Hepatitis B Surface Antigen Isoforms: Their Clinical Implications, Utilisation in Diagnosis, Prevention and New Antiviral Strategies.

The hepatitis B surface antigen (HBsAg) is a multifunctional glycoprotein composed of large (LHB), middle (MHB), and small (SHB) subunits. HBsAg isoforms have numerous biological functions during HBV infection-from initial and specific viral attachment to the hepatocytes to initiating chronic infection with their immunomodulatory properties. The genetic variability of HBsAg isoforms may play a role in several HBV-related liver phases and clinical manifestations, from occult hepatitis and viral reactivation upon immunosuppression to fulminant hepatitis and hepatocellular carcinoma (HCC). Their immunogenic properties make them a major target for developing HBV vaccines, and in recent years they have been recognised as valuable targets for new therapeutic approaches. Initial research has already shown promising results in utilising HBsAg isoforms instead of quantitative HBsAg for correctly evaluating chronic infection phases and predicting functional cures. The ratio between surface components was shown to indicate specific outcomes of HBV and HDV infections. Thus, besides traditional HBsAg detection and quantitation, HBsAg isoform quantitation can become a useful non-invasive biomarker for assessing chronically infected patients. This review summarises the current knowledge of HBsAg isoforms, their potential usefulness and aspects deserving further research.

Epstein-Barr virus infection as potential indicator of the occurrence and clinical presentation of systemic lupus erythematosus.

Introduction: The relationship between Systemic lupus erythematosus (SLE) and Epstein-Barr virus (EBV) infection has been suggested for decades, but the underlying mechanism of the EBV influence on SLE development remains to be elucidated. Methods: The goals of this research, which included 103 SLE patients and 99 controls, were to investigate the association of the parameters of EBV infection and SLE, to explore whether pooled demographic, clinical and EBV markers achieve a more significant effect on SLE development than each of them individually, and to evaluate EBV nuclear antigen 1 (EBNA1) and latent membrane protein 1 (LMP1) gene polymorphisms in isolates from SLE patients. Results: Comprehensive results related to serological, molecular and sequence markers of EBV infection in SLE patients demonstrated even 24 times higher possibility of having SLE if there is the presence of anti-EBV-EA(D) (early antigen) IgG antibodies (OR=24.086 95%CI OR=2.86-216.07, p=0.004). There was the same distribution of glucocorticoids (p=0.130), antimalarials (p=0.213), and immunosuppressives (p=0.712) in anti-EBV-EA(D) IgG positive and negative SLE patients. Further, higher anti-EBV-EA(D) IgG antibodies titers were identified as independent factors associated with lymphopenia, hematological SLE manifestation (OR=1.041, 95%CI OR=1.01-1.08, p=0.025, while a higher titer of anti-CA (viral capsid antigen) IgG antibodies (OR=1.015, 95%CI OR=1.01-1.03, p=0.019) and positive RF (rheumatoid factors) (OR=4.871, 95%CI OR=1.52-15.61, p=0.008) were identified as independent factors associated with alopecia within SLE. Finally, novel data on EBV EBNA1 and LMP1 gene polymorphisms in lupus are reported. Conclusion: The results support further investigation targeting EBV as a prognostic marker and therapeutic goal for lupus.

Transcriptome from Paired Samples Improves the Power of Comprehensive COVID-19 Host-Viral Characterization.

