Preliminary report: accurate assays for anti-HIV in urine

An innovative HIV testing service using the internet: Anonymous urine delivery testing service at drugstores in Beijing, China

Innovative human immunodeficiency virus (HIV) testing services will be needed to achieve the first 90 (90% of HIV-positive persons aware of their infection status) of the 90-90-90 target in China. Here, we describe an internet-based urine delivery testing service delivered through three pilot drugstores in Beijing that send specimens to a designated laboratory for HIV. From May 2016 to January 2017, we provided 500 HIV urine-testing service packs for display at the drugstores, and a total of 430 (86.0%) urine specimens were mailed back. All of the 430 urine specimens were of good quality and were tested. 70 urine specimens were HIV positive, showing a 16.3% (70/430) positivity rate. A total of 94.3% (66/70) of the HIV-positive participants obtained their test results through the internet, and 69.7% (46/66) of these participants received follow-up care. A total of 40 out of 46 (87.0%) participants agreed to have their results confirmed by a blood test, and 39 out of 40 (97.5%) participants were confirmed as HIV-1 positive, including two individuals that were previously diagnosed. Lastly, 28 out of 37 (75.7%) of the study participants were referred to the hospital and provided free antiviral treatment. Our data indicate that this innovative HIV testing service is effective and play an important role in HIV testing and surveillance.

Prevalence, risk factors, and uptake of interventions for sexually transmitted infections in Britain: findings from the National Surveys of Sexual Attitudes and Lifestyles (Natsal)

BACKGROUND

Population-based estimates of prevalence, risk distribution, and intervention uptake inform delivery of control programmes for sexually transmitted infections (STIs). We undertook the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3) after implementation of national sexual health strategies, and describe the epidemiology of four STIs in Britain (England, Scotland, and Wales) and the uptake of interventions.

METHODS

Between Sept 6, 2010 and Aug 31, 2012, we did a probability sample survey of 15,162 women and men aged 16-74 years in Britain. Participants were interviewed with computer-assisted face-to-face and self-completion questionnaires. Urine from a sample of participants aged 16-44 years who reported at least one sexual partner over the lifetime was tested for the presence of Chlamydia trachomatis, type-specific human papillomavirus (HPV), Neisseria gonorrhoeae, and HIV antibody. We describe age-specific and sex-specific prevalences of infection and intervention uptake, in relation to demographic and behavioural factors, and explore changes since Natsal-1 (1990-91) and Natsal-2 (1999-2001).

FINDINGS

Of 8047 eligible participants invited to provide a urine sample, 4828 (60%) agreed. We excluded 278 samples, leaving 4550 (94%) participants with STI test results. Chlamydia prevalence was 1·5% (95% CI 1·1-2·0) in women and 1·1% (0·7-1·6) in men. Prevalences in individuals aged 16-24 years were 3·1% (2·2-4·3) in women and 2·3% (1·5-3·4) in men. Area-level deprivation and higher numbers of partners, especially without use of condoms, were risk factors. However, 60·4% (45·5-73·7) of chlamydia in women and 43·3% (25·9-62·5) in men was in individuals who had had one partner in the past year. Among sexually active 16-24-year-olds, 54·2% (51·4-56·9) of women and 34·6% (31·8-37·4) of men reported testing for chlamydia in the past year, with testing higher in those with more partners. High-risk HPV was detected in 15·9% (14·4-17·5) of women, similar to in Natsal-2. Coverage of HPV catch-up vaccination was 61·5% (58·2-64·7). Prevalence of HPV types 16 and 18 in women aged 18-20 years was lower in Natsal-3 than Natsal-2 (5·8% [3·9-8·6] vs 11·3% [6·8-18·2]; age-adjusted odds ratio 0·44 [0·21-0·94]). Gonorrhoea (<0·1% prevalence in women and men) and HIV (0·1% prevalence in women and 0·2% in men) were uncommon and restricted to participants with recognised high-risk factors. Since Natsal-2, substantial increases were noted in attendance at sexual health clinics (from 6·7% to 21·4% in women and from 7·7% to 19·6% in men) and HIV testing (from 8·7% to 27·6% in women and from 9·2% to 16·9% in men) in the past 5 years.

INTERPRETATION

STIs were distributed heterogeneously, requiring general and infection-specific interventions. Increases in testing and attendance at sexual health clinics, especially in people at highest risk, are encouraging. However, STIs persist both in individuals accessing and those not accessing services. Our findings provide empirical evidence to inform future sexual health interventions and services.

FUNDING

Grants from the UK Medical Research Council and the Wellcome Trust, with support from the Economic and Social Research Council and the Department of Health.

