Hepatitis B virus splice-generated protein induces T-cell responses in HLA-transgenic mice and hepatitis B virus-infected patients

Hepatitis B virus splice-generated protein (HBSP), encoded by a spliced hepatitis B virus RNA, was recently identified in liver biopsy specimens from patients with chronic active hepatitis B. We investigated the possible generation of immunogenic peptides by the processing of this protein in vivo. We identified a panel of potential epitopes in HBSP by using predictive computational algorithms for peptide binding to HLA molecules. We used transgenic mice devoid of murine major histocompatibility complex (MHC) class I molecules and positive for human MHC class I molecules to characterize immune responses specific for HBSP. Two HLA-A2-restricted peptides and one immunodominant HLA-B7-restricted epitope were identified following the immunization of mice with DNA vectors encoding HBSP. Most importantly, a set of overlapping peptides covering the HBSP sequence induced significant HBSP-specific T-cell responses in peripheral blood mononuclear cells from patients with chronic hepatitis B. The response was multispecific, as several epitopes were recognized by CD8(+) and CD4(+) human T cells. This study provides the first evidence that this protein generated in vivo from an alternative reading frame of the hepatitis B virus genome activates T-cell responses in hepatitis B virus-infected patients. Given that hepatitis B is an immune response-mediated disease, the detection of T-cell responses directed against HBSP in patients with chronic hepatitis B suggests a potential role for this protein in liver disease progression.     

A microtiter solid-phase radioimmunoassay for hepatitis A antigen and antibody.

A microtiter solid phase radioimmunoassy for hepatitis A antigen (HA Ag) and antibody (anti-HA) was developed. The test was more sensitive than immune adherence hemagglutination for detecting HA Ag and almost as sensitive for detecting anti-HA. The specificity and sensitivity of reagents were examined and optimum conditions for the test were determined. Radioimmunoassay, immune adherence hemagglutination, and immune electron microscopy were compared for detecting anti-HA. A serologic response to HA Ag was detected in paired sera from patients with type A hepatitis but not from patients with type B or non-A, non-B hepatitis by all three techniques.     

Lymphocyte and neutrophil dysfunction associated with hepatitis B virus and hepatitis non-A, non-B virus infection in the chimpanzee.

Chimpanzees were examined for the effect of viral hepatitis infections on specific and nonspecific immune response mechanisms. The data suggest that infection with either hepatitis B virus or hepatitis non-A, non-B virus may result in suppression of cellular immune response components. Mitogen-induced lymphocyte proliferation was lower in virus-infected chimpanzees than in naive animals. Neutrophils from virus infected animals exhibited decreased or altered chemiluminescence kinetics.     

Hepatitis B Prevention in Small Rural Hospitals

A retrospective study of 246 potential hepatitis B exposure incidents in 12 rural hospitals in Arizona over a two-year period revealed a rate of 6.3 incidents per 100 employees per year. Needle punctures accounted for 68% of the incidents; 17% were cuts from instruments or broken glassware. Although 51% occurred in nursing personnel, housekeepers accounted for a surprising 19.5% of the reports. Only 50% of the employees received any medical attention following incidents. None received hepatitis B immune globulin (HBIG); seven received immune globulin (IG). The mean cost to the hospitals for the 122 incidents where treatment was given was $64.50 per incident. In all, 10 hospitals had no written policy for hepatitis B prevention, 3 did not stock IG and 11 did not stock HBIG. There was little awareness of hepatitis B as a nosocomial problem within these institutions, perhaps because no reported cases of clinical hepatitis B occurred in employees of the 12 hospitals in the two years.     

Non-B hepatitis in Melbourne: a serological study of hepatitis A virus infection.

A study was performed to establish the value of immune adherence haemagglutination tests for antibody to hepatitis A virus in the diagnosis of non-B hepatitis. Infection with hepatitis A virus was confirmed in 14 out of 16 patients from six families and seven out of nine patients in whom the source of infection was unknown. One additional patient, who had had two episodes of jaundice, was shown to have had an attack of hepatitis A followed by an attack of hepatitis B. In patients with acute hepatitis A antibody detectable by immune adherence haemagglutination becomes detectable three or four weeks after the onset of symptoms and reaches peak levels about five weeks later.     

