Susan I. Ie

Occult hepatitis B in blood donors in Indonesia: altered antigenicity of the hepatitis B virus surface protein

Background and aimsOccult hepatitis B virus infection (OBI) poses a challenge to the safety of blood donation. The prevalence of OBI is not well documented in Indonesia, although this information in such an endemic country is needed. This study was aimed to evaluate the prevalence of occult hepatitis B in blood donors from two cities of Indonesia, and to study the genetic variation and its effect on the predicted antigenicity of HBsAg.MethodsSerum samples of 309 regular blood donors negative for HBsAg were tested for anti-HBs and anti-HBc. Hepatitis B virus (HBV) DNA isolated from anti-HBc-positive samples were analyzed by polymerase chain reaction, cloned and sequenced. Antigenic properties of identified HBsAg mutants were predicted by calculation of the antigenic index.ResultsOf the 309 HBsAg-negative samples, anti-HBc was positive in 134 (43.4%) and HBV DNA was detected in 25 (8.1%). Seven of the viremic samples had nucleotide substitutions (A521G, A551T, C582T, and A562G) in the S gene, causing amino acid mutations (T123A, M133L, and T143M) in the ‘a’ determinant of HBsAg that resulted in changes in the predicted antigenicity.ConclusionsOBI was detected in blood donors’ samples in Indonesia. Anti-HBc was shown to be a better screening parameter than HBsAg, however, it might result in the loss of donors particularly in endemic countries. HBsAg detection failure in this study might be due to mutations altering the protein antigenicity and/or the low-level carriage of HBV.

Significance of hepatitis virus infection in the oncogenic initiation of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related death worldwide. Chronic infection of hepatitis B virus (HBV) and/or hepatitis C virus (HCV) is a major risk factor in the development of the HCC, independently from excessive alcohol abuse and metabolic disease. Since the biology of HBV and HCV is different, their oncogenic effect may go through different mechanisms, direct and/or indirect. Viral hepatitis infection is associated with cellular inflammation, oxidative stress, and DNA damage, that may lead to subsequent hepatic injuries such as chronic hepatitis, fibrosis, cirrhosis, and finally HCC. Direct oncogenic properties of these viruses are related with their genotypic characteristics and the ability of viral proteins to interact with host proteins, thus altering the molecular pathways balance of the cells. In addition, the integration of HBV DNA, especially the gene S and X, in a particular site of the host genome can disrupt chromosomal stability and may activate various oncogenic mechanisms, including those in hematopoietic cells. Recently, several studies also had demonstrated that viral hepatitis could trigger the population of hepatic cancer stem cells. This review summarize available pre-clinical and clinical data in literature regarding oncogenic properties of HBV and HCV in the early initiation of HCC.

Genogeography and Immune Epitope Characteristics of Hepatitis B Virus Genotype C Reveals Two Distinct Types: Asian and Papua-Pacific.

Distribution of hepatitis B virus (HBV) genotypes/subgenotypes is geographically and ethnologically specific. In the Indonesian archipelago, HBV genotype C (HBV/C) is prevalent with high genome variability, reflected by the presence of 13 of currently existing 16 subgenotypes. We investigated the association between HBV/C molecular characteristics with host ethnicity and geographical distribution by examining various subgenotypes of HBV/C isolates from the Asia and Pacific region, with further analysis on the immune epitope characteristics of the core and surface proteins. Phylogenetic tree was constructed based on complete HBV/C genome sequences from Asia and Pacific region, and genetic distance between isolates was also examined. HBV/C surface and core immune epitopes were analyzed and grouped by comparing the amino acid residue characteristics and geographical origins. Based on phylogenetic tree and geographical origins of isolates, two major groups of HBV/C isolates—East-Southeast Asia and Papua-Pacific—were identified. Analysis of core and surface immune epitopes supported these findings with several amino acid substitutions distinguishing the East-Southeast Asia isolates from the Papua-Pacific isolates. A west-to-east gradient of HBsAg subtype distribution was observed with adrq+ prominent in the East and Southeast Asia and adrq- in the Pacific, with several adrq-indeterminate subtypes observed in Papua and Papua New Guinea (PNG). This study indicates that HBV/C isolates can be classified into two types, the Asian and the Papua-Pacific, based on the virus genome diversity, immune epitope characteristics, and geographical distribution, with Papua and PNG as the molecular evolutionary admixture region in the switching from adrq+ to adrq-.

HBsAg, HBeAg and HBV DNA level changes and precore/basal core promoter mutations in the natural history of chronic hepatitis B in Indonesian patients

IntroductionChronic hepatitis B (CHB) is a state of complex interactions between the hepatitis B virus (HBV) and host. We studied the changes in hepatitis B surface antigen (HBsAg), hepatitis B ‘e’ antigen (HBeAg) and HBV DNA levels, considering the implications of HBV genotype, basal core promoter (BCP) A1762T/G1764A and precore G1896A mutations in CHB.MethodsOne hundred fifty-two treatment-naïve CHB patients were classified into immune-tolerant (IT), immune-clearance (IC), low/non-replicative (LR) and ‘e’-negative hepatitis B (ENH) phases, based on HBeAg status, HBV DNA and ALT levels. HBV DNA was detected and quantified by polymerase chain reaction, then analyzed by sequencing. HBsAg and HBeAg levels were measured serologically.ResultsHBsAg and HBV DNA levels varied between CHB phases, with HBsAg highest in IT and lowest in LR, and HBV DNA high in IT and IC, and lowest in LR. Both markers increased in ENH. Correlation between HBsAg and HBV DNA was significant in IT and IC, modest in ENH, but missing in LR. HBeAg and HBV DNA levels were dissociated in HBeAg-positive patients. Genotypes B and C were similarly distributed, with precore mutations higher in HBeAg-negative patients and BCP mutations comparable in all phases. Temporal association between HBeAg seroconversion and an increase of BCP/precore mutations was observed.ConclusionHBsAg and HBV DNA levels were high and correlated in early CHB phases and dissociated after HBeAg seroconversion, indicating different controls affecting HBV replication and HBsAg production. Selection of BCP/precore mutants may affect disease course and explain the HBeAg–HBV DNA dissociation, a precaution for clinical application of quantitative HBeAg.

