Incidence of Hepatitis E Antibodies in Swedish Lung Transplant Recipients

BACKGROUND

Hepatitis E virus (HEV) is an important cause of acute and chronic hepatitis in solid organ transplant recipients, especially liver transplant recipients. However, less is known of the incidence and prevalence of HEV in lung transplant recipients.

METHODS

In a prospective study, 62 patients were observed during the first year after lung transplantation. Sera were analyzed for anti-HEV immunoglobulin G (IgG) and IgM at 12 months after transplantation. Samples positive for anti-HEV were also analyzed for HEV RNA by polymerase chain reaction. Pretransplantation samples were analyzed for patients with detectable anti-HEV 1 year after transplantation.

RESULTS

Eight patients (13%) had anti-HEV IgG at the 12-month follow-up sample. HEV RNA could not be detected in any of these samples. One of these patients seroconverted during the follow-up without developing acute or chronic hepatitis.

CONCLUSIONS

Our results show that the prevalence of HEV antibodies among Swedish lung transplant recipients is similar when compared to the general population. It also suggests that the risk for HEV antibody seroconversion during first year is limited.

[Molecular epidemiology of hepatitis C in centers of hemodialysis in St. Petersburg]

AIM

Study molecular epidemiology of hepatitis C (HC) in 5 departments of hemodialysis (DH) in St. Petersburg.

MATERIALS AND METHODS

Sequences of nucleotides of 93 isolates including 67 isolates from patents of 5 DH and 26 isolates from patients, who never had hemodialysis in anamnesis, were obtained in 2010 by a method of limited sequencing of NS5B region of HC virus genome. Phyologenetic analysis was carried out by using PHYLIP veision 3.69 program package. Evolution differences were evaluated in DNADIST program using F84 algorithm. Phylogenetic trees were constructed by using nearest neighbor and UOGMA methods in PHYLIP program package.

RESULTS

Subtype 1b was established to dominate in all the DH (69.2 - 92.9%) and the same isolates of HC virus were detected in DH, that were isolated for the first time in 1999. Comparatively higher proportion of isolates of HC subgenotype 3a (26.7 - 30.8%) was detected in 2 of 5 DH in 2010. The same proportion of 3a isolates was detected in the control group.

CONCLUSION

The fact that HC 3a virus isolates were detected in DH in a higher proportion is proof that they have successfully integrated into circulation among dialysis patients over the last decade. ,

Endemic hepatitis E in two Nordic countries

Antibodies against hepatitis E virus (anti-HEV) were found in 248 Swedish and Danish patients between 1993 and 2007. Most patients were symptomatic and tested for anti-HEV due to travel abroad. Among patients with known country of infection, most were infected in Asia, mainly on the Indian subcontinent. However, 29 patients were infected in Europe, nine of these had HEV IgM and/or HEV RNA in serum. In sera from 65 of 141 tested patients HEV RNA could be detected, and 63 strains could be typed by limited sequencing within ORF2. HEV RNA was found in sera from 71% of the patients with HEV IgM and IgG and in 18% of the patients with only detectable HEV IgG. It was also found up to three weeks after the onset of disease in 67% of the patients with known date of onset. Patients infected in Europe were infected by genotype 3, and were older than those infected by genotype 1 (mean age 55.3 vs 30 years, p<0.001). Since it is known that genotype 3 can infect domestic pigs, HEV strains from 18 piglets in 17 herds in Sweden and Denmark were sequenced. Phylogenetic analyses of the genotype 3 strains showed geographical clades and high similarity between strains from patients and pigs from the same area. There are thus autochthonous hepatitis E cases in Scandinavia, and there are probably many undiagnosed ones. Patients with hepatitis of unknown etiology should therefore be investigated for anti-HEV even if they have not been outside Europe, since infections acquired from pigs or other animals should be taken into consideration.

A new core promoter mutation and premature stop codon in the S gene in HBV strains from Iranian patients with cirrhosis

In order to define hepatitis B virus (HBV) mutational patterns in Iran, nucleotide sequences obtained from 91 patients and encompassing the precore, basal core promoter (BCP) and surface (S) regions, were compared. The patients were grouped as asymptomatic carriers, chronic active hepatitis or cirrhotic patients. Genotypes and mutations were determined by sequencing and phylogenetic analysis. All strains belonged to genotype D, and most of them to subgenotype D1. All but two strains specified ayw2, one ayw3 and one adw2 determinants. Two deletions of 8- or 20-bp were found in the X region in eight strains, six from patients with chronic active hepatitis. Eight of 21 strains from patients with cirrhosis harboured unusual mutations such as a stop codon at position 69 in the S region or a previously not described mutation in the BCP region ((1761)TC/ATTTG(1766)). All patients infected by strains with the stop codon mutation had detectable HBsAg and high viral load. The accumulation of mutations found in the BCP and S regions in HBV strains from patients with chronic active hepatitis and cirrhosis may predict disease progression in Iranian HBsAg carriers.

The VIZIER project: preparedness against pathogenic RNA viruses

Life-threatening RNA viruses emerge regularly, and often in an unpredictable manner. Yet, the very few drugs available against known RNA viruses have sometimes required decades of research for development. Can we generate preparedness for outbreaks of the, as yet, unknown viruses? The VIZIER (VIral enZymes InvolvEd in Replication) (http://www.vizier-europe.org/) project has been set-up to develop the scientific foundations for countering this challenge to society. VIZIER studies the most conserved viral enzymes (that of the replication machinery, or replicases) that constitute attractive targets for drug-design. The aim of VIZIER is to determine as many replicase crystal structures as possible from a carefully selected list of viruses in order to comprehensively cover the diversity of the RNA virus universe, and generate critical knowledge that could be efficiently utilized to jump-start research on any emerging RNA virus. VIZIER is a multidisciplinary project involving (i) bioinformatics to define functional domains, (ii) viral genomics to increase the number of characterized viral genomes and prepare defined targets, (iii) proteomics to express, purify, and characterize targets, (iv) structural biology to solve their crystal structures, and (v) pre-lead discovery to propose active scaffolds of antiviral molecules.

Two outbreaks of acute hemorrhagic conjunctivitis in Africa due to genotype III coxsackievirus A24 variant

Reported here are two outbreaks of acute hemorrhagic conjunctivitis that occurred in the Democratic Republic of the Congo and in Morocco in the summers of 2003 and 2004, respectively, with a large impact on public health. Virus was isolated from the conjunctival swabs of 30 Congolese and 20 Moroccan patients. Enterovirus-specific cytopathic effect was observed in all samples. None of the strains could be typed using a conventional neutralization assay with the Melnick intersecting pools; however, by sequencing the VP1 region, the viruses could be identified as coxsackie A24 variants. Phylogenetic analysis of the 3C protease region revealed that these strains were closely related to each other as well as to genotype III isolates detected in Korea in 2002, thus proving their worldwide spread. This is the first report of an epidemic of acute hemorrhagic conjunctivitis due to a coxsackievirus A24 variant in Africa since 1987 and the first ever from Morocco.