Multiplication of hepatitis B virus in fulminant hepatitis B.

The presence in serum of hepatitis B e antigen (HBeAg) and hepatitis B virus DNA, which are each regarded as reflecting multiplication of hepatitis B virus, were looked for one to five days after the onset of hepatic encephalopathy in 64 patients with fulminant hepatitis B. HBeAg and hepatitis B virus DNA were found in the serum of only 24 (37%) and six (9%) patients, respectively. Hepatitis B virus DNA was absent from the serum in all 13 patients positive for anti-HBs. These findings indicate that replication of hepatitis B virus stopped after the onset of hepatic encephalopathy in most of the patients and support the view that an enhanced immune response stops the replication. Agents that inhibit viral multiplication would probably not have any effect at this stage of the disease.     

Arthritis and Hepatitis

The evidence relating four clinically distinct rheumatologic syndromes to infection by the hepatitis B virus is reviewed. Acute hepatitis B is not infrequently heralded by a prodromal rash and rheumatoidlike polyarthritis. Chronic active hepatitis B more rarely is associated with transient arthritis or arthralgias. Polyarteritis nodosa may be a manifestation of hepatitis B infection in as many as 40 percent of cases, and recently the syndrome of “essential” mixed cryoglobulinemia has also been linked to infection with this virus. The finding of immune complexes of varying composition, sometimes with the viral antigen or its antibody (or both) contained in both the serum and synovial fluid suggests that these four syndromes are clinical manifestations of immune complex disease resulting from hepatitis B infection.     

乙型肝炎IgA类HBsAg循环免疫复合物的检测及意义

本文报道用捕捉法ELISA检测各型乙肝IgA型HBsAg循环免疫复合物。结果表明,慢性乙肝IgA型HBsAg循环免疫复合物检出率显著高于急性乙肝;在慢性乙肝中,IgA型HBsAg循环免疫复合物的出现与HBVe系统关系密切,主要存在于HBeAg阳性血清中,并与HBeAg滴度有关。故IgA型HBsAg循环免疫复合物可作为HBV慢性感染的血清诊断标志之一;也可作为反映HBV在增殖并有传播危险的标志之一。     

Review of management of incidents involving exposure to blood in a London teaching hospital, 1989-91.

OBJECTIVE--To review management of incidents involving exposure to blood reported to an occupational health unit. DESIGN--Analysis of all reported incidents from January 1989 to June 1991. SETTING--London teaching hospital. SUBJECTS--447 health care workers and students. MAIN OUTCOME MEASURES--Immunisation against hepatitis B virus before exposure, proportion of known source patients tested for hepatitis B surface antigen and HIV antibodies, and reasons for not testing known source patients. RESULTS--447 incidents were reported: 337 sharps injuries and 110 other exposures. 310 staff reporting incidents (205 (82%) nurses) were already immune to hepatitis B virus, nearly always because of immunisation. 345 source patients were identified, 77 of whom had already been tested for hepatitis B surface antigen (28 positive results) and 58 for HIV antibodies (18 positive results). Of those not previously tested, 145 of 266 were subsequently tested for hepatitis B surface antigen (two positive) and 149 of 287 for HIV antibodies (none positive). The main reasons for not testing source patients were that the incident was not considered a risk, that the patient had gone home, and that the clinical team were unwilling to ask the patient. Specific hepatitis B immunoglobulin was given to 18 staff who were not immune and was avoided in 11 cases by a negative result for the patient. Prophylactic zidovudine was discussed but not given to any staff member. CONCLUSIONS--Management of exposure to blood is improved by widespread immunisation against hepatitis B virus and by knowledge of source patients'' hepatitis B virus and HIV status.     

