Re-treatment of chronic hepatitis C patients after relapse: efficacy of peginterferon-alpha-2a (40 kDa) and ribavirin.

We conducted a randomized multinational study to determine whether 48 weeks of re-treatment with peginterferon-alpha-2a (40 kDa) plus ribavirin would induce a sustained virological response (SVR) in relapsed chronic hepatitis C patients. Patients who had previously relapsed during 24 weeks of untreated follow-up, after having achieved an end-of-treatment virological response with 24 weeks of peginterferon-alpha-2a (40 kDa)/ribavirin combination therapy, within a phase III trial, were studied. Although the recommended dosage was the same as that used at the end of the initial trial, adjustments were permitted. Data on serious adverse events, or adverse events that resulted in dose reductions or discontinuations, were collected. Following re-treatment, the overall SVR rate in the 64 patients was 55%. The SVR rates in patients infected with hepatitis C virus (HCV) genotype 1 and non-1 genotypes were 51% and 63%, respectively. Early (week 12) virological responses were seen in 39 patients (61%) and were predictive of an SVR. Re-treatment was well tolerated. The most frequent adverse events recorded were fatigue (5%) and abdominal pain (3%). Dosages of peginterferon-alpha-2a (40 kDa) and/or ribavirin were modified because of adverse events in 3% and 13% of patients, and because of laboratory abnormalities in 23% and 5% of patients, respectively. Thus, a 48-week course of peginterferon-alpha-2a (40 kDa) plus ribavirin induces an SVR in 55% of patients who relapsed during follow-up after 24 weeks of combination therapy. Physicians should not hesitate to offer re-treatment to patients who relapse after an initial, 24-week course of combination therapy, or who have prematurely stopped treatment because, for example, of laboratory abnormalities.

Systematic review: treatment of chronic hepatitis B virus infection by pegylated interferon.

BACKGROUND: Pegylated interferon-alpha has been shown to be more efficacious than conventional interferon in treating chronic hepatitis C. The use of peginterferon in chronic hepatitis B virus infection with positive hepatitis B e antigen has also been tested in a number of trials since 2003. AIM: To systematically summarize and compare the results of these studies. METHODS: Four studies were identified from PubMed, Medline and reference lists. Data from the trials were extracted and analysed. Where appropriate, combined odds ratio of different trials was calculated. Safety data including serious adverse events and emergence of drug-resistant mutants were recorded. RESULTS: Three of the four trials contained predominantly Asian patients. Peginterferon is found to be superior to lamivudine monotherapy and induced sustained biochemical and virological responses in about one-thirds of patients after 12 months of therapy. Coadministration of lamivudine did not result in improvement in viral suppression. Peginterferon appears to reduce the emergence of YMDD mutation in the combination treatment groups. It was well tolerated with serious adverse events reported in <10% of patients in most trials. CONCLUSIONS: Peginterferon-alpha treatment of at least 6 months should be considered as one of the first-line therapeutic options for hepatitis B virus infection.

HBV core sequence: definition of genotype-specific variability and correlation with geographical origin.

There are eight genotypes and nine subtypes of HBV. Small differences in geographical origin are associated with sequence changes in the surface gene. Here, we compared core gene sequences from different genotypes and geographical regions. Specific combinations of 24 amino acid substitutions at nine residues allowed allocation of a sequence to a subtype. Six of these nine residues were located in different T cell epitopes depending on HBV geographical area and/or genotype. Thirty-seven nucleotide changes were associated uniquely with specific genotypes and subtypes. Unique amino acid and nucleotide variants were found in a majority of sequences from specific countries as well as within subtype ayw2 and adr. Specific nucleotide motifs were defined for Korean, Indian, Chinese, Italian and Pacific region isolates. Finally, we observed amino acid motifs that were common to either South-east Asian or Western populations, irrespective of subtype. We believe that HBV strains spread within constrained ethnic groups, result in selection pressures that define sequence variability within each subtype. It suggests that particular T cell epitopes are specific for geographical regions, and thus ethnic groups; this may affect the design of immunomodulatory therapies.

