First WHO International Reference Panel containing hepatitis B virus genotypes A-G for assays of the viral DNA

BACKGROUND

WHO International Standards (IS) are provided for the calibration and validation of diagnostic and screening assays, e.g. for hepatitis B virus (HBV). HBV forms numerous subgenotypes and the current IS for HBV DNA reflects subgenotype A2.

OBJECTIVE

A reference panel with the most prevalent subgenotypes should facilitate evaluation of genotype-specific detection efficiencies.

STUDY DESIGN

215 HBV positive plasma samples collected worldwide were characterized for HBV markers and sequenced. Fifteen subgenotype A1, A2, B2, B4, C2, D1, D3, E, F2 and G samples were selected for the panel. The lyophilized samples were tested in parallel with the IS in an international collaborative study with 16 laboratories using 13 different nucleic acid amplification techniques (NATs).

RESULTS

Eight of 13 NAT had a HBV DNA detection efficiency which was independent of the genotype and consistent with the IS, while with five assays, certain deviations were noted, particularly with genotype F which was under quantitated or even missed by three assays. The panel was accepted by the WHO as the "1st WHO International Reference Panel for HBV Genotypes for HBV NAT-Based Assays".

CONCLUSIONS

The evaluation of HBV DNA assays should include many different genotypes. The WHO Reference Panel is universally available for manufacturers of HBV DNA assays, diagnostic laboratories and control authorities to facilitate standardized validation of HBV genotype specific detection efficiency of both diagnostic (quantitative and qualitative) and screening NAT assays.

Elimination of hepatitis B virus surface antigen and appearance of neutralizing antibodies in chronically infected patients without viral clearance

Seroconversion from hepatitis B surface antigen (HBsAg) to antibodies against HBsAg (anti-HBs) usually indicates resolution of hepatitis B virus (HBV) infection. Here, two HBV-infected patients with seroconversion to anti-HBs were found to be persistently positive for HBeAg and HBV DNA. Immunohistology of liver biopsies confirmed the expression of HBV proteins in the liver of one patient. The neutralizing ability of anti-HBs in patient sera was demonstrated by blocking HBV infection of primary tupaia hepatocytes. Analysis of the HBsAg-encoding region of HBV isolates from patients indicated the coexistence of heterogeneous HBV genomes in patients. The majority of recombinant variant HBsAg was reactive in HBsAg assays and was able to bind to anti-HBs. Circulating immune complexes (CIC) of HBsAg in patient sera could be detected by polyethylene glycol precipitation and trypsin digestion. Thus, neutralizing anti-HBs may appear in chronic HBV carriers for long periods but does not necessarily lead to complete viral clearance.

An international collaborative study to establish the 2nd World Health Organization International Standard for hepatitis B virus DNA nucleic acid amplification technology-based assays

BACKGROUND AND OBJECTIVES

The aim of this study was to replace the 1st World Health Organization International Standard for hepatitis B virus DNA for nucleic acid amplification technique (NAT)-based assays (code 97/746) with a new International Standard. Two lyophilized preparations freeze dried from the same bulk were evaluated in the original collaborative study (coded 97/746 and 97/750, and termed AA and BB, respectively, in the original study). This present study re-evaluates these two preparations in terms of potency and real-time stability.

MATERIALS AND METHODS

The 1(st) International Standard (97/746) and the second lyophilized preparation (97/750) were coded Samples 1 and 2, respectively, in the present study. The samples were distributed to six laboratories and assayed on four separate occasions. Accelerated thermal degradation samples of the two preparations were examined after long-term storage at 4 degrees C and 20 degrees C for more than 51 months.

RESULTS

Data were returned from a total of nine different NAT-based assays, five in qualitative format and four in quantitative format. The results of this study confirm the results of the original collaborative study, with no significant differences being found in estimated international units (IU)/ml or polymerase chain reaction-detectable units/ml for the 1(st) International Standard (Sample 1 in this study) and the proposed replacement preparation, Sample 2 (97/750). Real-time and accelerated degradation studies indicate that both samples are very stable. Storage of both preparations at 20 degrees C for more than 51 months resulted in no detectable degradation.

CONCLUSIONS

On the basis of the data presented in this collaborative study, Sample 2 (code 97/750) was established as the 2nd International Standard for hepatitis B virus DNA for NAT-based assays with a potency of 10(6) IU/ml (500,000 IU/vial).

Alternative methods for validation of cell culture infection with duck hepatitis B virus

Hepatitis B virus (HBV) is an important virus used in disinfection procedures for blood spillage. However, validation of HBV inactivation is difficult, since there are no feasible infectivity assays. In some countries, the duck HBV (DHBV) is recognized as a suitable model for testing antiviral activity of chemical biocides against HBV. Currently, DHBV-infected ducks are required for preparation of the test virus as well as eggs from DHBV-free flocks for testing DHBV infectivity. To improve the practicality of the system, we suggested to use commercially available embryonated duck eggs for preparation of DHBV-susceptible hepatocyte cultures and to exclude infected hepatocytes by pre-screening with qualitative detection of DHBV DNA using polymerase chain reaction (PCR). A standardized DHBV test virus was prepared from the DHBV DNA-transfected hepatoma cell line D2, which contained 10(11)DHBV DNA molecules per mL detected by light cycler real-time PCR. Infection of cell cultures was most efficient 4 days after plating. The best identification of infected cultures was possible 6 days after infection with immunofluorescence using an antiserum against DHBV surface antigen.

