Success of a program of routine prenatal screening for hepatitis B surface antigen: the first 2 years.

Prenatal screening for hepatitis B surface antigen (HBsAg) restricted to women with defined risk factors for chronic hepatitis B virus (HBV) infection fails to identify many carriers. A centralized program of routine HBsAg screening for all pregnant women in Alberta was introduced in 1985. We collected and analysed data for the first 2 years of the program in Edmonton to determine the frequency of risk factors for HBsAg positivity, the proportion of multiparous HBsAg-positive women not identified in previous pregnancies, the efficiency and cost-effectiveness of providing immunoprophylaxis to infants at risk of HBV infection and the degree of success in inducing adequate protection. A total of 149 women (158 pregnancies) were found to be HBsAg positive. Risk factors were readily ascertainable for 85% of the women; the remaining 15% would not have been identified through risk-selective screening. The most common risk factors were Oriental ethnic origin, history of hepatitis, jaundice or multiple transfusions of blood or blood products, and occupational exposure to blood. Although 86% of the multiparous HBsAg-positive women had risk factors, only 7% had been identified in previous pregnancies. The Alberta program appears to be cost-effective. We conclude that only routine prenatal screening will identify all infants at risk of perinatal HBV infection and that a comprehensive public health program involving central laboratories, private physicians and public health staff can be highly effective and efficient in protecting infants against hepatitis B.     

Perinatal transmission of hepatitis B virus.

Transmission of hepatitis B virus from carrier mothers to their infants seems most likely to occur during birth. Both cord blood and breast milk have been found to be positive (in 35% and 72% of cases respectively) for hepatitis B surface antigen (HBsAg), but they do not appear to play an important role in transmission. To control this problem high-risk women should be tested during pregnancy for HBsAg. The infants of infected women should be given several doses of hepatitis B immunoglobulin starting at birth. In less developed regions, where hepatitis B is endemic, administration of the immunoglobulin in combination with vaccine, or even the vaccine alone, may be preferable in order to provide infants with lasting protection.     

Screening of Danish blood donors for hepatitis B surface antigen using a third generation technique.

The profit to be gained by testing Danish blood donors for hepatitis B surface antigen (HBsAg) with a third generation technique instead of the currently used immunoelectrophoresis was investigated by additional screening of 48 750 blood units by radioimmunoassay three weeks after donation. Twenty nine units were positive for HBsAg on radioimmunoassay (0.059%). Only six of these were found by immunoelectrophoresis (0.012%). Most of the 23 donors positive on radioimmunoassay and negative on immunoelectrophoresis were healthy carriers of HBsAg (20) or had asymptomatic chronic liver disease (two). One donor had acute hepatitis B. Fifteen of the 23 blood units were transfused. The 15 recipients were monitored biochemically and serologically for up to nine months. One recipient developed fulminant hepatitis B, three developed acute hepatitis B, and one became a healthy carrier of HBsAg. All these patients had received blood from healthy carriers of HBsAg. Two recipients were immunised against HBsAg, and in one patient no seroconversion was observed. The remaining recipients died soon after transfusion or were protected by antibodies to HBsAg that had been present before the transfusion. Testing of Danish blood donors using a third generation technique identified a substantial number of donors positive for HBsAg overlooked by immunoelectrophoresis. Most of these donors were healthy carriers of HBsAg. Blood taken from such carriers is highly infectious when transfused, probably because of the large amount of material transmitted.     

Immune tolerance to a defined heterologous antigen after intrasplenic hepatocyte transplantation: implications for gene therapy.

Development of a host immune response against gene products expressed by genetically modified cells could be a serious limitation for gene therapy. During examination of whether site-specific differences in antigen presentation could regulate the host immune response, we observed an absence of antibodies against hepatitis B virus surface antigen (HBsAg) when HBsAg producing transgenic hepatocytes were transplanted into the spleen. Intrasplenic transplantation resulted in translocation of a large number of cells into the portal vascular bed and liver sinusoids. In these recipients, HBsAg secreted by the transplanted hepatocytes circulated indefinitely in the blood. In contrast, subcutaneous or intraperitoneal transplantation of the transgenic hepatocytes induced an anti-HBs response, followed by clearance of serum HBsAg. Rechallenge with HBsAg in a highly immunogenic form failed to break the tolerance in intrasplenic hepatocyte recipients even though these animals responded to another antigen (keyhole limpet hemocyanin). Immunization with HBsAg in intraperitoneal recipients of HBsAg producing hepatocytes further elevated anti-HBs titers. Our results indicate that hepatocyte transplantation into the portal vascular bed via injection into the spleen can confer immune tolerance to secreted heterologous antigens. This finding should have important implications for human gene therapy as well as for analyzing the mechanisms of immune tolerance.     