Previous transcriptome profiling studies showed significantly upregulated genes and altered biological pathways in acute COVID-19. However, changes in the transcriptional signatures during a defined time frame are not yet examined and described. The aims of this study included viral metagenomics and evaluation of the total expression in time-matched and tissue-matched paired COVID-19 samples with the analysis of the host splicing profile to reveal potential therapeutic targets. Prospective analysis of paired nasopharyngeal swabs (NPS) and blood (BL) samples from 18 COVID-19 patients with acute and resolved infection performed using Kallisto, Suppa2, Centrifuge, EdgeR, PantherDB, and L1000CDS2 tools. In NPS, we discovered 6 genes with changed splicing and 40 differentially expressed genes (DEG) that yielded 88 altered pathways. Blood samples yielded 15 alternatively spliced genes. Although the unpaired DEG analysis failed, pairing identified 78 genes and 242 altered pathways with meaningful clinical interpretation and new candidate drug combinations with up to 65% overlap. Metagenomics analyses showed SARS-CoV-2 dominance during and after the acute infection, with a significant reduction in NPS (0.008 vs. 0.002, p = 0.019). Even though both NPS and BL give meaningful insights into expression changes, this is the first demonstration of how the power of blood analysis is vastly maximized by pairing. The obtained results essentially showed that pairing is a determinant between a failed and a comprehensive study. Finally, the bioinformatics results prove to be a comprehensive tool for full-action insights, drug development, and infectious disease research when designed properly.

Uncovering the Role of Epstein-Barr Virus Infection Markers for Remission in Rheumatoid Arthritis.

Epstein-Barr virus (EBV) infection has been shown as a potential risk factor for the development of rheumatoid arthritis (RA). This prospective research aimed to investigate whether EBV infection markers changed during the six-month follow-up period in 133 RA patients (80 newly diagnosed on methotrexate (MTX)-RA-A, and 53 on biologic therapy-RA-B) and whether it was related to a disease outcome. Reduction of disease activity and inflammation was obtained. A significant decline in seroprevalence and titer for anti-VCA-IgM (p = 0.022 and p = 0.026) and anti-EA(D)-IgM (p = 0.022 and p = 0.006) in RA-A, and in seroprevalence and titer of anti-EA(D)-IgG in the RA-B subgroup (p = 0.021 and p = 0.006) were detected after the follow-up. A lower titer of anti-EBNA1-IgG could be considered a significant marker of RA remission in all RA patients regardless of age and gender (OR = 0.99, 95% CI OR = 0.98-0.99, p = 0.038), and also in RA-B patients separately (OR = 0.988, 95% CI OR = 0.98-0.99, p = 0.041). This study supported the basic hypothesis that the immune response to EBV infection is involved in the RA pathogenesis, at the beginning of the disease or during the RA evolution. Moreover, the potential influence of MTX or TNF-alpha inhibitors on the impairment of the host to control EBV infection was indirectly refuted.

Markers of Epstein-Barr Virus Infection in Association with the Onset and Poor Control of Rheumatoid Arthritis: A Prospective Cohort Study.

Although the connection between Epstein-Barr virus (EBV) and rheumatoid arthritis (RA) has been studied for over 40 years, many questions still need clarification. The study aimed to analyze the possible association between anti-EBV antibody titers, EBV DNA viremia, EBV infection status and EBNA1 (Epstein-Barr nuclear antigen 1-EBNA1) variants and clinical parameters of RA patients. This prospective cohort study included 133 RA patients and 50 healthy controls. Active/recent EBV infection was more prevalent in RA patients than in controls (42% vs. 16%, p < 0.001). RA patients had higher titers of anti-EBV-CA-IgM (capsid antigen-CA) and anti-EBV-EA(D)-IgG (early antigen-EA) antibodies than controls (p = 0.003 and p = 0.023, respectively). Lower levels of anti-EBNA1-IgG and anti-EBV-CA-IgG were observed in RA patients who received methotrexate (anti-EBNA1 IgG p < 0.001; anti-EBV-CA IgG p < 0.001). Based on amino acid residue on position 487, two EBNA1 prototypes were detected: P-Thr and P-Ala. Patients with active/recent EBV infection had a five times more chance of having RA and a nearly six times more chance of getting RA. Also, EBV active/recent infection is twice more likely in newly diagnosed than in methotrexate-treated patients. Further studies are needed to clarify "who is the chicken and who is the egg" in this EBV-RA relationship.

Association of IL10RA, IL10RB, and IL22RA Polymorphisms/Haplotypes with Susceptibility to and Clinical Manifestations of SLE.

