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.

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.

COMPARISON OF HEARING THRESHOLD ESTIMATION USING AUDITORY STEADY STATE RESPONSES AND BRAINSTEM AUDITORY EVOKED POTENTIALS IN CHILDREN.

Current recommendations proposed by pediatric audiologists are to commence with hearing amplification in children aged 6 months and above, after previous determination of the type and degree of hearing impairment and audiometric configuration. The goal of this study was to compare results obtained by click-evoked auditory brainstem response (c-ABR) and auditory steady state response (ASSR) in a group of children. This study included 68 children with different degrees of hearing impairment evaluated by c-ABR and ASSR. It is well-known that the c-ABR threshold highly correlates with behavioral hearing level at 2 kHz. In our study, the correlation between the c-ABR and ASSR thresholds in the whole sample was 0.58, 0.73, 0.97, 0.96, 0.95, 0.97; in the group of children with c-ABR thresholds up to 40 dBHL, it was 0.42, 0.73, 0.86, 0.74, 0.81, 0.81; and in the group with c-ABR thresholds worse than 40 dBHL, it was 0.46, 0.56, 0.89, 0.83, 0.85, 0.89 at 0.5, 1, 2, 4, 1-4, 2-4 kHz, respectively. Individual differences between the c-ABR and ASSR thresholds in the whole sample were up to 95, 90, 20, 25 dB at 0.5, 1, 2, 4 kHz, respectively. Study results indicated that there was strong correlation between the c-ABR and ASSR thresholds at 2, 4, 1-4, 2-4 kHz. The ASSR can be used as a valuable clinical tool and an excellent complementary method which, along with other audiologic techniques, provides more accurate hearing threshold estimation at an early age in children.

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.

Molecular characterization of BK virus in patients infected with human immunodeficiency virus.

Immunosuppression seems to be the most important cause of BKPyV reactivation. Recently, a spectrum of diseases associated with BKPyV infection has been reported in HIV-infected patients. BKPyV isolates can be classified into four subtypes based on nucleotide polymorphisms within VP1 coding region. Mutations within the BC loop of the VP1 may be associated with an increase in the viral pathogenicity. The aims of this study were to determine prevalence and distribution of BKPyV subtypes, sequence variation and mutations within VP1 among HIV-infected patients and healthy donors. Urine samples from 114 HIV-infected patients and 120 healthy donors were collected. PCR followed by sequence analysis was carried out using primers specific for VP1 and NCRR of the virus genome. The predominant BKPyV subtype was I, followed by IV. In isolates from HIV-infected patients, the majority of non-synonymous alterations were located within the BC loop. BKV sequences from healthy donors showed non-synonymous alterations outside of the receptor loops in the ß-sheets. The higher frequency of mutations in the BC loop of VP1 protein was detected among HIV-infected patients. The most frequent mutation was E82D. All HIV-infected patients who harbored mutations had CD4(+) cell counts less than 200 cell/mm(3). It seems that immunosuppression is a very important factor for BKPyV reactivation that can increase viral replication rate and leads to higher frequency of mutations in the BC loop of the VP1. These mutations may change receptor specificity, and further studies are needed to determine the effect of these mutations on the biological properties of the BKPyV.

Distribution of JC virus genotypes among Serbian patients infected with HIV and in healthy donors.

Certain factors lead to increased reactivation of JC virus (JCV) and immunodeficiency seems to be the most important. JCV isolates can be classified into eight different genotypes and several subtypes based on nucleotide difference in the VP1 gene. JCV genotypes are strongly associated with particular ethnic groups and frequently used as genetic markers for human evolution and migration. The aim of this study was to determine the frequency of JCV urinary shedding and genotype distribution in Serbia among patients infected with HIV and healthy donors. Urine samples from 107 healthy donors and 93 patients infected with HIV were collected. PCR followed by sequence analysis was carried out using primers specific for VP1 and NCRR of the virus genome. Excretion rate of JCV-DNA in urine was higher in patients infected with HIV than in healthy donors (44.1% vs. 31.7%) although statistical significance was not found. Within the group infected with HIV, the degree of immunosuppression (measured by CD4(+) cell count) did not influence JCV excretion rate. Sequence analysis of JCV NCRR from both patients infected with HIV and healthy donors showed a pattern identical to archetype structure. In healthy Serbian donors the predominant genotype was 1 (41.2%), followed by 4 (32.4%) and 2 (26.4%). On the other hand, genotype distribution pattern was different in patients infected with HIV: 2 (43.9%), 1 (31.7%), and 4 (24.4%). This study showed that European, Eurasian, and Indian types are circulating in Serbia and that distribution corresponds to the origin of the inhabitants of Serbia.