Oral fluid for the serological and molecular diagnosis of measles

OBJECTIVES

Since measles presents mostly in children, a non-invasive sample collection technique such as oral fluid sampling would be very useful in the early detection of measles RNA and antibodies. The aim of this study was to validate the detection of anti-measles IgM and measles virus RNA in oral fluid and to make a comparison with the gold standard methods of ELISA using serum (Enzygnost(®) anti-Measles IgM) and in-house nested reverse transcriptase polymerase chain reaction (RT-PCR) using nasopharyngeal secretions.

METHODS

Three samples each from 73 measles-positive and 44 measles-negative subjects (serum, oral fluid, and nasopharyngeal secretions) were analyzed.

RESULTS

The anti-measles IgM ELISA (MicroImmune) on oral fluid was validated against the IgM ELISA (Siemens) for serum and this resulted in a sensitivity of 92% and specificity of 100%. A molecular nested RT-PCR using oral fluid was validated against the standard assay on nasopharyngeal secretions and gave a sensitivity of 100% and specificity of 100%.

CONCLUSIONS

The results confirm that both serological and molecular oral fluid assays are suitable for routine use. The use of oral fluid samples for the detection of measles virus may encourage patients, general practitioners, and pediatricians to participate in the Belgian measles surveillance system and other epidemiological studies in the framework of the World Health Organization elimination program.

Biological and behavioural impact of an adolescent sexual health intervention in Tanzania: a community-randomized trial

OBJECTIVE

The impact of a multicomponent intervention programme on the sexual health of adolescents was assessed in rural Tanzania.

DESIGN

A community-randomized trial.

METHODS

Twenty communities were randomly allocated to receive either a specially designed programme of interventions (intervention group) or standard activities (comparison group). The intervention had four components: community activities; teacher-led, peer-assisted sexual health education in years 5-7 of primary school; training and supervision of health workers to provide 'youth-friendly' sexual health services; and peer condom social marketing. Impacts on HIV incidence, herpes simplex virus 2 (HSV2) and other sexual health outcomes were evaluated over approximately 3 years in 9645 adolescents recruited in late 1998 before entering years 5, 6 or 7 of primary school.

RESULTS

The intervention had a significant impact on knowledge and reported attitudes, reported sexually transmitted infection symptoms, and several behavioural outcomes. Only five HIV seroconversions occurred in boys, whereas in girls the adjusted rate ratio (intervention versus comparison) was 0.75 [95% confidence interval (CI) 0.34, 1.66]. Overall HSV2 prevalences at follow-up were 11.9% in male and 21.1% in female participants, with adjusted prevalence ratios of 0.92 (CI 0.69, 1.22) and 1.05 (CI 0.83, 1.32), respectively. There was no consistent beneficial or adverse impact on other biological outcomes. The beneficial impact on knowledge and reported attitudes was confirmed by results of a school examination in a separate group of students in mid-2002.

CONCLUSION

The intervention substantially improved knowledge, reported attitudes and some reported sexual behaviours, especially in boys, but had no consistent impact on biological outcomes within the 3-year trial period.

A population-based prevalence study of hepatitis A, B and C virus using oral fluid in Flanders, Belgium

Ten years after the first seroprevalence study performed in Flanders, the aim of this cross sectional study was to follow the evolution of hepatitis A, B and C prevalence. The prevalence of hepatitis A antibodies, hepatitis B surface antigen and hepatitis C antibodies was measured in oral fluid samples collected by postal survey. Using the National Population Register, an incremental sampling plan was developed to obtain a representative sampling of the general population. A total of 24,000 persons were selected and 6,000 persons among them contacted in a first wave. With 1834 participants a response rate of 30.6% was achieved. The prevalence was weighted for age and was 20.2% (95% CI 19.43-21.08) for hepatitis A, 0.66% (95% CI 0.51-0.84) for hepatitis B surface antigen and 0.12% (95% CI 0.09-0.39) for hepatitis C. The prevalence of hepatitis A and C in the Flemish population is lower in 2003 compared with the results of the study performed in 1993. The difference may be due to a real decrease of the diseases but also to differences in the methodology. The prevalence of hepatitis B surface antigen remains stable. Considering the 30% response rate and the high quality of the self-collected samples as reflect of a good participation of the general population, saliva test for prevalence study is a good epidemiological monitoring tool.

Sexually transmitted Chlamydia trachomatis, Neisseria gonorrhoeae, and HIV-1 infections in two at-risk populations in Barcelona: female street prostitutes and STI clinic attendees

OBJECTIVE

To determine the prevalence of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), and HIV-1 infections in female street prostitutes and STI clinic attendees in Barcelona.

DESIGN

This was a prospective study carried out in two four-month periods over two years. Urine specimens were tested for CT and NG using a PCR pooling algorithm. Among street prostitutes HIV-1 testing in urine was also carried out.