Molecular epidemiology of hepatitis B, C and D viruses in Turkish patients

Different genotypes of the hepatitis viruses may influence the clinical outcome of the disease. The distribution of genotypes may vary according to geographical regions. The aim of this study was to evaluate hepatitis B virus (HBV), hepatitis C virus (HCV) and hepatitis D virus (HDV) genotypes in Turkish patients with chronic hepatitis in a large cohort of patients. Genotyping was performed in 41, 59 and 365 patients with chronic hepatitis B, D and C, respectively, and 36 hemodialysis patients with chronic hepatitis C. Genotypes were determined by direct sequencing in hepatitis B and by polymerase chain reaction-restriction fragment length polymorphism in hepatitis C and D patients. In addition, HBV subtyping by multiplex PCR and subtype specific ELISA were performed in 83 and 71 HBsAg (+) blood donors, respectively. All hepatitis B (100%) and hepatitis D (100%) patients had genotype D and type I, respectively. HBsAg subtyping by two methods yielded that 99% of the patients were subtype ayw. S gene amino acid sequence in the 41 patients included for HBV genotyping revealed the ayw2 subtype. Genotype distribution of 365 patients with chronic C hepatitis were as follows: 306 (84%) patients genotype 1b, 43 (11%) patients genotype 1a, 10 (3%) patients genotype 2, 3 (1%) patients genotype 3, 3 (1%) patients genotype 4. Among 36 patients receiving hemodialysis, 28 (78%) patients had genotype 1b and 8 (22%) patients had genotype 1a. The study indicates that Turkish patients with chronic viral hepatitis show very little genotypic heterogeneity. Subtype ayw and the genotype D of HBV DNA, and the type I of HDV RNA represent almost 100% of related infections. The genotype 1b of HCV RNA was found to be significantly dominant in Turkish patients.

Testing of corneoscleral discs and their culture media of seropositive donors for hepatitis B and C virus genomes

The prevalence of donors seropositive for hepatitis B virus (HBV) surface antigen (HBsAg) or hepatitis C virus (HCV) antibody (anti-HCV) in western countries is estimated to be 0.5%-1%. There have been only two cases, however, published so far, where hepatitis B was suspected to have been transmitted by penetrating keratoplasty [4]. Concerning HCV, no suspected transmission by keratoplasty has been reported so far. This is also true for the time before serological screening for infectious diseases became mandatory for corneal donors. In the Lions Cornea Bank North Rhine Westfalia, 4.7% (HBV) and 3.2% (HCV) respectively of the corneas of the years 1995 to 1999 were discarded due to a "non-negative serology". In about 50% of these cases the screening test (ELISA) generated no valid signal and, therefore, a "questionable positivity" was assumed. Since in Germany corneal graft shortage still is a limiting factor for penetrating keratoplasty, this study was to evaluate the detectability of HBV-DNA and HCV-RNA in the serum samples, organ culture media and corneas of donors tested seropositive for HBsAg or anti-HCV in an attempt to obtain information as to the potential infectivity of this donor material. In this study, 29 corneas of 17 donors seropositive by ELISA for HBsAg and 27 corneas of 14 donors seropositive by ELISA for anti-HCV were evaluated. The organ culture media and the sera were screened for the presence of HBV-DNA or HCV-RNA by PCR. The corneoscleral discs were divided into a central trephinate (7 mm) and the corneoscleral rim. Concerning HBV-DNA both tissues were examined separately by polymerase chain reaction (PCR). In the case of HCV-RNA, a further, more sensitive nucleotide amplification method (NAT), the transcription mediated amplification (TMA), was used to test media, central corneas and cornealscleral rims. The media were additionally tested by PCR. Viral nucleic acid was detected in the sera from 6 of 17 HBsAg positive donors and from 6 of 14 anti-HCV positive donors. Viral genomes could not be detected in the organ culture media nor in the central corneas or corneoscleral rims by PCR at a detection limit of 1000 and 100 copies/ml. Concerning HCV-RNA, two media were positive in the TMA with 50-100 copies/ml.

CONCLUSION

according to our results, the risk of transmitting hepatitis B or C virus by penetrating keratoplasty appears to be low: although hepatitis C virus RNA could be detected in 2 media (from two donors) out of 27 with a low concentration of virus copies between 50-100/ml. It remains open whether such a low virus particle number may cause infection in the recipient.