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.

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.

Carboxy-terminal sequence variation of LMP1 gene in Epstein-Barr-virus-associated mononucleosis and tumors from Serbian patients.

Seven strains of Epstein-Barr virus (EBV) are defined based on C-terminal sequence variations of the latent membrane protein 1 (LMP1). Some strains, especially those with a 30-bp deletion, are thought to be related to tumorigenic activity and geographical localization. The aims of the study were to determine the prevalence of different LMP1 strains and to investigate sequence variation in the C-terminal region of LMP1 in Serbian isolates. This study included 53 EBV-DNA-positive plasma and tissue block samples from patients with mononucleosis syndrome, renal transplantation, and tumors, mostly nasopharyngeal carcinoma. The sequence of the 506-bp fragment of LMP1 C terminus was used for phylogenetic analyses and identification of LMP1 strains, deletions, and mutations. The majority of isolates were non-deleted (66%), and the rest had 30-bp, rare 69-bp, or yet unknown 27-bp deletions, which were not related to malignant or non-malignant isolate origin. However, the majority of 69-bp deletion isolates were derived from patients with nasopharyngeal carcinoma. Less than five 33-bp repeats were found in the majority of non-deleted isolates (68.6%), whereas most 69-bp deletion isolates (75%) had five or six repeats. Serbian isolates were assigned to four LMP1 strains: B95-8 (32.1%), China 1 (24.5%), North Carolina (NC; 18.9%), and Mediterranean (Med; 24.5%). In NC isolates, three new mutations unique for this strain were identified. EBV EBNA2 genotypes 1 and 2 were both found, with dominance of genotype 1 (90.7%). This study demonstrated noticeable geographical-associated characteristics in the LMP1 C terminus of investigated isolates.

HHV-8-related hemophagocytic lymphohistiocytosis in a boy with XLP phenotype.

We report a 2.5-year-old boy with an X-linked lymphoproliferative disease (XLP) phenotype who presented with human herpes virus-8 (HHV-8)-related hemophagocytic lymphohistiocytosis (HLH). XLP is a rare primary immunodeficiency characterized by extreme susceptibility to herpes viruses, mainly Epstein-Barr virus (EBV). Approximately 60% of patients with XLP present with fulminant mononucleosis associated with HLH, whereas remaining patients present with hypogammaglobulinemia or lymphoproliferative disease. Most commonly, one of the XLP phenotypes appears after exposure to EBV, but at least 12% of affected individuals developed symptoms without an evidence of EBV infection. Rarely, patients with XLP may present with central nervous system vasculitis or aplastic anemia. HHV-8 is lymphotrophic and it is associated with lymphoproliferative disorders and Kaposi sarcoma in immunodeficient hosts. Kaposi sarcoma rarely occurs in children with well-defined primary immunodeficiency. Also, HHV-8-related HLH was previously reported in 2 siblings with a perforin gene deficiency. Recently, it became evident that besides EBV, other viruses may trigger the symptoms in XLP. We report for the first time HHV-8-related HLH in EBV-negative pediatric patient with an XLP phenotype.

Immune Evasion of SARS-CoV-2 Emerging Variants: What Have We Learnt So Far?

Despite the slow evolutionary rate of SARS-CoV-2 relative to other RNA viruses, its massive and rapid transmission during the COVID-19 pandemic has enabled it to acquire significant genetic diversity since it first entered the human population. This led to the emergence of numerous variants, some of them recently being labeled "variants of concern" (VOC), due to their potential impact on transmission, morbidity/mortality, and the evasion of neutralization by antibodies elicited by infection, vaccination, or therapeutic application. The potential to evade neutralization is the result of diversity of the target epitopes generated by the accumulation of mutations in the spike protein. While three globally recognized VOCs (Alpha or B.1.1.7, Beta or B.1.351, and Gamma or P.1) remain sensitive to neutralization albeit at reduced levels by the sera of convalescent individuals and recipients of several anti-COVID19 vaccines, the effect of spike variability is much more evident on the neutralization capacity of monoclonal antibodies. The newly recognized VOC Delta or lineage B.1.617.2, as well as locally accepted VOCs (Epsilon or B.1.427/29-US and B1.1.7 with the E484K-UK) are indicating the necessity of close monitoring of new variants on a global level. The VOCs characteristics, their mutational patterns, and the role mutations play in immune evasion are summarized in this review.

