Detection of antibodies against hepatitis C virus in saliva: a marker of viral replication

Evaluation of a new point-of-care oral anti-HCV test for screening of hepatitis C virus infection

BACKGROUND

Hepatitis C virus (HCV) infection is a public health issue for which an effective universal screening method is urgently needed. An oral anti-HCV test could provide a noninvasive and rapid screening strategy for HCV infection. This study evaluated the performance of a new point-of-care oral assay developed by Well for the detection of HCV antibody.

METHODS

Individuals from three centers with and without HCV infection were enrolled. All participants were tested for oral HCV antibody using the Well assay and for serum HCV antibody using established tests (ARCHITECT i2000 anti-HCV assay and InTec serum anti-HCV assay). For participants who obtained positive results, HCV RNA was tested for verification. Some patients underwent the OraQuick HCV test at the same time, and some self-tested with the Well assay during the same period.

RESULTS

A total of 1179 participants, including 486 patients with chronic HCV infection, 108 patients with other liver diseases, and 585 individuals who underwent physical examination, were enrolled. The Well anti-HCV test had a sensitivity of 91.88% (95% confidence interval [CI]: 88.97-94.09%) and a specificity of 98.00% (96.58-98.86%) for oral HCV antibody detection. The consistency between the Well and InTec assays was 97.02% (1138/1179). The consistency between the Well and OraQuick assays was 98.50% (197/200). Furthermore, the results of self-testing were highly consistent with those of researcher-administered tests (Kappa = 0.979). In addition, the HCV RNA results also showed that HCV RNA could only be detected on 1 of the 39 false-negative samples, and for 172 positive HCV RNA results, 171 could be detected by the Well oral anti-HCV assay.

CONCLUSIONS

The Well oral anti-HCV test offers high sensitivity and specificity and performed comparably to both the OraQuick assay and InTec assay for HCV diagnosis. Thus, the Well test represents a new tool for universal HCV screening to identify infected patients, particularly in regions with limited medical resources.

Detection of Hepatitis C Virus RNA in Blood and Saliva of Transfusion-Dependent Thalassemia Patients Diagnosed with Hepatitis C

Background:

The aim of the current study was to detect hepatitis C virus (HCV) RNA in blood and saliva of a population of patients with thalassemia who have HCV antibody in their serum.

Materials and Methods:

In this cross-sectional study, blood and saliva samples were collected and were analyzed with quantitative reverse transcription polymerase chain reaction (RT-PCR) for the detection of HCV RNA. In addition, liver-related blood tests were performed, and patients’ medical history was recorded. Data were analyzed by independent samples t-test and Chi-square with a significant level of 0.05.

Results:

Overall, 62 adult patients (29 males and 33 females) were included. Most (87%) of the patients had major thalassemia and genotype 1a was the most common (42%) type. HCV RNA was detected in 71 and 16% of blood and saliva samples, respectively. HCV RNA was detected more in female patients (31%) (P = 0.003) and in intermediate thalassemia (50%) (P < 0.005). The mean age of the patients with positive saliva was almost 10 years older (P < 0.001), and the mean number of blood transfusion was fewer in positive saliva group (P = 0.037). The sensitivity, specificity, and positive and negative predictive values of saliva PCR was calculated to be 18%, 88%, 80%, and 69%, respectively.

Conclusion:

Saliva contained HCV RNA in 16% of the assessed population. The probability of detection of HCV RNA in saliva increased in older patients, less number of blood transfusions, females and intermediate thalassemia. Saliva RT-PCR demonstrated low sensitivity and high specificity with high positive predictive value in the assessed population.

Performance of ANTI-HCV testing in dried blood spots and saliva according to HIV status

