A new artificial antigen of the hepatitis E virus.

An artificial antigen composed of 12 small antigenic regions derived from the ORF2 and ORF3 HEV proteins was designed. The gene encoding for this artificial antigen was assembled from synthetic oligonucleotides by a new method called Restriction Enzyme-Assisted Ligation (REAL). The diagnostic relevance of this second generation HEV mosaic protein (HEV MA-II) was demonstrated by testing this antigen against a panel of 142 well defined anti-HEV positive and anti-HEV negative serum samples. The data obtained in this study support the substantial diagnostic potential of this HEV mosaic antigen.

Transmission of hepatitis C virus in an orthopedic hospital ward.

Healthcare-associated infections with hepatitis C virus (HCV) hitherto have been observed mainly in hemodialysis settings as well as in hematology and oncology wards. In this communication, molecular and epidemiologic investigations to elucidate an HCV outbreak in an orthopedic ward are reported. One hundred and thirty-five patients hospitalized in the ward and 104 staff members were tested. In addition to extensive epidemiologic reviews and hygienic inspections, direct sequencing of HCV PCR fragments and phylogenetic analysis of more than 300 partial HCV sequences obtained by end-point limiting-dilution real-time PCR assay were carried out. Six patients were infected with very closely related HCV variants. Patient-to-patient spread of the virus was inferred to have started from one patient with previous HCV infection to the other five patients during their hospital stay. Inspections did not reveal substantial breaches in basic infection control practices and did not identify a specific activity that might have led to nosocomial transmission. As a result of the investigations, the hospital corrected the documentation of all medical and nursing activities undertaken in the ward, abandoned the use of all multidose saline and other medication vials, and included explicitly recommendations for the safe preparation and administration of injectable drugs into internal infection control guidelines. Thereafter, no further nosocomial transmissions of HCV have been recorded in the orthopedic ward. The events observed suggest that nosocomial transmission of HCV is not limited to hemodialysis, hematology or oncology settings, and they also reinforce the mandatory adherence to basic infection control practices.

Molecular confirmation of oysters as the vector for hepatitis A in a 2005 multistate outbreak.

Numerous hepatitis A outbreaks were linked to the consumption of raw molluscan shellfish in the United States between 1960 and 1989. However, there had been no major molluscan shellfish-associated hepatitis A outbreaks reported in the United States for more than a decade (1989 to 2004). Beginning in late August 2005, at least 10 clusters of hepatitis A illnesses, totaling 39 persons, occurred in four states among restaurant patrons who ate oysters. Epidemiologic data indicated that oysters were the source of the outbreak. Traceback information showed that the implicated oysters were harvested from specific Gulf Coast areas. A voluntary recall of oysters was initiated in September. Hepatitis A virus (HAV) was detected in multiple 25-g portions in one of two recalled samples, indicating that as many as 1 of every 15 oysters from this source was contaminated. Comparing 315 nucleotides within the HAV VPl-2B region, 100% homology was found among four amplicons recovered from a total of six independent experiments of the implicated oysters, and an identical HAV sequence was detected in sera from all 28 patient serum specimens tested. Ten percent heterogeneity over 315 nucleotides (31 variants) was observed between the outbreak strain (subgenotype 1A) and an HM-175 strain (subgenotype 1B) used in the laboratory where the oysters were processed. To our knowledge, this investigation is the first in the United States to identify an HAV-identical strain in persons with hepatitis A as well as in the food that was implicated as the source of their infections.

A new enzyme immunoassay for the detection of antibody to hepatitis E virus.