Hepatitis B virus DNA and e antigen in serum from blood donors in the United Kingdom positive for hepatitis B surface antigen.

Serum samples from 214 blood donors in the United Kingdom who were carriers of hepatitis B surface antigen (HBsAg) were examined for hepatitis B virus deoxyribonucleic acid (DNA) by DNA:DNA hybridisation and for hepatitis B e antigen (HBeAg) and its antibody. One fifth of the donors carried infectious virus in their circulation. The presence of hepatitis B virus DNA correlated well with that of HBeAg, although hepatitis B virus DNA was found in five serum samples that were negative for HBeAg. It is concluded that analysis of serum samples for hepatitis B virus DNA by hybridisation should be the method of choice for determining whether carriers of HBsAg are infectious.     

Incidence of hepatitis B in hemophilia patients

Hepatitis represents a serious complication in the transfusion of blood and blood products. In examining patients from the haemophilia centre in Jena HBsAg was identified in no case, HBsAK, however, in 80% of them. The rate of hepatitis infection increased here with the increasing frequency of transfusion. It should be determined by regularly checking HBsAG, HBsAK and transferases within the scope of prophylactic examinations.     

Use of a radioimmune method for determining HBsAg in preparations of human gamma-globulin

The work presents the results of studies made with a view to improve the method of testing gamma-globulin preparations for the presence of hepatitis B virus surface antigen (HBsAg) by means of radioimmunoassay (RIA). The work shows that this method requires the use of specially selected negative control samples made up of pooled gamma-globulin samples. Standard RIA techniques intended for detecting the presence of HBsAg in human plasma and blood serum is not suitable for the analysis of the preparations of human gamma-globulin.     

Importance of markers of hepatitis B virus in alcoholic liver disease.

To determine the importance of the presence of serological markers of hepatitis B virus infection in patients with alcohol related liver disease we compared cumulative alcohol intake and clinical and histological features in patients with markers of hepatitis B virus infection and in those without. Hepatitis B surface antigen (HBsAg) was detected in five (2%) out of 285 patients studied and antibody to HBsAg (anti-HBs) in 41 (14%); one patient had antibody to hepatitis B core antigen alone. The combined prevalence of markers of hepatitis B virus infection was similar in patients with alcoholic cirrhosis (18%) and precirrhotic liver disease (13%). Two patients positive for HBsAg had histological features of both alcoholic liver disease and chronic active hepatitis, with stainable HBsAg. Patients with anti-HBs were, however, histologically indistinguishable from patients without markers, and the mean cumulative alcohol intake of patients with anti-HBs was similar to or even higher than that of patients with liver disease of comparable severity who had no evidence of previous infection. The presence of markers of hepatitis B virus infection was related to former residence in countries with a high prevalence of the infection and to previous parenteral treatment and blood transfusions. Infection with hepatitis B virus does not enhance the development of chronic liver disease in heavy drinkers, except in the small number who remain positive for HBsAg.     

Hepatitis B virus-reactive human T lymphocyte clones: antigen specificity and helper function for antibody synthesis

To study immunity to hepatitis B surface antigen (HBsAg) at the cellular level, lymphocytes were obtained from the peripheral blood of hepatitis B vaccine recipients and were examined for various immune responses to HBsAg in vitro. The peripheral blood mononuclear cells (PBM) from most of the vaccinees did not proliferate to a great extent to HBsAg in vitro. However, HBsAg-reactive lymphocyte lines and clones were obtained from some of these individuals if the PBM were stimulated in vitro with HBsAg and were maintained in the presence of T cell growth supplement. Most of the HBsAg-reactive T cell clones obtained were found to be antigen-specific and some of them provided help in the production of anti-HBsAg antibodies by a cell population enriched for HBsAg-binding cells. These results indicate that HBsAg-specific T and B cells exist in the circulation of hepatitis B vaccine recipients, although they are at limiting concentrations for the in vitro cell proliferation and antibody production assays.     

Clinical aspects of delta infection.