The use of saliva and dried blood spots (DBS) could increase access to HCV diagnosis for high-risk populations, such as HIV-infected individuals, but the performance of these assays has not been well established in this group. This study aims to evaluate HIV status, particularly TCD4+ cell count and viral load, in the performance of anti-HCV testing using DBS and saliva. A total of 961 individuals classified as HCV+, HIV+, or HIV/HCV+, as well as negative controls, donated serum, DBS, and saliva samples for anti-HCV testing using a commercial enzyme immunoassay. Sample volume was modified for DBS and saliva, and an ROC curve was used for cut-off determination in saliva. Anti-HCV sensitivities were greater than 93% using DBS and saliva in the HCV+ group, while they were 83.3% and 95.6% for HCV/HIV+ individuals for DBS and saliva assays, respectively. Specificity varied from 91.7% to 100% using saliva and DBS in HIV monoinfected and control subjects. When only anti-HCV/HCV RNA+ serum samples, that is, true positives, were considered, the sensitivities were 98.3% and 100% for DBS and saliva, respectively, in the HCV+ group and 91.6% and 94.8% for DBS and saliva, respectively, in the HIV/HCV+ group. High absorbance values were observed among those presenting with HCV RNA in serum and low HIV viral load (less than 50 copies/mL). In conclusion, DBS and saliva samples could be used for anti-HCV detection, particularly to identify active HCV cases, but low sensitivity was observed for anti-HCV testing using DBS in the HIV/HCV+ group.

Accuracy of rapid oral HCV diagnostic test among a Saudi sample

OBJECTIVES

The objective of this study was to investigate the accuracy of the OraQuick® rapid diagnostic test in the detection of hepatitis C virus (HCV) antibodies in oral fluid among a Saudi population sample.

DESIGN

A case-control cross-sectional study was conducted on 60 HCV-positive patients and 100 HCV-negative control subjects.

PATIENTS AND METHODS

The HCV-positive patients were recruited from the Clinics of Infectious Diseases of King Abdulaziz University (KAU) Hospital, Jeddah, while the control group was collected from KAU, Faculty of Dentistry, including staff and students. The OraQuick® HCV rapid antibody test (OraSure Technologies, Inc. USA) utilized the oral fluid swab. Sensitivity and specificity for the test were calculated and correlated to the patients' viral load.

RESULTS

Out of the 60 PCR + ve patients, 53 (88.33 %) revealed a positive OraQuick test, whereas 7 (11.67 %) patients showed negative test, revealing 88.33 % sensitivity and 100 % specificity for detection of salivary HCV antibodies. Only PCR level was valuable in predicting the outcome of OraQuick test.

CONCLUSION

Using oral fluid for the detection of HCV antibodies could be a useful tool for epidemiological purposes and for field collection of samples in developing countries or in nonclinical settings by persons with minimal training.

CLINICAL RELEVANCE

Millions of pilgrims visit Saudi Arabia during every year, many of whom are from countries where HCV infection is endemic; therefore, it will be very helpful to use a noninvasive, quick, simple, specific, and sensitive method for detection of HCV antibodies using oral fluid.

An evaluation of different saliva collection methods for detection of antibodies against hepatitis C virus (anti-HCV)

BACKGROUND

Saliva samples can be used as an alternative fluid for against hepatitis C virus (anti-HCV) detection owing to the ease of collection and excellent acceptability. This study was conducted to optimize a commercial enzyme immunoassay (EIA) to detect anti-HCV in saliva samples.

METHODS

Ninety-six individuals donated paired serum and saliva samples that were obtained, using a commercial device (Salivette) and spitting into a sterile container. Initially, elution buffer for the Salivette samples, sample volume, incubation time and temperature, and two different anti-HCV EIAs were evaluated. Using the optimized assay, three methods for cut-off calculation were also evaluated.

RESULTS

A 20-fold increase in the sample volume for both collection methods was needed. Moreover, the Radim assay was the most appropriate assay for anti-HCV detection in saliva samples, and the quality parameters were increased when a ROC curve was used to determine the cut-off value. Using this optimized assay, the sensitivities, specificities, accuracies, positive and negative predictive values were above 90% for saliva obtained using both the Salivette and spitting methods. Using this assay, discordant false-negative results were obtained for only two Salivette samples and five spitting samples. The concordance kappa was 93% for the Salivette method and 86.1% for the spitting method, demonstrating excellent performance.

CONCLUSIONS

Saliva samples obtained for both methods can be employed for anti-HCV detection among HCV-infected or HCV-suspected cases, but several modifications must be performed on commercial EIAs to obtain good results. Moreover, samples obtained with commercial devices are more appropriate for anti-HCV detection in saliva samples.