Removal of noro- and enteroviruses, Giardia cysts, Cryptosporidium oocysts, and fecal indicators at four secondary wastewater treatment plants in Sweden

The aim of this study was to investigate variation in the occurrence and removal of enteroviruses, noroviruses, Giardia cysts, Cryptosporidium oocysts, and the most commonly used fecal indicators in four Swedish secondary wastewater treatment plants (WWTPs). Paired samples were taken from the inlet and outlet of each WWTP. (Oo)cysts and indicators were enumerated with standard methods and viruses with a reverse transcriptase polymerase chain reaction. Giardia cysts and enteroviruses were constantly detected (mean numbers were 10(3.31) cysts and 10(4.44) polymerase chain reaction (PCR) units L(-1), respectively). Oocysts were found in 5 out of 19 samples (mean number was 20 L(-1)). Noroviruses were found between November and February, with an average titer of 10(3.29( L(-1). Mean cyst removal was 2.6 log, while noroviruses and enteroviruses were removed by 0.9 and 1.3 log, respectively. There was no correlation between the removals of pathogens and indicators (p > 0.05). Coliphage removal resembled human viral removal better than did F-specific phage.

Removal of viruses, parasitic protozoa and microbial indicators in conventional and membrane processes in a wastewater pilot plant

The aim of this study was to investigate variations in the occurrence and removal of enterovirus and norovirus genomes, Giardia cysts, Cryptosporidium oocysts and the most commonly used faecal indicators in a Swedish wastewater pilot plant. Paired samples were taken from the inlet and outlet of each treatment line: tertiary filtration, membrane bioreactor (MBR) and upflow anaerobic sludge blankets (UASB). (Oo)cysts and indicators were enumerated using standard methods and viruses using RT-PCR. Giardia cysts and enteroviruses were constantly detected, mean numbers 10(3.11) cysts and 10(4.0) PCR units L(-1), respectively. Oocysts were found in 5/19 samples, mean number 5 L(-1). Noroviruses were found in 6/7 influent samples, with an average titre of 10(3.28)L(-1), during winter, but only in 2/15 in the rest of the year (mean 200 L(-1)). MBR treatment removed indicators more efficiently than did the other two lines, with 5log removal of E. coli. Human virus genome removal did not differ between the MBR and tertiary treatment line. Microorganism removal in UASB was significantly lower for all the organisms studied. E. coli, enterococci and Cl. perfringens removal was correlated (p<0.05) with enterovirus genome removal, with R-values around 0.4. However, values for removal of indicators were more strongly correlated to each other. Removal of viruses based on enumeration using RT-PCR probably underestimates infectious virion removal.

Genotypes and S-gene variability of Mexican hepatitis B virus strains

The genotypes and subtypes of 15 Mexican hepatitis B virus strains were determined by sequencing and phylogenetic analysis of the small S-gene. The most predominant strains were found to be divergent genotype/subtype F/adw4 strains (66.6%), followed by A/adw2 (20.0%), D/ayw3 (6.7%), and G/adw2 (6.7%). The S-genes of the Mexican genotype F strains and two Nicaraguan strains described previously formed a subcluster with more than 4% divergence from the other strains within this genotype. The Mexican strains within genotypes A and D showed the highest homology with strains from Europe and the United States. Ten amino acid substitutions not described previously were found in the S-genes of strains from nine chronic carriers, whereas the S gene in strains from six acute hepatitis B patients were highly conserved as compared to their respective genotypes. One genotype F strain from an HBsAg positive chronic carrier had a T to A mutation at position 647, forming a translational stop at codon 216. Two genotype F strains from HBsAg negative chronic carriers had a Val180 instead of an Ala found in the other genotype F strains. This study shows that a divergent genotype F predominates in Mexican strains analyzed, which presented amino acid substitutions not reported previously outside the a determinant.

Shift in predominating subtype of HCV from 1b to 3a in St. Petersburg mediated by increase in injecting drug use

The genotypes of 149 HCV strains from St. Petersburg were determined by limited sequencing and phylogenetic analysis within the NS5B region. One hundred two strains derived from patients that attended infectious disease clinics, of whom 48 admitted injecting drug use, and 47 derived from dialysis patients. Subtype 3a was predominant in the patients from infectious disease clinics, both in patients that admitted injecting drug use (56%) and in those with unknown source of infection (46%). However, 89% of the strains from dialysis patients belonged to subtype 1b. Eleven of twelve characterised strains from recent cases of hepatitis C at these units were at phylogenetic analysis shown to be related to strains already circulating there, demonstrating that within the dialysis units nosocomial transmission is the most important route of HCV infection. The predominance of subtype 1b strains in dialysis patients indicates that these strains have been circulating for a long time in dialysis units. The predominance of subtype 3a also among patients who did not admit drug use and that their strains were intermixed with the strains from injecting drug users in the phylogenetic analysis shows that the increase in injecting drug use is the major factor that explains the recent spread of HCV in the St. Petersburg population. This supports the concept that injecting drug use remains the major route for HCV infection in developed countries and that the control of drug abuse is the most important measure to prevent its spread.

Presumed common source outbreaks of hepatitis A in an endemic area confirmed by limited sequencing within the VP1 region

Hepatitis A virus isolates from anti-HAV IgM positive sera of 70 hepatitis cases in two outbreaks and 216 other cases in Central America, 136 sporadic cases and 53 cases from an hyper-endemic region in Costa Rica, were compared by phylogenetic analyses within the VP1 region. The outbreaks in all 531 cases, in 1992 and 1999, respectively, were presumed water borne. In the first outbreak, HAV RNA could be detected in 70% of the cases sampled during 6 weeks after onset of jaundice. In the hyper-endemic region of San Ramón in Costa Rica, 1,932 cases were registered between 1972 and 1985. All isolates belonged to subtype 1A. Background isolates from Costa Rica and El Salvador tended to form separate subclusters in the phylogenetic tree construction and were mostly unrelated to subtype 1A strains from other parts of the world. Based on their amino acid sequences, four HAV strains, all related to CR326 sampled in Costa Rica in 1960, were found to have circulated in the area during the last three decades. However, on the basis of nucleotide variability the isolates from the outbreaks could be distinguished from the strains from sporadic cases and sequence analysis could confirm the epidemiological homogeneity of both outbreaks. In the hyper-endemic region, 16 different sequences were encountered forming one single subcluster. Thus, limited sequencing within the VP1 region proved useful to identify outbreaks of hepatitis A in a highly endemic area, where most strains were local and only one subtype was prevalent.

