Hepatitis E virus infections among patients with acute febrile jaundice in two regions of Cameroon: First molecular characterization of hepatitis E virus genotype 4

BACKGROUND

Febrile jaundice is a common indicator of certain infectious diseases, including hepatitis E. In Cameroon, the yellow fever virus is the only pathogen that is monitored in patients who present with this symptom. However, more than 90% of the samples received as part of this surveillance are negative for yellow fever. This study aimed to describe the prevalence and hepatitis E virus (HEV) genotype among yellow fever-negative patients in the Far North and West regions of Cameroon.

METHODS

In a cross-sectional study, yellow fever surveillance-negative samples collected between January 2021 and January 2023 were retrospectively analyzed. Anti-HEV IgM and IgG antibodies were tested using commercially available ELISA kits. Anti-HEV IgM and/or IgG positive samples were tested for HEV RNA by real-time RT-PCR, followed by nested RT-PCR, sequencing and phylogenetic analysis.

RESULTS

Overall, 121 of the 543 samples (22.3%, 95% CI: 19.0% - 26.0%) were positive for at least one anti-HEV marker. Amongst these, 8.1% (44/543) were positive for anti-HEV IgM, 5.9% (32/543) for anti-HEV IgG, and 8.3% (45/544) for both markers. A total of 15.2% (12/79) samples were positive for HEV RNA real-time RT-PCR and 8 samples were positive for HEV RNA by nested RT-PCR. Phylogenetic analysis showed that the retrieved sequences clustered within HEV genotypes/subtypes 1/1e, 3/3f and 4/4b.

CONCLUSION

Our results showed that HEV is one of the causes of acute febrile jaundice in patients enrolled in the yellow fever surveillance program in two regions of Cameroon. We described the circulation of three HEV genotypes, including two zoonotic genotypes. Further studies will be important to elucidate the transmission routes of these zoonotic HEV genotypes to humans in Cameroon.

Genotype 4 HEV infection triggers the initiation and development of acute pancreatitis

The role of HEV infection in AP remains unclear. 1000 patients with AP and 1000 HCs were enrolled, and pancreatitis was evaluated in HEV-infected rhesus macaques. The positive rates of anti-HEV IgG, IgM, and HEV RNA in the AP patients were significantly higher than HCs. With the increase in the severity of AP, the percentage of HEV infection increased. AP patients were divided into AP- and AP + AHE groups. The percentage of severe AP in the AP + AHE group was significantly higher than in the AP- group. HEV infection was one of the main independent risk factors and had high predictive power for AP outcomes. A high level of HEV titer would prolong the recovery time and increase the risk of recurrent AP. Moreover, AP + AHE patients receiving conservative treatment showed a better prognosis. Furthermore, HEV can replicate in the pancreas of rhesus macaques. The pancreatic islet structure was damaged, the tissue was loose after 272 dpi, and a large amount of hyperemia appeared after 770 dpi. HEV infection also caused a large number of inflammatory cells in the pancreas. The pancreas and liver had a comparable viral load. HEV infection affects AP's occurrence, development, and prognosis.

Detection of Hepatitis E Virus in Rabbits and Rabbit Meat from Slaughterhouses in Hebei Province of China