Risk of hepatitis C virus transmission through drug preparation equipment: a systematic and methodological review

The use of blood-contaminated drug preparation equipment is believed to be associated with the transmission of hepatitis C virus (HCV) among injection drug users (IDUs), but the extent of HCV infection risk is unclear. The objective of this review was to appraise the evidence regarding HCV incidence associated with the use of drug preparation equipment such as drug mixing containers, filters and water. In June 2007, cohort and case-control studies examining the association of HCV incidence with the sharing of drug preparation equipment were identified by searching electronic reference databases as well as the reference lists of published papers. Ten studies (seven cohort and three nested case-control) met the inclusion criteria for the review. The relative risk of HCV infection associated with drug preparation equipment were mainly between 2.0 and 5.9; however, the precision of the estimates from individual studies were marked by wide confidence intervals. Few studies exist to allow an adequate assessment of the individual contributions of containers, filters and water to HCV incidence. The major methodological limitations of reviewed studies were short follow-up times, inadequate control of confounders and lack of exclusion of periods when IDUs were not at risk for HCV infection through drug injection. Current evidence implicating the association of drug preparation equipment with HCV incidence is limited by several methodological concerns.

Prevalence and determinants of hepatitis C virus infection among female drug injecting sex workers in Glasgow

Background

Few studies of the prevalence of hepatitis C virus (HCV) infection have focussed on women who work as street sex workers to finance their drug use.

Methods

The investigators report the survey findings of such a population in Glasgow. All women attending the health and social care drop-in centre, situated in Glasgow's "Red Light Area", during a four-week period in 1999 were invited to participate in a survey involving the provision of a saliva sample for anonymous HCV testing and the self-completion of a questionnaire seeking demographic, sexual and injecting practice data.

Results

Of the 223 women who attended, 51% agreed to participate. Of the 98 women who provided a sufficient saliva sample, 64% (95% CI: 54%–74%) tested HCV antibody positive; 98% of those who tested positive had ever injected drugs. Adjusting for the 85% sensitivity of the saliva test, the HCV antibody prevalence among IDU sex workers sampled was 81%; a rate which is considerably higher than those recorded, contemporaneously, among Glasgow IDUs generally. Two factors were independently associated with HCV antibody positivity in saliva: ever shared needles and syringes (adjusted OR 5.7, 95% CI 2–16) and number of times imprisoned (adjusted OR 7.3, 95% CI 1.4–39, for more than five times compared to zero times).

Conclusion

Women who engage in street sex work to finance their drug habit are a particularly desperate, chaotic and vulnerable population. This study demonstrates that their HCV infection risk may be greater than that for other IDUs. Those responsible for designing interventions to prevent HCV infection among IDUs should consider the special needs of this group.

Increased Cyfra 21-1 concentration in saliva from primary oral squamous cell carcinoma patients

BACKGROUND

Saliva is the body fluid in the oral cavity and contacts directly with oral mucosa. As a detective media, it is acceptable and non-traumatic. Cyfra 21-1, being the soluble fragment of cytokeratin 19(CK19), correlates well with oral squamous cell carcinoma (OSCC).

OBJECTIVE

To investigate the saliva Cyfra 21-1 concentrations in OSCC patients and healthy persons, and the correlation between the Cyfra 21-1 concentration in saliva and the CK19 expression in tissue from OSCC patients.

DESIGN

Saliva Cyfra 21-1 concentration was detected by ELISA in 30 OSCC patients and 30 healthy persons; CK19 protein expression and CK19 mRNA level were, respectively, detected by immunohistochemistry and fluorescent real-time RT-PCR in cancerous and paracancerous tissues from 33 OSCC patients.

RESULTS

Saliva Cyfra 21-1 concentration in OSCC patients (85.95+/-78.00 microg/L) was significantly higher than that in healthy persons (42.27+/-40.84 microg/L) (P=0.009); it was also significantly higher in the patients suffering later tumour recurrence (130.95+/-66.38 microg/L) than that in the patients without tumour recurrence (74.84+/-63.45 microg/L) (P=0.023). CK19 protein expression increased significantly in OSCC tissues (P<0.001) with positive rate of 90.9%, CK19 mRNA level in cancerous tissues was 2.21 folds higher than that in paracancerous tissues (P=0.020); significant correlation was found between tissue CK19 protein expression and tissue CK19 mRNA level (P=0.003), and great correlation was found between tissue CK19 protein expression and saliva Cyfra 21-1 concentration (P=0.051).

