in Iran.

METHODS

We systematically reviewed articles through a comprehensive search of the main electronic and Persian national databases up to November 2019.

RESULTS

The overall pooled prevalence of BKV infection among the Iranian population was 23% (95% CI; 15-33%). Comparing these studies revealed that the prevalence of BKV in plasma samples ranges from 3 to 40%, in renal biopsies 1-13%, and in urine samples 10-49%. Due to substantial heterogeneity among reported studies (I2 = 93%, p < 0.01), random-effect meta-analysis was performed. BKV infection rate was slightly higher in women than men (16%, p = 0.04 vs. 14%, p < 0.01, respectively). The majority of the studies employed real-time PCR (24%, I2 = 93, p < 0.01) and analyzed plasma samples alone or in combination with other types of specimens. BKV prevalence from 5 cities among the Iranian population showed a higher prevalence rate in Guilan.

CONCLUSION

Our analysis provides a preliminary estimate of the epidemiology of BKV infection in RT recipients in Iran. These results arouse a need for more epidemiological studies of BKV infection in different unanalyzed regions in Iran. Early detection of BKV in RT recipients helps timely nephropathy diagnosis and prevents graft loss.

Human BK and JC polyomaviruses: Molecular insights and prevalence in Asia

Polyomaviridae family consists of small circular dsDNA viruses. Out of the 14 human polyomaviruses described so far, BKPyV and JCPyV have been studied extensively since their discovery in 1971. Reportedly, both BKPyV and JCPyV are widely distributed across the globe with the frequency of 80-90 % in different populations. The primary infection of these viruses is usually asymptomatic and latent which is activated as a consequence of immunosuppression. Activated BKPyV and JCPyV viruses lead to the development of BK Virus Associated Nephropathy and Progressive Multifocal Leukoencephalopathy, respectively. Immense progress has been made during the last few decades regarding the molecular understanding of polyomaviruses. Epidemiology of polyomaviruses has also been studied extensively. However, most of the epidemiological studies have focused on European and American populations. Therefore, limited data is available regarding the geographical distribution of these potentially oncogenic viruses in Asian countries. In this article, we have presented a compendium of latest advances in the molecular understanding of polyomaviruses and their pathobiology. We also present a comprehensive review of published literature regarding the epidemiology and prevalence of BKPyV and JCPyV in Asian regions. For this purpose, a thorough search of available online resources was performed. As a result, we retrieved 24 studies for BKPyV and 22 studies for JCPyV, that describe their prevalence in Asia. These studies unanimously report high occurrence of both BKPyV and JCPyV in Asian populations. The available data from these studies was categorized into two groups: on the basis of prevalence (low, medium and high) and disease development (healthy and diseased). Altogether, Korean population hasbeen evidenced to possess highest frequency of BKPyV (66.7 %), while JCPyV was found to be most prevalent in Taiwan (88 %). Due to high and ubiquitous distribution of these viruses, frequent studies are required to develop a better understanding regarding the epidemiology and pathobiology of these viruses in Asia.

BK polyomavirus genotypes in renal transplant recipients in the United States: A meta-analysis

BACKGROUND

In the United States, increasing ethnic diversity has been apparent. However, the epidemiology and trends of BKV genotypes remain unclear. This meta-analysis was conducted with the aim to assess the prevalence of BKV genotypes among kidney transplant (KTx) recipients in the United States.

METHODS

A comprehensive literature review was conducted through October 2018 utilizing MEDLINE, Embase, and Cochrane Database to identify studies that reported the prevalence of BKV subtypes and/or subgroups in KTx recipients in the United States. Pooled prevalence rates were combined using random effects, generic inverse variance method. The protocol for this study is registered with PROSPERO (no. CRD42019134582).

RESULTS

A total of eight observational studies with a total of 193 samples (urine, blood, and kidney tissues) from 188 BKV-infected KTX recipients were enrolled. Overall, the pooled estimated prevalence rates of BKV subtypes were 72.2% (95% confidence of interval [CI]: 62.7-80.0%) for subtype I, 6.8% (95% CI: 2.5-16.9%) for subtype II, 8.3% (95% CI: 4.4-15.1%) for subtype III, and 16.1% (95% CI: 10.4-24.2%) for subtype IV, respectively. While metaregression analysis demonstrated a significant positive correlation between year of study and the prevalence of BKV subtype I (slopes = +0.1023, P = .01), there were no significant correlations between year of study and percentages of BKV subtype II-IV (P > .05). Among KTx recipients with BKV subtype I, the pooled estimated percentages of BKV subgroups were 22.4% (95% CI: 13.7-34.5%) for subgroup Ia, 30.6% (95% CI: 17.7-47.5%) for subgroup Ib1, 47.7% (95% CI: 35.8-59.9%) for subgroup Ib2, and 4.1% (95% CI:1.2-13.3%) for subgroup Ic, respectively.