Factors Associated With Cytomegalovirus Infection in Pediatric Allogeneic Hematopoietic Stem Cell Transplant Recipients: A Prospective Single-Center Study.

OBJECTIVES: The human cytomegalovirus is a notorious pathogen in the pediatric transplant setting. Although studies on factors in complicity with cytomegalovirus infection abound, the roles of age, sex, allogeneic hematopoietic stem cell transplant modality, and type of underlying disease (malignant vs nonmalignant) with regard to cytomegalovirus infection and viral load in children are seldom explored. Our aim was to examine the significance of these factors on cytomegalovirus infection and viral load in Serbian pediatric recipients of allogeneic hematopoietic stem cell transplant. MATERIALS AND METHODS: Thirty-two pediatric recipients of allogeneic hematopoietic stem cell transplant to treat various malignant and nonmalignant disorders were prospectively monitored for cytomegalovirus infection. The real-time quantitative polymerase chain reaction was used for pathogen detection and quantitation. Demographic and virologic parameters were statistically analyzed with SPSS statistics software (version 20). RESULTS: Cytomegalovirus DNA was detected in 23 patients (71.9%). Infection occurred significantly more often (P = .015) in patients with haploidentical donors. The opposite was noted for matched sibling grafts (P = .006). Viral load was higher in female patients (P = .041) and children with malignant diseases (P = .019).There was no significant relationship between viral infection or load and medical complications. CONCLUSIONS: Transplant recipients presented with a high incidence of cytomegalovirus viremia. The modality of allogeneic hematopoietic stem cell transplant was associated with the frequency of cytomegalovirus infection. Age, sex, type of underlying disease, and medically relevant events were not conducive to occurrences of viremia. Notably, we observed substantial viral loads in female patients and patients with neoplastic diseases. Studies comprising larger populations are needed to better understand these results.

Prevalence of hepatitis B virus MHR mutations and their correlation with genotypes and antiviral therapy in chronically infected patients in Serbia.

Understanding the prevalence and diversity of HBsAg variants in a population is fundamental to assay design and planning vaccination programs. It has been shown that mutations within the S gene, caused by selection or natural variation, can lead to false-negative results in assays for HBsAg, or have clinical implications, such as evading anti-HBV immunoglobulin therapy or vaccine-induced immunity. The region of HBsAg where most of these mutations occur is known as the major hydrophilic region (MHR). The aim of this study was to determine the prevalence and mutational patterns of MHR mutations in patients with chronic hepatitis B, and their correlation with patient characteristics, viral factors and antiviral therapy. The study comprised 164 plasma samples from patients with chronic hepatitis B, of which, 34.8% were on long-term lamivudine monotherapy. Direct sequencing of part of the S/pol gene was used for identification of HBsAg mutations, HBV genotypes, subgenotypes and HBsAg subtypes. The overall frequency of MHR mutations was 22.6%, but it varied significantly between untreated and treated patients (16.8% vs. 33.3%). The most frequent substitution was at position 120 (9.1%) whereas the most common vaccine-escape position, 145, was affected in 1.8% of isolates. The presence of MHR mutations was correlated with genotype D, subgenotype D3, and ayw2/ayw3 HBsAg subtypes and to older age (>40 years). It is concluded that natural viral variability present in a geographical region, duration of infection, and antiviral therapy are among the major factors associated with the occurrence of MHR mutations.

Cytomegalovirus glycoprotein B and N genotypes in pediatric recipients of the hematopoietic stem cell transplant.

Clinical significance of the cytomegalovirus (CMV) genotypes in patients undergoing allogeneic hematopoietic stem cell transplant (HSCT) has been evaluated mostly in adults. The studies of diverse CMV glycoprotein B (gB) and N (gN) genotype variants in transplanted children and adolescents are lacking. We analyzed the investment of gB and gN genotype variants in the HSCTed children and their relation to clinical complications and disease outcome. The cohort included forty two pediatric recipients of the HSCT. Patients positive for CMV DNAemia (24/42, 57.1%) were genotyped. The gB4 and gN1 genotype variants predominated and were evidenced in 7/18 (38.9%) and 9/19 (47.4%) patients, respectively. The graft-versus-host disease (GvHD) predominated in children with viremia (p < 0.05). Frequencies of the gB and gN genotypes contrasted those reported in recent studies. The GvHD scaled strongly with CMV reactivation whereas viral loads were uncorrelated to medical complications and treatment outcomes.