RESULTS

The prevalences of CT, NG, and HIV-1 in female street prostitutes (n=301) were 4.7%, 3.7%, and 1.0%, respectively. Women from Eastern Europe had the highest prevalence of CT (p=0.01). Prevalences of CT, NG, and HIV-1 among all clinic attendees (n=536) were 4.3%, 4.5%, and 4.4%, respectively. Prevalence of HIV-1 infection among homosexual men was higher compared with heterosexual men and women (p<0.001).

CONCLUSIONS

Overall CT prevalence is currently lower than in other European countries, although it could increase as a result of immigration. Rates of HIV-1 and of NG are higher among homosexual than among heterosexual men.

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.

Oral fluid as a medium for the detection of hepatitis B surface antigen

Currently viral antigens and antibodies are detected by traditional serological tests. However, the introduction of oral fluid as an alternative medium would allow other alternatives. The collection of oral fluid is, in comparison with venepuncture, less invasive, less painful, less expensive (i.e., no trained personal required), and safe (prevention of needle stick injuries). Also large numbers of samples can be collected easily for epidemiological purposes. Forty-three HBsAg positive and seventy-three HBsAg negative paired serum/oral fluid samples were tested. They were collected from patients attending university hospitals. The oral fluid samples were collected using the Oracol collection device and they were subjected to an IgG quantification assay to ensure their quality and quantity. The detection of HBsAg in oral fluid was carried out using a modified ETI-MAK-4 ELISA. The validation of this oral fluid test gave a sensitivity and specificity of 90.7% and 100%, respectively. The modified ETI-MAK-4 ELISA is a suitable test for oral fluid samples collected by the Oracol collection device for epidemiological purposes.

Detection of antibody to HIV in saliva: a brief review

BACKGROUND

The possibility that saliva could be used for HIV screening and diagnosis has been known since 1986. Despite the obvious advantages over venepuncture of ease of collection, safety, compliance and cost, interest in salivary testing has grown relatively slowly. Several studies have demonstrated that salivary anti-HIV testing can be highly accurate, particularly if specimen collection procedure are optimal.

OBJECTIVE

To review current knowledge about the detection of anti-HIV in oral fluids, with an emphasis on the identification of optimal procedures.

STUDY DESIGN

In the light of existing published data, the factors leading to accurate salivary diagnosis of HIV infection were identified and reviewed.

RESULTS

To achieve the best results it is essential to collect oral fluid specimens that are rich in IgG. Most IgG in the oral cavity derives from the crevicular space between the gums and the teeth, and not from salivary glands. Available methods for collecting salivary specimens are discussed. Until these collection methods are fully validated, individual specimens or at least clinical ones found anti-HIV negative should be tested for total IgG before being reported on. There is a lack of proven confirmatory methods for salivary anti-HIV and this problem is reviewed. Salivary anti-HIV testing has been employed mostly for surveillance, but life insurance applicants are increasingly screened in this way and clinical applications are under active consideration. With appropriate safeguards, diagnostic and pre-blood donation salivary testing could be introduced shortly. The necessary technology is also available to develop rapid single-use salivary tests. This would bring anti-HIV testing closer to the patient.

CONCLUSIONS

Salivary tests for anti-HIV offer advantages of convenience, economy and safety, and are more acceptable to subjects than blood tests. Further evaluation of the collection devices and assays, the introduction of safeguards against inadequate sampling and the development of suitable confirmatory assays are required. When these deficiencies have been met, salivary tests may supersede tests on serum for HIV and also other infections.

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.

Evaluation of a commercial enzyme immunoassay for HIV screening in urine

A cross-sectional study was conducted to evaluate the utility of a commercial enzyme immunoassay (EIA) as a screening test for detecting HIV-1 antibody in urine in a population at risk for HIV infection in Catalonia, Spain. Paired urine and serum samples were collected consecutively from 99 patients who attended two drug-dependency treatment centres and 151 patients who attended a sexually transmitted diseases (STD) clinic in Barcelona. Antibodies against HIV in urine samples were detected using the Calypte HIV-1 Urine EIA (Calypte Biomedical Corporation, Berkeley, CA, USA) and confirmed by urine-based Western blot (WB) analysis. Sera were analysed using Bioelisa HIV-1+2 EIA (Biokit Laboratories, Barcelona, Spain), and the results were verified using serum-based WB analysis. Results of both urine and serum testing were available for 246 of 250 participants. For 52 individuals the results of both urine and serum testing were positive and for five the results were discordant (2 with urine-negative/serum-positive results and 3 with urine-positive/serum-negative results). The respective sensitivity and specificity values obtained for the urine EIA were 100% and 96.2% for intravenous drug users (IDUs) and 80% and 99.3% for persons attending the STD clinic. According to the 1997 UNAIDS/WHO strategy I recommendations, these values are acceptable for surveillance purposes, particularly in populations with a high prevalence of HIV infection.

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.