Background: Hepatitis E virus (HEV) is a zoonotic pathogen. HEV has been found to be widely prevalent in rabbits. Its isolates are classified into HEV-3, rabbit subgenotype (HEV-3ra). The routes of human infection with HEV-3ra remain unclear; however, foodborne transmission is possible when asymptomatically infected animals enter the food chain. The prevalence of HEV infection in slaughtered rabbits and the presence of HEV in rabbit meat were evaluated in this study. Materials and Methods: In three slaughterhouses in Hebei province, China, samples of rabbit blood were collected during the slaughter process, and muscle, liver, and cavity juice were collected from the rabbit carcasses. Anti-HEV antibody in serum samples was detected using enzyme-linked immunosorbent assay. HEV RNA was tested in all samples by reverse transcription nested PCR (RT-nested PCR). The final amplicons of RT-nested PCR were sequenced and phylogenetically analyzed. Results: Of the 459 serum samples, 50 [10.9%, 95% confidence interval (CI): 8.1-13.7] were positive for anti-HEV antibody, and 17 (3.7%, 95% CI: 2.0-5.4) were positive for HEV RNA. HEV RNA was detected in 7 of 60 liver samples (11.7%, 95% CI: 3.3-20) and 2 cavity juice samples from semi-eviscerated carcasses, but was not detected in any muscle sample from either the eviscerated or semi-eviscerated carcasses. All the detected HEV strains belonged to HEV-3ra and related most closely with the rabbit HEV sequence previously reported in China. Conclusion: A portion of rabbits were in the viremia period of HEV infection at the slaughter age, resulting in the possibility of HEV carriage by rabbit carcass, particularly semi-eviscerated carcass containing liver. These findings suggest a potential risk of HEV transmission from raw rabbit products entering the food chain, whereas the presence of HEV appeared to be lower in the eviscerated carcass than in the semi-eviscerated carcass.

Evidences of HEV genotype 3 persistence and reactivity in liver parenchyma from experimentally infected cynomolgus monkeys (Macaca fascicularis)

Hepatitis E virus genotype 3 (HEV-3) is an emerging zoonotic pathogen, responsible for sporadic cases of acute hepatitis E worldwide. Primate models have proven to be an essential tool for the study of HEV pathogenesis. Here we describe the outcomes of HEV infection in Macaca fascicularis (cynomolgus) inoculated experimentally with genotype 3. Eight adult cynomolgus macaques were inoculated intravenously with HEV-3 viral particles isolated from swine and human samples. Liver, spleen, duodenum, gallbladder and bile were sequential assessed up to the end-point of this study, 67 days post-inoculation (dpi). Our previously published findings showed that biochemical parameters return gradually to baseline levels at 55 dpi, whereas anti-HEV IgM and HEV RNA become undetectable in the serum and feces of all animals, indicating a non-viremic phase of recovery. Nevertheless, at a later stage during convalescence (67 dpi), the presence of HEV-3 RNA and antigen persist in central organs, even after peripheral viral clearance. Our results show that two cynomolgus inoculated with swine HEV-3 (animals I3 and O1) presented persistence of HEV RNA low titers in liver, gallbladder and bile. At this same stage of infection, HEV antigen (HEV Ag) could be detected in all infected animals, predominantly in non-reactive Kupffer cells (CD68+iNOS-) and sinusoidal lining cells. Simultaneously, CD4+, CD3+CD4+, and CD3+CD8+ immune cells were identified in hepatic sinusoids and small inflammatory clusters of lobular mononuclear cells, at the end-point of this study. Inability of HEV clearance in humans can result in chronic hepatitis, liver cirrhosis, with subsequent liver failure requiring transplantation. The results of our study support the persistence of HEV-3 during convalescence at 67 dpi, with active immune response in NHP. We alert to the inherent risk of viral transmission through liver transplantation, even in the absence of clinical and biochemical signs of acute infection. Thus, besides checking conventional serological markers of HEV infection, we strongly recommend HEV-3 RNA and antigen detection in liver explants as public health measure to prevent donor-recipient transmission and spread of hepatitis E.

