The kinetics of antibodies against hepatitis C virus may predict viral clearance in exposed hemophiliacs

Comparative evaluation of Elecsys, Atellica, and Alinity assays for measuring the anti-Hepatitis C virus (HCV) antibody

BACKGROUND

Hepatitis C virus (HCV) infection is a major cause of liver diseases in Korea. Anti-HCV assays are used to screen for HCV infection. Here, we assessed the agreement and diagnostic performances of three different anti-HCV assays.

METHODS

We analyzed 1180 samples using three assay systems-Elecsys Anti-HCV II (Roche Diagnostics), Atellica IM aHCV (Siemens Healthineers), and Alinity s Anti-HCV (Abbott Diagnostics)-and evaluated the agreements between the results and diagnostic performances.

RESULTS

The Cohens kappa coefficients between the Roche and Siemens, Siemens and Abbott, and Roche and Abbott systems were 0.837, 0.961, and 0.849, respectively. The Fleiss kappa coefficient among the three systems was 0.883. The sensitivities and positive predictive values were 86.5 and 89.8 for Roche, 97.5 and 98.1 for Siemens, and 99.4 and 98.2 for Abbott, respectively. The area under the curves of the anti-HCV signal to cutoff (S/Co) ratios or cutoff index for predicting viremia in the Roche, Siemens, and Abbott systems were 0.432, 0.641, and 0.676, respectively; the optimal S/Co ratio was 14.715 for Siemens and 14.42 for Abbott.

CONCLUSIONS

All three assays showed excellent diagnostic performance; however, anti-HCV values need to be used with caution to predict viremia; therefore, supplementary tests are necessary to confirm viremia status, especially for samples with low values.

Sensitivity of hepatitis C virus rapid tests in detecting antibodies in general population

BACKGROUND

Evaluation of clinical performance of the anti-hepatitis C virus (HCV) rapid tests were carried out mostly in chronic hepatitis C patients and in individuals at high risk of HCV infection.

METHODS

The aim of this study was to evaluate the performance of OraQuick and Wantai rapid tests on archived serum samples from 1408 individuals (mean age 46, range 18-90; 65% female) recruited with a systematic sampling procedure during a general population survey.

RESULTS

The analysis of samples by Ortho HCV 3.0 ELISA and Cobas Taqman HCV RNA assays resulted in 69 anti-HCV antibody positive sera, including 42 HCV RNA positive (group 1) and 27 HCV RNA negative (group 2) samples. The performance of rapid tests was evaluated on the 69 anti-HCV positive (group 1+2) and 206 (OraQuick) and 198 (Wantai) anti-HCV negative sera, randomly selected from the 1339 anti-HCV negative samples. The OraQuick and Wantai rapid assays showed a sensitivity in group 1 of 92.9% and 90.5%, respectively. The sensitivity in group 2 was 40.7% and 51.9%, respectively. The anti-HCV antibodies signal/cutoff mean value was the only parameter that statistically differed between group 1 and group 2 individuals (P<0.0001). Further, 3 (OraQuick) and 4 samples (Wantai) from group 1, with very low HCV RNA level (<25 UI/mL), were misdiagnosed by rapid assays as false negative.

CONCLUSIONS

The proportion of infections with low level of viremia and the risk associated with rapid assay failure remained to be carefully estimated in general population.

Rapid decrease in titer and breadth of neutralizing anti-HCV antibodies in HIV/HCV-coinfected patients who achieved SVR