Serological pattern "anti-HBc alone": report on a workshop

In areas with low hepatitis B virus (HBV) endemicity such as most parts of Europe and the United States "anti-HBc alone" is found in 10-20% of all individuals with HBV markers, i.e., 1-4% of the population. In about 10% of these individuals HBV DNA is detected by PCR, the proportions varying greatly depending on the population studied, being highest in individuals coinfected with hepatitis C virus (HCV) (above 35%) and HIV (above 85%). A small proportion of individuals with "anti-HBc alone" are in the window phase of an HBV infection or in a stage of late HBV immunity. For the large proportion of these individuals this is not the case and they are thought to have an unresolved HBV-infection or a chronic infection in a late or "low grade" productive state. Currently, limited studies have been performed concerning the clinical aspects of individuals with "anti-HBc alone" and suspected chronic HBV infection. The majority of these individuals seem to be healthy. Some chronic carriers with "anti-HBc alone," however, do present signs of chronic hepatitis. Individuals with "anti-HBc alone" are potentially infectious. This is exemplified by a few case reports of HBV transmission to sexual contacts, perinatal transmission between mother and newborns and in blood recipients. Recommendations are given in relation to both the diagnostic and therapeutic procedures in the individuals with "anti-HBc alone" and in the blood banking and transplantation services.

An international collaborative study to establish a World Health Organization international standard for hepatitis B virus DNA nucleic acid amplification techniques

BACKGROUND AND OBJECTIVES

Twenty-two laboratories from nine countries participated in an international collaborative study to establish a World Health Organization (WHO) international standard for hepatitis B virus (HBV) DNA nucleic acid amplification techniques (NAT).

MATERIALS AND METHODS

Three samples, AA, BB (both of which were lyophilized) and CC (which was a liquid preparation), were analysed using several different NAT assays. The mean HBV DNA content of each sample was determined from the study.

RESULTS

Despite the range of assays (commercial and in-house) used by participants, there was good agreement among the overall mean 'equivalents'/ml obtained by the different assays, except for one laboratory (laboratory 4). The variation in estimates of log10 'equivalents'/ml was 1.75-1.25 for the three samples if results from laboratory 4 were excluded. The mean log10 'equivalents'/ml for all laboratories were 6.42 for sample AA, 6.30 for sample BB and 5.03 for sample CC (exclusion of results from laboratory 4 made little difference). The difference in titres between the two lyophilized samples (AA and BB) was not statistically significant but the titre of the frozen sample (CC) was significantly lower. Material AA (code 97/746) was accepted as the first WHO international standard for HBV DNA NAT assays and assigned a potency of 10(6) international units (IU)/ml.

CONCLUSIONS

The titres (genome equivalents/ml) of three HBV preparations were determined by several laboratories using different NAT assays. This study enabled the establishment of an international standard, 97/746, for HBV DNA NAT assays.

Serological pattern "anti-HBc alone": report on a workshop

In areas with low hepatitis B virus (HBV) endemicity such as most parts of Europe and the United States "anti-HBc alone" is found in 10-20% of all individuals with HBV markers, i.e., 1-4% of the population. In about 10% of these individuals HBV DNA is detected by PCR, the proportions varying greatly depending on the population studied, being highest in individuals coinfected with hepatitis C virus (HCV) (above 35%) and HIV (above 85%). A small proportion of individuals with "anti-HBc alone" are in the window phase of an HBV infection or in a stage of late HBV immunity. For the large proportion of these individuals this is not the case and they are thought to have an unresolved HBV-infection or a chronic infection in a late or "low grade" productive state. Currently, limited studies have been performed concerning the clinical aspects of individuals with "anti-HBc alone" and suspected chronic HBV infection. The majority of these individuals seem to be healthy. Some chronic carriers with "anti-HBc alone," however, do present signs of chronic hepatitis. Individuals with "anti-HBc alone" are potentially infectious. This is exemplified by a few case reports of HBV transmission to sexual contacts, perinatal transmission between mother and newborns and in blood recipients. Recommendations are given in relation to both the diagnostic and therapeutic procedures in the individuals with "anti-HBc alone" and in the blood banking and transplantation services.

Preoperative red cell production in patients undergoing weekly autologous blood donation

BACKGROUND

Modest autologous blood donation programs involving weekly phlebotomy and threshold hematocrits for blood donation higher than 33 percent are frequently used in patients scheduled for elective cardiac surgery. This study was performed to determine the gain in red cells (RBCs) obtained with such a program.

STUDY DESIGN AND METHODS

The blood bank and medical records of 225 adult patients (194 men, 31 women; mean age, 57 years [range, 18-77]) who donated blood for autologous use in elective cardiac surgery during a 3-year period were reviewed. Preoperative RBC production was estimated by the total volume of RBCs donated minus the change in circulating RBC volume between the first donation and the day before surgery.

RESULTS

A total of 604 blood units were donated (2.7 units/patient; range, 1-3). The mean volume of RBCs donated was 522 mL (range, 171-732). Mean RBC production (over baseline RBC production) was 351 mL (range, 9-719), or 19 percent (range, 0.5-40) of the circulating RBC volume at baseline.

CONCLUSION

A modest autologous blood donation program using three phlebotomies at weekly intervals and a threshold hematocrit for blood donation of 36 percent yields an average of 351 mL (range, 9-719) of RBCs. This is equivalent to 2 units (range, 0.5-4) of allogeneic packed RBCs at 180 mL per unit.