The clinical features of delta infection were analysed retrospectively in 191 hepatitis B surface antigen (HBsAg) carriers and 592 cases of acute hepatitis B seen over 11 years in the Swedish town of Malmö (population 250 000). With a few exceptions delta infections occurred exclusively in drug addicts. In the chronic HBsAg-carriers the most common clinical manifestation was an episode of acute hepatitis, which in some individuals became severe with a pronounced rise in serum alanine aminotransferase activity for many months. During the period of delta infection the HBsAg titre was lowered and in three out of 26 cases the patient lost HBsAg altogether and developed hepatitis B surface antibodies (anti-HBs). In one patient the acute hepatitis due to delta infection was fulminant and fatal. In patients with acute hepatitis B the clinical picture did not distinguish between those with and without simultaneous delta infection. The frequency with which acute hepatitis B was succeeded by a chronic carrier state was the same whether or not the patient was infected simultaneously with the delta agent. The discovery of the delta agent has improved understanding of the natural history of chronic hepatitis B infection in drug addicts. Thus, instances of acute hepatitis in a chronic carrier, previously termed hepatitis non-A, non-B, may actually be episodes of delta infection.     

Family incidence of type B hepatitis

Family incidence of HBsAg-positive viral hepatitis was confirmed to be high. In 499 families with a type B viral hepatitis patient, type B viral hepatitis morbidity among 1116 contacts amounted to 2.24% within 6 months of the primary patients' hospitalization (being 188.2 times higher than semiannual morbidity of the population of the Czech Socialist Republic, CSR) and the prevalence of HBsAg amounted to 8.96% (being 22.4 times higher than among the population of CSR). On deducting positive findings at first blood samplings, which at least partially eliminated individuals who could themselves have been the source of infection for the first patient in each family, the rate for contact cases equalled 0.70% (58.8 times higher morbidity than among the population) and the rate for HBsAg prevalence equalled 2.50% (6.25 times higher than among the population). Among 917 members of 335 families where a case of HBsAg-negative viral hepatitis occured, 0.32% developed HBsAg-positive viral hepatitis within 6 months (26.8 times higher morbidity than population morbidity) and the HBsAg prevalence was 2.94% (7.35 greater than among the population). On deducting the first positive findings no clinical illness remained and HBsAg prevalence equalle 0.98% (2.45 times higher than among the population). The highest HBsAg prevalence was found among contacts aged 0-5 years (17.09% for the whole period, 3.41% after deducting first positive findings) and 40 years and over (10.82% and 3.39%, respectively). Type B viral hepatitis morbidity was again highest in the age groups of 0-5 years (5.12%) and 40 years and over (2.54%) for the whole period. On deducting first positive findings, the 40+ years group displayed the highest morbidity (1.27%), whereas the 0-5 years group displayed zero morbidity. Disclosure of the mechanisms of nonparenteral or inapparently parenteral transmission specific for family environments would be important for the prospect of introducing adequate measures to limit or prevent the spread of type B viral hepatitis.     

Hemagglutinating test for HBsAg and antibodies in epidemiological practice

The use of Alsever's solution has abolished the necessity for taking intravenous blood and made it possible to divide the determination of HBsAg and antibodies to this antigen into two stages. The combined determination of HBsAg and its antibodies by the third-generation techniques improves the quality of the epidemiological survey of hepatitis B cases and the epidemiological observation of risk groups.     

Frequency of detecting viral hepatitis B markers in the patients of a hemodialysis ward

The data, obtained as the result of the examination of 22 patients with chronic renal insufficiency and analysis of 105 samples of transfusion blood at the department of chronic hemodialysis, are presented. To detect the markers of hepatitis B (HBsAg, anti-HBs, anti-HBc), a complex of biochemical investigations was carried out with the use of counter-current immunoelectrophoresis, the passive hemagglutination test, enzyme immunoassay, and solid-phase radioimmunoassay. The markers of hepatitis B were detected in 72.6% of patients with chronic renal insufficiency and in 21% of healthy persons. Changes in the activity of biochemical characteristics of hepatic samples were detected only in one patient. In no case clinical symptoms of the disease were observed. Out of 105 samples of transfusion blood, 9.5% contained HBsAg. The results of our investigations indicate that the markers of hepatitis B are widely spread among patients with chronic renal insufficiency, which makes it possible to consider them as a "high risk group" with respect to hepatitis B infection. To decrease the risk of hepatitis B among patients with chronic renal insufficiency, it is very important that highly sensitive tests be introduced into practice for the selection of donors and the detection of patients with the asymptomatic forms of hepatitis B and carriers at the department of chronic hemodialysis.     