The main targets for neutralizing anti-hepatitis C virus (HCV) antibodies (HCV-nAbs) are the E1 and E2 envelope glycoproteins. We have studied the characteristics of HCV-nAbs through a retrospective study involving 29 HIV/HCV-coinfected patients who achieved sustained virological response (SVR) with peg-IFNα + ribavirin anti-HCV therapy. Plasma samples at baseline and week 24 after SVR were used to perform neutralization assays against five JFH1-based HCV recombinant viruses coding for E1 and E2 from genotypes 1a (H77), 1b (J4), 2a (JFH1), 3a (S52) and 4a (ED43). At baseline, the majority of plasma samples neutralized 1a, 1b, 2a, and 4a, but not 3a, genotypes. Twenty-four weeks following SVR, most neutralizing titers declined substantially. Furthermore, titers against 3a and 2a were not detected in many patients. Plasma samples with high HCV-nAb titers neutralized all genotypes, and the highest titers at the starting point correlated with the highest titers at week 24 after SVR. In conclusion, high titers of broad-spectrum HCV-nAbs were detected in HIV/HCV-coinfected individuals, however, those titers declined soon after SVR.

Role of signal-to-cut-off ratios of anti-hepatitis C virus antibody by enzyme immunoassays along with ID-NAT for screening of whole blood donors in India

Background:

The use of elevated signal-to-cut off ratios (S/CO) as an alternate to further supplemental testing (i.e., RIBA) has been included in the guidelines provided by the Centres for Disease Control and Prevention for HCV diagnostic purposes since 2003. With availability of screening by NAT and non availability of RIBA, further confirmation of HCV infection has been possible at the molecular level (RNA).

Aims:

To study the role of S/CO ratios of anti hepatitis C virus antibody detection by enzyme immunoassays (EIA) along with ID-NAT for screening of whole blood donors.

Methods:

In this study we reviewed the donor screening status for anti HCV from January 2013 to May 2014. All the donations were screened for anti HCV with fourth generation ELISA (BioRad Monolisa Ag-Ab Ultra) as well as with ID NAT (Procleix Ultrio). The S/CO ratio of all the anti-HCV reactive samples were analysed for their presence of HCV RNA.

Results:

On screening 21,115 donors for HCV, 83 donors (0.39%) were found reactive on pilot tube and repeat plasma bag testing (S/Co ratio ≥1) by ELISA. 41 donors were HCV RNA reactive with ID-NAT. 4 samples out of 41 were NAT yields and 37 were concordant reactive with ELISA. The S/Co ratio of anti-HCV reactive samples ranged from 0.9-11.1 [mean = 5.1; SD ± 2.9] whereas S/Co ratio of anti HCV and NAT reactive samples (concordant positives) ranged from 4.1-11.1 [mean 7.3]. In our analysis we found that S/CO ratio of 4 showed positive predictive value (PPV) and sensitivity of 100%.

Summary/Conclusions:

Our study showed that S/CO of 4 for anti HCV on ELISA would have maximum positive predictive value of having donor with HCV RNA. S/CO ratio of 4 is very close to 3.8 which was the CDC guideline. The presence of anti-HCV does not distinguish between current or past infections but a confirmed anti-HCV-positive result indicates the need for counseling and medical evaluation for HCV infection.

Improving the safety of blood transfusion by using a combination of two screening assays for hepatitis C virus

BACKGROUND AND OBJECTIVES

To illustrate that the combination of a single nucleic acid amplification test (NAT) with a single immunoassay for hepatitis C virus (HCV) detection, as proposed internationally, may lead to the omission of anti-HCV reactive sera with non-reactive NAT results.

MATERIALS AND METHODS

In total, 822 of 519, 299 serum samples from 11 blood centres in China were retested for anti-HCV by using 10 screening assays to detect HCV antibodies. A recombinant immunoblot assay (RIBA HCV 3·0; Ortho-Clinical Diagnostics) was performed to define confirmed HCV infection status. Samples with positive or indeterminate RIBA-HCV results were tested by quantitative tests for HCV RNA (Roche Diagnostics).