Systemic lupus erythematosus (SLE) is characterized by an imbalance between proinflammatory and anti-inflammatory mediators. Single-nucleotide polymorphisms (SNPs) in genes coding IL10RA, IL10RB, and IL22RA could affect their expression or function and disrupt immune homeostasis. We aimed to analyze the associations of IL10RA, IL10RB, and IL22RA polymorphisms/haplotypes with patients' susceptibility to and clinical manifestations of SLE. Our study included 103 SLE patients and 99 healthy controls. The genotypes of the selected polymorphisms within IL10RA (rs10892202, rs4252270, rs3135932, rs2228055, rs2229113, and rs9610), IL10RB (rs999788, rs2834167, and rs1058867), and IL22RA (rs3795299 and rs16829204) genes were determined by TaqMan® Assays. IL10RB rs1058867 G allele carriers were significantly more frequent among the controls than among the SLE patients (76.8% vs. 61.2%; p = 0.017, OR = 0.477, 95% CI: 0.258-0.879). The IL10RB CAA haplotype was more frequent among the SLE patients than in the control group (42.7% vs. 30.7%; p = 0.027). The IL22RA rs3795299 C allele and rs16829204 CC genotype were associated with Hashimoto thyroiditis in the SLE patients (n = 103; p = 0.002 and p = 0.026, respectively), and in all the included participants (n = 202, p < 0.000 and p = 0.007, respectively), and the IL22RA CC haplotype was more frequent in the SLE patients with Hashimoto thyroiditis (p = 0.047) and in the overall participants with Hashimoto thyroiditis (n = 32, p = 0.004). The IL10RA, IL10RB, and IL22RA polymorphisms/haplotypes could be associated with SLE susceptibility and various clinical manifestations, and the IL22RA CC haplotype could be associated with Hashimoto thyroiditis.

The main predictive factors of worse outcome in patients with COVID-19 infection hospitalized in temporary COVID hospital.

INTRODUCTION: After the Serbian community hospitals had reached their full capacity during the pandemic, new institutions were enrolled into the coronavirus disease 2019 (COVID-19) system as temporary COVID hospitals (TCH). These hospitals usually had no intensive care units (ICU) and no possibility to treat severely ill patients. The aim of this study was to identify risk factors at the time of triage that could help identify patients that will require ICU treatment and cannot be treated in a TCH. METHODOLOGY: In this retrospective study, a total of 158 patients with COVID-19 infection were enrolled. The demographic information, underlying comorbidities, laboratory findings, chest X-rays, computed tomography scans, and clinical outcomes were obtained from medical records. Deterioration of a patient's condition was regarded as a need for further transfer to ICU. RESULTS: During the hospitalization 15.2% of patients required transfer to ICU. Patients with deterioration were significantly older and there was no difference between genders. We observed a higher prevalence of hypertension, other cardiovascular diseases, lower lymphocyte and platelet counts, and higher IL-6 and troponin T in patients with deterioration. The multivariate logistical regression model showed that only age was an independent risk factor for deterioration and with each year of age, the risk for poor outcome increased by 8%. CONCLUSIONS: Patients with cardiovascular risk factors, low lymphocyte and platelet counts, high IL-6 and troponin T and, especially, increased age should not be treated in a TCH because of the high possibility for deterioration and need for transfer to an ICU.

Epstein-Barr Virus Reactivation as a New Predictor of Achieving Remission or Lupus Low Disease Activity State in Patients with Systemic Lupus Erythematosus with Cutaneous Involvement.