Prevalence of HBsAg mutants and impact of hepatitis B infant immunisation in four Pacific Island countries.

The prevalence rate of hepatitis B virus (HBV) infection in Pacific Island countries is amongst the highest in the world. Hepatitis B immunisation has been incorporated into national programmes at various times, often with erratic supply and coverage, until a regionally co-ordinated programme, which commenced in 1995 ensured adequate supply. The effectiveness of these programmes was recently evaluated in four countries, Vanuatu and Fiji in Melanesia, Tonga in Polynesia and Kiribati in Micronesia. That evaluation established that the programmes had a substantial beneficial impact in preventing chronic hepatitis B infection [Vaccine 18 (2000) 3059]. Several studies of hepatitis B vaccination programmes in endemic countries have identified the potential significance of surface gene mutants as a cause for failure of immunisation. In the study outlined in this paper, we screened infected children and their mothers for the emergence and prevalence of these variants in specimens collected from the four country evaluation. Although the opportunity for the emergence of HBV vaccine escape mutants in these populations was high due to the presence of a considerable amount of the virus in the population and the selection pressure from vaccine use, there were no "a" determinant vaccine escape mutants found. This suggests that vaccine escape variants are not an important cause for failure to prevent HBV transmission in this setting. Other HBsAg variants were detected, but their functional significance remains to be determined. The failure to provide satisfactory protection during such immunisation programmes reflects the need for achieving and sustaining high vaccine coverage, improving the timeliness of doses as well as improving 'cold-chain' support, rather than the selection of vaccine-escape mutants of HBV.

Hepatitis A booster vaccination: is there a need?

Hepatitis A is one of the most common vaccine-preventable infectious diseases in the world. Effective vaccines against hepatitis A have been available since 1992, and they provide long-term immunity against the infection. However, there is no worldwide consensus on how long protection will last or whether there will be a need for hepatitis A virus (HAV) booster vaccinations in the future. In most countries, booster-vaccination policy is guided by manufacturers' recommendations, national authorities, or both. In June, 2002, a panel of international experts met to review the long-term immunogenicity and protection conferred by HAV vaccine in different population groups. Data have shown that after a full primary vaccination course, protective antibody amounts persist beyond 10 years in healthy individuals, and underlying immune memory provides protection far beyond the duration of anti-HAV antibodies. The group concluded that there is no evidence to lend support to HAV booster vaccination after a full primary vaccination course in a healthy individual. However, further investigations are needed before deciding if boosters can be omitted in special patient-groups.

A molecular comparison of T lymphocyte populations infiltrating the liver and circulating in the blood of patients with chronic hepatitis B: evidence for antigen-driven selection of a public complementarity-determining region 3 (CDR3) motif.

Despite a large number of T cells infiltrating the liver of patients with chronic hepatitis B, little is known about their complexity or specificity. To characterize the composition of these T cells involved with the pathogenesis of chronic hepatitis B (CHB), we have studied the clonality of VbetaT cell receptor (TCR)-bearing populations in liver tissue by size spectratyping the complementarity-determining region (CDR3) lengths of TCR transcripts. We have also compared the CDR3 profiles of the lymphocytes infiltrating the liver with those circulating in the blood to see whether identical clonotypes may be detected that would indicate a virus-induced expansion in both compartments. Our studies show that in most of the patients examined, the T cell composition of liver infiltrating lymphocytes is highly restricted, with evidence of clonotypic expansions in 4 to 9 TCR Vbeta subfamilies. In contrast, the blood compartment contains an average of 1 to 3 expansions. This pattern is seen irrespective of the patient's viral load or degree of liver pathology. Although the TCR repertoire profiles between the 2 compartments are generally distinct, there is evidence of some T cell subsets being equally distributed between the blood and the liver. Finally, we provide evidence for a putative public binding motif within the CDR3 region with the sequence G-X-S, which may be involved with hepatitis B virus recognition.

An efficient extraction method from blood clots for studies requiring both host and viral DNA.