[Trends in autologous blood transfusion in the old states of the Federal Republic of Germany, 1989-1993. 1. A panel study of 143 hopitals]

Increased perception of the risks of homologous blood transfusion has focused substantial interest on autologous blood transfusion (ABT). To evaluate the role of ABT in the Federal Republic of Germany (FRG), we conducted postal surveys of German hospitals in 1989 and 1993. In the present study, the responses of 143 hospitals in the "old" federal states (former West Germany) that replied to both of our surveys were analysed. The objective was to examine trends in ABT practice in the FRG from 1989 to 1993. The study was restricted to the "old" federal states because data for the "new" federal states (former German Democratic Republic) were not available for that period. METHODS. Data presented in this study were obtained by postal surveys of German hospitals in 1989 and 1993. Because of German reunification (3 October 1990), only hospitals in the "old" federal states were surveyed in 1989, while hospitals in both the "old" and "new" states were included in 1993. Four hundred randomly selected hospitals in the "old" federal states were included in both surveys, 143 of which responded to both. The completed questionnaires of these 143 hospitals were analysed. In addition, to estimate the magnitude of positive selection bias, the data provided by these 143 hospitals were compared with data provided by another set of 162 hospitals in the "old" federal states that replied to the 1993 but not to the 1989 survey. RESULTS. There were no significant changes from 1989 to 1993 in the 143 hospitals with respect to hospital size by number of beds and spectrum of surgical specialties. The proportion of hospitals that performed preoperative autologous blood donation grew by 20% (from 74% to 89%) and the proportion that used this technique regularly ("frequently" and "mostly") rose by 80% (from 25% to 45%). The percentage of hospitals that performed preoperative plasmapheresis had more than doubled (from 8% to 19%). The proportion that used acute isovolaemic haemodilution grew by 32% (from 62% to 82%), while those doing so regularly ("frequently" and "mostly") increased by only 17% (from 23% to 27%). The fraction of hospitals equipped with cell-washing devices grew by 29% (from 35% to 45%). General transfusion practice, as measured by acceptance of postoperative haemoglobin levels of less than 10.0 g/dl, had changed but little. CONCLUSIONS. Although the 143 hospitals are not representative on a national level, the findings of our study allow some conclusions on general trends in the "old" states of the FRG. The potential for ABT has substantially grown in the "old" states from 1989 to 1993, although more consistent advantage of this potential could be taken.

[Autologous blood transfusion in the Federal Republic of Germany--results of a questionnaire in 1993. 2. The use of autologous transfusion in the old and new federation]

In 1993, we conducted a postal survey to assess the use of autologous blood transfusion (ABT) in the Federal Republic of Germany after reunification. The results of this survey have already been reported in a previous paper, but without differentiation between the "old" and "new" states (former West Germany and former German Democratic Republic, respectively). In the present study, the data of our 1993 survey were further analysed to see if there were differences in the use of ABT between the "old" and "new" states. METHODS. The study is based on data of a 1993 postal survey of German hospitals. Details concerning the performance of the survey have been reported in a previous paper. Briefly, questionnaires were mailed to the anaesthesia departments of 400 randomly selected hospitals in the "old" states and 284 hospitals in the "new" states of the Federal Republic of Germany. The questionnaires contained 36 questions related to general information on the hospital and the use of ABT; 305 completed questionnaires were returned from the "old" states and 197 from the "new" states, response rates of 76% and 69%, respectively. For the present investigation, the responses of the hospitals of the "old" and "new" states were analysed separately. Frequency distributions of categorical variables were analysed by the chi-square test. Because of multiple testing, statistical significance was attained only at the 0.05% level (P < or = 0.0005). RESULTS. There were no significant differences between the "old" and "new" states with respect to hospital size by number of beds, percentage of general and specialised hospitals, and percentage of operations requiring blood transfusion. In both the "old" and "new" states, 9% of the responding hospitals maintained a hospital-based transfusion service, while the other depended on regional blood banks. Preoperative autologous blood donation (PABD) was performed at least "rarely" in 85% and 71% (P = 0.0001), and "mostly" in 20% and 10% (P = 0.0014) of the hospitals in the "old" and "new" states, respectively. Uniformly, the principal uses of PABD were for orthopaedic and cardiac surgery. In 62% and 27% (P < 0.0001) of those hospitals that reported performing PABD, the autologous blood service was run by the anaesthesia department. Preoperative plasmapheresis was performed in 14% and 8% (P = 0.008), and isovolaemic haemodilution in 82% and 56% (P < 0.0001) of the hospitals in the "old" and "new" states, respectively. Automated autotransfusion devices (cell savers) were available in 38% and 19% (P < 0.0001) of the hospitals, respectively. Simple collection devices for perioperative blood salvage were used in 17% and 15% (P = 0.24) of the hospitals in the "old" and "new" states, respectively. CONCLUSION. We conclude that ABT is more widely used in the "old" than the "new" states of the Federal Republic of Germany. ABT is regarded as a desirable alternative to homologous blood transfusion, and in the interest of equal standards of medical care throughout the nation, the use of ABT should be further promoted, especially in the "new" states of the Federal Republic of Germany.