Although Epstein-Barr virus (EBV) reactivation has long been associated with the pathogenesis of systemic lupus erythematosus (SLE), many aspects of this relationship remain unclear. Our objective was to investigate the association between EBV reactivation and the achievement of SLE remission and lupus low disease activity state (LLDAS) over a six-month period. Clinical, laboratory, and virological tests (anti-EBV antibodies and EBV DNA) were performed among 51 patients with the active form of SLE on two occasions six months apart. SLE remission and LLDAS achievement were assessed at the end of the follow-up period. Active EBV infection was detected in 45% of active SLE patients at baseline, and 77% transitioned to latent EBV infection at six months (p < 0.001). Multivariate regression revealed a higher titer of anti-EA(D) IgM-Abs and the presence of anti-EA(D) IgM-Abs as independent predictors of remission and LLDAS in SLE patients with mucocutaneous manifestations (p = 0.042) and rash only (p = 0.023), respectively. Since a higher C3 level was an independent predictor of transition to latent EBV infection (p = 0.027), the estimated cut-off value that could identify active SLE patients who will transition to latent EBV infection after six months was ≥0.780 g/L with a sensitivity of 70.6% and a specificity of 75.0% (AUC = 0.756, p = 0.003). EBV reactivation is common in patients with active SLE, and most of them transition to latent EBV infection after six months. Achieving remission and LLDAS in SLE patients with mucocutaneous manifestations can be predicted by a higher titer, whereas in SLE patients who have only a rash, the presence of anti-EA (D) IgM-Abs was a predictor of remission and LLDAS.

Clinical efficacy of anti-SARS-CoV-2 monoclonal antibodies in preventing hospitalisation and mortality among patients infected with Omicron variants: A systematic review and meta-analysis.

Until now, the treatment protocols for COVID-19 have been revised multiple times. The use and approval of therapeutic monoclonal antibodies (mAbs) for COVID-19 treatment represent exceptional achievements in modern science, technology and medicine. SARS-CoV-2 Omicron evasion of pre-existing immunity represents a serious public health problem nowadays. This systematic review with meta-analysis provided comprehensive and up-to-date evidence of the clinical efficacy of therapeutic anti-SARS-CoV-2 mAbs against Omicron subvariants in COVID-19 patients and included 10 articles. The prevalence of hospitalisation among Omicron-positive patients treated with anti-SARS-CoV-2 mAbs was 2.8% (89/3169) while it controls (Omicron-positive patients treated with other therapies) 11% (154/1371). There was a statistically significantly different number of hospitalisations between the two studied groups in favour of the anti-SARS-CoV-2 mAbs treated group. (OR = 0.56, 95% CI OR = 0.41-0.77, p < 0.001, respectively). Eight deaths (0.30%) out of 2619 Omicron-positive patients occurred in the anti-SARS-CoV-2 mAbs treated group, while in the control group (Omicron-positive patients treated with other therapies), 27 patients died out of 1401 (1.93%). There was a significantly different number of deaths between the two studied groups in favour of Omicron-positive patients treated with anti-SARS-CoV-2 mAbs (OR = 0.38, 95% CI OR = 0.17-0.85, p = 0.020). Using sotrovimab in treating Omicron-positive patients indicated a reduction of hospitalisation and mortality for 49% and 89% in favour of sotrovimab, respectively (OR = 0.51, 95% CI OR = 0.34-0.79, p = 0.002; OR = 0.11, 95% CI OR = 0.03-0.39, p = 0.001). We could only provide evidence of the positive impact in reducing hospitalisation and mortality rates when anti-SARS-CoV-2 mAbs were used to treat patients infected with Omicron variants BA.1 or BA.2 and not on other Omicron variants.

Systematic review with meta-analysis of active herpesvirus infections in patients with COVID-19: Old players on the new field.

OBJECTIVES: Herpesviruses are ubiquitous and after primary infection they establish lifelong latency. The impairment of maintaining latency with short-term or long-term consequences could be triggered by other infection. Therefore, reactivation of herpesviruses in COVID-19 patients represents an emerging issue. DESIGN AND METHODS: This study provided the first systematic review with meta-analysis of studies that evaluated active human herpesvirus (HHV) infection (defined as the presence of IgM antibodies or HHV-DNA) in COVID-19 patients and included 36 publications collected by searching through PubMed, SCOPUS, and Web of science until November 2022. RESULTS: The prevalence of active EBV, HHV6, HSV, CMV, HSV1, and VZV infection in COVID-19 population was 41% (95% CI =27%-57%), 3% (95% CI=17%-54%), 28% (95% CI=1%-85%), 25% (95% CI=1%-63%), 22% (95% CI=10%-35%), and 18% (95% CI=4%-34%), respectively. There was a 6 times higher chance for active EBV infection in patients with severe COVID-19 than in non-COVID-19 controls (OR=6.45, 95% CI=1.09-38.13, p=0.040), although there was no difference in the prevalence of all evaluated active herpesvirus infections between COVID-19 patients and non-COVID-19 controls. CONCLUSIONS: Future research of herpesvirus and SARS-CoV-2 coinfections must be prioritized to define: who, when and how to be tested, as well as how to effectively treat HHVs reactivations in acute and long COVID-19 patients.