The clot from blood is usually discarded after the collection of serum. Yet, it contains nucleated white blood cells and substantial serum. Here, we have compared four methods to enable quick and efficient extraction of human genomic and viral DNA from clotted blood. Two of these methods, a phenol-based in-house method and Tripure isolation reagent, only achieved a low polymerase chain reaction (PCR) yield. In contrast, the QIAamp blood kit and the High Pure Viral Nucleic Acid kit were equally efficient, with similar sensitivity to serum for extraction of viral DNA.

A review of Hib epidemiology in Asia.

Meningitis due to an invasive Haemophilus influenzae type b (Hib) infection, has been previously perceived to be relatively uncommon in Asia. However, the incidence of disease and its impact may have been underestimated. In addition to a lack of microbiological facilities in some hospitals, difficulties in culturing the organism and the widespread use of antibiotics may have hidden the true incidence of the disease in some countries. Furthermore, the reported disease burden probably underestimates the incidence of Hib pneumonia. The epidemiology of invasive Hib disease for various Asian nations is reviewed in this paper. Hospital-based studies show that Hib is a major cause of bacterial meningitis and/or pneumonia in the Philippines, India, Thailand, Malaysia, Indonesia and Vietnam. Singapore and Hong Kong have a low incidence of infection compared with Western and other Asian nations. This low incidence is not due to a higher level of natural protective antibodies, but may be related to an interaction between environmental and genetic factors. Therefore the widespread belief that Hib infection is unimportant in Asia does not refer to Asia as a whole and possibly to Chinese patients only, and failure to recognize this has serious implications. The inclusion of Hib vaccine in the routine infant immunization schedule in many industrialized nations has significantly reduced the incidence of invasive disease. Recent studies have shown Hib vaccination is also effective in preventing invasive disease in children in developing countries. While population-based data may be required to confirm the need for public-funded infant Hib immunization in Asia, its introduction in countries with a high incidence of Hib meningitis and/or pneumonia has the potential to significantly improve pediatric health and survival.

The DRD2A1allele: a behavioural genetic risk factor in hepatitis C infection of persistent drug abusers.

Hepatitis C is highly prevalent among intravenous drug abusers, but to date research has not widely explicated behavioural risk factors regarding acquisition of infection. The A1allele of the D2 dopamine receptor (DRD2) gene is a hypothesized risk factor in the development of severe drug dependence and alcoholism. The present study compares the frequency of the A1 allele of the DRD2 gene among 37 patients presenting to a hepatitis clinic for treatment of hepatitis C, 23 hepatitis C-negative drug-abusing patients maintained on methadone and 33 non-drug-abusing controls. The results indicated that hepatitis C-positive patients were significantly more likely to display the A1 allele than hepatitis C-negative patients, who were in turn more likely to have the A1 allele than controls. Furthermore, the hepatitis C subjects manifested more persistent drug-seeking behaviour than the other drug-abusing group. The implications of this finding in terms of drug-related reward are discussed. Future research should attempt to evaluate host risk factors, in order to enable more precisely targeted attempts at harm minimization.

Distinct patterns of T cell receptor distribution of peripheral blood CD8+ cells during different stages of chronic infection with hepatitis B virus.

We compared the Vbeta TCR repertoires of CD8+ peripheral blood lymphocytes between 21 patients with chronic hepatitis B (CHB) and 9 healthy individuals, using RT-PCR analysis. Several differences were seen between CHB patients and controls, including a marked increase in the expression of two to five Vbeta families in the CHB patients. There was no evidence for a superantigen effect, although an increase in Vbeta7 was seen in 64% of patients. A significant under-expression of Vbeta families were also detected, particularly in patients with active liver disease in which under-expression of Vbeta14 and Vbeta15 was associated with acute exacerbations of liver disease. We also did a longitudinal analysis of the TCR repertoire in two patients over a period of 6 months, from the initiation of a disease flare to its resolution. One patient continued to experience spontaneous flares following the completion of this study, while the other patient underwent spontaneous remission with long-term (> 12 months) loss of HBeAg following resolution of the flare. The TCR repertoires of both patients were altered during the flare, and there was a higher degree of TCR variability in the patient who went into remission.