The intrahepatic immune response during chronic hepatitis B infection can be monitored by the fine-needle aspiration biopsy technique

Frequent analysis of the intrahepatic cellular immune response during chronic hepatitis B infection is not feasible with the liver tissue biopsy technique, due to its risk profile and patient discomfort. We investigated whether the relatively safe and patient-friendly cytological fine-needle aspiration biopsy (FNAB) technique is suited for this purpose. FNABs taken during hepatitis flares in three chronic hepatitis B patients treated with interferon-alpha, showed significant increments of CD8(+)-lymphocytes compared with the FNABs taken before and after the flares. No increments were observed in peripheral blood. The increments of intrahepatic CD8+ lymphocytes detected by the FNAB were related to anti-viral immune reactivity, since they coincided with significant serum hepatitis B virus DNA level reductions and in two of three patients with HBeAg seroconversion. In conclusion, the FNAB technique is suited to investigate the intrahepatic immune response during chronic hepatitis B infection on a frequent basis.     

Mathematical models of e-antigen mediated immune tolerance and activation following prenatal HBV infection

We develop mathematical models for the role of hepatitis B e-antigen in creating immunological tolerance during hepatitis B virus infection and propose mechanisms for hepatitis B e-antigen clearance, subsequent emergence of a potent cellular immune response, and the effect of these on liver damage. We investigate the dynamics of virus-immune cells interactions, and derive parameter regimes that allow for viral persistence. We modify the model to account for mechanisms responsible for hepatitis B e-antigen loss, such as seroconversion and virus mutations that lead to emergence of cellular immune response to the mutant virus. Our models demonstrate that either seroconversion or mutations can induce immune activation and that instantaneous loss of e-antigen by either mechanism is associated with least liver damage and is therefore more beneficial for disease outcomes.     

Alterations in the human immune response to the hepatitis B vaccine among the elderly

The specific binding of hepatitis B (HBs) antigen by lymphocytes from old people immunized with hepatitis B vaccine was explored. For that purpose HBs antigen was combined with fluorescent microspheres, and labeled antigen was allowed to react with lymphocytes from HBs vaccine-responsive or unresponsive people. Lymphocytes from 10 responders and 14 nonresponders were tested for their antigen-binding ability. For controls, lymphocytes were incubated with microspheres bearing human albumin. Lymphocytes from 8 out of 10 responders were able to recognize HBs antigen; for the nonresponders the ratio was 9 out of 14. HBs-binding lymphocytes were B cells but not T lymphocytes. B and T cells from responders and nonresponders were combined and cultivated for 8 days in the presence of HBs antigen, and antibody-producing cells were counted. Neither B cells alone nor B cells plus T cells from nonresponders were able to produce antibody. On the other hand B cells from unresponsive old people produced antibodies when they were cultivated in the presence of HBs antigen and T cells from responsive old people. These data suggest that some elderly individuals who do not produce antibody after in vivo immunization by HBs vaccine do have antibody-producing cells. Instead of a gap in their immune repertoire, these people are suffering from immune dysfunction.     

Specific immune adherence assay for human hepatitis A antibody application to diagnostic and epidemiologic investigations.

A specific immune adherence (IA) test for hepatitis A antibody in human serum was described employing liver extract of marmosets infected with CR326 strain human hepatitis A virus. Persons with hepatitis A, but not hepatitis B, developed hepatitis A IA antibody soon after onset of the acute illness and this persisted thereafter. There was very close agreement in the tests for human hepatitis A immune adherence, complement fixing (CF) and neutralizing antibodies. IA antibodies appeared to develop somewhat later than CF or neutralizing antibody. A limited epidemiologic study of a family outbreak of hepatitis A and B in Costa Rica showed simultaneous occurrence of the two diseases and was supportive of the concept that susceptible persons in a country with high hepatitis A prevalence generally acquire their infections at an early age and are immune thereafter. Most persons of high socioeconomic level in an area of low hepatitis A incidence may proceed to adulthood without experience with hepatitis A. Person of low socioeconomic level, however, such as commercial blood bank donors and prisoners, show high incidence of hepatitis A antibody. Hepatitis IA and CF antibodies persisted in human subjects for at least 7 hr after hepatitis A virus infection. Captive chimpanzees and grivet and rhesus monkeys, not given hepatitis A virus, showed evidence of previous experience with human hepatitis A or an antigenically related virus based on tests for hepatitis A antibody. Other subhuman primates, rodents, and swine, not given hepatitis A virus, were without hepatitis A antibody. The IA test provides an excellent tool for diagnostic and epidemiologic investigations of hepatitis A and should be of considerable value to detect hepatitis A virus in attempts to propagate the virus in cell culture. There was considerable difference in hepatitis A IA antibody content of different lots of commercial human immune globulin, though the majority titered 1:4000 or 1:8000.     