RESULTS

We found that 47 of the 822 (5·72%) serum samples were RIBA-positive without detectable HCV RNA. For these samples, the 10 anti-HCV immunoassays gave discordant and unsatisfactory results (detection rate ranging from 10·64 to 34·04%; ratio per 100 000 donations ranging from 5·97 to 8·09). Compared with a single anti-HCV screening assay, the two-assay combination increased the detection of these samples. The five best combinations [Sorin and Lizhu enzyme immunoassays (EIAs), Ortho and Lizhu EIAs, Sorin and Wantai EIAs, Sorin EIA and Roche CIA and Ortho and Wantai EIAs] increased the detection rate from 46·81 to 55·57%, thus reducing the ratio per 100 000 donations of HCV-seropositive samples.

CONCLUSION

The combination of two anti-HCV screening immunoassays in parallel with an HCV NAT is a better strategy for HCV detection in blood centres to improve the safety of blood transfusion.

Hepatitis C virus (HCV) antibody dynamics following acute HCV infection and reinfection among HIV-infected men who have sex with men

BACKGROUND

A decline of hepatitis C virus (HCV) antibody titers (anti-HCV), ultimately resulting in seroreversion, has been reported following clearance of viremia in both acute and chronic HCV infection. However, frequency of seroreversion remains unknown in human immunodeficiency virus (HIV)/HCV-coinfected patients. We describe anti-HCV dynamics among HIV-infected men who have sex with men (MSM) following acute HCV infection and reinfection.

METHODS

Primary acute HCV infection was assumed when a subject was anti-HCV negative prior to the first positive HCV RNA test. Anti-HCV was measured at least annually in 63 HIV-infected MSM, with a median follow-up of 4.0 years (interquartile range [IQR], 2.5-5.7 years). Time from HCV infection to seroconversion, and from seroconversion to seroreversion, was estimated using the Kaplan-Meier method. Longitudinal anti-HCV patterns were studied using a random-effects model to adjust for repeated measures.

RESULTS

Median time from HCV infection to seroconversion was 74 days (IQR, 47-125 days). Subjects who cleared HCV RNA (n = 36) showed a significant decrease in anti-HCV levels (P < .001). Among 31 subjects with sustained virologic response (SVR), anti-HCV became undetectable during follow-up in 8; cumulative incidence of seroreversion within 3 years after seroconversion was 37% (95% confidence interval, 18%-66%). Eighteen subjects became reinfected during follow-up; this coincided with a subsequent increase in anti-HCV reactivity.

CONCLUSIONS

A decline of anti-HCV reactivity was associated with HCV RNA clearance. Seroreversion was very common following SVR. Upon reinfection, anti-HCV levels increased again. Monitoring anti-HCV levels might therefore be an effective alternative for diagnosis of HCV reinfection.

Use of an anti-hepatitis C virus (HCV) IgG avidity assay to identify recent HCV infection

There is no reliable and simple diagnostic marker available to diagnose recent hepatitis C virus (HCV) infection. It has been shown that the avidity of specific IgG antibody is low in primary viral infection and increases with time. We report the development of an anti-HCV avidity assay derived from a commercially available test. A panel of 117 sera was first examined for IgG avidity. It was composed of samples from patients with recent (group 1, n = 14), chronic (group 2, n = 70), and resolved (group 3, n = 33) HCV infections. Avidity index (AI) values observed in recently infected patients were significantly lower (12.0% +/- 9.2% [mean +/- standard deviation]) than those found in chronic carriers (83.1% +/- 15.2%). Using a threshold of 43.0%, this assay distinguished between groups 1 and 2 with very high sensitivity (98%) and specificity (100%). For group 3, a broader distribution of the AI values was observed (54.8% +/- 27.3%), suggesting that this index would not be useful in HCV RNA-negative patients. Blind validation of the test was carried out with a panel of 36 serum samples from 17 HCV seroconverters. The assay described here is a useful tool to distinguish recent from chronic infection in HCV-viremic patients.

High antibody level: an accurate serologic marker of viremia in asymptomatic people with hepatitis C infection

BACKGROUND

The screening and diagnosis of hepatitis C virus (HCV) infection is initiated by testing for antibody to HCV (anti-HCV). A positive anti-HCV test in blood donors represents ongoing infection in only a variable proportion of individuals. Because a high anti-HCV level has been associated with viremia, a study was conducted to determine whether a high antibody level is an accurate serologic marker for viremia in asymptomatic anti-HCV-positive persons.