Detection of Genotype 4 Swine Hepatitis E Virus in Systemic Tissues in Cross-Species Infected Rabbits

Increasing evidence demonstrates that hepatitis E virus (HEV) can be transmitted across species. According to previous reports, swine HEV has two genotypes, genotype 3 and 4, and both can infect humans by the fecal-oral route. Thus, it is crucial for the control of HEV zoonotic transmission to evaluate the dynamics of viral shedding and distribution in different tissues during cross-species infection by HEV. In this study, rabbits were infected with genotype 4 swine HEV by the intraperitoneal route. The results showed that HEV RNA not only shed in the feces but also in the saliva of some rabbits during infection with swine HEV. Viremia appeared late after infection, and anti-HEV IgG was not obvious until the appearance of high viremia levels. After the rabbits were euthanized, a histopathological examination showed that the livers developed overt hepatitis accompanied by an elevation of alanine aminotransferase (ALT) and aspartate transaminase (AST). Furthermore, HEV RNA was detected in various tissues, especially in the salivary glands and tonsils. Subsequently, negative-stranded HEV RNA was practiced in tissues with positive HEV RNA, which demonstrated that HEV replicated in the tissues. Next, we harvested additional tissues from the liver, salivary gland, tonsil, spleen, thymus gland, lymph node and intestine, which are known as replication sites of swine HEV. Additionally, we also observed the HEV antigen distributed in the organs above through immunohistochemical staining. These results demonstrate that rabbits could be used as an animal model for researching cross-species infection of genotype 4 HEV. It is also noteworthy that HEV can shed in the saliva and presents the risk of droplet transmission. These new data provide valuable information for understanding cross-species infection by HEV.

[Optimization of human anti-HBsAg scFv secretary expression in Escherichia coli]

OBJECTIVE

To explore the conditions for high expression of anti-HBsAg scFv A-15 in E. coli, increase the production of the scFv in the culture medium.

METHODS

By changing induction occasion, concentration of inductor IPTG and induction time, influence of various conditions on expression of anti-HBsAg scFv A-15 was analyzed through ELISA. In addition, the effects of sucrose, glycine and Triton X-100 at different concentrations on the scFv excretion into culture medium was evaluation.

RESULTS

The optimal expression conditions were as follows: the induction was started after culturing for 4 h, the concentration of IPTG was 0.5 mmol/L, and the induction lasted for 8 h. The scFv affinity in culture medium with 0.3 mol/L sucrose, 2% glycine, 1% Triton X-100, 16.78-fold higher, respectively than that without the three chemicals. The final yield of anti-HBsAg scFv A-15 was estimated to be 7.4 mg/L.

CONCLUSION

The conditions for production of anti-HBsAg scFv A-15 were optimized, which provides a practical method for more efficient production of the scFv in E. coli for further studying structure and function.

[Construction and screening of hepatitis E virus-specific phage antibody combinatorial library]

AIM

To construct HEV-specific phage combinatorial anti-body library and screen anti-HEV antibodies with neutralizing activity from the library.

METHODS

The total RNA was extracted from B-lymphocytes of 6 HE patients. Kappa chain and Fd segment of IgG gene were amplified respectively by RT-PCR using a set of Fab-specific primers. The amplified gene were inserted successively into vector pComb3 and electrotransformed E. coli XLI-Blue cells. Furthermore, the recombinant phage was rescued by being concultured with helper phage VCSM13 to construct HEV-specific phage anti-body library.

RESULTS

Fab displayed on the surface a as fusion protein with the N terminal of coat protein III, and 1. 8 x 10(7) clone library was established. Specific antibodies to HEV ORF2 recombinant antigen were acquired after five rounds of panning with HEV ORF2 recombinant antigen including neutralizing epitope.

CONCLUSION

Four clones exhibited specific binding to HEV ORF2 recombinant antigen including neutralizing epitope is identified by ELISA. The results show that we have got the recombinant phage antibodies.

Epidemiology of GB virus c/hepatitis g virus infection in patients on peritoneal dialysis

BACKGROUND

A new genus in the family Flaviviridae has recently been discovered; it has provisionally been designated GBV-C/HGV. As determined by virologic techniques [reverse-transcription polymerase chain reaction (RT-PCR)], infection with GBV-C/HGV is frequent in renal transplant (RT) recipients and in patients on chronic hemodialysis (HD). The epidemiology of GBV-C/HGV infection in patients on peritoneal dialysis is scarce and mostly based on RT-PCR technology.