Prevalence and incidence of bloodborne viral infections among Danish prisoners

In order to determine the prevalence and incidence of bloodborne viral infections among prisoners, we conducted a prospective study in a Danish medium security prison for males. The prisoners were offered an interview and blood test for hepatitis and human immunodeficiency virus HIV at inclusion as well as at release from prison or end of study. Of 403 prisoners available 325 (79%) participated in the initial survey and for 142 (44%) a follow-up test was available. 43% (140/325) of the participants were injecting drug users (IDUs) of whom 64% were positive for hepatitis B (HBV) and 87% for hepatitis C (HCV) markers. No cases of HIV or human T lymphotropic virus (HTLV) were found. 32% of all prisoners could transmit HBV and/or HCV by blood contact. 70% of IDUs had shared injecting equipment, and 60% had injected inside prison. Only 2% of IDUs were vaccinated against HBV. Duration of injecting drug use, numbers of imprisonments, and injecting in prison were independently and positively associated with the presence of HBV antibodies among IDUs by logistic regression analysis. The HBV incidence was 16/100 PY (95% CI: 2-56/100 PY) and the HCV incidence 25/100 PY (1-140) among injecting drug users (IDUs). We conclude that IDUs in prison have an incidence of hepatitis B and C 100 times higher than reported in the general Danish population. They should be vaccinated against hepatitis B and new initiatives to stop sharing of injecting equipment in and outside prison is urgently needed.

Outbreak of Hepatitis B among injecting drug users in Denmark

BACKGROUND

The incidence of hepatitis B is low in Denmark, but injecting drug users (IDUs) remains a high-risk group for this infection.

OBJECTIVES

The aim of the study was to describe a hepatitis B outbreak among IDUs by comparing existing registers. Additionally, we wanted to analyze the genetic variation of the hepatitis B virus involved in the outbreak.

STUDY DESIGN

In the County of Funen, registers of laboratory diagnosis, hospital records and reports from clinicians to the Medical Officer of Health (MOH) were compared between 1992 and 1998. HBsAg positive sera recovered from the epidemic were sequenced and compared to known HBV strains.

RESULTS

We identified 648 cases of hepatitis B of which 51% (332) were acute infections. The laboratory database identified 96% (319/332) of these, 45% (150/332) were admitted to hospital and 38% (127/332) were reported to public health. By capture-recapture analysis based on MOH reports and hospital records the estimated total number of acute cases were 334 (95% C.I. 283-385). We sequenced 75 HBsAg positive samples and identified two very similar strains of genotype D (serotype ayw3) among IDUs involved in the outbreak.

CONCLUSIONS

The current surveillance system did not detect the majority of acute hepatitis B cases in County of Funen. We suggest laboratory-based surveillance of hepatitis B to be implemented at a national level as this may identify new outbreaks faster and more complete than the current surveillance system.

Hepatitis B virus genotypes and HBsAg subtypes in refugees and injection drug users in the United States determined by LiPA and monoclonal EIA

Hepatitis B virus (HBV) genotyping and hepatitis B surface antigen (HBsAg) subtyping were carried out on sera from 196 HBsAg-positive patients, including 151 refugees entering the United States and 45 injection drug users in Seattle. HBsAg subtyping was performed by enzyme immunoassay (EIA) using a panel of monoclonal antibodies and the HBV genotype was determined by polymerase chain reaction (PCR) followed by detection of amplified HBV DNA by a reverse-phase hybridization line probe assay (LiPA) using genotype-specific probes. HBV DNA was detected by PCR in 155 (79%) of the 196 sera and all 155 were genotyped by LiPA. Samples from Southeast Asia were predominantly genotype B/subtype ayw1 and genotype C/adr; samples from the former Soviet Union and eastern Europe were mostly genotype D/ayw2 and genotype D/ayw3; samples from east Africa were mainly genotype A/adw2 and genotype D/ayw2; and samples from injection drug users were mostly genotype D/ayw3 and genotype A/adw2. Some strains of ayw3 gave atypical monoclonal antibody reactivity patterns in the subtyping assay due to a Val/Ala instead of a Thr at amino acid residue 118 and a Thr instead of a Met at residue 125. A strain of ayw2 also gave an atypical monoclonal antibody reactivity pattern due to an Ala instead of a Thr at amino acid residue 123. LiPA genotyping and monoclonal EIA subtyping can provide useful information for epidemiological studies.

[Hepatitis B outbreak in a day care center affected several families. It could have been prevented by vaccination of all children]

An outbreak of hepatitis B originating in a family day nursery affected several children with Somali background. The transmission chain was confirmed by sequence analysis of the S gene. In Africa hepatitis B is often spread horizontally among children of pre-school age, a pattern of transmission that was retained in this outbreak. To limit the outbreak 126 children in the nursery and 50 members of staff had to be vaccinated. The total cost for this intervention was estimated to about 300,000 SEK. Considering the great number of immigrants in Sweden from areas highly endemic for hepatitis B the inclusion of vaccination in the general child immunisation program seems to be the most cost effective measure for long term prevention not only of hepatitis B transmission among children but also of venereal spread in early adulthood.

Homotypic echoviruses share aminoterminal VP1 sequence homology applicable for typing

Molecular typing of enteroviruses should ideally focus on regions encoding determinants for neutralization. Mapping of monoclonal neutralizing antibodies has shown the VPI protein, in particular its aminoterminal part, encompassing the B-C loop, to be one major antigenic region. We therefore sequenced 570 nucleotides from the 5'-end of the VP1 region of the genome for all 28 echovirus prototypes, and for 61 clinical isolates representing all different echovirus types. An analysis of 133 sequences, including 39 sequences retrieved from GenBank, classified all echoviruses in enterovirus group B confirming results from sequencing within the VP2 region. The nucleotide and amino acid divergence of VP1 sequences of homotypic strains varied from 7.5-23.0% and from 0.0-5.3%, respectively, when compared to their corresponding prototypes, whereas strains belonging to different serotypes these divergences were 22.1-38.9 % and 4.9-16.4 %, respectively. Despite these minimal overlaps, the VP1 sequence was always more similar to that of the homotypic prototype than to that of any heterotypic strain. For 13 out of 14 echovirus types, where multiple isolates were available, the corresponding VP1 sequences diverged more from those of the prototype than from the other homotypic sequences as a reflection of genetic drift. Because there was a complete concordance between the sequences of the region encoding the VP1 aminoterminus and the serotype (P< 0.00001) sequence analysis of this region might complement typing by neutralization, and classify correctly echovirus isolates that may not be typed conveniently by the antisera in hand.

Confirmation of nosocomial transmission of hepatitis C virus by phylogenetic analysis of the NS5-B region

Four hepatitis C virus transmission chains at three dialysis units were disclosed by limited sequencing; three of these were disclosed by analysis of the NS5-B region of the genome. Dialysis on the same shift as that during which infected patients were dialyzed was the common factor for seven patients in two chains. Two nurses exposed to needle sticks and their sources of infection constituted two other chains. The strains of three chains belonged to subtype 1a and formed clusters with an intrachain variability of 0 to 6 nucleotides compared to 8 to 37 nucleotides for unrelated strains within this subtype. The clusters were supported by bootstrap values ranging from 89 to 100%.