STUDY DESIGN AND METHODS

In a diagnostic test study, we included 856 anti-HCV-positive blood donors in a blood bank at Guadalajara, Jalisco, Mexico, between 2002 and 2007. A third-generation amplified chemiluminescence assay (ChLIA HCV) was used to detect anti-HCV. A positive result of the qualitative nucleic acid test (HCV RNA) was considered the gold standard for viremia.

RESULTS

By receiver operating characteristic analysis, the signal-to-cutoff (S/CO) ratio of 20 or more was chosen as optimal to identify viremia and so was defined as high anti-HCV level. There was a significant difference in the proportion of viremia between subjects with high antibody level and those with lower levels (93.7% vs. 1.8%, respectively; p < 0.001). A high antibody level showed a sensitivity for viremia of 96.6% (95% confidence interval [CI], 93.8%-98.1%), a specificity of 96.6% (95% CI, 94.8%-97.8%), and a likelihood ratio of 28.6 (95% CI, 18.4%-44.6%).

CONCLUSION

A high antibody level (S/CO ratio >/=20 by ChLIA HCV) clearly divides the viremic from the nonviremic blood donors and functions as an accurate serologic marker to guide the use of routine HCV RNA testing to confirm hepatitis C infection.

Significance of anti-HCV signal-to-cutoff ratio in predicting hepatitis C viremia

BACKGROUND/AIMS

Hepatitis C virus (HCV) RNA testing can be performed using qualitative or quantitative assays, and it is still unclear which is more useful as a primary test in patients positive for anti-HCV. The present study evaluated the usefulness of anti-HCV signal-to-cutoff ratio (S/CO ratio) for predicting HCV RNA results.

METHODS

Patients on whom a qualitative HCV RNA test was performed due to a positive anti-HCV enzyme immunoassay were enrolled. Patients were divided into viremia and no-viremia groups according to HCV RNA results. Receiver-operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic accuracy of anti-HCV S/CO for a diagnosis of viremia.

RESULTS

In total, 487 patients were enrolled. HCV RNA was positive in 301 subjects (61.8%). Age, serum ALT level, and anti-HCV S/CO ratio were significantly different between the viremia and no-viremia groups. By ROC curve analysis, anti-HCV S/CO ratio (area, 0.989; 95% confidence interval, 0.981 to 0.998) accurately predicted the presence of viremia, with a cutoff value of 10.9 (sensitivity, 94.4%; specificity, 97.3%).

CONCLUSIONS

Anti-HCV S/CO ratio was found to be highly accurate at predicting HCV viremia. The anti-HCV S/CO ratio can be used to determine whether a quantitative or qualitative HCV RNA test should be used to confirm HCV viremia in patients with a positive anti-HCV by the following criteria: if the anti-HCV S/CO ratio is <10.9, a qualitative HCV RNA test can be used, and if the anti-HCV S/CO ratio is >or=10.9 a quantitative HCV RNA test can be performed.

Acute hepatitis B in patients with or without underlying chronic HCV infection

BACKGROUND AND AIM

Acute hepatitis B course may be significantly modified by underlying chronic hepatitis C. The aim of this study was to compare clinical and virological characteristics of acute hepatitis B in patients with or without chronic hepatitis C virus (HCV) infection.

MATERIALS AND METHODS

Twenty-seven patients with symptomatic acute hepatitis B were enrolled: 14 with underlying chronic HCV (Group A) and 13, matched by age and gender, with single hepatitis B (Group B). All patients were followed-up until HBsAg negativization.