PURPOSE

We report on the prevalence (as detected by serologic and virologic techniques) and the risk factors for GBV-C/HGV infection in a cohort of patients on continuous ambulatory peritoneal dialysis (CAPD). We also tested a control group of blood donors.

METHODS

Infection by GBV-C/HGV was assessed by serologic and virologic techniques. Cases of GBV-C/HGV viremia (GBV-C/HGV RNA) were detected by RT-PCR. Antibodies to the envelope protein of GBV-C/HGV (anti-E2 GBV-C/HGV antibody) were analyzed by serologic methods.

RESULTS

We found a high frequency [17/85 (20%)] of GBV-C/HGV. The rates of GBV-C/HGV viremia and anti-E2 GBV-C/HGV positivity were 10.5% (9/85) and 10.5% (9/85) respectively. In most patients [17/18 (94%)], the presence of anti-E2 GBV-C/HGV antibody was associated with clearance of GBV-C/HGV from serum. No relationship was noted between anti-E2 GBV-C/HGV antibody (or GBV-C/ HGV viremia) and age, sex, race, time on dialysis, anti-HCV antibody, HBsAg status, and anti-HIV positivity. The frequency of GBV-C/HGV infection in CAPD patients was much higher than that in blood donors, even if the difference did not approach statistical significance. No associations between GBV-C/HGV positivity and biochemical liver tests [aminotransferase and gamma glutamyl transpeptidase (GGT)] were apparent.

CONCLUSIONS

Infection by GBV-C/HGV as detected by RT-PCR and anti-E2 antibody was common in patients on CAPD and in controls alike. No association was seen between GBV-C/HGV and various demographic or clinical factors. The clinical significance of GBV-C/HGV in CAPD remains unclear. Larger investigations are in progress.

Four chimpanzee monoclonal antibodies isolated by phage display neutralize hepatitis a virus

Chimpanzee immunoglobulins are virtually identical to human immunoglobulins and may have clinically useful applications. Four chimpanzee monoclonal antibodies (MAbs) to the hepatitis A virus (HAV) capsid were isolated from a combinatorial cDNA library of gamma1/kappa antibody genes using phage display. Competition assays indicated that three of the MAbs recognized the same or overlapping epitopes, whereas the fourth recognized a different, nonoverlapping epitope on the HAV capsid. All four MAbs neutralized the homologous HAV strain, HM-175, in a radioimmunofocus assay and two of the four MAbs neutralized a heterologous simian HAV strain, AGM-27. From these data, we conclude that the MAbs must recognize at least three epitopes on the HAV capsid. Furthermore, competition assays performed with neutralizing murine MAbs suggested that three of the chimpanzee MAbs recognized epitopes on the HAV capsid which have not been defined previously.

Selection of human anti-HAV McAb from a phage antibody library

The phage displaying antibody fragments were subjected to three rounds of panning with hepatitis A virus (HAV) antigen in solid phase. The eluted phage was enriched nearly 100 fold, and the percentage of recombinant clones increased from 25% to 100% after three rounds of panning. The HAV antigen-specific monoclonal antibody (McAb) was screened by sandwich ELISA, and the specificity of these antibodies was further confirmed by competitive inhibition ELISA.

[Selection of human phage antibodies against HAV and DNA sequence analysis]

OBJECTIVE

To obtain the anti-HAV antibodies.

METHODS

The antibody-capturing antigen strategy was used in panning antibody library with impure antigen. The HAV-binding activity and specificity of phage antibodies were assayed by sandwich ELISA and competitive inhibition ELISA.

RESULTS

Phage antibodies(Fab) against HAV were screened from a human immunoglobulin combinatorial library. Fd and light chain genes were sequenced. Comparison of the Fd gene and light chain gene with KABAT database showed that the heavy chain belonged to IgG1 subclass, and its variable region was derived from rearranged germ-line gene of DP88, D3-3 and JH5; while the light chain was a member of V kappa III family, the germ-line gene was DP kappa 22 and J kappa 4.

