Seroprevalence of Hepatitis B and C among Children in Endemic Areas of Turkey

BACKGROUND AND AIMS

Hepatitis B virus (HBV) and Hepatitis C virus (HCV) infections are major worldwide public health problems. The objectives of this study were to evaluate the seroprevalence and epidemiological profile of hepatitis B and hepatitis C, to determine the impact of the national vaccination programme against hepatitis B on the prevalence of the hepatitis B surface antigen (HBsAg) carrier and the antibody to hepatitis B surface antigen (anti-HBs) occurrence rate among 0-14 year-old children in southeast Turkey.

METHODS

The seroprevalence of hepatitis B and hepatitis C markers was evaluated retrospectively in a group of 10,391 children who were admitted to a tertiary hospital, the Diyarbakir Education and Research Hospital, from January 2005 to December 2008, in order to obtain a better understanding of the regional hepatitis seroprevalence. Children were divided into three different age groups: pre-education period (0-6 years), primary school period (7-12 years) and secondary school period (13-14 years). Samples were analyzed for HBsAg, hepatitis B e antigen (HBeAg), antibody to HBeAg (anti-HBe), anti-HBs positive/antibodies to hepatitis B core antigen (anti-HBc) positive, isolated anti-HBs and antibodies to Hepatitis C virus (anti-HCV) using a commercially available enzyme-linked immunosorbent assay (ELISA).

RESULTS

The mean age of all participants was 8.5± 2 years (range, 0-14). The overall percentages for the prevalence of HBsAg, HBeAg, anti-HBe and anti-HCV were 8.1%, 2.1%, 5.9% and 0.5%, respectively. HBsAg seroprevalence differed significantly by age and gender (P < 0.001). HBeAg seroprevalence was high in the earliest years (P < 0.01). The overall prevalence of anti-HCV did not differ significantly by age (P > 0.5) but differed by gender (P < 0.001). The overall percentages for the prevalence of isolated anti-HBs and anti-HBs positive/anti-HBc positive were 34.2% and 56.9%,respectively.

CONCLUSIONS

Our study sheds new light on hepatitis seroprevalence in southeastern Turkey. For example, 1) The seroprevalence of hepatitis B in southeast Turkey is still at its highest rate, according to the averages reported in other studies conducted in the same and different regions of Turkey; and it has not decreased, as reported previously. 2) HBeAg seroprevalence in the earliest years of childhood is high in our study; this is evidence for early acquisition of the infection.3) Isolated anti-HBs positive and anti-HBs positive/anti-HBc positive prevalence is high; given these features, it is obvious that despite the high incidence of vaccinated children, the prevalence of hepatitis B is increasing; and children acquire these viruses in their earliest years. 4) We found the overall prevalence of HCV infection unchanged. Our region has a low endemicity for HCV.

Multidrug-resistant hepatitis B virus strain in a chronic Turkish patient

Hepatitis B virus (HBV) strains, resistant to at least two anti-HBV agents from different subclasses of nucleos(t)ide analogues (NUCs) without a cross-resistance profile, are defined as multidrug-resistant. However, there are limited in vivo data for resistance to multiple NUCs. In this study, we report the case of the emergence of a multidrug-resistant HBV strain in a Turkish patient receiving sequential therapy. Polymerase gene mutations of HBV were detected using direct sequencing, line probe assay and clonal analysis. Twelve months after the start of lamivudine (LAM) therapy, virological breakthrough occurred (4.2E+07 IU/ml) and the rtM204V variant was detected in the patient's sera: adefovir (ADV) was added to the therapy. ADV therapy was continued as monotherapy for 11 months, until the occurrence of clinical breakthrough i.e. alanine aminotransferase (ALT) 60 IU/L, and emergence of drug resistance to ADV (rtN236T). At that time, switch therapy was resumed with ADV + entecavir (ETV) in combination for 5 months. In the 18th month of the ETV monotherapy, direct sequencing showed reduced susceptibility to ETV (rtL180M+rtM204V). Currently, ETV + tenofovir (TDF) are being used as antiviral treatment and the HBV DNA load has decreased substantially (<1.0E+02 IU/ml). In conclusion, we have detected an HBV strain with multidrug-resistance, which had a very fast course of development. Patients with a multidrug-resistant profile should be more frequently followed up both by direct sequencing and line probe assay, for the detection of possible novel HBV variants and low level mutants present in the viral population, in case of the sudden emergence of drug resistance.

