Danijela Karalic

Human Cytomegalovirus and Epstein-Barr Virus Genotypes in Apical Periodontitis Lesions

INTRODUCTION Different genotypes of human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) possess specific pathogenic abilities because of various interactions with the hosts immune system and differences in cell tropism. The aim of this study was to determine the distribution of HCMV and EBV genotypes in apical periodontitis lesions in relation to their clinical and histopathologic features. METHODS One hundred samples of apical periodontitis lesions and 25 control samples (healthy pulp tissue) were collected. The presence of HCMV glycoprotein B (gB) and EBV nuclear antigen-2 genotypes was analyzed by nested polymerase chain reaction and restriction fragment length polymorphisms analysis. RESULTS EBV and HCMV were detected in apical periodontitis lesions at significantly higher frequencies than in healthy pulp controls (P = .020 and P = .020, respectively). HCMV gB type II was significantly more frequent compared with gB type I in the examined groups (P = .036). No HCMV gB type III or IV products were found. In both periapical lesions and controls, EBV-1 occurred more often compared with EBV-2 (P = .001). Dual EBV and HCMV coinfection was more frequently detected in large-size periapical lesions (P = .038). CONCLUSIONS Both HCMV and EBV are associated with inflammatory processes of periapical bone destruction. HCMV gB type II and EBV-1 are the most prevalent genotypes in apical periodontitis lesions.

Pro-inflammatory cytokine levels in human apical periodontitis: Correlation with clinical and histological findings

This study aimed to compare the levels of tumour necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and interleukin-6 (IL-6) between apical periodontitis lesions with different clinical and histological features. Based on clinical data and history of disease, 100 human apical periodontitis lesions were categorised as either asymptomatic or symptomatic lesions. According to histological examination, lesions were divided into periapical granulomas and radicular cysts. Pulp tissues of 25 impacted wisdom teeth were used as controls. Homogenised tissue samples were centrifuged and supernatants were used for the determination of cytokine levels by enzyme-linked immunosorbent assay. Significantly higher levels of IL-1β and IL-6 were found in symptomatic lesions compared with asymptomatic lesions and control tissues (P < 0.001, P < 0.001, respectively). The concentration of IL-1β was significantly higher in radicular cysts compared with periapical granulomas (P = 0.003). Symptomatic lesions, as judged by high local production of IL-1β and IL-6, represent an immunologically active stage of the disease.

The influence of single and combined IL28B polymorphisms on response to treatment of chronic hepatitis C

BACKGROUND Three single nucleotide polymorphisms (SNPs) near IL28B gene were shown to be highly predictive of sustained virological response (SVR) in patients with chronic hepatitis C virus (HCV) infection. OBJECTIVES This study attempted to demonstrate the role of single and combined IL28B polymorphisms (rs8099917, rs12979860 and rs12980275) and other host and viral factors in predicting response to treatment, in Caucasian patients infected with HCV genotype 1. STUDY DESIGN The IL28B genotypes at 3 SNPs were determined in 106 patients who underwent standard 48-week therapy and out of which 55.7% achieved SVR. RESULTS Patients carrying genotypes CCrs12979860 or AArs12980275 were 3.5 and 3 times more likely to achieve SVR, respectively. Genotypes GGrs8099917 and TTrs12979860 were identified as predictors of treatment failure. The presence of IL28B profiles including at least one of the favourable genotypes was identified as the most important factor associated with SVR, followed by younger age and lower grade of histological activity. Of all patients who achieved SVR, 88.1% was carrying one of these IL28B profiles. The strongest PPV of single SNPs for achieving SVR was observed for CCrs12979860 (76.9%). The presence of GGrs8099917 showed the strongest NPV of 85.7%. The correlation of SNPs with other host and viral factors revealed association of TTrs8099917 and lower AST levels. CONCLUSIONS Results of this study confirm that all investigated IL28B polymorphisms are associated with treatment response and that presence of any of the favourable IL28B genotypes can be considered independent pretreatment determinant of the effectiveness of therapy.

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. J. Med. Virol. 86:411–418, 2014.

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.

High-risk human papilloma virus genotypes in cervical carcinoma of Serbian women: Distribution and association with pathohistological findings

A significant role of high-risk Human papilloma viruses (HR HPV) in the development of cervical carcinoma is well known. HR HPV 16 and 18 account for approximately 70% of all cases of cervical cancer worldwide. The incidence of cervical cancer in Serbia, is one of the highest in Europe. The aim of our study was to investigate the distribution of HR HPV types in cervical carcinoma of Serbian women, as well as association between the HPV types and pathohistological findings. The study included 80 archival cervical cancer tissues from the same number of patients. The presence of HPV DNA was determined using MY09/MY11 primers for L1 gene and GP1/GP2 primers for E1 gene. HPV was detected in 78.75% tissues. HR HPV genotypes found in the decreasing order of frequency were: HPV16 (80.39%), HPV33 (7.84%), HPV58 (5.88%), HPV18 (1.96%), HPV45 (1.96%) and HPV53 (1.96%). The examined tissues were 91.25% squamous cell carcinomas and 8.75% adenocarcinoma. The high frequency of HPV 16 was observed in both types of carcinoma (80.8% and 75%, respectively) while the prevalence of HPV18 was low. These results may contribute to the implementation of cervical carcinoma prevention program in Serbia, including the selection of the most appropriate vaccine and immunization program.

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 β-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 β-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.

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

Summary 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.