Analysis of the precore DNA sequence and detection of precore antigen in liver specimens from patients with anti-hepatitis B e-positive chronic hepatitis

A number of naturally occurring hepatitis B virus (HBV) mutants unable to synthesize the hepatitis B e antigen (HBeAg) have been identified in patients characterized by HBV DNA and anti-HBe in their serum. Because the analysis of the HBV-associated DNA and antigens in the liver tissue is still not complete, we investigated the precore sequence of HBV DNA and its encoded proteins in the liver tissue of 32 patients positive for HBV DNA and anti-HBe in their serum. Three different groups of patients were identified. Group I (n = 14) was characterized by viral DNA sequences with a G-A transition in the distal precore gene region, thus creating a termination codon (TAG). Liver tissue from this group was negative for HBeAg but positive for hepatitis B core antigen (HBcAg) and a peptide containing the last 10 aminoacids of the precore and the first four aminoacids of the c region. Group II (n = 6) showed variable mutations in base sequences further upstream and negative for HBeAg and the precore peptide. Group III (n = 12) contained wild-type HBV DNA sequences in the tissue and positivity for precore- and core-encoded proteins. We conclude from our study that the group of patients with HBV DNA and anti-HBe in the serum is rather heterogeneous, including HBV DNA mutations in the precore region as well as infection with the wild-type virus being negative for HBeAg in the serum. The precore peptide is produced and expressed in the tissue even when the formation of a stop codon at base 1896 prevents the complete translation of the entire HBe protein.

[The importance of autologous blood transfusion in the Federal Republic of Germany. Results of a survey carried out in 1989]

The study was designed to evaluate the role of autologous blood transfusion in current clinical practice. METHODS. Standardized questionnaires were distributed to the anesthesia departments of 421 randomly selected hospitals in the 'old' Federal Republic of Germany and West Berlin in August 1989. The questionnaires contained 26 questions relating to (1) the particular hospital, (2) preoperative autologous blood donation (PABD), (3) preoperative plasmapheresis, (4) isovolemic hemodilution, (5) intra- and postoperative autotransfusion, (6) general practice followed in blood transfusion, and (7) blood salvage in children. RESULTS. In all, 207 completed questionnaires (49%) were returned, 12% of which came from university hospitals, 25% from hospitals with more than 500 beds, 58% from hospitals with fewer than 500 beds and 5% from smaller specialized hospitals. Over half (52%) of the responding hospitals were running their own transfusion services or were located in the vicinity of a regional blood bank. The overall proportion of surgical procedures requiring perioperative blood transfusions was 10%. PABD was performed "not at all" in 24% of the hospitals, "rarely" in 28%, "occasionally" in 24%, "frequently" in 10%, and "routinely" in 13%. PABD was standard in 75% of the departments of orthopedic surgery, in 68% of the departments of cardiac surgery, and in 33% of the departments of vascular surgery. In two-thirds of the hospitals reporting the use of PABD, the anesthesia departments were in charge of the autologous blood service. For 64% of the hospitals, liquid storage of whole blood was reported as the standard technique. Patients normally not eligible for homologous blood donation according to established donor criteria were accepted for autologous blood donation at most "occasionally" in 60% of the hospitals, but "frequently" or "mostly" in 36%. Preoperative autologous plasmapheresis was performed when major intraoperative blood loss was anticipated in 12% of the hospitals. Isovolemic hemodilution was performed "not at all" in 30% of the hospitals, "rarely" in 17%, "occasionally" in 25%, "frequently" in 14%, and "mostly" in 12%. The reasons most frequently given for not performing hemodilution were "too time-consuming" (41%) and "too little blood-saving effect" (32%). Autotransfusion devices were available in 40% of the hospitals. Others deemed such devices "badly needed" (5%) or "desirable" (43%), while 45% found them "not necessary." The principal use of intraoperative autotransfusion was in cardiac surgery (79% of the departments), orthopedics (47% of the departments) and vascular surgery (45% of the departments). In 29% of the responding hospitals autotransfusion devices were also used for postoperative autotransfusion ("seldom" in 7%, "occasionally" in 10%, "frequently" in 6%, "mostly" in 6%). In the absence of cardiopulmonary disease, hemoglobin concentrations below 8-10 g/dl were considered an indication for blood transfusion. In patients with compromised cardiopulmonary function the lowest acceptable level was 10-12 g/dl. Blood salvage techniques are obviously rarely used in children. Experiences with PABD in children were reported by 14.5% of the hospitals, experience with isovolemic hemodilution by 22% and with intra- and postoperative autotransfusion in 18% and 12.5% of the hospitals, respectively. Preoperative plasmapheresis was performed in children in 3.5% of the hospitals. CONCLUSIONS. Although the present sample is not representative on a national level, our findings allow the conclusion that the simple techniques of both preoperative autologous blood donation and isovolemic hemodilution are unduly neglected in surgical and anesthetic practice, whereas even smaller hospitals are fairly well equipped with sophisticated autotransfusion devices.