RESULTS

Group A patients were HCV-RNA-negative on hospital admission and all but one remained negative during follow-up. HBeAg tested positive in 92.9% and 84.6% of Groups A and B patients, respectively. ALT, bilirubin, prothrombin time values and HBsAg titer were similar in both groups. Nevertheless, lower mean HBV-DNA levels (p=0.03), a shorter duration of HBsAg positivity (p<0.01) and of symptoms before ALT peak (p=0.014), and significantly lower peak ALT values (p=0.03) were observed in Group A compared to Group B patients.

CONCLUSIONS

Acute HBV infection suppressed HCV replication. Conversely, the underlying HCV infection exerted a modulatory effect on HBV replication which influenced the course, though not the outcome, of the acute disease. Although acute hepatitis B showed a mild clinical course in both groups of patients, HBV vaccination should be suggested to risk subjects.

Absence of seroreversion in 80 HAART-treated HIV-1 seropositive patients with at least five-years undetectable plasma HIV-1 viral load

Partial or complete seroreversion for HIV-1, or incomplete antibody evolution are relatively rare events that have so far only been described in patients treated with HAART early after virus infection. Whether seroreversion is seen in patients treated effectively with HAART years after their acute infection has not been investigated so far. Therefore we have investigated anti-HIV antibody levels in 80 patients treated with HAART during chronic HIV-1 infection, who had an undetectable HIV-1 plasma viral load for at least five years. In none of the patients we observed seroreversion, and there was also no significant decrease or increase in antibody levels in this group of patients. So, successful HAART treatment during chronic HIV-1 infection does not induce seroreversion.

Prevalence of hepatitis C virus infection and HCV genotypes among hemophiliacs in the State of Bahia, Northeastern Brazil: analysis of serological and virological parameters

The objective of the present study was to analyze HCV serological and virological parameters from hemophiliacs in the State of Bahia. Anti-HCV was investigated by ELISA in a cohort of 268 hemophiliacs A/B who were followed-up in a reference unit for hemotherapy in the State of Bahia. HCV viremia and genotypes were also determined from a subset of 66 anti-HCV seropositive hemophiliacs. Seroprevalence among hemophiliacs was 42.2% (95% CI 36.5-48.1) and was significantly higher (p<0.05) according to age > or =10 years, presence of factor VIII/IX inhibitory antibodies and other infection markers. None of the hemophiliacs less than 5 years of age were anti-HCV seropositive. Viremia was detectable in 77.3% (51/66). HCV genotype 1 (74%) was the most prevalent followed by genotype 3 (22%) and genotype 2 (4%). Our results indicate that HCV prevalence is still high among hemophiliacs, although HCV transmission was not observed in young hemophiliacs.

Long-term evolution of serum and liver viral markers in patients treated for chronic hepatitis C and sustained response

Few studies have analysed the evolution of HCV markers in chronic hepatitis C (CHC)-treated patients. We have evaluated the presence or absence of serum and liver HCV-RNA, the core antigen (HCV-cAg) and the loss of specific antibodies (anti-HCV), in long-term sustained responders (SR). One hundred and seventy-six patients (132 SR and 44 nonresponders (NR) were included in the study. HCV-RNA was determined in serum and liver by a commercial PCR-kit. HCV-Ag was determined by ELISA and specific antibodies against HCV by means of a commercial line immunoblot assay (LIA) technique. Serum HCVcAg was found positive in three (4.2%) SR and in one (4%) NR (NS). Four SR (3.6%) and 44 NR (100%) were also HCV-RNA (+) in liver tissue. Two patients were HCV-cAg (+). A good correlation was found between the serum levels of HCV-cAg and HCV-RNA (r = 0.847, P < 0.001). Specific antibodies (anti-HCV) were determined by LIA in 45 patients. A decrease was found in the number of patients who presented reactivity to bands E2 and NS4 when we compared SR with a follow-up of more than 5 years with NR and SR with a follow-up <5 years (P < 0.01 and 0.005). A good correlation was found between the HCV-cAg and HCV-RNA serum levels in CHC-treated patients (P < 0.001). Few SR (3.6%) had HCV-RNA in the liver, and HCV-cAg (1.8%) in serum. In SR with more than 5 years of follow-up a clear tendency exists in the trend to clarify the bands E2 and NS4 of anti-HCV in serum.