CONCLUSIONS

The increased CK19 expression in OSCC tissues plays an important role in the increase of saliva Cyfra 21-1 concentration. Potential clinical value of saliva Cyfra 21-1 detection is suggested for OSCC. Further studies are encouraged to reveal the real diagnostic and prognostic value of detecting saliva Cyfra 21-1 concentration for OSCC.

Routine practice HCV infection screening with saliva samples: multicentric study in an intravenous drug user population

OBJECTIVE

The purpose of this randomized multicentric study was to evaluate the diagnostic contribution of screening for HCV infection on saliva samples in day-to-day practice in the intravenous drug-user (IVDU) population.

METHODS

Between January and May 2004, 274 presumably HCV-negative IVDU were screened for HCV infection in 15 centers in France (median age 29 years). After centralized randomization, screening tests were performed on blood samples (arm A) or saliva samples (arm B). Screening tests were performed in 78 subjects (28%) had never been screened before and in 196 subjects (72%) who had had a negative HCV screening test on average 12 months prior to the beginning of the study. In the event of a positive saliva test for anti-HCV Ab, a serum test for anti-HCV Ab was performed. In the event of a positive serum test for anti-HCV Ab, PCR was performed on serum to measure HCV-RNA.

RESULTS

Fourteen individuals were positive for HCV RNA (7 in each arm). Six of these cases had not been detected before. In eight cases, the median time between the last negative screening test and study inclusion was 11 months (range 6-94 months).

CONCLUSIONS

Viremia tests were positive in 5% percent of the target population, although one-third of the individuals in arm A (blood samples) were not tested. The saliva test may be a useful alternative in the event of refusal of a blood test or when poor venous conditions compromise venous puncture. A confirmatory blood test still remains difficult to obtain in nearly half of patients.

Modelling the impact on Hepatitis C transmission of reducing syringe sharing: London case study

BACKGROUND

Hepatitis C virus (HCV) prevalence and incidence among injecting drug users (IDUs) has increased in London and rest of UK. To inform public health action, mathematical modelling is used to explore the possible impact of strategies to decrease syringe sharing.

METHODS

A mathematical model was developed to simulate HCV transmission amongst IDUs in London. Because of parameter uncertainty, numerical search algorithms were used to obtain different model fits to HCV seroprevalence data from London for 2002-03. These simulations were used to explore the likely impact of HCV prevention activities that reduce syringe sharing amongst all IDUs, IDUs that have injected for greater than one year, or IDUs with lower or higher frequencies of syringe sharing.

RESULTS

Key differences between model fits centred on how they simulated the high HCV incidence amongst new injectors, either through assuming increased HCV infectivity during acute infection, a large sub-group of high frequency syringe sharers, or increased sharing among new IDUs. Despite parameter uncertainty, the model projections suggest that modest reductions in syringe sharing frequency (<25%) will reduce the HCV seroprevalence in newly initiated IDUs (injecting less than four years) but much larger and sustained reductions (>50%) are required to reduce the HCV seroprevalence in long-term IDUs (injecting more than 8 years). Critically the model also suggested that large reductions in HCV seroprevalence will be achieved only if interventions target all IDUs and reach IDUs within 12 months of injecting.

DISCUSSION

Public health interventions must reduce syringe sharing amongst all IDUs, including newly initiated IDUs, and be sustained for many years to reduce HCV infection. More accurate data on key behavioural (sharing frequency) and biological (percentage of infected IDUs that clear infection) parameters is required to improve model projections.

Hepatitis C virus infection among injecting drug users in Scotland: a review of prevalence and incidence data and the methods used to generate them

It is estimated that of 50,000 persons in Scotland (1% of the county's population), infected with the hepatitis C virus (HCV), around 90% injected drugs. This paper reviews data on the prevalence and incidence of HCV, and the methods used to generate such information, among injecting drug users (IDUs), in Scotland. The prevalence estimate for HCV among IDUs in Scotland as a whole (44% in 2000), is comparable with those observed in many European countries. Incidence rates ranged from 11.9 to 28.4/100 person-years. The data have shaped policy to prevent infection among IDUs and have informed predictions of the number of HCV-infected IDUs who will likely progress to, and require treatment and care for, severe HCV-related liver disease. Although harm reduction interventions, in particular needle and syringe exchanges and methadone maintenance therapy, reduced the transmission of HCV among IDUs during the early to mid-1990s, incidence in many parts of the country remains high. The prevention of HCV among IDUs continues to be one of Scotland's major public health challenges.