Antigenic diversity of hepatitis B virus strains of genotype F in Amerindians and other population groups from Venezuela

The adw4 subtype of hepatitis B virus (HBV) belongs to a unique genomic group (genotype F) representing the original HBV strains from the New World. Data regarding the prevalence of this subtype among HBV carriers in South America are, however, scarce, and those concerning HBV genotype F are based on only a few samples from Latin America. In this study, serum samples were obtained from 141 hepatitis B surface antigen (HBsAg) carriers from Amerindians and urban populations from Venezuela. The HBsAg subtype was identified with monoclonal antibodies in 105 samples, and the HBV genotype was identified by reverse-phase hybridization with DNA fragments in 58 samples. The adw4 subtype was highly prevalent in the population studied (75%); among the Amerindians, the prevalence was 97%. The adw2 subtype was also present (10%), while other subtypes (ayw3 and ayw4) were only occasionally found. The HBV subtype was associated with the expected genotype in most cases (80%), and thus genotype F was highly prevalent. Sequencing of viral strains that gave genotypes unpredicted by the HBsAg subtyping confirmed seven of them as belonging to not previously described genotype-subtype associations: namely, adw2 and ayw4 within genotype F.

Molecular epidemiology of hepatitis B virus in Central America reflected in the genetic variability of the small S gene

The S genes of 31 Central American hepatitis B virus (HBV) strains belonging to genotypes A, C, D, and F (4, 1, 4, and 22 strains, respectively) were compared with 104 published S genes. According to the deduced S gene product, 21 genotype F strains encoded adw4, while 1 encoded ayw4. Three clusters were revealed within genotype F, which correlated with substitutions at residue 45. In a cluster of 18 Central American and 1 Alaskan strain, all had Thr45. One cluster included 2 Central American strains and 6 strains from South America and Europe, which had Leu45. Two Nicaraguan strains differed by five substitutions, including a Pro45 in the S gene product from other F strains. In conclusion, the dominating HBV genotype was F, which might be the reason for a low prevalence of HBV in the area, despite high prevalence of hepatitis A. These infections otherwise vary in parallel and are considered to reflect socioeconomic conditions.

Genotype F prevails in HBV infected patients of hispanic origin in Central America and may carry the precore stop mutant

The distribution of HBV genotypes and the presence of the precore stop mutation were investigated in HBV strains from Central America. 333 HBsAg positive sera from chronic HBsAg carriers and acute hepatitis B cases from five different countries (Costa Rica, Nicaragua, Honduras, EI Salvador and Guatemala) were tested for HBV DNA by nested PCR. Genotyping by limited sequencing within the S gene was performed on 90 strains, 66 from sera with a high level of HBV DNA, and another 24 from sera positive for HBV DNA only after nested PCR. 23 of the samples were anti-HBe positive. Genotype F was found in 71 (79%), A in 13 (14%), D in 5 (6%) and C in one of the 90 sera. 18 patients with genotype F infection had anti-HBe and HBV DNA in serum. Since the three published precore sequences of genotype F strains have a C1858, which is known to prevent the precore stop mutation from G to A at position 1896, the precore and part of the core genes were sequenced from 19 anti-HBe positive sera with HBV DNA, 17 with genotype F and 2 with genotype A. The A1896 mutation was found in 11 of the 17 genotype F strains. All these had a T1858, which was also present in 5 of the 6 genotype F strains with G1896. The precore region was therefore sequenced from genotype F strains from 5 HBeAg positive sera from the five different Central American countries. These also had a T1858, which thus is the wild type substitution in genotype F in Central America. A number of mutations were recorded between residues 57 and 68 in the core protein corresponding to a unique clustering region of the genotype F strains. The predominance of genotype F in Central American populations of Hispanic origin was not anticipated since this genotype is regarded as indigenous to the Amerindian populations of the New World.

Genotype F prevails in HBV infected patients of hispanic origin in Central America and may carry the precore stop mutant

The distribution of HBV genotypes and the presence of the precore stop mutation were investigated in HBV strains from Central America. 333 HBsAg positive sera from chronic HBsAg carriers and acute hepatitis B cases from five different countries (Costa Rica, Nicaragua, Honduras, EI Salvador and Guatemala) were tested for HBV DNA by nested PCR. Genotyping by limited sequencing within the S gene was performed on 90 strains, 66 from sera with a high level of HBV DNA, and another 24 from sera positive for HBV DNA only after nested PCR. 23 of the samples were anti-HBe positive. Genotype F was found in 71 (79%), A in 13 (14%), D in 5 (6%) and C in one of the 90 sera. 18 patients with genotype F infection had anti-HBe and HBV DNA in serum. Since the three published precore sequences of genotype F strains have a C1858, which is known to prevent the precore stop mutation from G to A at position 1896, the precore and part of the core genes were sequenced from 19 anti-HBe positive sera with HBV DNA, 17 with genotype F and 2 with genotype A. The A1896 mutation was found in 11 of the 17 genotype F strains. All these had a T1858, which was also present in 5 of the 6 genotype F strains with G1896. The precore region was therefore sequenced from genotype F strains from 5 HBeAg positive sera from the five different Central American countries. These also had a T1858, which thus is the wild type substitution in genotype F in Central America. A number of mutations were recorded between residues 57 and 68 in the core protein corresponding to a unique clustering region of the genotype F strains. The predominance of genotype F in Central American populations of Hispanic origin was not anticipated since this genotype is regarded as indigenous to the Amerindian populations of the New World.

High prevalence of GB virus C strains genetically related to strains with Asian origin in Nicaraguan hemophiliacs

The presence of hepatitis GB virus C (GBV-C), also known as hepatitis G virus (HGV), and hepatitis C virus (HCV) were investigated in sera from 45 hemophiliacs from nine locations in Nicaragua using a nested polymerase chain reaction (PCR). Primers used to detect GBV-C and HCV derived from the helicase region and 5'UTR, respectively. Seventeen (38%) patients were positive for GBV-C RNA in serum by PCR. Twelve (27%) patients were positive for HCV RNA by PCR. Six (13%) of these were coinfected with GBV-C. Anti-HCV was detected in all the 12 HCV RNA positive hemophiliacs and in another 14 (31%) individuals, in whom GBV-C RNA was found in 2. Ten patients (22%) lacked markers for both GBV-C and HCV. The mean age of the patients positive for GBV-C but negative for HCV by PCR was significantly lower than for those negative for GBV-C but positive for HCV by PCR (P < 0.05; Student's t-test), indicating that the risk for this group of hemophiliacs to acquire GBV-C infection is higher as compared to the risk of acquiring HCV infection. Eleven GBV-C strains were sequenced in the 5'UTR. Sequence comparison to previously published GBV-C strains revealed that all 11 strains were more similar to Asian strains than to strains of European and African origin. Sequences in the NS5-B region were available for 8 HCV strains, all of which were found to belong to genotype 1a. The similarity of the Nicaraguan GBV-C strains to strains from Asia indicates that the GBV-C strains in the region presumably have an Amerindian origin. It is also considered that the HTLV II strains in the New World aboriginal populations are ancient and brought there by the ancestral Amerindian populations from Asia. Further, the genotype F of hepatitis B virus, known to represent the strains in populations with Amerindian background, predominates in Central American populations with Hispanic background. It remains to be clarified why Amerindian strains of GBV-C as well as of HBV predominate also in populations with mixed ethnic background in Central America.