CONCLUSION

BKV subtype I is the most prevalent subtype among KTx recipients in the United States and its prevalence seems to increasing overtime. Subgroup Ib2 is the most common subgroup among BKV subtype I.

A correlation study of BK Polyoma Virus infection and prostate Cancer among Sudanese patients - immunofluorescence and molecular based case-control study

Background

Polyomavirus hominis1, also called BK virus (BKV) is a well-known etiological agent of renal transplant nephropathy and cystitis. Recently, it got great attention from the researcher as a principal predisposing factor for different kinds of cancers including prostate cancer (PCa). Thus, this study aims to determine the correlation between BKV infection and PCa through a descriptive case-control based study.

Methods

A total of 55 paraffin-embedded tissue blocks of patients with PCa and another 55 tissue blocks from BPH patients were obtained. In parallel, respective urine samples were collected from all the cases and controls. The existence of BKV large T antigen (LTAg) was analyzed by Direct Immunofluorescence assay. Only BKV LTAg positive specimens were further analyzed for the presence of viral DNA by using a conventional PCR then subjected to viral load quantitation by using Q-PCR.

Result

BKV LTAg was identified in 30% (17/55) of cases tissue specimens and only in 7% (4/55) of the controls tissue specimens with P-value 0.002 and Odd ratio 5.7. The conventional PCR detects the BKV DNA in 16 out of 17 cases specimens while only two out of four controls specimens were identified with a viral DNA. The mean of the BKV DNA load was higher significantly among cases 6733 ± 6745 copies/ml when compared to controls 509.0 ± 792.9 copies/m with a p-value of 0.002.

Conclusion

More BKV prevalence with high viral load was observed in PCa patients tissue compared to BPH specimens. PCa Gleason scores 9 and 7 were the most cancer grades identified with the presence of BKV DNA. Our findings are thus consistent with a significant link between the BKV infection and the PCa risk. Prostate or seminal fluids should be selected as principal specimens for future studies and can, therefore, be designated as screening samples to find early virus evidence in the prostate tissue. Detection of early virus evidence may help to reduce the risk of PCa cancer due to BKV.

BK virus characterisation among HIV-1-Infected individuals and its association with immunosuppression

Purpose

BK virus (BKV) is an opportunistic pathogen which causes significant morbidity and mortality in individuals who are immunodeficient. We aimed to quantitate and characterise BKV and to correlate with the degree of immunosuppression among human immunodeficiency virus (HIV)-1-infected individuals.

Methods

BKV DNA detection was carried out using an in-house quantitative real-time polymerase chain reaction on paired whole-blood and urine samples collected from 187 antiretroviral therapy (ART)-naïve HIV-1-infected individuals and 93 healthy individuals who served as controls. Sequencing was performed for a proportion of high BK viral load (VL) samples to observe non-coding control region (NCCR) rearrangements.

Results

BKV positivity in urine was 25.6% among HIV-infected individuals and 10.7% in control individuals (P = 0.03). The BK VL showed a significant negative correlation with CD4+ T-cell counts, a positive correlation with WHO clinical staging and no significant correlation with HIV-1 VL. Of 42 BKVs from urine samples sequenced, two showed rearrangements without clinically severe disease or high VL. Their NCCR and VP1 sequence-based genotyping revealed genotype I. In a small subset of individuals (n = 8) on ART who were being followed up, six individuals showed either decrease or complete clearance of virus with ART.

Conclusion

There was a higher frequency of BK viruria in HIV-1-infected individuals than among healthy controls and the positivity correlated with the degree of immunosuppression. There was no association of high VL with NCCR rearrangements in urine.

Tumor growth factor-β is an important factor for immunosuppression and tumorgenesis in Polyoma BK virus infection; a systematic review article

Polyoma BK virus (PBK) is a prevalent human specific virus and the cause of several malignancies in human. The main mechanisms used by PBK to induce/stimulate human cancers are yet to be clarified but it has been proposed that PBK may use several mechanisms to induce/stimulate cancers in human including attenuation of immune responses via up-regulation of immunosuppressor molecules. Transforming growth factor beta (TGF-β) is a key multifunctional factor from modulation of immunosurveillance to angiogenesis. The key roles of TGF-β in the progression of Th17 and T regulatory subsets, the most important immune cells involved in development of cancers, have been demonstrated. Thus, this review article aims to describe the mechanisms used by PBK in induction/stimulation of human cancers in TGF-β dependent manner..