Anti-hepatitis A virus immunoglobulin M antibodies in urine samples for rapid diagnosis of outbreaks

The main goal of this study was to test the feasibility of using urine for diagnosing hepatitis A virus (HAV) infections. A correlation of 90.78% between the test results of urine and serum samples was obtained. Four outbreaks of hepatitis A were confirmed by testing only urine samples. The levels of anti-HAV immunoglobulin M (IgM) antibodies in urine samples remained stable during 6 months of storage at -70 degrees C but decreased when the samples were stored at 4 degrees C. The results of tests of samples obtained 2 and 6 months after infection suggested that IgM levels decline more rapidly in urine than in serum.

School based HIV prevention in Zimbabwe: feasibility and acceptability of evaluation trials using biological outcomes

OBJECTIVE

To determine the feasibility and acceptability of conducting a community randomized trial (CRT) of an adolescent reproductive health intervention (ARHI) using biological measures of effectiveness.

SETTING

Four secondary schools and surrounding communities in rural Zimbabwe.

METHODS

Discussions were held with pupils, parents, teachers and community leaders to determine acceptability. A questionnaire and urine sampling survey was undertaken among Form 1 and 2 pupils. Studies were undertaken to inform likely participation and follow up in a future CRT. A community survey of 16-19-year-olds was conducted to determine levels of secondary school attendance and likely HIV prevalence at final follow up in the event of a trial.

RESULTS

Form 1 and 2 pupils aged 12-18 years (n = 723; median age, 15 years) participated in the research. Prevalences of HIV, Chlamydia and gonorrhoea were 3.6% [95% confidence interval (CI), 2.3-5.3%], 0.4% (95% CI, 0.1-1.3%) and 1.9% (95% CI, 1.0-3.3%) respectively. There was poor correlation between biological evidence of sexual experience and questionnaire responses, due to concerns about confidentiality. Only 13% (95% CI, 4-27%) of those infected with HIV and/or a sexually transmitted disease admitted to having had sex. In the community survey of 573 adolescents aged 16-19 years, 6.6% (95% CI, 3.9-10.3%) of females and 5.1% (95% CI, 2.9-8.2%) of males were HIV positive. High participation and retention rates are achievable within a trial in this setting.

CONCLUSIONS

It is acceptable and feasible to conduct randomized trials to establish the effectiveness of ARHIs. However, self-reported behavioural outcomes will probably be biased, emphasizing the importance of using externally validated biological outcome measures to determine effectiveness.

Stability of total and rubella-specific IgG in oral fluid samples: the effect of time and temperature

Oral fluid (saliva) samples are increasingly used as a minimally invasive alternative to serum to detect antibody for viral diagnostics and population-based surveys of immunity to common infections. Postal collection of these samples is convenient, but it is uncertain how oral fluid antibody levels may deteriorate during transit. In this study multiple oral fluid samples, from a group of individuals, were collected and kept at two different temperatures (10 and 20 degrees C, simulating winter and summer conditions ) for periods of up to 7 days. They were then tested for total immunoglobulin G (IgG) and for rubella-specific IgG. Total IgG concentrations ranged from 2.0 to 48.6 mg/l but showed no significant decrease over the 7-day period. There was also no significant change in rubella-specific IgG measured using an antibody capture ELISA, but testing with an indirect rubella IgG ELISA revealed a significant decrease in absorbance values between day 1 and day 7 at 20 degrees C. The difference in the rubella assay results may reflect the different assay formats with the signal in the indirect procedure related to the concentration of rubella IgG in the oral fluid sample, rather than the proportion of virus-specific IgG measured with the antibody capture format. The study demonstrated that total and rubella specific IgG in oral fluid samples were stable for up to 7 days at differing temperatures and that an antibody capture assay format should be used for virus-specific testing to minimise inaccurate results due to low IgG concentrations in oral fluid samples.

Diagnostic detection of human immunodeficiency virus type 1 antibodies in urine: a brazilian study

We evaluated, for the first time in Latin America, the performance of a commercial enzyme immunoassay (EIA) (Calypte Biomedical Corporation, Berkeley, Calif.) that detects human immunodeficiency virus type 1 (HIV-1)-specific antibodies in urine in comparison to standard serological assays (two commercial EIAs and a commercial Western blot [WB] assay). Paired serum and urine specimens were collected from two different groups of Brazilian patients: 225 drug users with unknown HIV status who attended drug treatment centers in Rio de Janeiro, Brazil, and 135 subjects with known HIV status. Patients showing positive results in the serum EIAs and/or in the urine EIA were serologically confirmed by WB assay. For 135 individuals with known HIV status, the urine EIA showed 100% sensitivity (74 positive samples) and 95.1% specificity (58 of 61 negative specimens). For 225 drug users, the test showed 100% sensitivity (2 positive samples) and 98.7% specificity (220 of 223 negative samples) compared to WB-confirmed serological EIA results. Thus, in a total of 360 samples, the urine EIA correctly identified all 76 HIV-positive samples and 278 of 284 negative samples (100% sensitivity and 97.9% specificity). Detailed analysis of the urine EIA results indicates that an increase of the recommended cutoff value might raise the specificity of the assay without affecting its sensitivity. Our results suggest that the HIV-1 urine EIA is a good screening test suitable for developing countries like Brazil. However, as for all other HIV screening tests on the market, it is not specific enough to be used as a one-step test and therefore requires confirmation.