BACKGROUND AND AIM: The purpose of the present study was to develop enzyme immunoassay (EIA) for the detection of IgG anti-hepatitis E virus (HEV) activity using two new recombinant proteins as antigenic targets, and to evaluate these EIA with the aid of statistical methods. METHODS: Two proteins, a mosaic protein and pB166 containing region 452-617 aa of the ORF2 of the HEV Burma strain, were used to develop the new HEV EIA. This EIA was evaluated using several panels of serum specimens obtained from: (i) acutely HEV-infected patients; (ii) patients with non-A, non-C hepatitis; (iii) normal blood donors (NBD) from non-endemic countries; and (iv) experimentally infected chimpanzees. RESULTS: A new HEV EIA was developed using two new recombinant proteins. This assay was able to detect anti-HEV activity in all specimens from acutely HEV-infected patients. When NBD were tested, more than 15% of specimens were found to be IgG anti-HEV positive. All NBD anti-HEV-positive specimens were tested with overlapping synthetic peptides spanning the entire HEV ORF2-encoded protein. More than 90% of the anti-HEV-positive NBD specimens immunoreacted with an average of 15 synthetic peptides derived from different regions of the HEV ORF2 protein. These data suggest that the HEV EIA is at least 90% specific in detecting remote HEV infections. CONCLUSION: The new HEV EIA developed in the present study is a highly specific diagnostic assay for the detection of anti-HEV activity in serum specimens obtained from different epidemiologic settings.

Identification and characterization of the neutralization epitope(s) of the hepatitis E virus.

The neutralization epitope(s) of the hepatitis E virus (HEV) was studied by an in vitro neutralization assay using antibodies obtained by immunization of mice with 51 overlapping 30-mer synthetic peptides spanning the region 221-660 amino acids (aa) of the HEV open reading frame 2 encoded protein (pORF2) and 31 overlapping recombinant proteins of different sizes derived from the entire pORF2 of the HEV Burma strain. Antibodies against synthetic peptides and short recombinant proteins of approximately 100 aa did not neutralize HEV, suggesting the HEV neutralization epitope(s) is conformation-dependent. However, one recombinant protein of approximately 400 aa in length comprising the pORF2 sequence at position 274-660 aa as well as all truncated derivatives of this protein containing region 452-617 aa elicited antibodies, demonstrating HEV neutralizing activity. These findings establish for the first time that the minimal size fragment, designated pB166, that can efficiently model the neutralization epitope(s) is 166 aa in length and is located at position 452-617 aa of the HEV pORF2. Additionally, antibodies against pB166 were found to cross-neutralize three different HEV genotypes, suggesting that a common neutralization epitope(s) may exist within the different HEV genotypes. Thus, recombinant proteins constructed in this study may be considered as potential candidates for the development of an HEV subunit vaccine as well as for the development of highly sensitive and specific diagnostic tests.

Detection and characterisation of swine hepatitis E virus in New Zealand.

The objectives of the present study were to establish the presence of hepatitis E virus (HEV) in New Zealand pigs, first by testing for HEV antibody in pig herds throughout New Zealand to measure the herd prevalence, then by attempting to amplify HEV genomic sequences by PCR. Antibody was measured by two independently designed ELISA serology tests. HEV RNA fragments were amplified by RT-PCR of nucleic acid extracted from faeces of 10-12-week-old piglets using primers targeting ORF1, ORF2, and ORF2/3. PCR products were subject to phylogenetic analysis. Antibody to HEV was found throughout New Zealand pig herds as well as in the different age groups within the herds. Twenty herds from 22 tested were positive for HEV antibody (91% herd prevalence). Phylogenetic analysis of the amplified sequences placed this New Zealand strain of HEV closest to the human European strain It-1 (AF 110390) and U.S. swine strain (AF 082843) with 88% and 83% similarity respectively in ORF1. It was concluded that HEV is widely distributed in the New Zealand pig population. Phylogenetic analysis shows that this is a new HEV strain, grouping most closely with the United States/European cluster, which includes HEV strains of both human and swine origin.

Related TT viruses in chimpanzees.