Interferon-alpha 2b treatment in hepatitis B carriers. Effect on hepatitis B virus DNA levels in children infected with different genotypes

Eleven hepatitis B virus (HBV) carrier children, infected with genotypes A-D, were treated with interferon-alpha. Two children had a sustained loss of hepatitis B e-antigen and HBV DNA. They were infected with the non-Asian genotypes A and D, and had low HBV DNA and high ALT levels in serum before treatment. However, HBV DNA titres decreased during treatment also in children infected with the East-Asian genotypes B and C.

Genetic relatedness of Sindbis virus strains from Europe, Middle East, and Africa

The relatedness of 40 strains of Sindbis virus (SIN) from Europe, the Middle East, and Africa was investigated by limited sequencing within the gene encoding the E2 glycoprotein corresponding to amino acid residues 117 to 229 and encompassing one of the major neutralization epitopes. Phylogenetic analyses using distance matrix and parsimonious methods identified two major genetic clusters of western SIN strains, although the variability was less than that of the corresponding region for Venezuelan equine encephalomyelitis virus with a maximum divergence of 12.4% versus 28.5%, respectively. One cluster comprising 19 strains included the HR derivate of the Egypt SIN prototype, AR339, and strains from Israel, Saudi-Arabia, Italy, Slovak Republic, Azerbaijan, as well as three Swedish strains. Another cluster of 17 strains included the Ockelbo virus (OCK) prototype, Edsbyn 5/82, and the majority of SIN strains from northern Europe including strains from Sweden, Norway, and Karelia, as well as two strains from South Africa. A third cluster, supported by the Neighbor joining method, was made up of four strains from South Africa, Uganda, and Cameroon. Residue 212, either Ser or Thr, previously appointed important for the differences in neutralization assays between SIN and Edsbyn 5/82, respectively, correlated with the two major genetic clusters, but was a Thr for two of the three Swedish strains in the SIN prototype cluster, and a Ser in one Swedish and one Karelian strain in the OCK cluster. The finding of strains similar to prototype SIN in Middle Sweden and of strains in South Africa relating to the northern cluster of SIN strains supports the notion of the dispersal of SIN by migrating birds as previously suggested for New World alphaviruses.

Complete sequencing of a gibbon hepatitis B virus genome reveals a unique genotype distantly related to the chimpanzee hepatitis B virus

We have sequenced the complete genome of a hepatitis B virus (HBV) strain that was transmitted from a gibbon with chronic hepatitis B to a chimpanzee that subsequently developed acute hepatitis B. The genome was 3,182 nucleotides long and had a genetic organization identical to and including the characteristics of other mammalian hepadnaviruses. Thus, the regulatory elements, the direct repeats, and the four open reading frames (ORFs) of this virus were all maintained, although there were amino acid substitutions affecting all the ORFs. Within the S gene encoding for the hepatitis B surface antigen (HBsAg), the subtype could be deduced as ayw3 in accordance with previous serological results. There were 25 amino acid substitutions affecting the P gene, 12 of which were within the spacer region. This region, which was the most divergent part of the genome compared to other HBV strains, also encodes for the pre-S proteins. A comparison with sequences of other hepadnaviruses revealed that the genome of gibbon HBV was unique as compared to previously described HBV genotypes. It was most similar to the chimpanzee HBV strain with which it shared 90.3% nucleic acid homology at the level of the complete genome and 96.3% homology at the level of the S-gene region corresponding to HBsAg, although being a distinct genotype as compared to the latter virus. Analyses performed using five different algorithms for phylogenetic tree construction showed more than 99% bootstrap support for the gibbon and the chimpanzee HBV to be grouped within the human HBV strains and that they represented later offshoots than the HBV strains of genotype F. However, in most of the dendrograms both the gibbon and the chimpanzee strains represented early lineages, indicating that these viruses are indigenous to their respective hosts and not recent acquisitions from man.

Nosocomial spread of hepatitis B virus (HBV) in a haemodialysis unit confirmed by HBV DNA sequencing

An outbreak of hepatitis B virus (HBV) infection in a haemodialysis unit is described. Four patients in the unit contracted subclinical HBV infection within three months. DNA sequence analysis of the S gene of HBV isolates from chronic carriers and newly infected patients in the unit aided in tracing possible transmission pathways. Three newly infected patients had received partial or complete HBV vaccination previously. HBV was rapidly cleared from all three although the anti-HBs titre had not reached 10 IU L-1 in any of them at the time of infection.

Subtypes, genotypes and molecular epidemiology of the hepatitis B virus as reflected by sequence variability of the S-gene

The serologic heterogeneity of the hepatitis B virus (HBV) has been established from immunodiffusion experiments for a long time. Four serotypes called subtypes of the hepatitis B surface antigen (HBsAg) have been defined by two mutually exclusive determinant pairs, d/y and w/r, and a common determinant a. These subtypes are adw, ayw, adr and ayr. By subdivision of the four major subtypes in the mid-70s, nine different subtypes were identified. Sequencing of viral genomes has now become a major goal of descriptive virology, and sequence data is now used to trace routes of infection, to reconstruct the phylogenetic history of viruses and two delimit genetic subtypes. A genetic classification based on the comparison of complete genomes has defined four genomic groups of HBV, later referred upon as genotypes, which were designated with A-D. However, the interrelation of the nine subtypes to the genotypes, the possible presence of more than four human HBV genotypes as well as their global geographical prevalence remained to be determined. By sequencing the S-gene of HBV the molecular basis was assessed for the serological variations of HBsAg within the major four subtypes. Thereby, also two new genotypes of HBV designated with E and F were identified. Complete genomic sequencing of E and F strains confirmed their status as new genotypes. The F genotype was found to diverge from other HBV genomes sequenced by 14%, thus being the most divergent HBV genome so far characterized. When the worldwide molecular epidemiology of HBV based on the variability of the S-gene was defined, the E and F strains seemed to originate in aboriginal populations of Africa and the New World, respectively. They shared a unique substitution at residue 140 in the second immunodominant loop of their encoded surface antigen when compared to the vaccine strain. Future research will establish whether this substitution may predispose to a vaccine escape mutant at residue 141, that now has been reported to occur in conjunction with the 140 substitution.