Mucosal immunity and primary biliary cirrhosis: presence of antimitochondrial antibodies in urine

We have shown that IgA-class antimitochondrial autoantibodies (AMA) can be detected in the bile and saliva of patients with PBC, suggesting that AMA are secreted into the luminal fluid across bile ducts and salivary glands. These data prompted us to determine whether AMA of the IgA isotype may be transported across other epithelial mucosa. Therefore, we tested for the presence of AMA in the urine specimens of 83 patients with PBC and 58 non-PBC controls including healthy individuals and patients with other liver diseases. Patients enrolled in this study had no history of renal disease, and we confirmed there was less than 50 microgram/mL of protein in each of the urine specimens. Interestingly, we found that AMA were present in the urine of 71/83 (86%) of all patients with PBC and in 71/78 (91%) of patients with PBC that were serum AMA positive. In contrast, AMA were not detected in any of the 58 control urine specimens. Of particular interest, AMA of the IgA isotype was present in 57/83 (69%) of patients with PBC, and in 52 of these 57, we found secretory-type IgA. In a nested random subgroup of urine samples, the prevalence of the IgA2 AMA was 6/18 (33%), significantly lower than in matched serum samples, 13/16 (81%, P =.007). These data show that AMA of the IgA isotype is secreted into urine from the uroepithelium of patients with PBC, and support the thesis that PBC originated from either a mucosal challenge or a loss of mucosal tolerance.

Diagnosis of rubella infection by detecting specific immunoglobulin M antibodies in saliva samples: a clinic-based study in Niterói, RJ, Brazil

This study was designed to investigate whether saliva could be a feasible alternative to serum for the diagnosis of recent rubella infection in a clinic setting. Forty-five paired blood and saliva samples collected 1 to 29 days after onset of illness were tested for specific immunoglobulin (Ig) M by antibody-capture radioimmunoassay (MACRIA). Rubella IgM was detected in all serum samples and in 38 (84.4%) saliva specimens. Forty-six serum and saliva samples from other patients with rash diseases were tested by MACRIA for control purposes and two saliva specimens were reactive. The saliva test had specificity of 96%. These results indicate that salivary IgM detection may be a convenient non-invasive alternative to serum for investigation of recent rubella cases, especially for disease surveillance and control programmes.

Detection of measles specific IgG in oral fluid using an FITC/anti-FITC IgG capture enzyme linked immunosorbent assay (GACELISA)

An IgG antibody capture enzyme linked immunosorbent assay (GACELISA) for the detection of measles specific IgG in oral fluid was developed using an FITC/anti-FITC amplification system. The GACELISA was evaluated by testing paired oral fluid and serum samples from 787 subjects in an epidemiological study of measles in rural Ethiopia. Oral fluids were tested by GACELISA and corresponding serum samples by a sensitive indirect ELISA for measles IgG (Behring Enzygnost). By comparison with the serum measles IgG assay, the oral fluid GACELISA had a sensitivity of 97.4% (95% confidence intervals: 95.9, 98.2) and a specificity of 90.0% (81.9, 94.3), with no significant differences observed by age group. Total IgG concentrations were measured on a subset of 160 oral fluids by an in-house ELISA. This showed that false negative GACELISA results tended to occur in samples with low concentrations of total IgG, although the trend was not statistically significant. It is concluded that the overall performance of the GACELISA was satisfactory, showing close agreement to the serum ELISA, and has potential to serve as an easily transferable tool for large scale epidemiological studies as required for the World Health Organisation's programme for the global control of measles.

Detection of antibodies against hepatitis A virus in eluates of blood spotted on filter-paper: a pilot study in Rio de Janeiro, Brazil

The validity of blood spotted on to filter-paper (BSOFP) eluates for the detection of antibodies against hepatitis A virus (HAV) was investigated in 718 individuals (children and adults) during a field study in a small area in Rio de Janeiro State, Brazil. Serum samples were considered the 'gold standard'. BSOFP eluates were analyzed by 2 different techniques: microplate competitive enzyme-linked immunosorbent assay (ELISA) of the whole study group and microparticle enzyme immune assay (MEIA) of a subsample of 59 individuals. For BSOFP eluates by ELISA, sensitivity and specificity were 89.6% (95% CI: 84.7-93.1) and 97.5% (95% CI: 95.6-98.7), respectively. For a seroprevalence of anti-HAV antibodies of 32%, the positive predictive value was 94.5% (95% CI: 90.3-97.0) and the negative predictive value was 95.2% (95% CI: 92.8-96.8). The test efficiency was 95.0% (95% CI: 93.1-96.4). Similar results were found for BSOFP eluates by MEIA. Agreement between the 2 techniques used for BSOFP (ELISA and MEIA) was also high (kappa = 0.93). These results encourage the more widespread application of BSOFP as a means of surveillance for large-scale epidemiological studies for hepatitis A.