A series of serum specimens obtained from two chimpanzees experimentally infected with hepatitis A virus (HAV), hepatitis C virus, and hepatitis G/GB-C virus were tested for TT virus (TTV) by polymerase chain reaction (PCR). All PCR fragments obtained from both animals were directly sequenced, and the nucleotide sequences were compared to each other and to all known TTV sequences. This comparison showed that both animals were infected simultaneously with four new TTV variants designated A, M1, M2, and M3. One chimpanzee was found to be infected with TTV only after HAV inoculation, whereas the other animal was infected with TTV before any experimental procedure was performed. A set of PCR primers specific for these four new TTV variants was used to amplify TTV-like sequences from nine naive chimpanzees. None of these animals was infected with the prototype TTV variant. Two of these animals, however, were infected with one of the new TTV variants, while one animal was infected with an additional new TTV variant designated T. Among 99 hepatitis patients, 29 were found to be infected with the prototype TTV variant. None of these human specimens was found to be positive by PCR specific for TTV variants A, M1, M2, and M3. Similarly, not a single specimen from a smaller subset of human serum samples was found to be positive for the TTV variant T. Phylogenetic analysis performed on all known TTV sequences demonstrated that TTV can be classified into 13 different, yet closely related TTV species, designated as TTV-I for the prototype variant through TTV-XIII. The new variants M1 and M2 were classified as two different genotypes of TTV-VI, variant M3 was classified as TTV-VII, variant A was classified as TTV-VIII, and variant T was classified as TTV-IX. Thus, the data obtained in this study suggest that TTV represents a large swarm of TTV-like species, some of which have not been detected in humans and circulate predominantly among chimpanzees.

Sequence heterogeneity of TT virus and closely related viruses.

TT virus (TTV) is a recently discovered infectious agent originally obtained from transfusion-related hepatitis. However, the causative link between the TTV infection and liver disease remains uncertain. Recent studies demonstrated that genome sequences of different TTV strains are significantly divergent. To assess genetic heterogeneity of the TTV genome in more detail, a sequence analysis of PCR fragments (271 bp) amplified from open reading frame 1 (ORF1) was performed. PCR fragments were amplified from 5 to 40% of serum specimens obtained from patients with different forms of hepatitis who reside in different countries (e.g., China, Egypt, Vietnam, and the United States) and from normal human specimens obtained from U.S. residents. A total of 170 PCR fragments were sequenced and compared to sequences derived from the corresponding TTV genome region deposited in GenBank. Genotypes 2 and 3 were found to be significantly more genetically related than any other TTV genotype. Moreover, three sequences were shown to be almost equally related to both genotypes 2 and 3. These observations suggest a merger of genotypes 2 and 3 into one genotype, 2/3. Additionally, five new groups of TTV sequences were identified. One group represents a new genotype, whereas the other four groups were shown to be more evolutionary distant from all known TTV sequences. The evolutionary distances between these four groups were also shown to be greater than between TTV genotypes. The phylogenetic analysis suggested that these four new genetic groups represent closely related yet different viral species. Thus, TTV exists as a "swarm" of at least five closely related but different viruses. These observations suggest a high degree of genetic complexity within the TTV population. The finding of the additional TTV-related species should be taken into consideration when the association between TTV infections and human diseases of unknown etiology is studied.

Artificial NS4 mosaic antigen of hepatitis C virus.

An artificial antigen composed of 17 small antigenic regions derived from the NS4-protein of hepatitis C virus (HCV) genotypes 1 through 5 was designed and constructed. Eleven antigenic regions were derived from the 5-1-1 region, and 6 others were derived from the C-terminus of the NS4-protein of different genotypes. The gene encoding for this artificial antigen was assembled from synthetic oligonucleotides by a new approach designated as restriction enzyme-assisted ligation (REAL). The full-length synthetic gene was expressed in Escherichia coli as a fusion protein with glutathione S-transferase. By the use of site-specific antibodies raised against synthetic peptides, it was shown that all regions for which sequence-specific antibodies were obtained were accessible to antibody binding. The diagnostic relevance of the NS4 artificial antigen was demonstrated by testing this antigen with 4 HCV seroconversion panels and a panel of previously tested and stored serum specimens. The artificial antigen was found to specifically detect anti-NS4 antibodies in a number of specimens that were previously found to be anti-NS4 negative. Furthermore, this antigen detected anti-NS4 activity earlier in 2 of 4 seroconversion panels than did the antigen used in a commercially available supplemental assay. Equally important is the observation that the artificial NS4 antigen demonstrated equivalent anti-NS4 immunoreactivity with serum specimens obtained from patients infected with different HCV genotypes, whereas the NS4 recombinant protein derived from genotype 1, used in the commercial supplemental test, was less immunoreactive with serum specimens containing HCV genotypes 2, 3, and 4. Collectively, these data support the significant diagnostic potential of the NS4 mosaic antigen. The strategy employed in this study may be applied to the design and construction of other artificial antigens with improved diagnostically pertinent properties. J. Med. Virol. 59:437-450 1999.