Composition of peripheral blood lymphocyte populations during different stages of chronic infection with hepatitis B virus.

To characterize the immunological populations associated with different stages of chronic infection with hepatitis B virus (HBV), we performed flow cytometric analyses on the peripheral blood leucocytes of 29 patients with various forms of chronic hepatitis B. The clinical spectrum of the patients ranged from asymptomatic infections, in the presence of high virus production, to intermittent or recurrent exacerbations of liver injury alternating with relatively normal liver function. Patients with partial resolution of disease who experienced an initial acute flare followed by prolonged seroconversion showed decreased percentages of CD3+ cells during the seroconversion phase when levels of serum alanine transferase (ALT) had normalized. These CD3+ cells were predominantly CD4+ cells bearing the alpha beta+ T-cell receptor (TCR). In addition, we saw an increase in CD4+ and CD8+ cells bearing the gamma delta TCR in those patients who had seroconverted. No significant differences were seen between any of the groups with respect to percentage of cells with a naive (CD45RA) or memory (CD45RO) phenotype, or of cells displaying the activation markers CD38, HLA-DR or CD57. Longitudinal analyses of 15 patients failed to show any consistent pattern of changes in the immunophenotypic profile during acute flares and their resolution. Our results indicate that the turnover of circulating T lymphocytes during the apparent quiescent phase of chronic infections is higher than that during acute exacerbations, suggesting an active immunosurveillance role of T-cell subpopulations in maintaining low virus levels during seroconversion.

Hepatitis A virus: declining seroprevalence in children and adolescents in Southeast Asia.

The prevalence of hepatitis A virus (HAV) in a country largely reflects its standards of hygiene and socioeconomic conditions. Countries which undergo socioeconomic development show major change in HAV prevalence from high to low endemicity, and this is largely reflected in patterns of age-related seroprevalence. This paper presents age-related HAV seroprevalence patterns of SE Asian countries, and highlights how these patterns have changed over recent decades. Singapore, Thailand and Malaysia have experienced a decline in childhood and adolescent HAV seroprevalence, typical of countries which undergo socioeconomic development. By contrast, India has remained a country of high endemicity, with almost universal seroconversion in childhood. The Philippines and Vietnam show age-related seroprevalence patterns typical of high to moderate endemicity, while Indonesia shows significant regional variation in HAV seroprevalence. Populations within countries which exhibit major improvements in endemicity and age related HAV seroprevalence patterns are at risk of HAV epidemics, and a paradoxical increase in incidence tends to occur as seroconversion shifts from children to adults. The residents of these countries, a significant number of whom are at-risk, would benefit from a program of vaccination, as would non-infected individuals visiting high-risk areas.

Frequency of mutation and deletion of the tumor suppressor gene CDKN2A (MTS1/p16) in hepatocellular carcinoma from an Australian population.

The tumor suppressor gene CDKN2A (MTS1/p16), located on chromosome 9p21, is inactivated in a variety of tumors including melanomas and tumors of the biliary tract, pancreas, and stomach. The aim of the present study was to determine whether this gene is inactivated in hepatocellular carcinoma (HCC). Twenty-three primary HCCs and four HCC cell lines were examined. Loss of heterozygosity (LOH) analysis was performed using eight polymorphic markers immediately surrounding CDKN2A, and showed a contiguous region of loss, with the two most commonly deleted markers being D9S1604, located between the p16 and p15 genes, at which 7 of 13 informative tumors (54%) showed loss, and D9S171, with 4 of 14 LOH (29%). Exons 1, 2, and 3 of CDKN2A were amplified by polymerase chain reaction to detect homozygous deletions, and single-strand conformation polymorphism (SSCP) analysis was performed to screen for mutations. No homozygous deletions were detected in any sample. SSCP and sequence analysis showed the same nucleotide change at codon 148 in four tumors. This has been reported elsewhere as a polymorphism. One of these four tumors also contained a mutation at codon 119, resulting in the substitution of an acidic amino acid for a basic one. It is concluded that CDKN2A is infrequently deleted or mutated in HCC. The region of allelic loss upstream from CDKN2A might result in inactivation of regulatory sequences important in the expression of this gene; alternatively, a second tumor suppressor gene may be present in the region 9p21-22, proximal to CDKN2A. These possibilities require further investigation.