Chronic hepatitis B in pregnant women: is hepatitis B surface antigen quantification useful for viral load prediction?

BACKGROUND New cases of hepatitis B virus (HBV) infection continue to occur worldwide. Most of these are due to mother-to-child transmission (MTCT), with maternal viraemia as the most important contributing factor. The hepatitis B surface antigen (HBsAg) level, which correlates positively with viral load, has been used for treatment monitoring in chronic hepatitis B. This study evaluated the usefulness of quantitative HBsAg for viral load prediction in HBsAg-positive pregnant women. METHODS A total of 943 pregnant women in Makassar, Indonesia, were screened for HBsAg. Sixty-four women were HBsAg-positive and investigated. HBsAg level and hepatitis B e antigen (HBeAg)/hepatitis B e antibody (anti-HBe) status were determined serologically. Viral load was measured by real-time PCR. HBV DNA was sequenced and analysed for identification of genotype and basal core promoter (BCP)/precore (PC) mutations. RESULTS Of 64 subjects, 12 (18.8%) were HBeAg-positive and 52 (81.3%) were HBeAg-negative. HBsAg and HBV DNA levels were significantly higher in the HBeAg-positive group (p<0.001). HBsAg and HBV DNA levels were positively correlated in the HBeAg-positive group (r = 0.659; p=0.02), but not in the HBeAg-negative group (r=0.194; p=0.168). Low HBsAg levels (<3.0 log10 IU/ml) corresponded with HBV DNA levels<6.0 log10 IU/ml (r=0.404; p=0.001), a recognized threshold for MTCT. Genotype C was more prevalent than genotype B, but not associated with HBsAg level, viral load, or HBeAg status. Two-thirds of HBeAg-negative subjects with high HBV DNA levels harboured BCP (A1762T/G1764A) and/or PC (G1896A) variants. CONCLUSIONS HBsAg levels provide a good viral load predictor in HBeAg-positive but not HBeAg-negative pregnant women. The HBeAg-negative group had a frequent occurrence of BCP/PC variants, which may have contributed to the lack of correlation observed. Samples with a low HBsAg level, which is associated with a low risk of MTCT, do not require HBV DNA measurement.

High Prevalence of Hepatitis B Virus Infection in Young Adults in Ternate, Eastern Indonesia

The incidence of hepatitis B virus (HBV) infection has been declining thanks to the universal hepatitis B infant immunization program. Nevertheless, young adults born before the program implementation might have acquired HBV in early childhood or remain susceptible to infection. This study aimed to evaluate hepatitis B epidemiology in asymptomatic young adult population in Ternate, eastern Indonesia. Serum samples of 376 subjects (aged 17-25, mean 19.82 ± 1.69 years; male/female 138/238) were screened for HBV parameters serologically (HBV surface antigen [HBsAg]; its antibody [anti-HBs]; anti-core antigen [anti-HBc]), and molecularly (HBV DNA). HBsAg, anti-HBc, anti-HBs, and HBV DNA prevalence were 15.7%, 36.2%, 24.2%, and 27.9%, respectively, with male predominance. Of all subjects, 13.0% were HBsAg negative with detectable HBV DNA (occult hepatitis B [OHB]), and 56.4% showed negativity for all seromarkers. This population showed high hepatitis B prevalence with substantial occurrence of OHB. However, a high percentage of the population were still susceptible and at risk of HBV infection. This study emphasizes the necessity to improve prevention strategies to screen and manage HBV carriers, including the adoption of catch-up or booster vaccination targeted to young adult populations. Investigations on the roles of host-virus interactions associated with OHB and its implications are warranted.

Activation of hepatic stem cells compartment during hepatocarcinogenesis in a HBsAg HBV-transgenic mouse model

Chronic infection of Hepatitis B Virus (HBV) is one of the highest risk factors of hepatocellular carcinoma (HCC). The accumulation of HBV surface antigen (HBsAg) into hepatocytes induces inflammation and oxidative stress, impairing their replicative ability and allowing the activation of the hepatic stem cells (SC) compartment. This study aimed to understand the involvement of SC during hepatocarcinogenesis in HBsAg-related liver damage, from early injury until HCC. HBsAg-transgenic (TG) and wild type (WT) mouse were followed at several stages of the liver damage: inflammation, early hepatocytes damage, dysplasia, and HCC. Serum transaminases, liver histology, and diagnostic data were collected. The expressions of SC and cancer stem cells (CSC) markers was analyzed by RT-qPCR, immunohistochemistry and Western blot. Starting from 3 months, TG animals showed a progressive liver damage characterized by transaminases increase. The up-regulations of SCs markers Cd34 and Sca-1 started from the beginning of the inflammatory stage while progressive increase of Krt19 and Sox9 and CSCs markers Epcam and Cd133 from early hepatic injury. The expressions of Cd133, Cd34, and Afp were significantly higher in HCC compared to paired non-HCC tissue, in contrast to Epcam and Krt19. Western blot and IHC confirmed the positivity of Cd34 and Cd133 in small cells subpopulation.