Antigenic domains of the open reading frame 2-encoded protein of hepatitis E virus.

The antigenic composition of the hepatitis E virus (HEV) protein encoded by open reading frame 2 (ORF2) was determined by using synthetic peptides. Three sets of overlapping 18-, 25-, and 30-mer peptides, with each set spanning the entire ORF2 protein of the HEV Burma strain, were synthesized. All synthetic peptides were tested by enzyme immunoassay against a panel of 32 anti-HEV-positive serum specimens obtained from acutely HEV-infected persons. Six antigenic domains within the ORF2 protein were identified. Domains 1 and 6 located at the N and C termini of the ORF2 protein, respectively, contain strong immunoglobulin G (IgG) and IgM antigenic epitopes that can be efficiently modeled with peptides of different sizes. In contrast, antigenic epitopes identified within the two central domains (3 and 4) were modeled more efficiently with 30-mer peptides than with either 18- or 25-mers. Domain 2 located at amino acids (aa) 143 to 222 was modeled best with 25-mer peptides. A few 30-mer synthetic peptides derived from domain 5 identified at aa 490 to 579 demonstrated strong IgM antigenic reactivity. Several 30-mer synthetic peptides derived from domains 1, 4, and 6 immunoreacted with IgG or IgM with more than 70% of anti-HEV-positive serum specimens. Thus, the results of this study demonstrate the existence of six diagnostically relevant antigenic domains within the HEV ORF2 protein.

Antigenic epitopes of the hepatitis A virus polyprotein.

Forty-two antigenic domains were identified across the hepatitis A virus (HAV) polyprotein by using a set of 237 overlapping 20-mer synthetic peptides spanning the entire HAV polyprotein and a panel of serum samples from acutely HAV-infected patients. The term "antigenic domain" is used in this study to define a protein region spanned with consecutive overlapping immunoreactive peptides. Nineteen antigenic domains were found within the structural proteins, and 22 were found within the nonstructural proteins, with 1 domain spanning the junction of VP1 and P2A proteins. Five of these domains were considered immunodominant, as judged by both the breadth and the strength of their immunoreactivity. One domain is located within the VP2 protein at position 57-90 aa. A second domain, located at position 767-842 aa, contains the C-terminal part of the VP1 protein and the entire P2A protein. A third domain, located at position 1403-1456 aa, comprises the C-terminal part of the P2C protein and the N-terminal half of the P3A protein. The fourth domain, located at position 1500-1519 aa, includes almost the entire P3B, and the last domain, located at position 1719-1764 aa, contains the C-terminal region of the P3C protein and the N-terminal region of the P3D protein. It is interesting to note that four of the five most immunoreactive domains are derived from small HAV proteins and/or encompass protein cleavage sites separating different HAV proteins. The HAV-specific immunoreactivity of each antigenically reactive peptide was confirmed by using seven HAV seroconversion panels. Collectively, these data demonstrate that HAV structural and nonstructural proteins contain antigenic epitopes that can be efficiently modeled with short synthetic peptides.

Antigenic heterogeneity of the hepatitis C virus NS4 protein as modeled with synthetic peptides.