Unsatisfactory specificities and sensitivities of six enzyme immunoassays for antibodies to hepatitis B core antigen

To examine the consistency and comparability of anti-hepatitis B core antigen (anti-HBcAg) assays, four blood donation centers of the Red Cross in the Federal Republic of Germany tested 4,080 unselected blood donors with six different tests in parallel. Confirmation testing of reactive samples was done in the National Reference Center for Viral Hepatitis. Depending on the test kit used, 4.1 to 9.9% of serum samples were initially positive and 2.9 to 7.5% were repeatedly positive. Sixteen percent of serum samples were positive in at least one test but only three percent were positive in all six tests. Statistical analysis of frequency distribution of optical densities for each test suggested that there should be a correction of the cutoff values. This reduced the number of false-positive results by half, but a significant proportion of discrepant results could not be resolved. The lack of specificity and consistency requires cautious interpretation of isolated anti-HBcAg results in clinical specimens. Screening of predominantly anti-HBcAg-negative populations (e.g., blood donors) by the current anti-HBcAg test kits will almost necessarily give unsatisfactory results.

The effect of recombinant alpha-interferon treatment on serum levels of hepatitis B virus-encoded proteins in man

The effect of alpha-interferon treatment on serum levels of hepatitis B virus-encoded proteins was analyzed in eight patients with chronic type B hepatitis who participated in a pilot study of interferon therapy. Three individuals became HBsAg-negative, 4 lost HBeAg but remained HBsAg-positive and 1 remained positive for both HBsAg and HBeAg. Initiation of interferon treatment was rapidly followed by reduction or loss of hepatitis B virus DNA in the serum but by little immediate change in hepatitis B virus antigen levels. Changes in hepatitis B virus antigens were usually delayed. Loss of HBsAg from the serum was preceded by the sequential disappearance of pre-S-encoded proteins (pre-S1 and polymerized human serum albumin) and HBeAg. In patients who lost HBeAg but remained HBsAg-positive, serum levels of pre-S1 and polymerized human serum albumin usually, but did not always, decrease. The individual who remained HBsAg- and HBeAg-positive had unchanged serum levels of pre-S1, polymerized human serum albumin and HBsAg. These results suggest that alpha-interferon inhibits hepatitis B virus DNA replication but has little direct effect on synthesis of hepatitis B virus gene products.

Treatment of hepatitis B surface antigen (HBsAg)-positive chronic hepatitis with recombinant leucocyte alpha-A interferon

A total of 32 individuals with HBsAg-positive and anti-delta-negative chronic hepatitis were treated with recombinant alpha-A interferon in phase I and phase II studies. In 5/32 patients HBsAg could be eliminated and in 19/32 individuals HBeAg became negative including all those who also eliminated HBsAg. Side-effects were tolerable in most patients and were readily reversible upon discontinuation of interferon therapy. In conclusion, treatment of HBsAg-positive chronic hepatitis with interferon seems to be a promising therapeutic approach. Future studies will have to establish the optimal dose, duration of treatment and factors predicting a favourable outcome of the treatment.

[Preparation and testing of a hepatitis B vaccine (author's transl)]

Starting with 41.5 l of plasma from anti-HBe positive carriers of HBs antigen, 11,400 doses of a hepatitis B vaccine with 42 micrograms HBsAg-protein and 11,300 national units HBsAg activity per dose were obtained. After purification, HBsAg is obtained in 99% purity with a yield of more than 90% protein. A possible residual infectivity was inactivated by a diluted formalin solution. The infectivity test in chimpanzees confirmed the absence of infectious hepatitis viruses (HBV and nonA-nonB). In guinea pigs the immunogenicity of the vaccine was comparable to that of the reference preparation from the U.S. National Institute of Health. The presence of Al(OH)3 in the vaccine increased the anti-HBs titre by factors of 30-50. After vaccination with two doses 41 of 45 persons became anti-HBs positive, with three doses 42 of 45 persons developed anti-HBs. Median anti-HBs titre after the third doses: schedule I (three doses in intervals of 6 weeks) 427 mWHO-U/ml; schedule II (two doses at an interval of 4 weeks, third doses 4 months after the first doses) 1535 mWHO-U/ml. The vaccine was well tolerated. There were minor local reactions only.

Experimental non-A, non-B hepatitis: four types of cytoplasmic alteration in hepatocytes of infected chimpanzees

On the occasion of an outbreak of non-A, non-B hepatitis in a plasmapheresis centre (81 cases, incubation period: 3--6 weeks) a pool of 12 plasma samples was obtained in the early phase of increasing transaminases. Two chimpanzees were inoculated, each receiving 12 ml of the pooled plasma. After an incubation period of 10--12 weeks a mild non-A, non-B hepatitis developed. Serum transaminases were slightly elevated. Needle biopsies, taken fortnightly, showed a slight activation of Kupffer cells (6--8 weeks), single cell necroses, and infiltration of the portal tracts (10--13 weeks). Electron microscopically four types of cytoplasmic change, were found in hepatocytes and assumed to be specific for the infection, Type I: Sponge-like inclusion (6 weeks after inoculation) composed of a dense matrix and irregularly arranged membranes. Type II: Attaching curved membranes (8 weeks), developing by close apposition of two cisternae of smooth endoplasmic reticulum. Type III: Cylindrical complexes (10 weeks), already described in literature. Type IV: Microtubular aggregates, usually neighbouring type III structures. The findings suggest 1) that the agent of the present infection is, at least in part, identical with that of the long incubation type of experimental non-A, non-B hepatitis, and 2) that ultrastructural alterations may precede manifest hepatitis.