Detection of HCV salivary antibodies by a simple and rapid test

Hepatitis C (HCV) is common in developing countries, where blood sampling and expensive sophisticated methods for detection are less available. Hemodialysis patients have high prevalence of HCV and may resemble sick populations in developing countries in relation to immunosuppression and antibodies production. For these reasons anti-HCV antibodies were assayed in saliva of hemodialysis patients by ImmunoComb II assay that is less laborious, relatively inexpensive and easy to perform If the findings are confirmed by larger studies this method may be useful especially in developing countries. Serum and saliva samples were obtained from 37 hemodialysis patients and assayed by ImmunoComb II kit. In positive PCR patients the saliva test had 100% sensitivity, which was as good as serum anti-HCV Axsym testing. Saliva testing had a similar or better specificity than the serum method.

The use of the OraSure® collection device for hepatitis virus testing in health care settings

Oral mucosal transudate (OMT) has levels of IgG and IgA that, although lower than in serum, are of the same specificity as serum. Blood can be a difficult sample to take especially from persons with an aversion to the process or with poor veins. There is also a small exposure risk to the phlebotomist. OMT has been shown to be useful in screening for a range of bloodborne viruses, however, the ELISA assays need to be modified, usually by increasing test volumes and incubation times and/or by modifying the substrate. A number of commercial serum kits have been modified successfully in this way. The major roles for these assays are for epidemiology or for screening high risk populations. If used for screening, it is imperative that any positive is confirmed by a serum test. The use of OMT samples using the OraSure(R) collection device, which is FDA approved and with which we have the most experience, has increased in recent years in community health care settings, with positive feedback from users.

Prevalence of, and risk factors for, hepatitis C virus infection among recent initiates to injecting in London and Glasgow: cross sectional analysis

Our aim was to compare the prevalence of antibody to hepatitis C virus (anti-HCV) among recently initiated injecting drug users (IDUs) in London and Glasgow, and to identify risk factors which could explain differences in prevalence between the cities. Complementary studies of community recruited IDUs who had initiated injection drug use since 1996 were conducted during 2001-2002. Data on HCV risk behaviours were gathered using structured questionnaires with identical core questions and respondents were asked to provide an oral fluid specimen which was tested anonymously for anti-HCV but was linked to the questionnaire. Sensitivities of the anti-HCV assays for oral fluid were 92-96%. Prevalence of anti-HCV was 35% (122/354) in London and 57% (207/366) in Glasgow (P < 0.001). Multifactorially, factors significantly associated with raised odds of anti-HCV positivity were increasing length of injecting career, daily injection, polydrug use, having had a needlestick injury, and having served a prison sentence. In addition lower odds of anti-HCV positivity were associated with non-injection use of crack cocaine and recruitment from drug agencies. After adjustment for these factors, the increased odds of anti-HCV associated with being a Glasgow IDU were diminished but remained significant. HCV continues to be transmitted among the IDU population of both cities at high rates despite the availability of syringe exchange and methadone maintenance. Effectiveness of harm reduction interventions may be compromised by inadequate coverage and failure to reduce sufficiently the frequency of sharing different types of injecting equipment, as well as the high background prevalence of HCV, and its high infectivity. Comprehensive action is urgently required to reduce the incidence of HCV among injectors.