Detection of IgG antibody to bovine leukaemia virus in urine and serum by two enzyme immunoassays

Four hundred blood sera from a cattle production unit were tested for BLV-(Bovine Leukaemia Virus) antibody with IP (Institut Porquier) and SB (Svanova Biotech) ELISA kits. Seventy-seven cattle with BLV-antibody (19.25%) and 77 without the antibody were used. No significant difference was found between O.D. of sera of PL+ (Persistent Lymphocytosis Positive) and PL- (Negative) cattle. The mean O.D. of urine samples of 77 seropositive cattle was significantly higher than that of 77 seronegative cattle (P < 0.01). There were also differences between urine O.D.s of seropositive (PL+) and seropositive (PL-) groups of cattle with IP (P < 0.05) and SB (P < 0.01) kits. All the results revealed the presence of BLV-antibody in the urine of the cattle without any urinary dysfunction.

Human immunodeficiency virus antibody testing by enzyme-linked fluorescent and western blot assays using serum, gingival-crevicular transudate, and urine samples

The aim of the present study was to evaluate the possible utilization of saliva and urine as alternative samples to serum for the diagnosis of human immunodeficiency virus (HIV) infection. A total of 302 individuals participated in the study: 187 HIV-infected individuals (106 had Centers for Disease Control and Prevention [CDC] stage II infection, 19 had CDC stage III infection, and 62 had CDC stage IV infection) and 115 noninfected persons (46 of the noninfected persons were blood donors and 69 belonged to a group at high risk of HIV infection). Paired saliva and urine samples were taken from each of the participants in the study. The presence of HIV-specific antibodies was detected by an enzyme-linked fluorescent assay (ELFA), and the result was confirmed by Western blot analysis (WB). The ELFA with saliva gave maximum sensitivity and specificity values, while ELFA had lower sensitivity (95.2%) and specificity (97. 4%) values for detection of HIV antibody in urine samples. WB with all saliva samples fulfilled the World Health Organization criterion for positivity, while only 96.8% of the urine samples were confirmed to be positive by WB. Among the four reactivity patterns found by WB of these alternative samples, the most frequent included bands against three groups of HIV structural proteins (was ENV, POL, and GAG). The reactivity bands most frequently observed were those for the proteins gp160 and gp120. The least common reactivity band was the band for protein p17. The detection of HIV antibodies in saliva samples by means of ELFA with the possibility of later confirmation by WB makes saliva an alternative to serum for possible use in the diagnosis of infection. In contrast, HIV antibody detection in urine samples by the same methodology (ELFA) could be taken into consideration for use in epidemiological studies.

[Prevalence of human immunodeficiency virus and risk behaviours among opioid users seen in an emergency room]

INTRODUCTION

As prevalence of HIV-1 among drug users in Spain is high and it is difficult to contact them because of their hidden behaviors, emergency rooms are one of the health facilities where they can be located. A cross-sectional interview study was planned. The aims of the study were to estimate prevalence of HIV-1 and to describe risk behaviors.

METHODS

The sample included all patients that in spring 1992 were detected and referred by the doctor as being current opiate users, defined as any use in the 30 days prior the interview. Drug users who did not know their HIV status or were negative for more than six months were asked to provide a urine sample to test HIV serology. A descriptive analysis with simple stratification was carried out. Row and adjusted odds ratio were used to analyse association between different variables and HIV status. Logistic regression was used to examine variables associated with HIV infection and risk behaviors (injecting drug use, sharing needles, and no use of condom).

RESULTS

Three hundred and eighty three opiate users were interviewed. It was possible to know HIV status of 94% of the subjects. Of them, 61% were positive (219). The best adjusted logistic model to predict associated variables with HIV included being female, primary school level, sickness absence, to attend because of organic pathology, and more years of parenteral use. Seventy five percent of the sample injected drugs during the past 30 days, and among them 30% shared syringes. The variables associated with a higher probability of having injected heroin or cocaine in the last 30 days were to have completed at least primary education, to be unemployed or reliant on illegal activities, not to be in drug treatment, and a larger number of drugs used in the last 30 days. A higher probability of sharing syringes was associated with a lower educational level, not to be in drug treatment, to live alone and a higher number of drugs used during last 30 days. Twenty one percent of the subjects who were sexually active always or nearly always used condom with regular partners and 56% with casual partners. Women were more likely to use condom than men with casual partners. Subjects who shared syringes during last 30 days were nearly three times more likely not to use condom with casual partners.

