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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, LM P1, and EBNA1 were amplified using nested-PCR. EBNA2 genotyping was performed by visualization of PCR products using gel electrophoresis. Investigation of LM P1 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 LM P1 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, LM P1, and EBNA1 polymorphisms, deleted LM PI/P-thr and non-deleted LMp1/P-ala, as well as genotype 1/ 4 .5 33-bp LM P1 repeats or genotype 2 / 4 .5 33-bp LM P1 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.

Human polyomaviruses, BK virus (BKV) and JC virus (JCV), are world widely distributed in human population. After primary infection, BKV and JCV establish latency in kidneys and upper part of urinary tract. In seropositive healthy individuals asymptomatic reactivation of both viruses occurs in in 0.5-20%. On the other hand, reactivation of these viruses in imunosuppressed patients, primarily in patients with T cell immunodeficiency, can lead to development of polyomavirus-associated diseases. Some of these diseases such as progressive multifocal leukoencephalopathy (PML), polyomavirus-induced nephropathy (PVN), hemorrhagic cystitis (HC) are life-threatening diseases with high mortality and morbidity rate. However, they do not affect all immunosuppressed patients, suggesting that other factors, such as genetic variability of BKV and JCV, can contribute to their occurrence. Immunosuppression leads to increased levels of replication of both viruses. Increased levels of replication are associated with higher incidence of mutations in the VP1 gene. Mutations, especially those located in outer loops, may lead to changed tropism and generation of more aggressive variants of BKV and JCV. This review is focused on clinical significance of BK and JC virus infection in immunosuppressed patients, especially in HIV-infected, and sequence changes in the VP1 gene that can contribute to selection of more virulent variants of BKV and JCV via adaptive evolution.

BK virus (BKV) and JC virus (JCV) persist as latent infection in the kidneys. Reactivation of both viruses may be linked to immunodeficiency. The aims of this study were to determine the prevalence of BKV and JCV viruria and to evaluate the relationship between immunodeficiency and viruria in a cohort of HIV-infected patients. Urine samples from 93 HIV-infected patients were collected and tested for the presence of BKV and JCV DNA by PCR. The overall prevalence of polyomavirus DNA in urine was 74.2%. BKV DNA was detected in 30.1% urine samples and JCV DNA in 23.7% samples. Both BKV and JCV DNA were detected in 20.4% samples. There was no association between BKV/JCV urinary shedding and the degree of immunosuppression measured by CD4+ cell count. However, taking into account the severity of disease resulting from reactivation of BKV and JCV, patients with HIV/polyomavirus co-infection should be kept under frequent and regular supervision. [Projekat Ministarstva nauke Republike Srbije, br. 175073]

This study aimed to determine the prevalence and mutational patterns of lamivudine-resistant hepatitis B virus (HBV) strains in chronically infected Serbian patients. The study included 154 patients on long-term lamivudine monotherapy. Resistance-associated mutations were identified by direct sequencing of the S/P gene. The genotypic resistance to lamivudine was confirmed in 54.5% of patients. Three primary resistance-associated mutations were found: rtM204V (55.9%), rtM204I (40.5%), rtA181T (3.6%) and two compensatory mutations rtV173L (17.8%) and rtL180M (67.8%). Seven mutational patterns were discovered with rtL180M+rtM204V being dominant (41.6%). The presence of resistance associated mutations was correlated to the older age of patients, the presence of clinically relevant HBsAg mutations and higher values of viral load. No correlation with HBV genotypes, subgenotypes or HBsAg subtypes was observed. High prevalence of resistance supports the use of genotypic testing in monitoring patients on lamivudine therapy and selecting those who would benefit from therapy with newly developed nucleos(t)ide analogs. [Projekat Ministarstva nauke Republike Srbije, br. 175073]

Cervical cancer incidence and mortality rates in Serbia are among the highest in Europe and data on Human papilloma virus (HPV) type distribution are scarce. The aim of this study was to determine the prevalence of HPV types in archival specimens of cervical cancer tissues of women in the Serbian population. A total of 45 paraffin-embedded tissue samples of cervical carcinoma were used in this study. The procedure included deparaffinization of tissue samples, DNA extraction, PCR, gel electrophoresis and HPV genotyping by direct sequencing. HPV was detected in 32 samples (71%). Genotyping revealed the presence of 6 high-risk HPV types 16, 18, 33, 45, 53 and 58, where HPV type 16 was the most prevalent type (73.7%). The results of this study and further studies will provide more detailed information about HPV genotype distribution and may contribute to the formulation of national guidelines for the prevention of cervical cancer. [175073]

Gene polymorphisms result from evolutionary processes representing mutations that survive in the population with a frequency higher than 1%. The most investigated type of gene polymorphisms are single nucleotide polymorphisms (SNPs). The SNPs of IL-12B (rs 3212227) A/C among a population of kidney graft CMV-seropositive recipients have an impact on a clinical events in cytomegalovirus (CMV) disease. Constitutive -308 G/A TNF-α polymorphism (rs1800629) is related to the susceptibility of HR-HPV-associated cervical dysplasia and cancer. SNP located 3 kb upstream of the IL- 28B gene (rs12979860) seems to be the strongest host genetic predictor of sustained virologic response (SVR) in hepatitis C genotype 1 patients. It is very important to identify viral and host genetic markers that may facilitate the risk of developing viral disease or some viral-associated cancers. In addition, these markers could be useful in the choice of effective treatments and preventive strategies against virally induced infection. [Projekat Ministarstva nauke Republike Srbije, br. 175073 i br. 175038]

The BK (BKV) and JC viruses (JCV) are human polyomaviruses. After primary infection, they persist as latent infection in the kidneys. Immunosuppression leads to their reactivation, which is associated with life-threatening diseases such as polyomavirus-induced nephropathy and progressive multifocal leukoencephalopathy. However, the behavior of these viruses in immunocompetent individuals is still an open question with no right answer. The aim of this study was to determine the prevalence of BKV and JCV shedding in the urine of immunocompetent individuals from the Serbian population. Sixty-five urine samples were collected and tested for the presence of BKV and JCV DNA by PCR. JCV DNA was detected in 19/65 (29.2%) and BKV DNA in 3/65 (4.6%) of the urine samples. Forty-three (66.2%) urine samples of the immunocompetent donors were negative for both viruses. The present study provides the first results of urinary excretion of human polyomaviruses in the Serbian population. [Projekat Ministarstva nauke Republike Srbije, br. 175073]

Viruses are the main cause of opportunistic infections after kidney transplantation. The aim of this study was to determine the prevalence of cytomegalovirus (CMV), Epstein-Barr virus (EBV), B. K. virus (BKV) and John Cunningham virus (JCV) infections in renal transplant recipients (RTR). This retrospective study of 112 RTR investigated the presence of CMV, EBV and polyomaviruses DNA in plasma and/or urine by PCR. The visualization of PCR products was performed by electrophoresis on 2% agarose gel stained with ethidium bromide and photographed under a UV light. The chi-square test was used for statistical analysis. CMV DNA was detected in 14/112 (12.5%), EBV DNA in 4/49 (8.16%), BKV DNA in 10/31 (32.26%) and JCV DNA in 3/31 (9.68%) RTR. These results show that CMV infection is more often present in RTR compared to other investigated viral infections. In the light of these results, molecular testing could be useful in identifying recipients at high risk of symptomatic post-transplant viral infection. [Projekat Ministarstva nauke Republike Srbije, br. 175073, br. 175038 and br. 175089]