Contrasting roles of rivers and wells as sources of drinking water on attack and fatality rates in a hepatitis E epidemic in Somalia

In early 1988, an increased incidence of acute hepatitis was observed in villages along the Shebeli River in the Lower Shebeli region of Somalia. This was followed by a large epidemic that lasted until late 1989. In a survey of 142 villages with a population of 245,312 individuals, 11,413 icteric cases were recorded, of which 346 died, corresponding to an attack rate and a case fatality rate of 4.6% and 3.0%, respectively. The etiologic role of hepatitis E virus (HEV) in this epidemic was proven by demonstrating anti-HEV in 128 of 145 sampled cases as a sign of recent infection with HEV. In three villages, where a special study protocol was implemented, the attack rate was found to increase significantly with age from 5% in the group 1-4 years of age to 13% in the group 5-15 years of age and to 20% for persons older than 15 years of age. Among cases 20-39 years of age, the female-to-male ratio was 1.5:1, which was a significant predominance of females. As in other hepatitis E outbreaks, there was a high fatality rate in pregnant females, estimated to be 13.8%. The epidemic peaked with the rise in the level of the river during rainfall, suggesting that the disease was waterborne. The attack rate was higher (6.0%) in villages supplied with river water, while fewer cases were recorded in those relying on wells or ponds for their water supply, 1.7% and 1.2%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Complete genomes, phylogenetic relatedness, and structural proteins of six strains of the hepatitis B virus, four of which represent two new genotypes

The genomes of six hepatitis B viral (HBV) strains were sequenced from 10 overlapping amplificates obtained by the polymerase chain reaction. Four of the strains, specifying subtypes ayw4 and adw4q-, represented on the basis of divergency within the S gene two new genomic groups identified by us. The other two strains, encoding adrq- and of Pacific origin, belonged to genomic group C. The relation of these genomes to 21 published human, 1 chimpanzee, and 4 rodent hepadnaviral genomes was analyzed by constructing a phylogenetic dendrogram. Thereby, the segregation of human HBV strains into six genomic groups was confirmed. A consistent grouping of the genomes compared was also obtained in dendrograms based on the P and S genes, although the branching order differed from that based on the entire genomes. Each of the two representatives of genomic groups E and F differed by 8.1 to 13.6% and by 12.8 to 15.5% from the genomes of the other groups and by 1.5 and 3.7% from each other. The two Pacific group C strains differed by 2.7% from each other and by 4.1 to 5.4% from other group C genomes, suggesting that they diverged early from the other group C genomes. The F strains formed the most divergent group of HBV genomes, which may be explained by their representing the original strains of the New World. Within the structural gene products, 17 and 34 amino acids unique for human HBV strains were recorded in the sequenced E and F strains, respectively. Most notable is the Ser81 to Ala81 substitution in an immunodominant region of HBcAg, and the four extra cysteine residues in HBsAg at residues 19, 183, 206, and 220, which might be engaged in additional disulphide bridges. Five residues shared by E and F strains were also unique for human HBV strains. Two of these, Leu127 and Ser140 in HBsAg, were the only substitutions that may explain the w4 reactivity shared by these HBV strains. Interestingly, the Ser140 substitution occurs in an immunodominant loop of the a determinant claimed to be important for the protective immune response to HBV vaccination.

Genetic relatedness of hepatitis B viral strains of diverse geographical origin and natural variations in the primary structure of the surface antigen

A 681 nucleotide fragment of the hepatitis B virus (HBV) genome was sequenced that corresponded to the complete gene for hepatitis B surface antigen (HBsAg) in 80 HBsAg- and hepatitis B e antigen (HBeAg)-positive sera of diverse geographical origins. These and 42 previously published HBV sequences within the S gene were used for the construction of a dendrogram. In this comparison, each of the 122 HBsAg genes was found to be related to one or other of the six previously identified genomic groups of HBV, A to F. The HBV strains within each genomic group showed a characteristic geographical distribution. Group A genomes were represented by 23 strains mainly originating in northern Europe and sub-Saharan Africa. The group B and C genomes, represented by 17 and 28 strains respectively, were confined to populations with origins in eastern Asia and the Far East. The group D genomes, represented by 38 strains, were found worldwide, but were the predominant strains in the Mediterranean area, the Near and Middle East, and in south Asia. Group E genomes, represented by nine strains, were indigenous to western sub-Saharan Africa as far south as Angola. There were indications that the F group, made up of six strains, represented the genomic group of HBV among populations with origins in the New World. Thus, HBV has diverged into genomic groups according to the distribution of mankind in the different continents. As well as giving information on the genetic relationship of HBV strains of different geographical origin, this study also provides information on the primary structure of HBsAg in different regions of the world. Such data might prove valuable in explaining the reported failures to obtain protection with current HBV vaccines.

Severe aplastic anemia associated with seronegative community-acquired hepatitis C virus infection

Aplastic anemia (AA) is a rare complication of viral hepatitis affecting mainly children or young adults. Most reported cases have been associated with community-acquired non-A, non-B hepatitis, but hepatitis A and B have also been implicated in a few patients. We report on a 43-year-old woman with severe AA, in association with acute hepatitis C virus (HCV) infection, diagnosed by detection of HCV RNA by the polymerase chain reaction technique. Her AA was successfully treated with anti-thymocyte globulin and cyclosporin A. The hepatitis C progressed to chronic disease but, despite a follow-up time of 2 years, the patient still has no detectable anti-HCV antibodies, as evaluated with a second-generation anti-HCV assay.

Late seroconversion and high chronicity rate of hepatitis C virus infection in patients with hematologic disorders

BACKGROUND

Patients with hematologic disorders requiring repeated blood and platelet transfusions are at high risk for development of post-transfusion non-A, non-B hepatitis.

PATIENTS AND METHODS

Fifty-five patients with hematologic diseases and post-transfusion non-A, non-B hepatitis were studied. Sera were assayed for hepatitis C virus (HCV) antibodies with a second-generation enzyme-linked immunoassay. Sera from 40 patients were examined for the presence of HCV RNA with a nested PCR method.

RESULTS

The clinical picture of acute non-A, non-B hepatitis did not differ from that described in other patient groups: however, progression to chronic hepatitis was very common (95%). Thirty-eight (95%) of 40 patients, whose sera were analysed both serologically and for the presence of HCV RNA had verified HCV infections. In some patients time to seroconversion was prolonged, up to more than 14 months. Seventeen patients with resistant or relapsed acute leukemia were treated with combination chemotherapy during the acute or chronic phase of hepatitis. Suppression of the inflammatory activity as reflected by a decrease of serum aminotransferase levels was recorded during the subsequent pancytopenic period.

CONCLUSIONS

Hepatitis C has a high chronicity rate in patients with hematologic disorders which parallels the situation of hepatitis B in the immunocompromised host. Furthermore, like the situation in hepatitis B, the hosts' immune response to infection seems to be involved in the pathogenesis of liver injury. Time to seroconversion may be prolonged and detection of HCV RNA is therefore important for diagnosis.