The characteristics of the immune response during the development of hepatitis B against a background of chronic alcoholic liver lesions

In two groups of patients with viral hepatitis B (100 patients in each group) the comparative evaluation of immune response was carried out on the basis of the results obtained in the study of the duration of the presence of HBsAg in the blood, the time of the primary appearance of anti-HBsAg antibodies, cell-mediated and humoral immunity characteristics. The study revealed the aggravating influence of alcohol on the outcome of hepatitis B, manifested by the prolonged circulation of HBsAg, decreased antibody formation and T-immunosuppressive deficiency, which was linked with defective immune response in hepatitis B patients with disposition to the excessive use of alcohol.     

Screening for hepatitis B during pregnancy. Awareness of current recommendations among Washington hospitals.

Acute care hospitals in Washington State that reported births (n = 77) were surveyed regarding their awareness of and compliance with the Centers for Disease Control recommendations for hepatitis B screening of pregnant women. Of these, 62 hospitals (81%) were aware of the recommendations and 39 (51%) routinely screened pregnant women who did not have a history of prenatal care at the time of delivery. In all, 68 hospitals (88%) had hepatitis B vaccine and 54 (70%) had hepatitis B immune globulin available on site. Despite awareness of the current recommendations for hepatitis B screening, barriers exist that prevent many hospitals from fully implementing them.     

Vaccine- and hepatitis B immune globulin-induced escape mutations of hepatitis B virus surface antigen

Hepatitis B virus surface antigen (HBsAg) vaccination has been shown to be effective in preventing hepatitis B virus (HBV) infection. The protection is based on the induction of anti-HBs antibodies against a major cluster of antigenic epitopes of HBsAg, defined as the 'a' determinant region of small HBsAg. Prophylaxis of recurrent HBV infection in patients who have undergone liver transplantation for hepatitis B-related end-stage liver disease is achieved by the administration of hepatitis B immune globulins (HBIg) derived from HBsAg-vaccinated subjects. The anti-HBs-mediated immune pressure on HBV, however, seems to go along with the emergence and/or selection of immune escape HBV mutants that enable viral persistence in spite of adequate antibody titers. These HBsAg escape mutants harbor single or double point mutations that may significantly alter the immunological characteristics of HBsAg. Most escape mutations that influence HBsAg recognition by anti-HBs antibodies are located in the second 'a' determinant loop. Notably, HBsAg with an arginine replacement for glycine at amino acid 145 is considered the quintessential immune escape mutant because it has been isolated consistently in clinical samples of HBIg-treated individuals and vaccinated infants of chronically infected mothers. Direct binding studies with monoclonal antibodies demonstrated a more dramatic impact of this mutation on anti-HBs antibody recognition, compared with other point mutations in this antigenic domain. The clinical and epidemiological significance of these emerging HBsAg mutants will be a matter of research for years to come, especially as data available so far document that these mutants are viable and infectious strains. Strategies for vaccination programs and posttransplantation prophylaxis of recurrent hepatitis need to be developed that may prevent immune escape mutant HBV from spreading and to prevent these strains from becoming dominant during the next decennia.     