Clinical Utility of Quantitative HBV Core Antibodies for Solving Diagnostic Dilemmas.

The present-day management of hepatitis B virus (HBV) infection relies on constant and appropriate monitoring of viral activity, disease progression and treatment response. Traditional HBV infection biomarkers have many limitations in predicting clinical outcomes or therapy success. Quantitation of HBV core antibodies (qAnti-HBc) is a new non-invasive biomarker that can be used in solving multiple diagnostic problems. It was shown to correlate well with infection phases, level of hepatic inflammation and fibrosis, exacerbations during chronic infection and presence of occult infection. Further, the level of qAnti-HBc was recognised as predictive of spontaneous or therapy-induced HBeAg and HBsAg seroclearance, relapse after therapy discontinuation, re-infection after liver transplantation and viral reactivation upon immunosuppression. However, qAnti-HBc cannot be relied upon as a single diagnostic test to solve all dilemmas, and its diagnostic and prognostic power can be much improved when combined with other diagnostic biomarkers (HBV DNA, HBeAg, qHBsAg and anti-HBs antibodies). The availability of commercial qAnti-HBc diagnostic kits still needs to be improved. The comparison of results from different studies and definitions of universal cut-off values continue to be hindered because many methods are only semi-quantitative. The clinical utility of qAnti-HBc and the methods used for its measurement are the focus of this review.

The Expression of Hypoxia-Related Biomarkers: A Significance of HIF-1α C1772T Polymorphism as Predictor of Laryngeal Carcinoma Relapse.

INTRODUCTION: The association between the expression of HIF-1α in the laryngeal carcinoma and the prognosis of disease is quite well documented, but the significance of HIF-1α C1772T polymorphism and its relation to disease phenotype have to be clarified. The aim of this study was to investigate the influence of C1772T polymorphism on the clinical-pathological characteristics and disease-free survival after initial surgical treatment of patients with laryngeal carcinoma. MATERIALS AND METHODS: The prospective cohort study included 65 patients with laryngeal carcinoma. Two representative tumor tissue specimens were taken in each patient during surgery; 1 specimen was used to asses HIF-1α C1772T polymorphism and the other 1 to determine the immunohistochemical expression of HIF-1α, VEGF, as well as CD 34 proteins. The comparison of polymorphism frequency between study and control population was conducted by collecting a 5 mL of peripheral venous blood samples in each subject. RESULTS: Clinicopathological characteristics of laryngeal carcinoma didn't affect the expression of hypoxia-related biomarkers, such as HIF-1α, VEGF or MVD. The statistically significant association between HIF-1α and VEGF expression was found (P = .034), but not between HIF-1α expression and MVD value (P = .696). The expression of HIF-1α was significantly higher among CT heterozygotes (P = .029). We found a significantly more recurrence among CT heterozygotes compared with patients with CC homozygous alleles (57.10% and 24.30%, respectively; P = .007). Patients with C1772T polymorphic variants had significantly worse disease-free survival compared with patients without polymorphism (Log-rank test, P = .007). CONCLUSION: HIF-1α C1772T polymorphism was significantly associated with worse disease-free survival which nominates it as a predictor of laryngeal carcinoma relapse. The preoperative assessment of hypoxia-related biomarkers should be used in everyday practice in order to determine the treatment modalities for laryngeal carcinoma.