The effect of sequence heterogeneity on the immunologic properties of two strong antigenic regions of the hepatitis C virus (HCV) NS4 protein was studied by using a set of 443 overlapping 20-mer synthetic peptides. One antigenic region comprising the cleavage site between NS4a and NS4b (region 5-1-1) was modeled with peptides derived from 73 different known sequences, representing HCV genotypes 1-6. The other antigenic region, designated region 59 and located at the C-terminus of the NS4b protein, was modeled with peptides from 7 known sequences representing genotypes 1-3. All peptides were tested for antigenic reactivity by enzyme immunoassay with a panel of anti-HCV-positive serum specimens representing genotypes 1-5. The data demonstrated that immunoreactive peptides fell into two groups. One group, represented by N-terminal peptides, demonstrated genotype-independent immunoreactivity; the other group, from the central part of region 5-1-1, showed strict genotype specificity. Nineteen peptides from the genotype-independent group strongly immunoreacted with a wide range of serum samples containing antibodies to all 5 HCV genotypes. Twenty-five peptides from the genotype-specific group were found to strongly react with serum containing antibodies only to the genotype from which the peptides were derived. Similar to the N-terminal part of region 5-1-1, peptides derived from region 59 did not show genotype-specific immunoreactivity. Some peptides derived from the central part of region 59 showed very strong and broad antigenic reactivity. Thus, after examining two antigenic regions of the NS4 protein, we identified short sequences that can be used for the efficient detection of either genotype-independent or genotype-specific HCV antibodies.

Sequence heterogeneity within three different regions of the hepatitis G virus genome.

Two sets of primers derived from the 5'-terminal region and the NS5 region of the hepatitis G virus (HGV) genome were used to amplify PCR fragments from serum specimens obtained from different parts of the world. All PCR fragments from the 5'-terminal region (5'-PCR, n = 56) and from the NS5 region (NS5-PCR, n = 85) were sequenced and compared to corresponding published HGV sequences. The range of nucleotide sequence similarity varied from 74 and 78% to 100% for 5'-PCR and NS5-PCR fragments, respectively. Additionally, five overlapping PCR fragments comprising an approximately 2.0-kb structural region of the HGV genome were sequenced from each of five sera obtained from three United States residents. These sequences were compared to 20 published sequences comprising the same region of the HGV genome. Nucleotide and deduced amino acid sequences obtained from different individuals were homologous from 82.9 to 93. 6% and from 90.4 to 99.0%, respectively. Sequences obtained from follow-up specimens were almost identical. Comparative analysis of deduced amino acid sequences of the HGV structural proteins and hepatitis C virus (HCV) structural proteins combined with an analysis of predicted secondary structures and hydrophobic profiles allowed prediction of processing sites within the HGV structural proteins. A phylogenetic sequence analysis performed on the 2.0-kb structural region supports the existence of three previously identified HGV genetic groups. However, phylogenetic analysis performed on only small DNA fragments yielded inconsistent genetic grouping and failed to confirm the existence of genetic groups. Thus, in contrast to HCV where almost any region can be used for genotyping, only large or carefully selected genome fragments can be used to identify consistent HGV genetic groups.

Primary structure of open reading frame 2 and 3 of the hepatitis E virus isolated from Morocco.

The nucleotide sequence from position 5,014 to 7,186 of the hepatitis E virus (HEV) genome was determined using a set of 10 polymerase chain reaction (PCR) fragments amplified directly from a pool of fecal specimens obtained from patients with well-documented epidemic HEV infection in Morocco. This sequence contains the 3'-terminal region of open reading frame 1 (ORF1), full length ORF2 and ORF3, and a portion of the 3'-noncoding region. The HEV Morocco nucleotide sequence was compared with the corresponding sequences of 13 HEV strains. A region of ORF2 that overlaps with ORF3 was found to be the most conserved region of ORF2, whereas a protein segment encoded by this region was found to be the most variable. Theoretical RNA secondary structure analysis predicted that this region may be folded into a strong secondary structure that may constrain nucleotide sequence variability. In addition, the nucleotide sequence comparison revealed that the HEV Morocco sequence is most homologous to the sequences of the HEV Asian strains compared with the HEV Mexico, swine, and US strains. Phylogenetic analysis performed on the entire ORF2 and ORF3 sequences and on a small fragment of ORF2 allowed classification of the HEV Morocco strain together with a few other known African strains as a separate subtype within the Asian-African genotype.

Neutralization of different geographic strains of the hepatitis E virus with anti-hepatitis E virus-positive serum samples obtained from different sources.