CONCLUSION

Phage antibodies against HAV were selected from the antibody library by using the antibody-capturing antigen strategy. The result also suggested that the antibody library was constructed successfully.

[Dynamics of anti-HEV ORF2, ORF3, IgM and IgG in serial sera of patients with hepatitis E and their clinical significance]

OBJECTIVE

To study the dynamics of anti-HEV ORF2, ORF3, IgM and IgG in serial sera of patients with hepatitis E.

METHODS

Anti-HEV was detected in serial sera of 52 patients, by an enzyme-linked immunosorbent assay (EIA) based on two synthetic peptides separated or combined from open reading frame (ORF) 2 and 3 of HEV genome.

RESULTS

Both anti-ORF2 and anti-ORF3 in serum were at the highest levels in early acute phase of the disease, and declined gradually with the course, especially anti-ORF3. The sensitivity of the EIA using both ORF2 and ORF3 peptides was higher than that of either alone. The positive rates of anti-HEV IgM and anti-HEV IgG were separately 71.1% (32/45) and 97.8% (44/45) within 15 days after onset, then decreased more dramatically in IgM than in IgG with the course.

CONCLUSION

Both ORF2 and ORF3 proteins should be used for the development of anti-HEV EIA kit. It seems to be more specific in anti-HEV IgM and more sensitive in anti-HEV IgG as a diagnostic marker of hepatitis E.

Genotype-dependent serologic reactivities in patients infected with hepatitis C virus in the United States

OBJECTIVE

To evaluate the serologic reactivities in patients infected with different hepatitis C virus (HCV) genotypes to four HCV proteins that are components of the second-generation recombinant immunoblot assay.

MATERIAL AND METHODS

Serum samples from 36 patients with chronic HCV infection were obtained. RNA was extracted by using chaotropic lysis and isopropanol precipitation. Reverse-transcriptase polymerase chain reaction of the NS-5 region was performed, followed by automated single-pass dideoxy sequencing of desalted amplification products. Classification of isolated HCV subtypes was based on Simmonds' system. All samples were tested for antibodies to proteins 5-1-1, C100-3, C33c, and C22-3 with the second-generation recombinant immunoblot assay.

RESULTS

Reactivity to protein 5-1-1 was significantly lower for patients with genotypes 2b and 3a than for those infected with HCV types 1a or 1b (P < 0.05). Antibody reactivity to the C100-3 protein was also reduced in patients infected with HCV types 2b and 3a.

CONCLUSION

These data indicate that the genotype-dependent differences in serologic reactivities are substantial among patients with chronic HCV infection.

Evaluation of a multiple peptide assay for typing of antibodies to the hepatitis C virus: relation to genomic typing by the polymerase chain reaction

A panel of 16 type-specific synthetic peptides corresponding to variable antigenic regions within the hepatitis C virus (HCV) core, nonstructural 4 (NS4), and NS5 proteins was synthesised. The peptide panel was used to develop an enzyme immunoassay (EIA) for the detection of antibodies directed to HCV type 1 (genotypes I/1a and II/1b), type 2 (genotypes III/2a and IV/2b), and type 3 (genotype V/3). The peptides corresponded to residues 68-81 of the HCV core (types 1, 2, and 3), residues 1692-1705 and 1710-1728 of HCV NS4 (types 1a, 1b, 2a, 2b, and 3), and residues 2303-2319 of HCV NS5 (types 1a, 1b, 2a, and 2b). The 16-peptide panel was evaluated using human sera from 46 carriers of HCV, which were genotyped in parallel by the polymerase chain reaction (PCR) using primers specific for types I, II, III, IV, and V of HCV core. Of the 46 carriers, 14 (30%) were infected by HCV genotype I, 7 (15%) by genotype II, 16 (35%) by HCV genotype IV, and 6 (13%) by HCV of genotype V. Two carriers had double infections of types I and II, and the HCV strain of one carrier could not be genotyped. Using the serotyping system, 40 (89%) out of the 45 genotyped carriers were found to contain type-specific antibodies corresponding to the genotypes identified by PCR. In 5 of the 23 carriers infected by genotypes I and/or II, antibodies specific for HCV type 1 could not be detected, whereas all 16 carriers infected by genotype IV were serologically typed as type 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of hepatitis C virus genotypes by a line probe assay and correlation with antibody profiles