New Evidence of Significant Association between EBV Presence and Lymphoproliferative Disorders Susceptibility in Patients with Rheumatoid Arthritis: A Systematic Review with Meta-Analysis.

Development of lymphoproliferative disorders (LPDs) is one of the well-known life-threatening complications in rheumatoid arthritis (RA) patients. However, there is a lack of definitive conclusions regarding the role of Epstein-Barr virus (EBV) activity in RA initiation and progression, especially in promoting LPDs. A systematic review and meta-analysis of studies that reported an EBV positive result in RA-LPD patients and controls were conducted. Studies published before 27 July 2021 were identified through PubMed, Web of Science, and SCOPUS. A total of 79 articles were included in the systematic review. The prevalence of EBV positive result among RA-LPD patients was 54% (OR = 1.54, 95% CI = 1.45-1.64). There was a statistically significant association between EBV presence and LPD susceptibility in RA patients in comparison with all controls (OR = 1.88, 95% CI = 1.29-2.73) and in comparison with LPD patients only (OR = 1.92, 95% CI = 1.15-3.19). This association was not shown in comparison with patients with autoimmune diseases other than RA who developed LPD (OR = 0.79, 95% CI = 0.30-2.09). This meta-analysis confirmed a high prevalence of EBV in the RA-LPD population. Furthermore, it provides evidence for the association between EBV presence and LPD susceptibility in RA patients, but not in those with other autoimmune diseases who developed LPD.

A Systematic Review of Epstein-Barr Virus Latent Membrane Protein 1 (LMP1) Gene Variants in Nasopharyngeal Carcinoma.

Nasopharyngeal carcinoma (NPC) is an aggressive tumor with a complex etiology. Although Epstein-Barr virus (EBV) infection is known environmental factor for NPC development, the degree to which EBV naturally infects nasopharyngeal epithelium and the moment when and why the virus actively begins to affect cell transformation remains questionable. The aim of this study was to explore the association between LMP1 gene variability and potential contribution to NPC development. A systematic review was performed through searches of PubMed, Web of Science (WoS) and SCOPUS electronic databases. Additionally, meta-analysis of the difference in the frequency of seven LMP1 gene variants in NPC and control individuals was accomplished. The results from this study give a proof of concept for the association between 30 bp deletion (OR = 3.53, 95% CI = 1.48-8.43) and Xhol loss (OR = 14.17, 95% CI = 4.99-40.20) and NPC susceptibility when comparing biopsies from NPC and healthy individuals. Otherwise, 30 bp deletion from NPC biopsies could not distinguish NPC from EBV-associated non-NPC tumors (OR = 1.74, 95% CI = 0.81-3.75). However, B95-8, China1 and North Carolina variants were uncommon for NPC individuals. Much more efforts remains to be done to verify the biological significance of the differences observed, define so-called "high-risk" EBV variants and make it available for clinical application.

Comparison and Sensitivity Evaluation of Three Different Commercial Real-Time Quantitative PCR Kits for SARS-CoV-2 Detection.

Real-time reverse transcription polymerase chain reaction (RT-qPCR) is the most sensitive and specific assay and, therefore, is the "gold standard" diagnostic method for the diagnosis of SARS-CoV-2 infection. The aim of this study was to compare and analyze the detection performance of three different commercially available SARS-CoV-2 nucleic acid detection kits: Sansure Biotech, GeneFinderTM, and TaqPathTM on 354 randomly selected samples from hospitalized COVID-19 patients. All PCR reactions were performed using the same RNA isolates and one real-time PCR machine. The final result of the three evaluated kits was not statistically different (p = 0.107), and also had a strong positive association and high Cohen's κ coefficient. In contrast, the average Ct values that refer to the ORF1ab and N gene amplification were significantly different (p < 0.001 and p < 0.001, respectively), with the lowest obtained by the TaqPathTM for the ORF1ab and by the Sansure Biotech for the N gene. The results show a high similarity in the analytical sensitivities for SARS-CoV-2 detection, which indicates that the diagnostic accuracy of the three assays is comparable. However, the SanSure Biotech kit showed a bit better diagnostic performance. Our findings suggest that the imperative for improvement should address the determination of cut-off Ct values and rapid modification of the primer sets along with the appearance of new variants.