A recently developed polymerase chain reaction (PCR)-based cell culture neutralization assay was used to investigate cross-neutralization of known hepatitis E virus (HEV) strains obtained from various HEV-endemic regions of the world with different anti-HEV-positive serum samples. Serum specimens obtained from cynomolgus macaques experimentally infected with strains from Burma, Mexico, or Pakistan cross-neutralized the infectivity of each strain as well as an isolate from Morocco. Serum samples obtained either from infected patients who reside in HEV-endemic regions of the world or from U.S. residents who became infected while traveling to such regions also neutralized all four strains. In contrast, antibodies obtained from rabbits immunized with full-length Burma strain ORF2 protein neutralized only the Burma and Pakistan strains, not the Mexico or Morocco strains. In addition, antibodies obtained from guinea pigs immunized with an N-terminal truncated Burma strain ORF2 protein neutralized each strain except the Morocco strain. These data strongly suggest that antibodies elicited during an HEV infection demonstrate broad HEV neutralizing activity, whereas antibodies elicited after immunization with recombinant Burma ORF2 protein demonstrate a more limited ability to neutralize various HEV strains obtained from different regions of the world endemic for the disease.

Detection of hepatitis C virus core protein circulating within different virus particle populations.

Progress in studying pathogenesis and increasing the reliability of hepatitis C diagnosis can be achieved by analysis of different forms of virus particles circulating in blood of both patients and infected persons. Detection of hepatitis C virus (HCV) proteins faces two basic difficulties: low concentration of HCV proteins, and their blocking by antibodies. The aim of this work was to develop a method for the detection of nucleocapsid (core) protein in the plasma of HCV-infected persons using monoclonal antibodies (MABs). Twenty-seven anti-HCV-positive donor plasmas were studied of which 21 contained HCV RNA and 6 were negative. The plasmas were centrifuged for 3 hr at 143,000 g and the antigenic activity of core-protein was studied in the pellets by EIA using four MABs able to recognize four nonoverlapping determinants, two at N-terminus and two at C-terminus of recombinant core (1-150 aa). The determinants detected were present in the natural core protein of at least two genotypes (1b and 3a). Maximal efficiency of recombinant protein detection was achieved with 2 MABs, whereas a combination of 4 MABs was necessary for optimal detection of natural core protein. This is indicative of different conformational structures of natural protein and its gene-engineered analog. The sensitivity of core detection by monoclonal sandwich assay was 1 ng/ml in the pellet or 5 pg/ml after normalization to the initial plasma volume. To dissociate immune complexes, the pellet was treated with 2.5 M KBr after first treating the pellet with the nonionic detergent Tween 80 to remove the virus lipid envelope. Using this treatment protocol, core protein was found in 19 of 21 RNA positive plasmas.

Hepatitis G virus infection in Amerindians and other Venezuelan high-risk groups.

Recently, a new virus related to flaviviruses, the hepatitis G virus (HGV), or GBV-C virus, was discovered as a putative blood-borne human pathogen. HGV RNA (NS5 region) was amplified by reverse transcription-nested PCR in the sera of 6 of 64 (9%) hemodialysis patients; 2 of 80 (2.5%) West Yukpa Amerindians, a population with a high rate of HBV infection but negative for HCV infection; and 1 patient with an acute episode of non-A, non-B, non-C hepatitis (NABCH). The patterns of single-strand conformation polymorphism of the amplified products were unique among different specimens and similar on follow-up for hemodialysis patients. All patients tested remained HGV RNA positive 1 and 2 years later, without major sequence variation, except for the NABCH patient, for whom a double infection and an apparent clearance of the original dominant variant was observed after 2 years. The sequences of the NS5 amplified products demonstrated 85 to 90% identity with other reported HGV sequences.

Sequence variation within a nonstructural region of the hepatitis G virus genome.