Increased systemic sST2 in patients with end stage renal disease contributes to milder liver damage during HCV infection.

INTRODUCTION: Hepatitis C Virus (HCV) is the leading cause of chronic liver disease and is a serious global health problem. Hepatitis C infection is highly prevalent in patients with end stage renal disease (ESRD), due to frequent exposure to blood and blood products, nosocomial transmission of HCV, and prolong hemodialysis duration. The aim of the study was to evaluate the influence of IL-33/ST2 signaling pathway on severity of the liver disease in ESRD HCV+ patients. METHODOLOGY: Blood samples from patients with end stage renal disease (ESRD) and hepatitis C infection (HCV), 20 patients with HCV infection, 20 patients with ESRD and 20 healthy control donor patients were taken for the examination of biochemical parameters, for the determination of the serum cytokine concentration, and for the molecular diagnostics of HCV. RESULTS: Systemic sST2 positively correlated with serum level of urea and creatinine, respectively. Serum sST2 was significantly increased in ESRD HCV+ patients in comparison to HCV+ group. sST2/IL-1, sST2/IL-4 and sST2/IL-23 ratios were significantly increased in serum of ESRD HCV+ patients in comparison to HCV+ patients. Significantly higher systemic level of sST2 and sST2/IL-1 and sST2/IL-4 ratios were measured in ESRD patients compared to non-ESRD patients. CONCLUSION: These results suggested that elevated level sST2, as the consequence of renal failure, causes less destruction of liver in HCV infection.

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 influence of standardized dry ivy leaf extract on the proportion of nasal secretion after post-septoplasty nasal packing removal.

INTRODUCTION: After post-septoplasty nasal packing removal, a certain proportion of nasal secretion occurs, leading to local and sometimes systemic infections. OBJECTIVE: The aim was to determine if standardized dry ivy leaf extract application after nasal packing removal influences the reduction of nasal secretion and diminish the occurrence of local infections. METHODS: The study included 70 post-septoplasty patients (divided into two equal groups) whose nasal packing was removed on the third day after the procedure. Group I was treated with standardized dry ivy leaf extract syrup along with regular nasal irrigation for the five days after the nasal packing removal whereas the Group II had only nasal lavage. On the sixth day after nasal packing removal, the quantity of nasal secretion was determined using a visual analog scale and nasal endoscopic examination. RESULTS: The group treated with standardized dry ivy leaf extract syrup had significantly lesser nasal secretion both by subjective patients' assessment (p<0.001) and by nasal endoscopic examination (p=0.003). The post-surgical follow up examination on the sixth day after nasal packing removal showed no development of local infection in the Group I, while in the Group II a local infection was evident in five patients (14.29%) and antibiotic therapy was required. CONCLUSION: The use of the standardized dry ivy leaf extract after nasal packing removal significantly lowers the proportion of nasal secretion.

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.

Analysis of the Variability of Epstein-Barr Virus Genes in Infectious Mononucleosis: Investigation of the Potential Correlation with Biochemical Parameters of Hepatic Involvement.

BACKGROUND: Primary Epstein-Barr virus (EBV) infection is usually asymptomatic, although at times it results in the benign lymphoproliferative disease, infectious mononucleosis (IM), during which almost half of patients develop hepatitis. The aims of the present study are to evaluate polymorphisms of EBV genes circulating in IM isolates from this geographic region and to investigate the correlation of viral sequence patterns with the available IM biochemical parameters. METHODS: The study included plasma samples from 128 IM patients. 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. RESULTS: The presence of EBV DNA in plasma samples showed correlation with patients' necessity for hospitalization (p=0.034). The majority of EBV isolates was genotype 1. LMP1 variability showed 4 known variants, and two new deletions (27-bp and 147-bp). Of the 3 analyzed attributes of LMP1 isolates, the number of 33-bp repeats less than the reference 4.5 was the only one that absolutely correlated with the elevated levels of transaminases. EBNA1 variability was presented by prototype subtypes. A particular combination of EBNA2, LMP1, and EBNA1 polymorphisms, deleted LMP1/P-thr and non-deleted LMP1/P-ala, as well as genotype 1/ 4.5 33-bp LMP1 repeats or genotype 2/ 4.5 33-bp LMP1 repeats showed correlation with elevated AST (aspartate aminotransferase) and ALT (alanine transaminase). CONCLUSIONS: This is the first study which identified the association between EBV variability and biochemical parameters in IM patients. These results showed a possibility for the identification of hepatic related diagnostic EBV markers.