The First Molecular Characterization of Serbian SARS-CoV-2 Isolates From a Unique Early Second Wave in Europe.

March 6, 2020 is considered as the official date of the beginning of the COVID-19 epidemic in Serbia. In late spring and early summer 2020, Europe recorded a decline in the rate of SARS-CoV-2 infection and subsiding of the first wave. This trend lasted until the fall, when the second wave of the epidemic began to appear. Unlike the rest of Europe, Serbia was hit by the second wave of the epidemic a few months earlier. Already in June 2020, newly confirmed cases had risen exponentially. As the COVID-19 pandemic is the first pandemic in which there has been instant sharing of genomic information on isolates around the world, the aim of this study was to analyze whole SARS-CoV-2 viral genomes from Serbia, to identify circulating variants/clade/lineages, and to explore site-specific mutational patterns in the unique early second wave of the European epidemic. This analysis of Serbian isolates represents the first publication from Balkan countries, which demonstrates the importance of specificities of local transmission especially when preventive measures differ among countries. One hundred forty-eight different genome variants among 41 Serbian isolates were detected in this study. One unique and seven extremely rare mutations were identified, with locally specific continuous dominance of the 20D clade. At the same time, amino acid substitutions of newly identified variants of concern were found in our isolates from October 2020. Future research should be focused on functional characterization of novel mutations in order to understand the exact role of these variations.

Immune-Escape Hepatitis B Virus Mutations Associated with Viral Reactivation upon Immunosuppression.

Hepatitis B virus (HBV) reactivation occurs as a major complication of immunosuppressive therapy among persons who have recovered from acute hepatitis and those who have controlled chronic infection. Recent literature data emphasize the presence of a high degree of S gene variability in HBV isolates from patients who developed reactivation. In reactivated HBV, the most frequently detected mutations belong to the second loop of "a" determinant in HBsAg. These mutations were identified to be immune escape and responsible for vaccine- and diagnostic-escape phenomena. Their emergence clearly provides survival in the presence of a developed humoral immune response and is often associated with impaired serological diagnosis of HBV reactivation. The knowledge of their existence and roles can elucidate the process of reactivation and strongly highlights the importance of HBV DNA detection in monitoring all patients with a history of HBV infection who are undergoing immunosuppression. This review discusses the possible influence of the most frequently found immune-escape mutations on HBV reactivation.

The sequence analysis of Epstein-Barr virus EBNA1 gene: could viral screening markers for nasopharyngeal carcinoma be identified?

Epstein-Barr virus (EBV) has been identified as a group 1 carcinogenic agent, particularly for nasopharyngeal carcinoma (NPC). The sequence diversity of EBV nuclear antigen 1 (EBNA1) reflects region-restricted polymorphisms, which may be associated with the development of certain malignancies. The aims of the present study were to evaluate EBV EBNA1 gene polymorphisms circulating in NPC, infectious mononucleosis, and isolates from patients with transplanted organs to determine if EBNA1 sequence specificities are useful as viral biomarkers for NPC. Forty biopsies of undifferentiated carcinoma of nasopharyngeal type (UCNT), 31 plasma samples from patients with mononucleosis syndrome, and 16 plasma samples from patients after renal transplantation were tested in this study. The EBNA1 gene was amplified by nested PCR. Further investigation included sequencing, phylogenetic, and statistical evaluations. Eighty-seven sequences were identified as one of the four EBNA1 subtypes, P-Ala, P-Thr, V-Val, and V-Ala, with further classification into ten subvariants. Of these, P-Thr-sv-1 and P-Thr-sv-3 have never been identified in Europe, while V-Val-sv-1 was newly discovered. Statistical analysis revealed significant differences in the distribution of EBNA1 P-Thr subvariants between the three groups of patients, with noticeable clustering of P-Thr-sv-5 in NPC isolates (p < 0.001). EBV EBNA1 showed no sequence specificity in primary infection. This research revealed a newly discovered EBNA1 subvariant. Importantly, EBNA1 P-Thr-sv-5 showed carcinoma-specific EBNA1 variability. Thus, identification of this subvariant should be considered as a viral screening marker for NPC or UCNT.