The 5' untranslated regions derived from 54 patients with a chronic hepatitis C virus infection were analyzed to determine the (sub)type of hepatitis C virus. Labelled polymerase chain reaction products from 5' untranslated region were used as probes for reverse hybridization in a line probe assay (Inno-LiPA) and results were validated by comparison with direct sequencing data. Five different genotypes could be distinguished based on 5' untranslated region sequence diversity. Results of typing by line probe assay and direct sequencing were similar. Antibody responses against core, NS-3, NS-4 and NS-5 epitopes were detected by RIBA-4 and Inno-LIA HCVAb II confirmatory assays. There was no consistent correlation between genotype and anti-HCV responses, although types 2, 3 and 4 hepatitis C virus isolates show poor reactivity with NS-4 ep!%"pes.

Rescue, expression, and analysis of a neutralizing human anti-hepatitis A virus monoclonal antibody

A human anti-hepatitis A virus mAb was rescued from a hybridoma cell line by conventional cDNA cloning, and expressed in CHO cells. The full nucleotide sequences of the mAb H and L chains were determined, revealing a VHI/V lambda II V region combination. Comparisons with germline V genes suggest that the V regions had undergone somatic mutations characteristic of an Ag-driven immune response. A comparison of the binding to hepatitis A virus between mAb derived from the CHO cells and the original hybridoma cell line using ELISA, radioimmunoprecipitation, and solid-phase competition RIA, indicated that the CHO cell-derived mAb fully retained the specificity of the mAb produced by hybridoma cells. Analysis of viral neutralization using a radioimmunofocus inhibition assay demonstrated the retention of antibody functionality after expression in CHO cells, demonstrating the use of this technique in the rescue and high level expression of unstable efficacious human mAb.

ELISA for antibody to hepatitis E virus (HEV) based on complete open-reading frame-2 protein expressed in insect cells: identification of HEV infection in primates

A recombinant baculovirus containing the complete open-reading frame (ORF)-2 region of the hepatitis E virus (HEV) genome was constructed. The major protein synthesized in insect cells infected with recombinant virus was about the size expected for the complete ORF-2 product. This protein reacted in a Western blot assay with plasma from an HEV-infected chimpanzee. Lysates of the recombinant virus-infected insect cells were used in ELISA to monitor seroconversion of eight primate species (chimpanzees, four species of Old World monkeys, and three species of New World monkeys) inoculated with HEV. Homologous detector anti-immunoglobulin was more sensitive than heterologous anti-immunoglobulin for detecting anti-HEV by ELISA. All primate species except tamarins seroconverted after inoculation with HEV, although anti-HEV titers of Old World monkey species were generally higher than those of New World monkey species. The ELISA with complete ORF-2 antigen appeared to be a sensitive and practical method for detecting anti-HEV.