Detection of hepatitis B virus in used razor blades by PCR

BACKGROUND AND AIMS

Hepatitis B virus (HBV) infection ranks among the most devastating health problems in the world.The most probable transmission routes of HBV are blood contact, sexual, and horizontal transfer. Other sources of HBV transmission are razor sharing, beauty treatments, tattooing, piercing, and manicures and other chiropody treatments.Many infections have been reported in South-East Asia, where barbers commonly share and reuse razors. Detection of HBV DNA in contaminated devices such as razor blades is important in the demonstration of transmission routes and indirect estimation of HBV prevalence in specific subpopulations such as barbershop clientele. Therefore, we aimed to detect the presence of HBV contamination on razor blades by nucleic acid testing.

METHODS

Used razor blades (n = 151) were purchased from different barber's shops. Used razor blades purchased from chronic HBV patients (n = 8) were included as a positive control. The amplification and detection of HBV DNA was carried out by a semi-nested PCR method in a thermal cycler.

RESULTS

The presence of HBV DNA was found in 10 (6.6%) used razor-blade samples by the detection of a specific positive band with agarose gel electrophoresis.

CONCLUSIONS

In conclusion, used razor blades may be contaminated with HBV, and the practice of sharing used razor blades may pose a risk of transmission. Nucleic acid detection methods involving PCR can be used to detect HBV contamination of razor blades. HBV control and prevention programs should educate barbers about the importance of contagious diseases, proper sterilization techniques, and avoiding reuse and sharing of contaminated equipment and supplies such as razor blades. As an infection control measure, prohibition of razor reuse can reduce the spread of HBV infection in rural areas, where the practice is often common at barbershops.

Cloning and sequence analysis of complete genome of hepatitis B virus isolates of genotypes B, C, D/C and A from Chinese patients with chronic hepatitis B

AIM: To clone and sequence the complete genome of hepatitis sequence of hepatitis B virus (HBV) isolates of genotypes B, C, D/C and A from the sera of Chinese patients with chronic hepatitis B (CHB).

METHODS: Long-distant polymerase chain reaction (L-PCR) technique was used to amplify the complete genome of HBV isolates from Chinese patients with CHB. After the resulting amplicons were cloned into the TA vector and sequenced, the complete sequences of HBV isolates of genotypes B, C, D/C and A were analyzed using the DNAStar and Simpot software.

RESULTS: The complete genome sequences of HBV isolates of genotypes B, C, D/C and A, which had been deposited into GenBank, were composed of 3215, 3215, 3215 and 3182 bp, respectively. A 33-bp deletion mutation at position 2853-2885 and two point mutations at positions 1762A-T and 1764G-A were observed in one of four clones of sample H3. The coexistence of wild-type and mutant HBV strains in a patient with chronic hepatitis B may provide a molecular basis for the development of drug resistance during antiviral therapy.

CONCLUSION: The complete genome sequences of HBV isolates of genotypes B, C, D/C and A are successfully cloned and can be used as reference sequences for the study of HBV in Chinese patients with chronic hepatitis B.

Relationship between therapeutic efficacy of interferon in treating chronic hepatitis B and HBV genotypes

AIM: To study the effects of HBV genotypes on anti-virus-therapeutic efficacy of interferon in chronic HBV-infected patients.

METHODS: Thirty HBV-infected patients were treated with interferon for anti-virus. HBV genotypes were detected using PCR-RFLP and the response levels of interferon in different genotypes were observed.

RESULTS: For the 30 patients, the HBV genotypes were mainly type B (40.0%) and type C (56.67%). Level of HBV DNA was significantly higher in patients with type C than with type B (6.03 ± 1.35 vs 5.45 ± 1.21, P < 0.05), and the interferon response rate was higher in patients with type B than with type C. Among those with no response, 1 case with type B and another case with type C changed into type D.

CONCLUSION: It is suggested that HBV genotypes is correlated with the serum levels of HBV DNA and therapeutic efficacy of interferon. The genotype could be changed during the process of therapy.