[Follow-up study on antibody dependent cell-mediated cytotoxicity and cell-mediated cytotoxicity to HBs-antigen conjugated target cells in patients with hepatitis B (author's transl)]

Results of a follow up study on ADCC and CMC to HBs antigen conjugated target cells in patients with hepatitis B are given. The cytotoxic reaction was measured immediately after onset of the disease, three weeks and three months thereafter CMC was increased over the whole observation period. The results in hepatitis B patients were significantly different to those in normal controls. The ADCC in the presence of an antiserum to HBs antigen was in patients with hepatitis B immediately after onset of the disease reduced in comparison to the controls; it increased during the three months to the values of the controls in patients with uncomplicated disease. Experiments with isolated lymphocyte populations showed that the ADCC is mainly dependent on Fc receptor bearing lymphocytes whereas the CMC is mediated by T-cells and Fc-receptor bearing cells.

[Studies on the serological manifestation of the hepatitis B-virus-infections in the Republic of Liberia (author's transl)]

The prevalence of hepatitis B virus infections was examined in four groups from Liberia using radioimmunoassays for HBsAg, anti-HBs and anti-HBc. At the age of 15-19 years 90% have been infected, at the age of 40 years 100%. In a rubber plantation 30% had HBsAg, in the remaining 3 groups only 13% were HBsAg-positive. In the first group onchocerciasis was also a more frequent finding. However the parasitic infection was not the cause of the HBs-antigenemia. The HBsAg-concentration is mostly lower in the positive Liberians than in German HBsAg-carriers. Apparently the HBV caused frequently latent infections with low production of viral antigens in Liberia.

Detection of antibodies to Sendai virus by enzyme-linked immunosorbent assay (ELISA)

An enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to Sendai virus, a paramyxovirus, is described. The assay was found to be about 20-fold more sensitive than the hemagglutination inhibition assay. Differentiation between virus specific IgG and IgM is possible. The test appears to be especially useful in the study of early events in antibody formation in vivo as well as in vitro.

[Experiments for the development of a hepatitis B vaccine: immunogenicity of HBsAg in guinea pigs (author's transl)]

Hepatitis B surface antigen (HBsAg) was purified from human plasma by gel chromatography, isopyknic centrifugation, and zonal centrifugation. The final product had about 60% of the original activity and was essentially free from hepatitis B virus particles (HBV) and plasma proteins. Treatment with formaldehyde concentrations up to 0.1% for inactivation of residual infectivity did not significantly reduce antigenicity in vitro and immunogenicity in guinea pigs. Adsorption to aluminum hydroxide resulted in 16-fold higher concentrations of antibody against HBsAg (anti-HBs) than did injection of soluble HBsAg. After two injections of 0.2 microgram HBsAg, which was treated with 0.1% formaldehyde and absorbed to aluminum hydroxide, the median titer of anti-HBs in guinea pigs was 4 IU/ml (normal value in human hepatitis B convalescents: about 0.1) for 1 year without further injections. When guinea pigs received 12 equivalents of homologous anti-HBs serum before the first injection of adsorbed HBsAg, the same anti-HBs titers were found after the booster injection as in animals which had not been passively immunized. A simultaneous application of an experimental HBsAg vaccine and hepatitis B immunoglobulin would probably decrease the potential risk of HBV infections caused by the vaccine itself and also produce rapid protection. To establish absence of HBV as completely as possible, the vaccine should be produced from anti-HBe-positive plasma by efficient purification procedures and it should be inactivated by formalin.

Antibody-dependent cell-mediated cytotoxicity (ADCC) and cell-mediated cytotoxicity (CMC) to HBsAg-coated target cells in patients with hepatitis B and chronic hepatitis (CAH)

A new technique using HBsAg-coated Chang cells as target cells was developed in order to measure cell-mediated immune reactions to HBsAg. The specificity of cytotoxic reactions was tested in experiments using Chang cells conjugated with human serum albumin. Antibody-dependent cell-mediated cytotoxicity (ADCC) specific for the HBsAg-coated target cells was demonstrated up to dilutions of anti-HBsAg serum of 10,000 : 1, when lymphocytes from the peripheral blood of normal individuals were added to the target cells. Spontaneous cell-mediated cytotoxicity (CMC) to HBsAg-coated target cells was demonstrated for lymphocytes from patients with hepatitis B and from patients with chronic active hepatitis (CAH), but not for lymphocytes from healthy controls. The CMC of hepatitis B lymphocytes to HBsAg-coated target cells was inhibited in the presence of antiserum to HBsAg. In experiments using purified lymphocyte populations evidence is presented that the CMC is T-cell dependent. HLA-restriction of the CMC was not observed. The described cytotoxicity test system has the advantage that target cells conjugated with defined antigens are used and that relevant control target cells are available.