Nine sets of nested PCR primers from a 2.6-kb region of the hepatitis G virus (HGV) genome at nucleotide positions 5829 to 8421 were designed and used to analyze serum specimens obtained from patients with community-acquired non-A, non-B hepatitis who were HGV RNA positive. One set of primers was found to be most efficient in detecting HGV and was subsequently used to test 162 HCV-positive and 11 HCV-negative plasma units obtained from individual paid donors. HGV RNA was detected in 30 (17.3%) plasma units, 2 of which were found among the 11 HCV-negative specimens. A complete set of nine PCR fragments was obtained from two patients with community-acquired acute non-A, non-B hepatitis and from four paid donors. All PCR fragments were sequenced and were shown to have a nucleotide similarity of 85.9 to 92.3% and a derived amino acid similarity of 96.0 to 99.0%. The majority of nucleotide changes occurred in the third position of codons. The HGV nucleotide and protein sequences obtained in this study were compared with HCV sequences. Based on this analysis the 2.6-kb fragment was predicted to encode the C-terminal part of the putative NS4b, the entire NS5a, and almost the complete NS5b proteins. Putative protease cleavage sites separating these proteins were also predicted. In serial specimens obtained from the two HGV-infected patients, no significant variations were found in the HGV nucleotide and derived amino acid sequences over time. The HGV sequences obtained from one patient showed no changes over 6 months, whereas more than 99.0% homology was observed for sequences from the second patient over 2.5 years. Heterogeneity analysis performed on 10 sequences obtained in this study and corresponding regions from 6 known full-size sequences of the HGV genomes demonstrated notable discrete heterogeneity consistent with the existence of HGV genetic groups or types.

Detection of hepatitis G virus (HGV) RNA: clinical characteristics of acute HGV infection.

The role of hepatitis G virus (HGV) infection in acute non-A-E hepatitis was investigated in adults with viral hepatitis. HGV RNA was present in 1 of 28 patients with non-A-E hepatitis but 9 of 22 with hepatitis C (P < .003). HGV RNA-positive patients (HGV-infected and HGV-hepatitis C virus [HCV]-coinfected) developed light-to-moderate jaundice. Clinical and biochemical features of HGV-positive and HCV-positive patients and patients with non-A, non-G hepatitis were similar. Three patients with HGV-HCV coinfection, tested within 18 months after disease onset, have remained HGV RNA-positive but have become HCV RNA-negative. Only 1 non-A-E hepatitis patient was confirmed as being infected with HGV alone, suggesting that HGV is not the main etiologic agent of non-A-E hepatitis. Although HGV RNA was significantly associated with hepatitis C, patients with mixed HCV-HGV infections did not demonstrate a more severe course of disease than did patients with HCV infection.

Hepatitis G virus co-infection in liver transplantation recipients with chronic hepatitis C and nonviral chronic liver disease.

Hepatitis G virus (HGV) is a newly described RNA virus that is parenterally transmitted and has been found frequently in patients with chronic hepatitis C infection. To determine the impact of hepatitis G virus co-infection on morbidity and mortality following liver transplantation, we measured HGV RNA by polymerase chain reaction in pre and posttransplantation sera from a cohort of patients transplanted for chronic hepatitis C and a control group of patients transplanted for nonviral causes who were negative for hepatitis C virus (HCV) RNA in serum. The overall prevalence rate of HGV RNA in transplanted patients with chronic hepatitis C was 20.7%. HGV infection was present before transplantation in 13% while it appeared to have been acquired at the time of transplantation in 7.4%. Mean serum alanine aminotransferase activity, hepatic histological activity, and patient and graft survival were similar between HGV-positive and HGV-negative patients. The prevalence rate of HGV RNA in transplanted controls was 64% (P < .01) with a significantly higher rate of acquisition of HGV infection following transplantation (53%, P < .001) when compared with patients with chronic hepatitis C. Mean serum alanine aminotransferase activity was significantly lower in the control patients with HGV infection alone following transplantation than in patients co-infected with hepatitis C (37 +/- 9 vs. 70 +/- 33 U/L, P < .01). Thus, HGV is frequently found in transplantation patients co-infected with hepatitis C although it appears to have minimal clinical impact. In patients transplanted for nonviral causes of end-stage liver disease, a high rate of hepatitis G acquisition at the time of transplantation may occur but does not appear to predispose to chronic hepatitis.