Post-transfusion hepatitis. Sudden drop of its incidence associated with hyperbilirubinemic donors disqualification

The lacking impact of various precautions on the incidence of post-transfusion hepatitis (PTH) in the last 15 years is presented. In 1984, however, PTH dropped from 0.12 to 0.04%. This PTH drop did not coincide with the disqualification of HBsAg carriers, nor with that of high ALT, nor with the introduction of complete voluntary donorship in 1982, but with the systematic exclusion of hyperbilirubinemic donors. Circulating immune complexes (CIC) were found in 28.9% of PTH compromised donors, and CIC are therefore supposed to be a marker of PTH risk even if HBsAg was not demonstrable. Re-examining donors compromised in 120 PTH found 12.4% HBsAg carriers who had not been detected by CIEP prior to the transfusions. Accumulation of more than one HBsAg positive transfusion in 56.5% of the PTH patients suggests a cumulative effect. The inability of specific tests to identify sources of infection in 50% of PTH suggests that doubts must be raised as to their post-transfusional origin. This thesis is also supported by the relative increase of this group after the considerable drop of PTH. The importance of viral sources non-B and B undetectable by sensitive specific methods must be emphasized. The latter is in accordance with the observed PTH drop due to a non-specific marker effect. The bilirubin level screening in each donor before stored blood collection is recommended by means of the described extended AST screening test and, besides HBsAg screening, this is supposed to be the most effective precaution for preventing PTH.     

New strategies for blood donor screening for hepatitis B virus: nucleic acid testing versus immunoassay methods

Serologic testing for hepatitis B virus (HBV) surface antigen (HBsAg) and antibody to HBV core antigen (anti-HBc) has historically been the foundation of blood screening, while HBV nucleic acid testing (NAT) was recently developed to detect HBsAg-negative, anti-HBc-negative blood units donated during early acute infection. Comparison data on seroconversion panels using HBsAg assays of varying sensitivities and pooled- or single-sample NAT, along with viral load estimates corresponding to HBsAg assay detection limits, have provided information on the theoretical benefits of NAT relative to HBsAg. Model-derived estimates have generally been predictive of the yields of DNA-positive, HBsAg-negative window period blood units detected in a number of studies from Europe, Japan, and the US. Studies indicate that the added benefit of pooled-sample NAT is relatively small in areas of low endemicity, with greater yields in areas highly endemic for HBV. Single-sample NAT would offer more significant early window period closure and could prevent a moderate number of residual HBV transmissions not detected by HBsAg assays; however, no fully automated single-sample HBV NAT systems are currently available.Even single-sample HBV NAT may not substitute for anti-HBc screening, as indicated by studies of donors with isolated anti-HBc who have extremely low DNA levels undetectable by standard single-sample NAT and who have been associated with transfusion-transmitted HBV. Moreover, HBsAg testing may still be needed even in the setting of combined anti-HBc and NAT screening. HBsAg-positive units from donors in the chronic stage of infection may contain very low or intermittently detectable DNA levels that single-sample NAT would miss. Although such donors are usually anti-HBc reactive and would be interdicted by anti-HBc screening, some lack anti-HBc. Extensive parallel testing will be needed to determine whether single-sample NAT in combination with anti-HBc might be sufficient to detect all the infectious donors currently interdicted by HBsAg testing. In countries that do not screen for anti-HBc, HBsAg testing would be the only means of detecting donations from chronically infected individuals with low/intermittently detectable DNA, since even single-donor NAT would not identify these potentially infectious blood units. In the future, the current fully automated HBsAg assays may incorporate significant sensitivity improvements, and automated single-sample HBV NAT may become a reality. Each country will need to develop its blood screening strategy based on HBV endemicity, yields of infectious units detected by different serologic/NAT screening methods, and cost effectiveness of test methods in ensuring blood safety.     

Hepatitis B infection among patients attending a sexually transmitted diseases clinic in Rio de Janeiro, Brazil

Hepatitis B virus (HBV) has a low endemicity in Rio de Janeiro, Brazil. Sexual transmission must play an important role in this virus, but the prevalence and risk factors have never been properly investigated. The aim of this paper is to determine the prevalence and risk factors for HBV infection in patients attending a Sexually Transmitted Diseases Clinic of the Universidade Federal Fluminense, from the State of Rio de Janeiro, Brazil. In a retrospective study, HBV seroprevalence was investigated in 440 patients. Serum of each patient was assayed for antibodies against hepatitis B core antigen (anti-HBc), hepatitis B surface antigen (HBsAg) and antibodies against hepatitis B surface antigen (anti-HBs). Demographic and risk factor data were extracted from clinic notes. The overall seroprevalence of exposure markers for HBV (anti-HBc, HBsAg and anti-HBs) were 13%, 3.4% and 8.5% respectively. Homo/bisexual behaviour, anal intercourse, HIV infection, positive serology for syphilis and blood transfusion were predictors of the HBV exposure. Among demographic data, age and place of birth were associated with the anti-HBc seropositivity.     