Correlation between detection of antibodies against hepatitis C virus in oral fluid and hepatitis C virus RNA in serum

Reported here are the results of a study designed to determine the correlation between hepatitis C virus (HCV) RNA positivity in serum and the detection of antibodies against HCV in oral fluid by testing paired serum/oral fluid samples. For the 85 serum samples found positive for antibodies against HCV, using a screening assay and a confirmation assay, 70 of the corresponding oral fluid samples tested positive for HCV antibodies using a previously modified screening assay. For 52 of the 59 serum samples found positive for HCV RNA, the corresponding oral fluid samples also tested seropositive for HCV, while 18 of the 26 serum samples that were negative for HCV RNA had corresponding oral fluid samples that tested seropositive for HCV. For the control group of 54 serum samples that were negative for HCV antibodies, all of the corresponding oral fluid samples were also negative for HCV antibodies, while 53 of the serum samples tested negative for HCV RNA. These results suggest that HCV antibody detection in oral fluid has a slightly higher sensitivity when used to test patients whose serum samples are positive for HCV RNA (chi-square test, p=0.035; Mid-P exact, p=0.049).

Diagnosis of norwalk virus infection by indirect enzyme immunoassay detection of salivary antibodies to recombinant norwalk virus antigen

Simple diagnostic tests are needed for the detection of norovirus (NoV) outbreaks. Salivary antibody assays provide an attractive alternative to collecting and testing serum or stool samples. Antibodies to Norwalk virus (NV) in oral fluid samples were compared with NV antibodies in serum collected from 38 volunteers challenged with NV inoculum. Pre- and postchallenge (day 4, 8, 14, and 21) saliva and serum samples were examined by enzyme immunoassay (EIA) using recombinant NV antigen. Of 18 infected subjects (those who shed NV in stool or who demonstrated immunoglobulin G [IgG] seroconversion), 15 (83%) had > or =4-fold increases in NV-specific salivary IgA and 15 (83%) had > or =4-fold increases in NV-specific salivary IgG when prechallenge and postchallenge saliva samples were compared. When the results of the IgA and IgG assays were combined, all 18 infected subjects showed > or =4-fold increases in NV-specific salivary IgG or IgA postchallenge titers compared to their prechallenge titers. One of 19 uninfected subjects had a > or =4-fold increase in NV-specific salivary IgG. The sensitivity of the combined assay results was 100%, and the specificity was 95%. NV-specific salivary IgA titers peaked around 14 days postchallenge. NV-specific salivary IgG and serum IgG titers continued to rise through 21 days postchallenge. The application of this EIA to an elementary school outbreak indicated that 67% of the subjects with confirmed infections had >4-fold rises in anti-NoV IgA when an antigen in the same genetic cluster as the outbreak virus was used. This is the first documented mucosal antibody response to NoV in children. This EIA provides a useful approach for diagnosing NoV outbreaks.

Detection of HCV antibodies in oral fluid

Although conventionally the detection of HCV antibodies is carried out on serum, the collection of oral fluid is non-invasive, safe and cost effective. In this study, the efficacy of the detection of HCV antibodies in oral fluid was assessed. 73 anti-HCV positive and 73 anti-HCV negative paired serum/oral fluid samples, drawn from patients visiting a Belgian academic hospital, were tested using the modified Ortho HCV 3.0 and LIA confirmation assay. Performing the test on oral fluid with the modified protocol, 61/73 anti-HCV positive samples were tested positive, while 73/73 anti-HCV negative samples were tested negative, giving a sensitivity and specificity of 83.6% (95% CI: 72.7-90.9%) and 100.0% (95% CI: 93.8-100.0%), respectively. Comparing S/CO of concordantly positive and negative samples, the cut-off point was lowered by 30% resulting in a sensitivity of 89.0% (95% CI: 79.0-94.8%) while the specificity remained 100.0% (95% CI: 93.8-100.0%). The confirmation assay was carried out as described by the manufacturer, diluting the oral fluid 1:10. Testing paired samples gave a concordance of 85.6% (125/146), yielding no more accurate results. These findings suggested that the modified ELISA method for anti-HCV detection in oral fluid can be used for epidemiological surveys.