Interaction between fibrinogen alpha chain and the whole S protein of hepatitis B virus

AIM: To screen the proteins interacting with the whole S protein of hepatitis B virus (HBV) from hepatocyte cDNA library by yeast two-hybrid system, and to validate interacting behavior between fibrinogen alpha chain and the whole S protein by reverse yeast two-hybrid.

METHODS: The whole S gene of HBV was cloned into yeast expression vector pDEST32 to construct a bait plasmid, which was verified by Western blot. The bait plasmid and prey plasmids inserted liver cDNA fragments were cotransformed into yeast cells MaV203 by Liac-mediated transformation. Diploid yeasts were plated on synthetic dropout nutrient medium to screen positive colonies. After extracting and sequencing of prey plasmids from positive colonies, the inserted sequences were bioinformatically analyzed. For reverse yeast two-hybrid, the bait plasmid expressing partial fibrinogen alpha chain and four prey plasmids expressing the whole S protein mutants were re-combined. The reconstituted bait plasmid was cotransformed into yeast cells MaV203 with the four prey plasmids, respectively. Diploid yeasts were plated on synthetic dropout nutrient medium and X-gal assay was performed to validate the interacting behavior.

RESULTS: By yeast two-hybrid technique, prey plasmids that were inserted partial gene coding 266-644 amino acid of fibrinogen alpha chain had a positive reaction with bait plasmid coding the whole S protein of HBV. By reverse yeast two-hybrid, fibrinogen alpha chain protein interacted with the four whole S protein mutants. The protein binding domain of the whole S protein might be the leading 268 amino acids.

CONCLUSION: Fibrinogen alpha chain protein may bind the whole S protein of HBV. The interacting domain is in the 266-644 amino acids of fibrinogen alpha chain and the frontal 268 amino acids of the whole S protein, respectively.

Advances of candidate binding protein to envelope protein of hepatitis B virus

There are at least 4 initial coding positions in S gene of hepatitis B virus (HBV), encoding pre-pre-S, pre-S1, pre-S2 as well as major protein. There are no definite evidences to prove that envelope protein will interact with human cellular protein. This review focused on research approaches to the existing protein - protein interaction and summarized proteins of liver cells that may interact with current HBV envelope protein. However, most of currently available results need further verification.

Establishment and primary application of a mouse model with hepatitis B virus replication

AIM: To establish a rapid and convenient animal model with hepatitis B virus (HBV) replication.

METHODS: A naked DNA solution of HBV-replication-competent plasmid was transferred to BALB/C mice via the tail vein, using a hydrodynamic in vivo transfection procedure. After injection, these mice were sacrificed on d 1, 3, 4, 5, 7 and 10. HBV DNA replication intermediates in the liver were analyzed by Southern blot hybridization. The expression of hepatitis B core antigen (HBcAg) and hepatitis B surface antigen (HBsAg) in the liver was checked by immunohistochemistry. Serum HBsAg and hepatitis B e antigen (HBeAg) was detected by enzyme-linked immunosorbent assay (ELISA). Inhibition of HBV replication was compared in HBV replication model mice treated intraperitoneally with polyinosinic-polytidylin acid (polyIC) or phosphate-buffered saline (PBS).

RESULTS: After hydrodynamic in vivo transfection, HBV DNA replication intermediates in the mouse liver were detectable on d 1 and abundant on d 3 and 4, the levels were slightly decreased and remained relatively stable between d 5 and 7, and were almost undetectable on d 10. The expression patterns of HBcAg and HBsAg were similar to that of HBV replication intermediate DNA, except that they reached a peak on d 1 after injection. No obvious differences in HBV DNA replication intermediates were observed in the left, right and middle lobes of the liver. After treatment with polyIC, the level of HBV intermediate DNA in the liver was lower than that in the control mice injected with PBS.

CONCLUSION: A rapid and convenient mouse model with a high level of HBV replication was developed and used to investigate the inhibitory effect of polyIC on HBV replication, which provides a useful tool for future functional studies of the HBV genome.