Body composition in nonalcoholic cirrhosis: the effect of disease etiology and severity on nutritional compartments.

BACKGROUND/AIMS: Previous studies of body composition in cirrhosis have either measured only one body compartment, used alcoholic subjects, or not corrected body composition for physical characteristics. The aim of this study was to perform a detailed analysis of body composition in subjects with nonalcoholic cirrhosis. METHODS: Simultaneous measurements of total body potassium and total body water were performed and values of body cell mass and body fat were corrected for physical characteristics. RESULTS: Child's class C patients had a significantly lower mean total body potassium index (i.e., percent observed value/expected value) and body fat index than class A or B patients. Eighty-one percent of class C patients had simultaneous reductions in body fat and body cell mass, and 71% of patients with class A disease had a significant reduction in either or both compartments. Nine patients showed the pattern of tissue loss seen with short-term starvation. Fourteen patients showed the pattern of tissue loss seen in physiological stress. CONCLUSIONS: Severe liver disease is characterized by significant reductions in body fat and body cell mass, most class A patients have a significant reduction in some nutritional compartments, and the pattern of tissue loss may reflect mechanisms of tissue wasting.

Comparative study of three doses of interferon-alpha 2a in chronic active hepatitis B. The International Hepatitis Trial Group.

To determine the efficacy of interferon-alpha 2a in chronic active hepatitis B, 238 patients were randomly divided, into four groups: three groups received either 2.5 MIU m-2, 5.0 MIU m-2 or 10.0 MIU m-2, three times weekly by intramuscular injection for 12-24 weeks; and a control group received no treatment. Patients were followed for up to 12 months after treatment was discontinued. There was a statistically significant difference in response [clearance of hepatitis B e antigen (HBeAg) and hepatitis B viral DNA (HBV-DNA)] between treated and untreated patients (37 vs 13%) but no statistically significant difference was seen between treatment groups (33%, 34% and 43% for the 2.5, 5.0 and 10.0 MIU m-2 groups, respectively). A transient rise in transaminases (seroconversion hepatitis) was seen in responders, but levels returned to within the normal range after response to treatment. In patients responding to interferon therapy there was a significant reduction in the severity of the hepatitis. Interferon-alpha 2a was generally well tolerated with respect to vital signs and laboratory parameters.

Hepatitis B virus differentially suppresses myelopoiesis and displays tropism for immature hematopoietic cells.

The hematopoietic cell lines HL-60 and THP-1 were challenged with hepatitis B virus (HBV) in vitro to study interactions between the virus and host cell. Exposure to HBV suppressed the ability of HL-60 cells to differentiate into granulocytes after treatment with retinoic acid (RA) or dimethyl sulfoxide (DMSO), and RA-induced activation of the monocytic cell line THP-1 was also suppressed. Terminal differentiation of both cell lines by phorbol 12-myristate 13-acetate (PMA) was not affected by HBV. The suppressive effect on RA- or DMSO-induced differentiation was unique to HBV, since cell exposure to human cytomegalovirus, another virus that inhibits hematopoiesis, failed to block cellular differentiation. At 5 days postinfection, extracellular viral DNA was detected in immature but not in differentiated cultures and higher levels of core antigen (HBcAg) and surface antigen (HBsAg) were seen in undifferentiated cells than in RA- or PMA-treated cells. In addition, release of HBsAg into the medium was 2 to 12 times greater in untreated cultures than for RA- or PMA-treated cells. Thus, HBV suppresses hematopoiesis by blocking the maturational development of progenitors and selectively infects immature myeloid cells compared with mature end-stage cells.