Improved detection of antibodies to hepatitis C virus by the second-generation assay in patients with chronic non-A, non-B liver disease

Serum samples from 337 Japanese patients with chronic non-A, non-B liver disease were tested for antibodies to hepatitis C virus (HCV) by means of first-generation (c100-3; anti-c100) and second-generation (pHCV-34, pHCV-31, c100-3; anti-HCV II) enzyme linked immunosorbent assays (ELISA) and for antibody to the GOR epitope (anti-GOR) also by ELISA. Anti-HCV II was detected in 314 (93.2%), anti-c100 in 247 (81.3%) and anti-GOR in 211 (62.6%) samples. Thus, anti-HCV II was more sensitive in detecting HCV infection than either anti-c100 or anti-GOR (P < 0.001). All serum samples reactive with anti-c100 or anti-GOR reacted with anti-HCV II. Among 314 anti-HCV II-positive patients, we found that 185 (58.9%) were positive for both anti-c100 and anti-GOR while 14 (4.5%) were positive for anti-HCV II alone. Nine (64.3%) of the 14 are presently infected with HCV, as revealed by detection of HCV RNA in their serum; the remaining five may have been infected in the past with HCV. These findings indicate that HCV is a major causative agent of chronic non-A, non-B liver disease in Japan and that detection of anti-HCV II is a specific and more sensitive diagnostic test for HCV infection.

Development of a specific enzyme-linked immunosorbent assay for the hepatitis C virus antibody using clone 14

The authors isolated a specific cDNA clone (clone 14) for non-A, non-B hepatitis virus infection. In this study, we developed an enzyme-linked immunosorbent assay (ELISA) using a synthetic oligopeptide encoded by clone 14 and examined its usefulness for detecting hepatitis C virus (HCV) antibody in 181 patients with chronic NANB hepatitis, 88 with cirrhosis and 24 with hepatocellular carcinoma associated with NANB hepatitis virus. Anti-clone 14 antibody was detected in 75% of patients with chronic NANB hepatitis, 57% of cirrhotic patients and 58% hepatocellular carcinoma patients. Anticlone 14 and anti-C-100 antibody assayed using a commercial kit were found in serum from 199 (69%) and 205 (70%) of these 294 patients, respectively. Approximately 85% of the patients showed the presence of anticlone 14 and/or anti-C-100 antibodies. We compared the presence of these antibodies and the second generation anti-HCV antibody using ELISA and HCV RNA by the polymerase chain reaction assay, in the same blood samples from 49 patients with chronic liver disease who had anti-clone 14 and/or anti-C-100 antibody. HCV RNA was detected in 38 of 40 (95%) plasma samples containing anti-clone 14 antibody, the prevalence of which was similar to that for anti-C-100 antibody (41/42, 98%) and the second generation anti-HCV antibody (46/47, 98%). Furthermore, 6 of 7 plasma samples containing anti-clone 14 antibody and lacking anti-C-100 antibody were positive for the second generation anti-HCV antibody and HCV RNA.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of hepatitis C virus (HCV) RNA by PCR related to HCV antibodies in serum and liver histology in Swedish blood donors

Serum samples from 103 blood donors or patients with slightly increased serum levels of liver enzymes were tested for antibodies to hepatitis C virus (anti-HCV) using second generation tests and for HCV RNA by the polymerase chain reaction (PCR). PCR was in a nested configuration, using primer pairs from the 5'-nontranslated region. The anti-HCV antibody was found by enzyme linked immunosorbent assay (ELISA) in 93 patients. The anti-HCV confirmatory second generation recombinant immunoblot assay (RIBA) was positive in 44, indeterminate in 34 and negative in 25 subjects. Histopathological examination of the liver was carried out in 51 subjects. HCV RNA was detected in serum of 39/41 (95%) RIBA positive patients, and in 7/34 (21%) RIBA indeterminate subjects, but in none of the RIBA negative subjects. All but one of the PCR positive patients with a RIBA indeterminate pattern exhibited the C22 band. HCV RNA was found in the serum of all but one patients with chronic active or persistent hepatitis, but also in one RIBA positive subject with normal liver tissue. These results imply that most patients with antibodies to two or more HCV antigens by RIBA will have a chronic replicative HCV infection associated with viraemia. HCV viraemia can also be present in some patients, who have antibodies to only one HCV antigen particularly the C22 epitope.