Knowledge and Attitude of Dental Practitioners in Ta-briz Regarding Infection Control Procedures

BACKGROUND AND AIMS

Blood-borne infections such as hepatitis B, hepatitis C and HIV might be transmitted from one individual to another during dental procedures. Therefore, sterilization and personal protection procedures are of utmost significance in dental offices. The importance of awareness of cross-infection and antiseptic principles lies in the fact that in most cases it is not possible to identify patients with hepatitis or AIDS. The aim of the present study was to evaluate awareness of infection control procedures among dental practitioners in Tabriz.

MATERIALS AND METHODS

In this descriptive study, 150 dental practitioners working in clinics and pri-vate offices of Tabriz were randomly selected. Data was collected by means of a self-administered questionnaire, which included respondents' personal profile and questions on infection control and sterilization methods.

RESULTS

There were no statistically significant differences in the level of knowledge between male and female dental practitioners regarding infection control; however, there was a decline in awareness as age increased.

CONCLUSION

The results of the present study suggest that in some cases dental practitioners neglect the principles for personal protection and cross-infection control. Therefore, our society is subject to widespread infection in dental offices and clinics. This potential risk necessitates careful monitoring along with government support of treatment procedures, the inclusion of infection control costs into treatment expenses and an emphasis on continuing education about infection control procedures through seminars and congresses.

Sequence polymorphism in the surface gene of hepatitis B virus and its distribution in the Beijing area

AIM: To investigate the sequence polymorphism of the surface (S) gene of hepatitis B virus (HBV), to study the distribution of viral genotypes/serum subtypes circulating in the Beijing area, and to search for possible correlations between viral genotypes/serum subtypes and clinical conditions.

METHODS: HBV DNA samples from 69 patients from the Beijing area were isolated and purified. The viral S gene was amplified by polymerase chain reaction (PCR) and then directly sequenced. Genotypes and serum subtypes were determined by sequence alignment and comparison with the standards with MEGA3.1. Nucleotide polymorphisms and amino acid changes of the S gene were analyzed using DnaSP software.

RESULTS: In the 69 patients, HBV from 14 samples was identified as genotype B (20.3%), and that of the remaining 55 as genotype C (79.7%). Adrq+ and adw2 of HBV were the predominant subtypes (75.4% and 20.3%, respectively). Further, 1 sample was determined as adrq- and 2 were detected as a previously unreported subtype. Mutation type showed significant differences in hydrophilic and hydrophobic regions of the S gene (P < 0.05, P < 0.001, respectively, in genotypes C and B). Compared to genotype B, higher sequence polymorphism was observed in genotype C. Nucleotide variation (π value) was not equally distributed in the S gene, and π in the "a" determinant was lower than that in other regions. Clinical symptoms were significantly associated with genotypes B and C, but not with serum subtypes (P < 0.05 and P = 0.381, respectively).

CONCLUSION: There is higher sequence variation of the surface gene in genotype C compared with genotype B. Mutations in the S gene are not randomly distributed. The two hydrophilic regions appear more conserved, while mutation frequency in the hydrophobic region is higher.

RNA interference inhibits hepatitis B virus gene expression and replication in HepG2-N10 cells

AIM: To evaluate the effect of vector-based small interfering RNA promoted by U6 (pSilencer2.0-U6) on the inhibition of hepatitis B virus (HBV) replication in HepG₂-N10 cells.

METHODS: Several sequences targeting on different regions of HBV genome were inserted into pSilencer vectors. The expression plasmids were then transfected into HepG₂-N10 cells, a cell line which stably expressed HBsAg, HBeAg and adw2 subtype Dane Particles. Viral antigens were measured by enzyme linked immunosorbent assay (ELISA). Viral mRNA was analyzed by reverse transcription-polymerase chain reaction (RT-PCR). The covalent closed circular DNA (cccDNA) secreted into the culture media were measured by quantitative real-time PCR.

RESULTS: Vector-based RNA interference potently reduced HBsAg and HBeAg expression in cell culture. Furthermore, RT-PCR analysis showed that viral mRNAs were effectively degraded, thus eliminating the messengers for protein expression as well as templates for reverse transcription. Quantitative Real-time PCR analysis of cccDNAs revealed that vector-based RNA interference inhibited HBV replication efficiently (HBV DNA log10: pS: 4.00 ± 0.13; pC: 4.08 ± 0.10; pX: 4.28 ± 0.06; pN: 5.05 ± 0.07; HepG₂-N10: 4.74 ± 0.06; HepG₂: <2.70).