Analysis of variability of urinary excreted JC virus strains in patients infected with HIV and healthy donors.

In immunocompromised individuals, especially in patients with T cell immunodeficiency, reactivation of JCPyV can cause serious life-threatening diseases. Nowadays, HIV infection is one of the most important factor for reactivation of JCPyV and the development of of the progressive multifocal leukoencephalopathy (PML). Mutations in the outer loops of the VP1 region can lead to the selection of the viral variants with changed tropism and increased pathological potential. The aims of this study were to determine sequence variation and amino acid changes within VP1 loops and the structure of non-coding control region (NCCR) of urinary excreted JCPyV isolates among HIV-infected patients and healthy donors. Single urine samples from 114 HIV-infected patients and 120 healthy donors were collected. PCR was performed for amplification of VP1 and NCCR. Amplified fragments were directly sequenced and analyzed by using bioinformatics tools. Nucleotide substitutions were detected within DE and EF loops and in the ß-sheets of both studied groups. In HIV-infected patients group, 70% of mutations were detected within receptor domains. Among healthy donors, one mutation was identified within ß-sheets while the remaining were located within receptor domains. The most prevalent mutation was L157V in both groups. Analysis of NCCR revealed that all isolates had archetype structure with some minor changes. Since single point mutations at specific place within outer loop of VP1 region can cause formation of variants with changed receptor specificity, identification of these mutations in HIV-infected patients can help to single out those with higher risk for development of polyomavirus-associated diseases.

Characterization of the Variability of Epstein-Barr Virus Genes in Nasopharyngeal Biopsies: Potential Predictors for Carcinoma Progression.

Epstein-Barr virus (EBV) infection is a significant factor in the pathogenesis of nasopharyngeal carcinoma, especially in the undifferentiated carcinoma of nasopharyngeal type (UCNT, World Health Organization type III), which is the dominant histopathological type in high-risk areas. The major EBV oncogene is latent membrane protein 1 (LMP1). LMP1 gene shows variability with different tumorigenic and immunogenic potentials. EBV nuclear antigen 1 (EBNA1) regulates progression of EBV-related tumors; however, the influence of EBNA1 sequence variability on tumor pathogenesis is controversial. The aims of this study were to characterize polymorphisms of EBV genes in non-endemic nasopharyngeal carcinoma biopsies and to investigate potential sequence patterns that correlate with the clinical presentation of nasopharyngeal carcinoma. In total, 116 tumor biopsies of undifferentiated carcinoma of nasopharyngeal type (UCNT), collected from 2008 to 2014, were evaluated in this study. The genes EBNA2, LMP1, and EBNA1 were amplified using nested-PCR. EBNA2 genotyping was performed by visualization of PCR products using gel electrophoresis. Investigation of LMP1 and EBNA1 included sequence, phylogenetic, and statistical analyses. The presence of EBV DNA was significantly distributed between TNM stages. LMP1 variability showed six variants, with the detection of the first China1 and North Carolina variants in European nasopharyngeal carcinoma biopsies. Newly discovered variants Srb1 and Srb2 were UCNT-specific LMP1 polymorphisms. The B95-8 and North Carolina variants are possible predictors for favorable TNM stages. In contrast, deletions in LMP1 are possible risk factors for the most disfavorable TNM stage, independent of EBNA2 or EBNA1 variability. A newly discovered EBNA1 subvariant, P-thr-sv-5, could be a potential diagnostic marker, as it represented a UCNT-specific EBNA1 subvariant. A particular combination of EBNA2, LMP1, and EBNA1 polymorphisms, type 1/Med/P-thr was identified as a possible risk factor for TNM stage IVB or progression to the N3 stage.