Validation of a modified commercial assay for the detection of rubella-specific IgG in oral fluid for use in population studies

Matching serum and oral fluid (saliva) samples were collected from 369 subjects in Tunisia in 2002, from a city in the north and a rural district in the south. Rubella-specific IgG was detected in sera by commercial ELISA (Dade Behring) and in matching oral fluids by two methods, a previously described IgG-capture ELISA (GACELISA) [J. Clin. Microbiol. 37 (1999) 391] and the Dade Behring ELISA with the assay protocol modified for use with oral fluids. Total IgG concentration of oral fluids was also measured. Rubella-specific IgG was detected in 289 (78.3%) sera overall. Differences in the age distribution of the study population in the north and south led to a higher prevalence being found in the north (86.2%) than in the south (71.8%). This difference was reflected in the oral fluid rubella-specific IgG results. With GACELISA, rubella-specific IgG was detected in 79.4% of oral fluids from the north and 69.7% from the south and with the modified Dade Behring assay, in 81.4% of oral fluids from the north and in 64.9% from the south. The sensitivity and specificity of GACELISA in comparison to results from the matching sera were 92.4 and 93.2%, respectively. The sensitivity and specificity of the modified Dade Behring ELISA were 89.8 and 92.0%, respectively. Total IgG concentration in oral fluid showed a weak correlation (r=0.19) with the modified Dade Behring results and with samples where total IgG was >7.5 mg/l, the sensitivity and specificity were 94.4 and 90.0%, respectively. Twenty-nine oral fluids, which gave false negative rubella-specific IgG results with the modified Dade Behring ELISA, had a lower mean total IgG concentration than 256 oral fluids which gave concordant positive results (7.0mg/l versus 15.8 mg/l, P<0.001). The study validated the modified Dade Behring ELISA, providing an alternative to the GACELISA for assessing levels of rubella immunity for population studies using oral fluid samples.

Evaluation of a modified commercial assay in detecting antibody to hepatitis C virus in oral fluids and dried blood spots

Oral fluid testing is an effective alternative to serum antibody testing for surveillance of human immunodeficiency virus (HIV) and hepatitis B infections, and is being extended to hepatitis C infections. The objective of this study was to determine and compare the sensitivity and specificity of a modified commercial assay for the detection of antibody to hepatitis C virus (anti-HCV) in oral fluids collected by two different oral fluid collection devices (the Epitope OraSure trade mark and Sarstedt Salivette ) and in dried fingerprick blood spots. In this study, 253 anti-HCV seropositive patients and 394 blood donors (all anti-HCV negative) were recruited between August 2000 and January 2001. Each participant provided oral fluid specimens by OraSure and Salivette, and at least one dried blood spot. Serum specimens were collected from the patients whenever possible. For those injecting drug users who did not provide a serum specimen, HCV status was established on the basis of previous testing. All the nonserum samples were tested for the presence of anti-HCV, using a modified Ortho HCV 3.0 SAVe enzyme-linked immunosorbent assay (ELISA) protocol. The recommended preliminary cutoffs for the modified ELISA were suboptimal. Further, the sensitivity, specificity, and positive and negative predictive values could be improved by varying the cutoff and taking into account the likely prevalence of HCV in the population under investigation. For instance, given a population with a 50% prevalence of anti-HCV, the optimal sensitivities of the modified assay on OraSure, Salivette, and dried blood spots were 92%, 83%, and virtually 100%, respectively, in contrast to 83%, 59%, and 99% using the preliminary cutoffs. The respective optimal specificities were 99%, 93%, and 100%. In conclusion, oral fluids collected by the OraSure device provide an extremely useful method to conduct public health surveillance of not only HIV, but also hepatitis C, among injecting drug users. In addition, dried blood spot specimens may be useful for surveillance and could be employed as a first line diagnostic specimen.

Recognition of multiple classes of hepatitis C antibodies increases detection sensitivity in oral fluid

Paired serum-oral fluid samples from 127 hepatitis C virus (HCV)-positive and 31 HCV-negative patients were tested for the presence of anti-HCV using the Ortho HCV 3.0 ELISA. Using the immunoglobulin G (IgG)-specific detection antibody provided with the HCV 3.0 ELISA we attained 100% sensitivity and specificity with serum samples; however, sensitivity in oral fluid samples was only 81%. By modifying the HCV 3.0 ELISA to utilize a secondary antibody cocktail that recognizes not only IgG but IgA and IgM as well, we attained 100% specificity and sensitivity with oral fluid samples.

Prevalence of hepatitis C among injection drug users in England and Wales: is harm reduction working?

OBJECTIVES

This study sought to establish the prevalence of hepatitis C antibodies (anti-HCV) and hepatitis B antibodies (anti-HBc) among injection drug users in England and Wales.

