High frequency of genotype D and spontaneous hepatitis B virus genomic mutations among Haitians in a multiethnic North American population

Novel X gene point mutations in chronic hepatitis B and HBV related cirrhotic patients

INTRODUCTION

HBx is a multifunctional modulator viral protein with key roles in various biological processes such as signal transduction, transcription, proliferation, and cell apoptosis. Also, HBx has an important role in the progression of cirrhosis and hepatocellular carcinoma (HCC). This study aimed to determine mutations in X gene, enhancer II (EnhII), and basal core promoter (BCP) of genotype D of Hepatitis B Virus (HBV) in cirrhotic and chronic HBV patients.

MATERIAL AND METHODS

This cross-sectional study was performed on 68 cases with chronic HBV (cHBV) and 50 cases with HBV related cirrhosis. Serum samples were obtained for genomic DNA extraction. Semi-nested PCR was used to amplify the HBx region. Point mutations in the HBx region were detected by sequencing.

RESULT

Novel mutations were detected, including C1491G, C1500T, G1613T, and G1658T in the N-terminal of the X gene. The frequency of C1481T/G1479A, T1498C, C1500T, G1512A, A1635T, C1678T, A1727T, and A1762T/ G1764A/ C1773T was significantly higher in cirrhotic patients compared to chronically HBV infected ones. A higher rate of A1635T, C1678T, A1727T, A1762T, G1764A, and C1773T was observed in cirrhotic patients.

CONCLUSION

Our findings showed that the frequency of mutations in the basal-core promoter, enhancer II, and regulatory region of the HBx gene was more seen in cirrhotic patients than in chronic HBV cases. Novel mutations were detected in the HBx gene, causing amino acid substitutions; however, the clinical impact of these novel mutations is yet to be cleared.

Integrated HIV surveillance finds recent adult hepatitis B virus (HBV) transmission and intermediate HBV prevalence among military in uncharacterized Caribbean country

Background

Guyana expanded its HIV response in 2005 but the epidemiology of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections has not been characterized.

Methods

The 2011 Seroprevalence and Behavioral Epidemiology Risk Survey for HIV and STIs collected biologic specimens with demographic and behavioral data from a representative sample of Guyana military personnel. Diagnostics included commercial serum: HIV antibody; total antibody to hepatitis B core (anti-HBc); IgM anti-HBc; hepatitis B surface antigen (HBsAg); anti-HBs; antibody to HCV with confirmatory testing; and HBV DNA sequencing with S gene fragment phylogenetic analysis. Chi-square, p-values and prevalence ratios determined statistical significance.

Results

Among 480 participants providing serologic specimens, 176 (36.7%) tested anti-HBc-positive. Overall, 19 (4.0%) participants tested HBsAg-positive; 17 (89.5%) of the HBsAg-positive participants also had detectable anti-HBc, including 1 (5.3%) IgM anti-HBc-positive male. Four (6.8%) females with available HBV testing were HBsAg-positive, all aged 23–29 years. Sixteen (16, 84.2%) HBsAg-positive participants had sufficient specimen for DNA testing. All 16 had detectable HBV DNA, 4 with viral load >2x10⁴IU/ml. Sequencing found: 12 genotype (gt) A1 with 99.9% genetic identity between 1 IgM anti-HBc-positive and 1 anti-HBc-negative; 2 gtD1; and 2 with insufficient specimen. No statistically significant associations between risk factors and HBV infection were identified.

Conclusions

Integrated HIV surveillance identified likely recent adult HBV transmission, current HBV infection among females of reproductive age, moderate HBV infection prevalence (all gtA1 and D1), no HCV infections and low HIV frequency among Guyana military personnel. Integrated HIV surveillance helped characterize HBV and HCV epidemiology, including probable recent transmission, prompting targeted responses to control ongoing HBV transmission and examination of hepatitis B vaccine policies.

Hepatitis B virus infection in Latin America: A genomic medicine approach

Hepatitis B virus (HBV) infection is the leading cause of severe chronic liver disease. This article provides a critical view of the importance of genomic medicine for the study of HBV infection and its clinical outcomes in Latin America. Three levels of evolutionary adaptation may correlate with the clinical outcomes of HBV infection. Infections in Latin America are predominantly of genotype H in Mexico and genotype F in Central and South America; these strains have historically circulated among the indigenous population. Both genotypes appear to be linked to a benign course of disease among the native and mestizo Mexicans and native South Americans. In contrast, genotypes F, A and D are common in acute and chronic infections among mestizos with Caucasian ancestry. Hepatocellular carcinoma is rare in Mexicans, but it has been associated with genotype F1b among Argentineans. This observation illustrates the significance of ascertaining the genetic and environmental factors involved in the development of HBV-related liver disease in Latin America, which contrast with those reported in other regions of the world.