Mathematical model of antiviral immune response. II. Parameters identification for acute viral hepatitis B

Considering the mathematical model of antiviral immune response, we describe a method of fitting the model to the data characterizing acute viral hepatitis B. The corresponding procedure employs an idea of sequential parameter estimation to make the problem of fitting manageable. The underlying mechanisms responsible for the quantitative manifestations of the four basic phases of acute hepatitis B are used to select the model parameters. The identified model of acute hepatitis B is then tested with regard to the following situations: the effect of HBsAg-specific antibodies on HBV challenge; the vaccination and the resistance to challenge using live hepatitis B virus; the dose of viruses--the incubation time relationships. The sensitivity of the model with respect to parameters variations is then analysed. The developed model allows us to quantitatively simulate the basic features of the antiviral immune response during acute hepatitis B and some closely related phenomena.     

Current Concepts of Viral Hepatitis and A Peek into the Future

New information has prompted revision of the conceptual framework for considering the epidemiology and virology of viral hepatitis. The means are now at hand to identify infections due to either Hepatitis A or B, as well as to implicate other etiologic agents in hepatitis. Immunologic evidence of variation in the antigens associated with Hepatitis B, and possibly in Hepatitis A, may explain some well known epidemiologic phenomena and has important implications in immune serum globulin prophylaxis. The ambiguous relationship of antigenemia and viremia in Hepatitis B is explored in relation to the hepatitis hazard of blood products, to trials of immune serum globulin, and to the potential role of the carrier-health worker in hepatitis transmission. The emerging concept of non-parenteral transmission of Hepatitis B is reviewed and future developments in the production of hepatitis vaccines and in experimental viral hepatitis in non-human primates is briefly discussed.     

Interrelation between the activity of hepatitis, liver fibrosis and immune status in children with chronic hepatitis B and C

The lesion of the liver in viral hepatitis was found to depend on the state of the immune system. Relationship between the content of lymphocyte subpopulations (CD3+, CD4+, CD8+, CD20+) in the blood and immunoglobulins (IgG, IgM, IgA) with parameters of semi-quantitative evaluation of the activity of hepatitis and the stage of liver fibrosis in children with chronic virus hepatitis B, C, B + C was studied. The characteristic feature of all hepatitis was a decrease in the number of T lymphocytes CD4+ below the normal level and an increase in the content of B lymphocytes. The correlation between the morphological activity of hepatitis and the amount of T lymphocytes CD8+ was established only in chronic hepatitis B. In chronic hepatitis B and B + C the absolute amount of blood lymphocytes decreased with the increase of the age of the patients, but in chronic hepatitis B this was accompanied by the decrease of the morphological activity of hepatitis and in hepatitis B + C by its increase. The amount of lymphocytes CD4+ rose with the increase of liver fibrosis in chronic hepatitis B. In children with chronic hepatitis C and B + C the amount of blood lymphocytes was found to be unrelated to the morphological activity of hepatitis.     

低出生体重儿乙肝疫苗免疫持久性与安全性分析

目的:研究低出生体重儿乙肝疫苗免疫持久性与安全性。方法:选择86例低出生体重儿作为研究组,另选取86例正常出生体重儿作为对照组,分别对两组接种全程酵母乙肝疫苗后的抗-HBs阳性率、抗体平均滴度进行检测,并观察不良反应的发生情况。结果:研究组与对照组接种全程乙肝疫苗后3年内的抗-HBs的有效阳性率分别是74%和72.1%(P0.05),抗体平均滴度分别是214.2 mIU/mL与210.8 mIU/mL(P0.05);6年内的抗-HBs的有效阳性率分别是82.6%和81.4%(P0.05),抗体平均滴度分别是178.6 mIU/mL与170.4 mIU/mL(P0.05)。研究组与对照组接种第1针、第2针乙肝疫苗后均未发现发热、体温波动与败血症等不良反应。结论:免疫后数年内,低出生体质量对乙肝疫苗抗体的持久性没有影响,也不影响乙肝疫苗抗体的安全性。