A case of hepatitis B reactivation due to the hepatitis B virus escape mutant in a patient undergoing chemotherapy

A 62-year-old man had chronic hepatitis B virus (HBV) infection and was diagnosed with liver cirrhosis. At the time of diagnosis the patient’s virologic markers were positive for hepatitis B surface antigen (HBsAg), antibody to hepatitis B e antigen (anti-HBe) and antibody to hepatitis B core antigen (anti-HBc), while antibody to hepatitis B surface antigen (anti-HBs) and HBV DNA were negative. Later the patient received chemotherapy for malignancy. However, this was interrupted due to elevated liver enzymes. At the same time HBV DNA became positive. Lamivudine (LMV) therapy was administered immediately. However, the levels of serum aminotransferase and total bilirubin (TB) were still rising. Finally the patient died of fulminant hepatic failure. A sequence revealed HBV genotype C (HBsAg subtype adw) with immune escape mutations, F8L, S34L, F41S, G44V, F93C, V96G, L110I, C149Y and F161Y. The high morbidity and mortality of this complication is one of the major obstacles to completing the standard treatment for malignancy in HBV carriers. Therefore, the relative risk of antiviral prophylactic failure should be further assessed and the optimal strategy for antiviral prophylaxis in HBsAg-positive patients with oncologic and hematologic malignancies undergoing chemotherapy should be revised.     

Hepatitis B virus infection in dental surgical practice.

Sixty-one dental surgeons at King''s College Hospital were interviewed to establish the incidence of attacks of viral hepatitis and to relate this to environmental risk factors. Six (10%) had a history of hepatitis, in one case due to infection with the hepatitis B virus. Screening blood for HBsAg by radioimmunoassay showed no carriers of the antigen, but transient antigenaemia was observed in one dentist. Antibody to HBsAg, tested by radioimmunoassay, was detected in four dentists (7%), only one of whom had had clinical hepatitis. Dental surgeons may be more at risk from infection with the hepatitis B virus than the general population, although this should be minimised in hospital practice, where the most infected patients will already have been identified and appropriate precautions can be taken. The risk of transmission from an antigen-positive dentist to his patients is probably much smaller, and there is no evidence to restrict his clinical activities.     

Functional properties of lymphocyte subpopulations in hepatitis B virus infection. II. Cytotoxic effector cell killing of targets that naturally express hepatitis B surface antigen and liver-specific lipoprotein

Cytotoxic effector cell responsiveness to host and/or virus-determined hepatocyte surface membrane antigens has been postulated as an important pathogenetic determinant of hepatocellular injury in hepatitis B virus infection. Assuming that such effector cell populations would be detectable in peripheral blood, the present study was designed to examine 2 questions: first, whether target cells that normally express liver-specific protein (LSP) and hepatitis B surface antigen (HBsAg) are selectively destroyed by peripheral blood effector cells from patients with viral hepatitis; second, whether cytotoxic effector cell function emerges coincident with the development of defective suppressor cell activity in the same patients. No evidence of increased HBsAg or LSP specific cytotoxic effector cell activity was found in the peripheral blood natural killer (NK) or T killer cell populations of patients with acute or chronic viral hepatitis.     

Intracellular inhibition of hepatitis B virus S gene expression by chimeric DNA-RNA phosphorothioate minimized ribozyme

Chronic hepatitis B virus (HBV) infection is a major problem in Asia. Current therapies for chronic hepatitis B have limited efficacy. The successful use of ribozymes for intracellular inhibition of HBV gene expression was recently reported. As an alternative to ribozymes, the use of DNA-containing, phosphorothioate-modified, minimized hammerhead ribozymes (minizymes) to inhibit hepatitis B surface antigen (HBsAg) expression and viral replication was investigated. Such molecules can be synthesized and supplied exogenously. Two conserved sites within the HBsAg open reading frame (ORF) were targeted. PLC/PRF5 cells or 2.2.15 cells were treated with minizymes or antisense oligomers to assess the effects on cell viability, HBsAg expression, and viral DNA production. Treatment with the minizyme, MZPS1, resulted in >80% inhibition of HBsAg expression in PLC/PRF5 cells. MZPS1 had more inhibitory effect than the antisense oligonucletoide target at the same region, whereas the control minizyme had little effect. Another gene-specific minizyme, MZPS2, did not show any effect. Treated cells remained fully viable. Treatment of 2.2.15 cells with MZPS1 also led to decreased HBsAg expression. In addition, a 2.3-fold decrease in viral production was observed. Our data showed that minizymes can inhibit HBV gene expression and may potentially be useful for clinical therapy against chronic HBV infection.