CONCLUSIONS

Although a high prevalence of HIV-1 was estimated among opioid users seen in an emergency room, it is not higher than estimates for intravenous drug users recruited from treatment centres, prison or needles exchange programs. A high frequency of risk behavior was also observed indicating a need to develop specific prevention programs for drug users.

A comparison of oral fluid and serum for the detection of rubella-specific antibodies in a community study in Addis Ababa, Ethiopia

OBJECTIVE

To assess the utility of oral fluid compared with serum for the determination of age-prevalence of rubella-specific antibodies in an urban African community setting.

METHOD

Paired serum and oral fluid samples were collected from 439 individuals aged 0-49 years in Addis Ababa, Ethiopia, as part of a larger seroepidemiological survey in 1994. Oral fluid was sampled using a simple sponge device that was well accepted by subjects of all ages; venous blood was collected by Vacutainer system. We measured rubella-specific antibodies in serum by the Radial Haemolysis (RH) test, supported by two confirmatory assays, and in oral fluid by IgG antibody-capture radioimmunoassay (GACRIA).

RESULTS

Sensitivity and specificity of oral fluid results compared to serum were 89% and 76%, respectively. Sensitivity declined from 96% in age group 0-19 years to 90% in age group 20-29 and 78% in age group 30-49. Specificity was 86% in 0-9 year olds contrasting with 61% in older groups (10-49 years). The positive predictive value of an oral fluid sample was high in all age groups (range 92-100%), while the negative predictive value declined from > or =80% in those aged <10 years to <10% in those aged > or =30 years. Serum confirmatory tests suggested a proportion of false serum RH negatives, increasing with age, indicating a need to standardize serum as well as oral fluid tests.

CONCLUSION

In the community setting of a developing country, oral fluid surveys could be useful to estimate age-prevalence of rubella immunity and identify rubella-susceptible children for follow-up. Further work is required to simplify assays and sample processing, improve assay sensitivity and estimate assay specificity more precisely, and compare and standardise collection methods suitable for surveillance of a variety of childhood viral infections.

HIV infection among family planning clinic attenders in Glasgow: why prevalence has remained low in this general population group

OBJECTIVE

During 1991-2, unlinked anonymous testing of dried blood spots from neonatal metabolic screening cards showed the prevalence of HIV among childbearing women from Glasgow to be extremely low at 0.01%. A study was conducted to determine if non-pregnant sexually active women who engaged in unprotected sexual intercourse were more likely to be infected than those who were pregnant.

METHODS

Unlinked anonymous HIV testing of urine specimens submitted by attenders of the family planning clinic in Glasgow for pregnancy testing.

RESULTS

Of 11,990 urine specimens tested, 7664 were from women with a negative pregnancy test and two of these were HIV positive (0.026%); none of the remainder from those with a positive pregnancy test had HIV antibodies.

CONCLUSION

No hidden epidemic was unearthed among a population which had engaged in unprotected sexual intercourse and was not pregnant. Other data from Glasgow strongly suggest that the control of HIV transmission among the city's population of current injectors (HIV prevalence, 1% of 8500) has prevented the spread of infection into its wider heterosexual population. It is essential that preventive measures which have been responsible for this public health success should be maintained.

Urine samples as a possible alternative to serum for human immunodeficiency virus antibody screening

The detection of specific antibodies against human immunodeficiency virus (HIV) was tested by dot blot enzyme immunoassay in 95 urine samples from 72 individuals infected with HIV and 23 seronegative individuals. Western blot of paired serum samples from these same individuals was used as the gold standard. The dot blot tested had a sensitivity of 97.2% and a specificity of 100%; only two samples from HIV-infected individuals at Centers for Disease Control (CDC) stages II and IV were non-reactive. Reactive and discrepant samples (serum/urine) were confirmed by Western blot, which had a sensitivity of 98.6% and a specificity of 100%. The most commonly observed Western blot reactivity pattern in urine samples included bands against three groups of HIV structural proteins (ENV, POL, and GAG). The results indicate that urine can be used in screening for HIV antibodies in epidemiological studies of high-prevalence populations, though it is not recommended for individualized diagnostic purposes.