CONCLUSION: RNA interference can inhibit HBV gene expression and virus replication.

Variable fragment of heavy chain antibody against TP region of Hepatitis B Virus polymerase inhibits replication of hepatitis B virus in vitro

AIM: To study a functional variable fragment of heavy chain (VH) antibody against the terminal protein (TP) region of hepatitis B virus (HBV) polymerase (Pol) and its inhibition on the replication of HBV in vitro.

METHODS: The TP region of HBV Pol secreted by the HepG2.2.15 cells was used as an antigen, and the antibodies were selected with protein fragment complementation assay (PCA). The VH antibody gene was cloned into expression vector pZeoSV2(+), and then pZeoSV2(+)-VH was transfected into HepG2.2.15 cells. The contents of HBV DNA in the cells were detected by fluorescent quantitative polymerase chain reaction (FQ-PCR).

RESULTS: Three antibodies against the TP region of HBV were selected. The replication of HBV was markedly inhibited by the anti-TP Pol VH antibodies. The contents of HBV DNA in the pZeoSV2(+)-VH transfected cells (Group C) were significantly higher than those in the non-transfected and pZeoSV2(+) transfected cells (Group A and C)(Supernate: 3.480±0.32 vs 5.268±0.07, 5.105±0.78, P<0.05; Intracellular: 5.718±0.15 vs 7.716±0.74, 7.394±0.97, P<0.05).

CONCLUSION: The anti-TP Pol VH antibodies can inhibit the replication of HBV in HepG2.2.15 cells.

Drug-resistant mutation andgenotype of hepatitis B virus Heilongjiang Province

AIM: To determine the relationship between YMDD mutation of hepatitis B virus (HBV) and HBV genotypes during lamivudine treatment.

METHODS: HBV genotypes were determined by nested polymerase chain reaction (PCR) with six pairs of HBV genotype-specific primers (A to F). Then YMDD mutations were detected by real-time fluorescent PCR in serum specimens from 106 hepatitis B patients receiving lamivudine therapy.

RESULTS: Of 106 serum specimens, there were 8 samples belonging to genotypes B (7.6%), 94 genotypes C (88.7%), and 4 genotypes D (3.8%). Sixty-three YMDD mutations were found (59.4%) and the other 43 were YMDD of wild type. The mutant rates of YMDD were 62.5%(5/8) and 58.5%(55/94) in genotypes B and C respectively and no significant difference existed between them (P>0.05). Of 5 genotypes B with YMDD mutations, 1 YIDD (YMDD+YIDD) mutation (20%) and 4 YVDD (YMDD+YVDD) mutations were found. Of genotypes C with YMDD mutations, there were 26 YIDD mutations, (47.3%)17 YVDD mutations (30.9%) and 12 YIDD+YVDD mutations (21.8%). No significant differences were manifested in YMDD mutant types between genotypes B and C (P>0.05).

CONCLUSION: The mutant rate of YMDD is 59.4% after 2-4 years of treatment with lamivudine. The mutant rates and types show no significant differences between genotype B and C of HBV in Heilongjiang Province.

Effects of Distinct Adjuvant on HCV DNA Vaccine at Different Dosages

AIM: To explore the effects of different adjuvants on different dosages of hepatitis C virus (HCV) DNA vaccine.

METHODS: Female Balb/c mice were primed by HCV DNA vaccine composed of HCV structure gene DNA, HCV nonstructure gene 3 (NS3) and NS5b at the dosages of either 100 mg/each or 50mg/each with liposome DDAB/EPC or aluminum hydroxide and boosted twice accordingly. The cytokine profiles induced by various HCV antigens on splenocytes from the immunized mice were assessed by ELISPOT assay using in vitro splenocyte culture stimulated with recombinant HCV core, E2, E1/E2, NS3 or NS5b protein.