HCV viremia is associated with drug use in young HIV-1 and HCV coinfected pregnant and non-pregnant women

AIMS

Vertical transmission of HCV is increased among HIV-1/HCV coinfected women and is related to HCV viral load. In this study we assessed clinical and demographic factors associated with HCV viremia in a cohort of young pregnant and non-pregnant mothers coinfected with HIV-1.

DESIGN

A cross-sectional clinic-based study nested within a prospective cohort study.

METHODS

From 1988 to 2000, HIV-1 + pregnant and non-pregnant women with children followed in a large maternal, child and adolescent HIV-1 clinic were evaluated for HCV infection using EIA 3.0. HCV RNA levels were determined for HCV antibody + women using polymerase chain reaction. Demographic and clinical characteristics between HCV-RNA(+) and HCV-RNA(-) women and between pregnant and non-pregnant HIV-1/HCV coinfected women were compared using univariate and multivariate analyses.

FINDINGS

Among 359 HIV-1(+) women, 84 (23%) were HCV-ab + and 49/84 (58%) had detectable HCV-RNA in plasma. Median age was 31. CD4 counts, HIV-1 RNA levels and demographic characteristics were similar for viremic and non-viremic women and pregnant and non-pregnant women. However, viremic women were more likely to report a history of (88% versus 43%; P < 0.001) or active injection drug use (AIDU) (83% versus 29%; P < 0.001). Logistic regression analysis showed that HCV viremia was associated significantly with AIDU (adjusted OR: 15.17; 95% CI: 3.56, 64.56) after adjusting for age, race, number of sexual partners, pregnancy status, CD4 counts and HIV-1 viral load.

CONCLUSION

In this cohort of young HIV-1 and HCV coinfected women, HCV viremia was associated strongly with active injection drug use, perhaps due to reinfection or reactivation of HCV. Thus, careful evaluation for HCV infection and counseling related to drug use may be necessary.

Lymphocyte T helper-specific reactivity in sustained responders to interferon and ribavirin with negativation (seroreversion) of anti-hepatitis C virus

BACKGROUND

Seroreversion, negativation of anti-hepatitis C virus previously positive, is sometimes found in some chronic hepatitis C-sustained responders (SRs) to antiviral therapy.

AIMS

To determine the probability of seroreversion in SR treatment with Interferon and Ribavirin, and lymphocyte T helper (CD4+) reactivity to HCV antigens.

METHODS

Thirty SR were followed on average for 54.8 months. Anti-HCV was tested by third generation test. Peripheral blood mononuclear cells (PBMCs) were isolated from venous blood and cultured to evaluate CD4+ proliferation in response to 2 microg/ml of eight HCV recombinant antigens from core, NS3, NS4, NS5 regions.

RESULTS

Seroreversion was verified in 23% of patients (7/30), appearing at 47.5+/-24.0 months. The probability of anti-HCV loss in this group was 25% at 56 months after ending therapy. In 57% (4/7), anti-HCV returned to positive. These 7 SR patients with seroreversion also showed weaker CD4+ reactivity in 5% of tests (3/56) than the remaining 23 anti-HCV-positive SRs who showed stronger reactivity in 18% of tests (33/184), P=0.036.

CONCLUSIONS

One-quarter of the SR showed seroreversion of anti-HCV and weaker CD4+ specific HCV proliferation than those who remained anti-HCV positive. The data suggest that complete viral eradication is a possible and achievable clinical objective.

Complete or partial seroreversion in immunocompetent individuals after self-limited HCV infection: consequences for transfusion

BACKGROUND

The disappearance of anti-HCV antibodies over time, after a self-limited infection, also referenced seroreversion, has been observed. The frequency of this phenomenon remains controversial, especially in immunocompetent subjects. However, it has important implications in the context of transfusion inquiries, in particular in case of a blood donor suspected to have transmitted HCV through a past blood donation.