Interferon alpha-2b treatment in an HIV-infected patient with hepatitis B virus induced nephrotic syndrome

A 31-year-old male patient with an asymptomatic HIV infection but with a hepatitis B (HBV) related membraneous glomerulonephritis with nephrotic syndrome was given interferon alpha-2b subcutaneously 3 times weekly for 7.5 months. Zidovudine was added at the 10th week due to low CD4+ cell counts. Before the 6th week of treatment the patient reported a reduced need for diuretics to keep his lower limb edemas at a minimum. This response was partially sustained even after the 7.5 months interferon treatment course. The titers of HBV-DNA decreased markedly during the treatment with interferon but rose to pretreatment levels after discontinuation of the interferon treatment. The serum albumin increased but the proteinuria and hematuria were unaffected. Adverse reactions like fever, myalgias and anemia were tolerable and did not require dose reduction of either interferon or zidovudine. This treatment regimen, at least temporarily, improved the situation for the patient and can be worthwhile to try in HIV-infected patients with HBV related nephritis with nephrotic syndrome.

Important role of hepatitis C virus infection as a cause of chronic liver disease in Somalia

In a case-control study, 62 Somali patients with chronic liver disease (CLD) including primary hepatocellular carcinoma (HCC) and the same number of age and sex matched controls were investigated for serological markers of hepatitis C virus (HCV) and hepatitis B virus (HBV) infections. Antibody to HCV (anti-HCV) was detected in 40.3% and 6.5% of cases and controls, respectively. The corresponding prevalences of hepatitis B surface antigen (HBsAg) were 37.1% and 9.7%, respectively. Of the HBsAg-positive cases, 34.6% had antibodies to hepatitis D virus (anti-HD) compared with 14.3% among the HBsAg-positive controls. Anti-HCV was less prevalent in HBsAg-positive cases than among HBsAg-negative patients (p < 0.001), indicating that these agents were independent causes of CLD/HCC. The odds ratios for patients with CLD/HCC associated with the presence of anti-HCV, anti-HD, HBsAg without anti-HD and anti-HCV, were found to be 9.8, 10.4, and 3.3, respectively. When the patients were divided into tumour and non-tumour cases, using the criteria of serum alpha-fetoprotein > 100 ng/ml and/or solid hepatic lesions detected by ultrasonography, they did not differ with regard to frequencies of HBsAg and/or anti-HCV, although they did differ when these markers were taken together (43/49 versus 5/13, respectively). The mean age of the tumour patients with anti-HCV alone was significantly higher than that of tumour patients with HBsAg as the sole marker, 61.7 versus 31.4 years (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Complete nucleotide sequences of six hepatitis B viral genomes encoding the surface antigen subtypes ayw4, adw4q-, and adrq- and their phylogenetic classification

The complete nucleotide sequences of six hepatitis B viral (HBV) genomes were determined by dideoxy chain termination sequencing of ten overlapping nucleotide fragments obtained by the polymerase chain reaction. Four of the genomes belonged to the two genomic groups E and F of HBV which have been previously identified by us on the basis of sequence divergences within the S gene. Genomic group E encodes the HBsAg subtype ayw4, group F adw4q-. The other two genomes were of Pacific origin within group C and encoded adrq-. The relationship of these complete human HBV genomes to 21 that have been previously published, together with one chimpanzee virus and four rodent hepadnaviral genomes, was investigated by constructing a phylogenetic tree utilizing a combination of distance matrix and approximate parsimonious methods. Thereby, the previously demonstrated segregation of human HBV strains into six genomic groups was confirmed. Both of the representatives of the groups E and F were found to differ by 8.1-13.6% and by 12.8-15.5% from the genomes of the other genomic groups and by 1.5 and 3.7% from each other. Since they differed by more than 8% from the genomes in the other groups, the limit originally used to define HBV, genomic groups their status as new genomic groups was confirmed. The two Pacific group C strains were found to differ by 2.7% from each other and by 4.1 to 5.4% from other group C genomes, suggesting that they diverged early from the other group C genomes. According to both the overall similarity and the phylogenetic dendrogram the F strains formed the most divergent cluster of HBV genomes favoring the concept that they represented the original HBV strains of the New World. The next split in the dendrogram segregated the A, D, E and the chimpanzee strains from the Asian B and C strains. Information on the nucleotide sequences and their encoded products of HBV strains of different genomic groups will provide a basis to understand biological variations of the HBV infection in different parts of the world.

Molecular basis of hepatitis B virus serotype variations within the four major subtypes

Amino acid residues 101 to 180 of hepatitis B surface antigen (HBsAg) were predicted by sequencing the corresponding part of the S gene of hepatitis B virus (HBV) DNA in 46 HBsAg-positive sera, which had been subtyped by immunodiffusion with respect to d/y, w/r, w1 to w4 and q. The sequences of the nine different HBV serotypes defined by these specificities were found to be homogeneous proving that they represent consistent variations of HBV at the genomic level. Residue 127 was found to be important as were Pro, Thr and Leu for w1/w2, w3 and w4, respectively. Five residues were found to differ between ayw1 and ayw2. These were at positions 134 (Phe instead of Tyr), 143 (Thr instead of Ser), 159 (Ala instead of Gly), 161 (Tyr instead of Phe) and 168 (Val instead of Ala). However, all these residues were shared by ayw1 and adw2, implying that Arg122 was also important for w1 expression. All genomes expressing r, apart from one ayr strain, had an Ile126, which might explain the pseudo-allelism of w1 to w4 in relation to r, since this substitution might influence the w epitope. There were two regions where adw4q- and adrq- differed from all the q+ subtypes. These were located at residues 158 and 159, and at residues 177 and 178, where both the q- subtypes had amino acid substitutions in adjacent positions. The mapping of the epitopes defining these antigenic specificities will help to link information on the world-wide distribution of HBsAg subtypes to future molecular epidemiology with regard to HBV.

The risk for hepatitis A, B, and C at two institutions for children in Somalia with different socioeconomic conditions

The prevalence of serologic markers for hepatitis A, B, and C was investigated in children from two residential institutions in Somalia. Among 596 individuals at one residence (Shebeli), the prevalences were 96% for antibody to hepatitis A virus (anti-HAV), 75% for total hepatitis B virus (HBV) markers, 16% for hepatitis B surface antigen (HBsAg), and 1.5% for antibody to hepatitis C virus (anti-HCV). Corresponding figures for the 76 individuals at a smaller residence (Societe Organisation Sociale, SOS) were 59%, 20%, 3.9%, and 0%, respectively. At Shebeli, the HBsAg carrier rates in the 1-10-year-old age group was 28% for boys and 16% for girls. These rates were significantly higher than in the older children (16% and 7.4% for boys and girls, respectively). Fifty-eight percent of the HBsAg carriers were positive for hepatitis B e antigen. Total HBV markers were significantly more frequent in girls from Shebeli, when their duration of residence was longer than five years (89% versus 63%). The duration of stay did not influence the prevalences of HBsAg, HAV, or HCV antibodies. A followup study of children initially seronegative for HBV markers was carried out after two years. For children at Shebeli 1-10 years old, the annual seroconversion rates to HBV markers (95% confidence interval) was 60.5% (42.7-77.0%). The corresponding rate for children at SOS was 10.2% (5.2-17.5%). The differences between the two institutions in the prevalence of serologic markers for hepatitis A and B, and in the annual seroconversion rate to HBV markers reflected different rates of horizontal transmission.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of the amino acid sequences of nine different serotypes of hepatitis B surface antigen and genomic classification of the corresponding hepatitis B virus strains