[Differing results of direct and indirect solid phase radioimmunoassay for HBsAg in acute hepatitis (author's transl)]

In 54 patients suffering from acute viral hepatitis the indirect solid phase radioimmunoassay (ind-SPRIA) for HBsAg was positive in 9 cases the direct solid phase radioimmunoassay (d-SPRIA) being negative. In 2 further cases ind-SPRIA was positive during several weeks but d-SPRIA only once. AntiHBc could be detected in 9 of these patients. In 7 patients the usual decrease of the transaminase activity was followed by a second elevation with prolongation of disease. The unknown factor detected by ind-SPRIA suggests a special form of acute hepatitis.

[Asymptomatic chronic-persisting hepatitis B in a young child as source of infection of hepatitis B within a family (author's transl)]

Five members of an eight-member family fell ill with an acute icteric hepatitis B of the same subtype within eleven months. In all probability the source of the infection was a just over one-year-old fostered child with asymptomatic chronic persisting hepatitis B and signs of massive viraemia (usually high HBs antigen concentration, high virus-specific DNA-polymerase activity and positive HBe antigen test). No relation could be demonstrated between HLA constellation and illness in the family members. Since no specific treatment is available, the only possible prophylactic measure is to isolate the child in the present environment, to avoid further cases of the disease.

The seroepidemiological pattern of acute viral hepatitis. An epidemiological study on viral hepatitis in the Hannover region

The natural incidence of the etiologically distinct types of viral hepatitis was determined by investigating acute phase sera of symptomatic hepatitis cases occuring in the Hannover area in 1975 for the presence of hepatitis B surface antigen, antibodies to hepatitis A, hepatitis B core and surface antigens, and by measuring the IgM serum levels. Fourteen different seroepidemiologic patterns were recognized. Although there was a high prevalence of hepatitis A antibody in the population, the frequency of hepatitis A was low (n = 56) suggesting that the hepatitis A virus does not play a major role in symptomatic hepatitis in the Hannover area at present. Spread of the hepatitis A virus was mostly associated with person-to-person contact or tourist travel in southern Europe. Hepatitis B was the predominant type of hepatitis (n = 211). Hepatitis non-A, non-B was observed infrequently (n = 62). A high percentage of patients with hepatitis B and hepatitis non-A, non-B reported parenteral exposure to potentially contaminated materials. No other findings, however, suggested an infectious etiology of hepatitis non-A, non-B.

Radioimmunoassay for LCM virus antigens and anti-LCM virus antibodies and its application in an epidemiologic survey of people exposed to syrian hamsters

A specific and sensitive solid-phase radioimmunoassay has been developed for the detection of LCM virus antigens and anti-LCM virus antibodies. The test was performed in a microtiter system using polyvinylcholoride wells coated with anti-LCM virus rabbit hyperimmune serum. LCM virus antigens were allowed to bind to this antibody and afterwards detected by 125J-labeled anti-LCM virus-gamma-globulin. Anti-LCM virus antibodies were assayed by specific inhibition of these bound antigens. Since this technique is rapid and easy to perform the solid-phase radioimmunoassay is a valuable test for detecting LCM virus infections. Selected at random, 208 girls with, and 208 girls without, contact to Syrian hamsters were investigated for anti-LCM virus antibodies. Five (2.4%) of the hamster-exposed girls had anti-LCM virus antibodies (RIA-titer 1:8-1:32) in contrast to none of the control group (P=0.03).

[Separation of morphological types of hepatitis B-antigen (author's transl)]

Hepatitis B Antigen from plasma of a healthy chronic carrier was separated by gel chromatography using 6% agarose gel into fractions with different size (Fig. 1). Single fractions were further purified by isopycnic centrifugation in CsCl (Fig. 2) and characterized by electron microscopy (Fig. 3). The amount of the different particle groups was determined comparing the extinction peaks in the centrifugates (Table 1). 88% of antigen protein was located in the 18 to 25 nm spheres (Fig. 3a), 10% in tubules with a length between 30 and 100 nm and about 2% form tubules 100-200 nm long (Fig. 3b and 3c). Together with the tubules were found 40 nm spheres representing about 0,1% of the HBAg-substance (Dane paticles, Fig. 3d). The proportion of the larger antigen particle seems to be absent or very low in acute Hepatitis B patients, but is frequently found in chronic carriers.

[Determination of particle size by gel chromatography with sepharose 6B]

Gel chromatography with 6% agarose gel (Sepharose 6B) can be used for measuring the Stokes’ radius of biological particles within the range of 1,5 nm and 35 nm. The molecular weight determination of proteins is not very reliable with this method. Hepatitis sera have been chromatographied to measure the size of hepatitis associated antigen (Australia-antigen).

The radius of this antigen was determined to be 10,3 nm, which agrees with the results of electron microscopy and ultracentrifugation. The Stokes’ radius of human serum IgM was found to be 10,6 nm.