STUDY DESIGN AND METHODS

Our findings are presented of a longitudinal study, including 16 patients from a cohort of 78 immunocompetent, multitransfused individuals who were positive for anti-HCV (EIA and confirmatory assay [RIBA]) and followed over a long period of time without having received any antiviral therapy. The aim was to establish whether a past and self-resolved HCV infection could evolve toward a negative serology.

RESULTS

The 16 patients were classified in three groups: 1) 12 patients who remained anti-HCV positive with no evolution in their RIBA pattern after a mean follow-up of 7.6 years; 2) one patient who presented a complete seroreversion 6 years after enrollment; and 3) three patients with a partial seroreversion over a mean follow-up of 16 years.

CONCLUSION

HCV infection is not always characterized by a persistent antibody response, even in immunocompetent individuals. This should be taken into consideration when transfusion inquiries are conducted.

Frequent recovery and broad genotype 2 diversity characterize hepatitis C virus infection in Ghana, West Africa

Hepatitis C virus (HCV) infection is thought to mostly become chronic and rarely resolves. HCV infection was serologically screened in 4,984 samples from Ghanaian blood donors, and 1.3% prevalence was found. At least 53% of confirmed anti-HCV carriers had no detectable viral RNA and were considered to have cleared the virus and recovered from the infection. Confirmation was authenticated by the presence of antibodies specific to at least two viral antigens, mostly NS3 and E2. Reactivity to HCV core antigens was lower in Ghanaian than United Kingdom blood donors. The minority of chronically infected donors carried a viral load significantly lower than an unselected comparative group of United Kingdom blood donors (2.5 x 10(5) versus 2.9 x 10(6) IU/ml; P = 0.004). HCV genotype 2 was largely predominant (87%). Sequence clustering was similarly broad in the E1/E2 and NS5 regions. The phylogenetic diversity and the incapacity to distinguish subtypes within genotype 2 in our and others' West African strains suggested that West Africa may be the origin of HCV genotype 2. The genetic diversity extended to the identification of strains clearly separated from known subtypes of genotype 2 and genotype 1. One strain appears to be part of a new HCV genotype. HCV infection in Ghana is characterized by a high rate of recovery and the predominance of broadly divergent genotype 2 strains.

The IgG antibody profile to various antigen regions of hepatitis C virus differs in oral fluid and serum of patients with chronic hepatitis C

Antibodies to hepatitis C virus (HCV) can be detected not only in serum but also in oral fluid. The aim of the study was to determine IgG antibody reactivity directed to six antigen regions of HCV in oral fluid and to evaluate the significance of the antibody pattern in oral fluid compared to serum. Oral fluid and serum samples of 32 HCV viremic patients were collected to detect antibodies to six antigen regions incorporated as antigen bands into modified commercial updated third generation line immuno-assay. Compared to serum, a significantly lower cumulative antibody response and reactivity to five HCV antigens was found in oral fluid. The significantly highest prevalence of oral fluid reactivity was recorded with antigen C1 (78%), whereas in serum the most significantly frequent reactivity was detected with antigen NS3 (100%). The absence of antibody reactivity with antigen E2 was similar in both body fluids. The discrepancy in antibody pattern to HCV antigens between oral fluid and serum indicates the possible existence of local viral replication, viral mutants, viral inhibitors in oral cavity and, most probably, leakage of the muco-vascular barrier.