METHODS

A voluntary cross-sectional survey collected oral fluid samples and behavioral information; 2203 injectors were recruited through drug agencies, and 758 were recruited in the community.

RESULTS

Prevalence was 30% for anti-HCV, 21% for anti-HBc, and 0.9% for HIV antibodies. Anti-HCV prevalence rates were significantly greater among those with longer injecting careers, those in older age groups, those residing in London, those recruited in drug agencies, those positive for anti-HBc, and those with a previous voluntary HIV test.

CONCLUSIONS

Anti-HCV prevalence rates among injectors in England and Wales, where comprehensive harm reduction programs exist, are lower than rates in other industrialized countries.

Rheumatic disorders associated with hepatitis C

The hepatitis C virus (HCV) is a common virus of world-wide distribution affecting up to 3% of the world's population. Its genetic diversity, with multiple subtypes, and existence in the form of quasispecies in individual hosts, is, in part, responsible for high rates of chronic infection. Individuals with HCV infection will undoubtedly present to rheumatologists and other health care professionals with rheumatic and other immunological disorders related to what was usually a remote and asymptomatic acute infection. The goals of this review are: (1) to summarize clinical observations regarding rheumatological and immunological diseases linked with HCV infection; (2) to provide relevant information on the molecular biology of HCV; (3) to discuss the state of the art regarding the use of diagnostic studies; (4) to consider the differential diagnosis of liver disease and rheumatic disorders; and (5) to provide a practical guide to the history, physical examination, laboratory work-up, disease monitoring, and therapy of HCV patients with rheumatic disorders.

Prevalence of hepatitis C virus infection among injecting drug users in Glasgow 1990-1996: are current harm reduction strategies working?

OBJECTIVES

To determine the prevalence of HCV antibodies among injecting drug users and to gauge the effectiveness of needle/syringe exchange in preventing the transmission of HCV infection.

METHODS

Between 1990-1994 and in 1996, annual cross-sectional surveys of injecting drug users in Glasgow were conducted. In order to ensure as representative a sample as possible, the 1949 respondents were recruited from both 'in-treatment' and 'out-of treatment' settings. Injectors were interviewed about their risk behaviours for blood-borne viruses and provided a saliva sample which was initially tested, anonymously, for HIV antibodies, and subsequently tested for hepatitis C infection.

RESULTS

Among 1949 injectors, the prevalence of salivary antibodies, indicative of hepatitis C viraemia, was 61%(95%, confidence interval (CI) 59%-63%): the estimated prevalence of serum antibody positivity was 72%. Length of injecting, year of commencing drug injecting and the number of times in prison were predictive of antibody positivity. Thirty-one per cent of injectors who commenced their injecting after 1992, following the full establishment of needle/syringe exchange in the city, were salivary antibody positive, and the majority of their infections were acquired outside the prison setting. Respondents who began injecting after the introduction of needle/syringe exchange in the city were significantly less likely to test HCV antibody positive than those who commenced injecting prior to the advent of needle/syringe exchange, after adjusting for length of injecting career.

CONCLUSION

The prevalence of HCV among injectors in Glasgow has decreased during the era of needle/syringe exchange. However, there is evidence to suggest that the incidence of infection remains high. Since the prevalence of hepatitis C viraemia among the city's injecting population is extremely high, ongoing transmission is inevitable unless more effective interventions are identified and implemented urgently.

Hepatitis C antibody detection in dried blood spots

In the UK, there have been few studies of the seroprevalence of antibodies to hepatitis C virus (anti-HCV). As part of an ongoing prevalence study of HCV in injecting drug users, we have developed a technique for detecting anti-HCV in blood spots dried on filter paper using a commercially available assay. Subjects with and without serum anti-HCV were studied. The manufacturer's recommended cut-off (CO) for a positive anti-HCV result is kit-dependent, and therefore a ratio of test result (T) to kit CO was used to standardize results. T/CO values greater than 0.99 had a sensitivity of 100% and a specificity of 87.5% for anti-HCV detection. T/CO values greater than 1.99 had a sensitivity of 97.2% and a specificity of 100%. Hence, testing dried blood spots may be useful for detecting anti-HCV in epidemiological studies and as a diagnostic test in patients with poor peripheral venous access.