The surface (S) genes of 12 hepatitis B viruses (HBVs) encoding nine different serotypes of hepatitis B surface antigen (HBsAg) were amplified by the polymerase chain reaction and sequenced. These represented the eight strains of HBV, P1 to P8, defined at an international workshop on HBsAg subtypes in Paris in 1975, and the adrq- subtype. The S genes from additional HBV strains, one ayw4, one adw4 and one ayw1, of sub-Saharan African origin, were also sequenced. The relationship of these 12 new S gene sequences to those of the 20 published previously was investigated by constructing a phylogenetic tree, which confirmed a previous classification into four groups, designated A to D, based on 18 complete HBV genomes. When relating our sequenced S genes to these genomic groups, ayw1 of African origin and P6 (adw2) were both allocated to group A, the reference P1 (ayw1 of Vietnamese origin) was allocated to group B, P5 (ayr), P8 (adr) and adrq- were all related to group C, and P2 (ayw2) and P3 (ayw3) could both be allocated to group D. Interestingly, the S genes of w4 serotype viruses, i.e. P4 (ayw4) and P7 (adw4q-), differed by 4% or more from both previous groups and from each other, suggesting their classification into two new groups, for which the designations E and F are proposed. Genomes specifying ayw were also found in groups A and B; previously sequenced genomes specifying the ayw subtype have all been confined to group D. There were indications that the epitope for subdeterminants of w resided at amino acid positions 125 to 127. Thus, at positions 125 and 127, ayw1, ayw2 and adw2 had T and P residues, respectively, whereas M and T residues were at the corresponding positions of ayw3. Both ayw4 and adw4 had L at residue 127, and all strains expressing r, apart from P5, had an I instead of a T residue at position 126.

Detection of HBV DNA by PCR in serum from an HBsAg negative blood donor implicated in cases of post-transfusion hepatitis B

An HBsAg negative blood donor, and three of her recipients, who developed HBsAg positive post-transfusion hepatitis B, were all positive for serum HBV DNA by polymerase chain reaction (PCR), and by subtype discriminating PCR were found to harbour HBV specifying ayw. Thus HBV specifying ayw. Thus HBV DNA may be detected and sub-typed by PCR in infectious HBsAg negative individuals.

HBcAg induced T-cell independent anti-HBc production in chronic HBsAg carriers

The capacity of the nucleocapsid protein of HBV to function as a T-cell independent antigen in man was studied. When T-cell depleted B-cell cultures were challenged with E coli-derived HBcAg, anti-HBc production was registered in culture supernatants from the majority of chronic HBsAg carriers in a quiescent stage of disease. In contrast, similarly prepared and stimulated cultures from donors with natural acquired immunity to hepatitis B or HB-susceptible controls were non-responsive. Addition of autologous T-cells effectively restored anti-HBc responsiveness in T-cell depleted B-cell cultures from HB-immune donors, demonstrating the T-cell dependency for anti-HBc induction in natural HBV-infection.

Late seroconversion to hepatitis B in a Somali village indicates the important role of venereal transmission

Hepatitis B virus (HBV) markers were investigated in a cross-sectional study in 1985 on sera from 84% of the 648 inhabitants in a rural Somali village. The prevalence of HBV markers increased with age, from 9.7% in subjects less than 12 years old, to 38% in the age group 12-19 years, and to 68% in adults. HBV markers were more common in boys less than 12 years old, 13%, than in girls of the same age group, 5.8% (P less than 0.05). A rapid increase of HBV markers started at adolescence in both sexes. The female cohort showed their highest seroconversion rate during their second decade of life, while the male cohort seroconverted more rapidly in the third decade. Thus, an initially more rapid seroconversion among boys was reversed when the females reached reproductive age, and no sex difference in marker frequencies was observed in the age group 12-19 years. There was a steady increase of HBV markers during the reproductive years in both sexes. The frequencies of HBsAg, as well as total markers, were significantly higher in adult males than females, 14 vs 5.6%, and 77 vs 62%, respectively. HBV markers were more frequent in wives of HBV positive husbands than in those married to HBV negative husbands. No increased marker prevalence was observed among siblings of HBV positive children, nor among their mothers, which disproved the role of vertical and early horizontal transmission. In 1989 the four-year rate of seroconversion was investigated in villagers who were seronegative in 1985. On testing 158 sera from 319 individuals, the seroconversion rate was significantly lower among those younger than 12 years in 1985 compared to those in the older age group, 5 vs 17%.(ABSTRACT TRUNCATED AT 250 WORDS)

IgG subclasses in circulating immune complexes with hepatitis B e antigen in chronic hepatitis B

IgG subclasses of antibodies to hepatitis B e antigen (anti-HBe) complexed to HBeAg were determined in 126 HBsAg-positive sera. In the assay HBeAg complexes were bound to microtitre plates by monoclonal anti-HBe and indicated by biotinylated monoclonals to each of the four human IgG subclasses. To evaluate the specificity of the complexed IgG, serum dilutions were also tested for HBeAg and for subclasses of anti-HBe IgG. Two groups of sera were investigated: (i) 64 sera from 64 HBsAg carriers; and (ii) 62 sera from 13 HBeAg-positive patients, of whom five seroconverted to anti-HBe. At least four sera were available from each of these patients. Complexed anti-HBe IgG was detected in 22 of 30 HBeAg-positive, and in three of HBeAg-negative carrier sera. There was no significant association between presence of complexed anti-HBe and levels of HBeAg in these sera. Complexes with multiple subclass composition were found in 13 of the 25 sera with complexed anti-HBe. The most common IgG subclasses found complexed to HBeAg were IgG1 (75%) and IgG4 (67%). A significant association (P less than 0.05) was found between the presence of free and complexed anti-HBe IgG1 in the carrier sera, indicating that the IgG1 antibodies, complexed to HBeAg, were specific for HBeAg. In the five patients who seroconverted to anti-HBe, anti-HBe IgG1 was detected in the HBeAg-positive phase before seroconversion. In the eight patients with persistent HBeAg antigenemia, free anti-HBe IgG1 was detected in only two sera from two different patients. In one patient, complexed anti-HBe IgG1/IgG4 was detected in all serum samples drawn during a period of 111 months. In conclusion, complexed anti-HBe might be detected several years before apparent seroconversion to anti-HBe in conventional anti-HBe assays. In contrast 'free' anti-HBe IgG1, when detected in HBeAg-positive sera with our anti-HBe subclass assay, seemed to signal ensuing apparent seroconversion to anti-HBe.