Antibody responses against B-cell epitopes of the hypervariable region 1 of hepatitis C virus in self-limiting and chronic human hepatitis C followed-up using consensus peptides

A rare collection of serum samples from patients with hepatitis C virus (HCV) infection followed up from the onset of clinical symptoms was acquired. RNA corresponding to the hypervariable region 1 (HVR1) of E2 protein of HCV isolated from nine patients was reverse-transcribed, amplified, sequenced, and HVR1 amino acid sequences were deduced. These sequences and a selection of HVR1 amino acid sequences of matching HCV genotypes from protein and translated DNA sequence databanks were used to create the HVR1 amino acid consensus. The degenerated peptides mimicking N- and C-termini of the consensus were synthesized. Most (76%) of 17 patients followed up for the period from 1 week to a minimum of 7 months from the onset of acute symptoms developed antibodies reacting with peptides representing N- and/or C- termini of HVR1. Antibody recognition of the consensus HVR1 peptides indicates that the variability of HVR1 sequence on the protein level is limited with certain conserved structure(s) being untouched. A tendency was observed for a slower development of anti-HVR1 antibody response in patients developing chronic HCV, as compared to those with self-limiting HCV infection.

Hepatitis C viral clearance and antibody reactivity patterns in persons with haemophilia and other congenital bleeding disorders

We studied hepatitis C virus (HCV) clearance and antibody reactivity patterns in a cohort of 100 haemophiliacs exposed to unsterilized blood products, of whom 25 were antiHCV negative and 75 were antiHCV positive [49 human immunodeficiency virus (HIV) negative and 26 HIV positive]. HCV RNA was measured by the 2.0 bDNA assay and an 'in-house' polymerase chain reaction assay. Antibody reactivity patterns were examined using a recombinant immunoblot assay (RIBA). Prior HCV infection was found in two (8%) of 25 antiHCV negative patients. HCV viraemia persisted in all 26 antiHCV+ patients who were coinfected with HIV. HCV RNA clearance was found in 12 (25%) of 49 antiHCV+, HIV- patients. Viral clearance was associated with younger current age (P < 0.01) and age at infection (P < 0.001), but not with duration of infection or with dose or frequency of clotting factor use. RIBA ratios reflecting an index of each patient's overall reactivity to four HCV epitopes were significantly lower in those with viral clearance (P < 0.0001). Over a period of 15 years, those with viral clearance demonstrated significant loss of reactivity to the NS3, NS4 and NS5 epitopes, while those with viral persistence demonstrated relatively stable reactivities to all epitopes. We conclude that spontaneous HCV RNA clearance in haemophiliacs is age-related and is unlikely to occur in those coinfected with HIV. The loss of antibody reactivity for some epitopes, especially c22 (core), may be a marker for the natural resolution of chronic HCV infection.

HCV RNA in blood donors with isolated reactivities by third-generation RIBA

BACKGROUND

The objective of this collaborative study was to learn the proportion of HCV RNA-positive samples obtained from a population of donors with isolated anti-HCV reactivities by third-generation RIBA (RIBA-3) (indeterminate results).

STUDY DESIGN AND METHODS

During a 2-year period, 11 blood transfusion centers kept all samples with indeterminate RIBA-3 results to test them by PCR, using both local and commercial techniques.

RESULTS

Of the 758 RIBA-3 indeterminate samples, 10 (1.3%) were positive for HCV RNA: 3. 3 percent (6/180) and 1.3 percent (4/317) of samples with anti-core or anti-NS3 reactivity, respectively, and none of the 52 and 209 samples with anti-NS4 or anti-NS5 reactivity, respectively. HCV RNA-positive donors with anti-core reactivity were infected with different subtypes (1 with HCV subtype 1b, 1 with 2, 1 with 2a/2c, 2 with 3a, and 1 with 5a), and a follow-up indicated a chronic-carrier state in two of the six donors. Acute hepatitis was diagnosed in three of the four donors with anti-NS3 reactivity alone. Two of these three were IV drug users and were infected with subtype 1a.

CONCLUSION

HCV RNA-positive donors with indeterminate results in RIBA-3 are extremely rare, but they do exist. They were observed only when either anti-core or anti-NS3 was present. With such a RIBA-3 profile, PCR testing remains necessary to reveal an eventual acute or chronic HCV infection.