RESULTS: The frequency of IFN-g or IL-4 secreting cells found in splenocytes stimulated with HCV core, E2, or E1/E2 from the mice vaccinated with HCV recombinant DNA in DDAB/EPC adjuvant was significantly higher (P<0.05) than that from mice immunized with either naked DNA or DNA formulated in aluminum hydroxide. The frequency of IL-4 secreting cells from mice immunized with HCV DNA at a dosage of 100 mg/each mixed with aluminum hydroxide was significantly higher than that from naked DNA when the splenocytes were stimulated with all the antigens tested except E2 (P<0.05). At many cases, lymphocytes from mice received 100 mg/each DNA have more IFN-g or IL-4 productions compared with those from mice with 50 mg/each (P<0.05). The lymphocytes from mice primed and boosted with HCV DNA plus aluminum hydroxide can produce more IL-4 than IFN-g in contrast with the cytokine profile of mice immunized with naked DNA or DDAB/EPC adjuvant.

CONCLUSION: Liposome DDAB/EPC has strong adjuvant effects on HCV DNA vaccine. Aluminum hydroxide is a Th2 adjuvant and can convert the Th1 nature of DNA vaccine to Th2-biased immunity. It seems that the dosage of 50 mg of HCV DNA vaccine is not adequate to elicit efficient immunity in mice.

Expression and immunoactivity of chimeric particulate antigens of receptor binding site-core antigen of hepatitis B virus

AIM: To improve the immunogenicity of receptor binding site of hepatitis B virus (HBV) on preS1 antigen using HBV core antigen as an immuno-carrier.

METHODS: One to 6 tandem copies of HBV preS1 (21-47) fragment were inserted into HBcAg at the sites of aa 78 and 82, and expressed in E.coli. ELISA, Western blot and animal immunization were used to analyze the antigenicity and immmunogenicity of purified particulate antigens. The ability to capture HBV by antibodies elicited by chimeric particles was detected with immuno-capture PCR.

RESULTS: Recombinant antigens CI, CII, CIII carrying 1-3 copies of HBV preS1 (21-47) individually could form virus-like particles (VLPs), similar to HBcAg in morphology. But recombinant antigens carrying 4-6 copies of HBV preS1 (21-47) were poorly expressed in E.coli. Chimeric antigens were lacking of immunoreactivity with anti-HBc monoclonal antibodies (McAbs), but still reserved good immunoreactivity with anti-HBe McAbs. CI, CII, CIII could strongly react with anti-preS1 McAb, suggesting that preS1 (21-47) fragment was well exposed on the surface of chimeric VLPs. Three chimeric VLP antigens (CI, CII and CIII) could stimulate mice to produce high-level antibody responses, and their immunogenicity was stronger than non-particulate antigen 21-47*6, containing 6 copies of preS1 (21-47). Mouse antibodies to CI, CII and CIII were able to capture HBV virions in immuno-capture PCR assay in vitro.

CONCLUSION: Chimeric particulate antigens of receptor binding site-core antigen of HBV can elicit strong antibody responses to preS1. They have a potential to be developed into prophylactic or therapeutic vaccines against HBV infection.

Detection of hepatitis B virus DNA by real-time PCR using TaqMan-MGB probe technology

AIM: To develop a real-time PCR for detecting hepatitis B virus (HBV) DNA based on TaqMan technology using a new MGB probe.

METHODS: Plasmid containing the sequence of X gene (1414-1744 nt) was constructed as HBV-DNA standard for quantitative analysis. A TaqMan-MGB probe between primers for amplification was designed to detect PCR products. The interested sequence contained in the plasmid and in clinical specimens was quantitatively measured.

RESULTS: The detection limit of the assay for HBV DNA was 1 genome equivalent per reaction. A linear standard curve was obtained between 10⁰ and 10⁹ DNA copies/reaction (r>0.990). None of the negative control samples showed false-positive reactions in duplicate. HBV DNA was detected in 100% (50/50) of HBV patients with HbeAg, and in 72.0% (36/50) with HBsAg, HBeAb and HBcAb. The coefficient of variation for both intra- and inter-experimental variability demonstrated high reproducibility and accuracy.

CONCLUSION: Real-time PCR based on TaqMan-MGB probe technology is an excellent method for detection of HBV DNA.