IL-2 and polyoma BK virus infection; A systematic review article

It has been demonstrated that IL-2 plays a dual role in induction/suppression of immune responses via activation of conventional and regulatory T lymphocytes, respectively. IL-2 contacts complete IL-2 receptor (IL-2R) which contains CD25 (α chain) on the antigen specific activated T helper and cytotoxic lymphocytes and also T regulatory cells. Additionally, previous investigations revealed that polyoma BK virus (PBK) reactivation and induction of PBK associated nephropathy (PBKAN) is a main complication following renal transplantation. Based on the important dual roles played by IL-2 in the immune responses, it may be hypothesized that IL-2/IL-2R interaction could be considered a potential mechanism against/toward PBK reactivation and also PBKAN. Accordingly, the aim of the current review article is to determine the roles of IL-2 IL-2/IL-2R interaction in PBK reactivation and PBKAN complications.

Innate Immunity and BK Virus: Prospective Strategies

Recent information demonstrated that BK virus reactivation is a dominant complication after kidney transplantation, which occurs because of immunosuppression. BK virus reactivation is the main reason of transplanted kidney losing. Immune response against BK virus is the major inhibitor of the virus reactivation. Therefore, improving our knowledge regarding the main parameters that fight against BK viruses can shed light on to direct new treatment strategies to suppress BK infection. Innate immunity consists of numerous cell systems and also soluble molecules, which not only suppress virus replication, but also activate adaptive immunity to eradicate the infection. Additionally, it appears that immune responses against reactivated BK virus are the main reasons for induction of BK virus-associated nephropathy (BKAN). Thus, improving our knowledge regarding the parameters and detailed mechanisms of innate immunity and also the status of innate immunity of the patients with BK virus reactivation and its complications can introduce new prospective strategies to either prevent or as therapy of the complication. Therefore, this review was aimed to collate the most recent data regarding the roles played by innate immunity against BK virus and also the status of innate immunity in the patients with reactivation BK virus and BKAN.

BK Viremia among Iranian Renal Transplant Candidates

BACKGROUND

Primary infection with BK virus (BKV) is occurred during childhood and usually asymptomatic, but after initial infection, BKV may persist lifelong in the kidney and genitourinary tract. Reactivation may occur in individuals with compromised immunity such as renal transplant recipients. Due to the role of BKV in BK virus-associated nephropathy (BKVAN) and potentially renal allograft rejection, the detection of BKV in renal transplant candidates is very important. The aim of this study was to evaluate the frequency of BK viremia in end stage renal disease cases who were candidates for renal transplantation.

METHODS

In this cross-sectional study, 50 cases with end stage renal disease who were candidates for renal transplantation were recruited from the main dialysis unit in Tehran, Iran. Presence of BK viremia was determined in plasma samples of cases using real time PCR.

RESULTS

A total of 50 renal transplant candidates with mean age 37.8±13 yr were enrolled in the study. Fifty two percent of subjects were male. Forty six (92%) of them were under HD and 4 (8%) were on PD. BK virus was not detected in any plasma samples of renal transplant candidates.

CONCLUSION

This study showed absence of BK viremia in our renal transplant candidates. However, due to the important role of BKV in BKVAN and renal graft failure and rejection, further studies involving larger number of cases are required to elucidate the rate of the BKV in renal transplant candidates.

Frequency and subtype of BK virus infection in Iranian patients infected with HIV

Human polyomavirus BK virus (BKV) is a double-stranded DNA virus that infects approximately 90 % of the general population as a subclinical or mild infection. In immunosuppressed patients, such as HIV cases, BKV may be reactivated resulting hemorrhagic cystitis and tubulointerstitial nephritis. However, there are limited studies on prevalence and molecular epidemiology of BKV in Iran. We therefore aimed to evaluate the prevalence and subtypes of BKV in Iranian HIV patients. A total of 99 patients with HIV infection were enrolled in the study. Presence of BKV DNA in plasma was evaluated by nested PCR. PCR products were sequenced directly, and phylogenetic analysis was performed. BKV DNA was detected in 8.08 % of HIV patients. BKV viremia presented in 4 out of 25 patients (16 %) not receiving antiretroviral therapy in comparison with 4 out 74 of HAART-treated patients (5.4 %) (P = 0.023). In patients with CD4 counts ≥200 cells/mm(3), viremia was found more commonly (7/80 = 8.8 %) than in those with lower counts (1/19 = 5.2 %) (not significant). All sequenced BKV isolates belonged to subtype Ib-2. Our findings indicated that the prevalence of BKV viremia is relatively prevalent in patients with HIV infection and significantly higher in naïve than HAART-treated cases. Therefore, HAART can eliminate BKV infection from plasma and reduce viremia although the actual implication of BKV viremia in HIV patients is not clear.