A school outbreak of parvovirus B19 infection investigated using salivary antibody assays

An outbreak of parvovirus B19 infection at a primary school was investigated using saliva samples. Antibody capture immunoassays for salivary B19 IgG and IgM were developed using a recombinant B19 antigen and monoclonal antibody to B19 virus. Evaluation of the salivary IgG assay using paired serum and saliva samples from 43 staff at St Thomas' Hospital showed that it had a sensitivity of 100% and a specificity of 95%. Evaluation of the salivary B19 IgM assay using 87 paired blood and saliva samples from a study of general practitioner rubella notifications showed it had a sensitivity of 60% and a specificity of 98%. Using the salivary assay the level of B19 IgG within 2 weeks of the start of the outbreak ranged from 5-33% in children and 29% in staff. By detecting salivary B19 IgM and/or B19 IgG seroconversions, attack rates of 8-50% in children in different classes and 47% in staff were observed. Household transmission was also studied and an attack rate of 45% was recorded in 11 susceptibles. After the outbreak, the level of B19 IgG in children with the highest attack rates was 60-70%, similar to that seen in adults in the UK. This study highlights the risk of B19 infection in an institutional setting and shows that saliva samples are a useful alternative to blood.

Anti-HIV antibody in saliva: an assessment of the role of the components of saliva, testing methodologies and collection systems

The various components of saliva, namely mixed saliva, parotid saliva, submandibular saliva, crevicular fluid and minor (labial) gland secretions, were collected from 63 known HIV antibody seropositive patients. A commercial test system, Wellcozyme HIV 1+2, and an antibody capture ELISA (GACELISA), were compared for sensitivity against all components. Sensitivity of the GACELISA system was 100% in 123 mixed saliva, 121 parotid saliva and 127 labial fluid samples, and 98% in 99 submandibular samples and 127 crevicular fluid samples. Respective figures for Wellcozyme 1+2 were 92%, 55%, 73%, 66% and 63%. Mixed saliva was most easily, conveniently and effectively collected using a plain Salivette. In 241 Salivette samples examined from the 63 patients, GACELISA proved 100% sensitive, and Wellcozyme 95% sensitive. Another form of Salivette impregnated with citric acid was unsuitable for GACELISA and gave a false negative value of 45%. In 197 samples from the gingival margin taken by a dry swab, GACELISA showed a sensitivity of 98% and Wellcozyme 81%. The most sensitive method for demonstrating anti-HIV antibody in saliva is to collect mixed saliva with the plain Salivette system and assay anti-HIV antibody levels by GACELISA.

Evaluation of antigen and antibody detection in urine specimens from children with congenital human cytomegalovirus infection

Fetal infection with human cytomegalovirus (HCMV) is the leading viral cause of brain damage among newborns at birth or later in life. Efforts to screen newborns routinely for shedding of the virus by immunoassay have been hampered by inhibitors in urine, reportedly the host protein beta2-microglobulin (beta 2m). An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of HCMV antigen in which the reactivity was not affected by the presence of beta 2m, but nevertheless inhibition was observed when urine samples with high levels of virus were tested. The presence of antibodies to HCMV was demonstrated in these urine samples by antibody ELISA and immunoblot using the major antigenic protein of HCMV (pp150) expressed in Escherichia coli; this offers an alternative explanation for the inhibition in ELISA. The presence of HCMV antibodies correlated significantly with congenital HCMV infection (as detected by tissue culture isolation of virus from urine samples of newborns), especially with asymptomatic cases (sensitivity 70%; specificity 94%). The data indicate a local (renal) immune response to HCMV in congenitally infected children, which may have future diagnostic applications.

Prevalence of measles antibody among children under 15 years of age in Santa Cruz, Bolivia: implications for vaccination strategies

We conducted a community-based survey in Santa Cruz city, Bolivia, to determine the age-specific prevalence of measles antibodies, determine factors associated with absence of detectable measles antibodies, and to compare results of salivary and serum measles immunoglobulin G (IgG) antibody assays. Serum samples from 1654 children were assayed for measles IgG antibody using the haemagglutination inhibition (HI) assay, and salivary samples were also obtained from 187 children and tested for measles IgG antibody using an antibody capture radioimmunoassay. Reported measles vaccine coverage in children aged 12-35 months was 77% (95% confidence interval [CI], 72-81%). Eighty-seven percent (95% CI 85-89%) had detectable HI antibody, but a high proportion had antibody levels below 200 miu (30-40% of 2-14 years old children). Measles seronegativity was associated with not being vaccinated against measles, a negative history of measles disease, living in the inner city, being a lifetime resident of Santa Cruz, and young age. Of 212 children without detectable measles antibody, 58% had a positive history of vaccination or measles disease, so that historical information was not sufficiently reliable to identify susceptibles. The salivary measles antibody assay was not sufficiently sensitive to be used for population screening; only 54% of 171 salivary samples from children who had detectable serum HI antibody were positive. A mass measles vaccination campaign of all children under 15 years of age is planned in Bolivia in 1994. Although only 7% of school-age children in Santa Cruz were seronegative, the effectiveness of a mass campaign in this age group depends in part on the response to revaccination of children with low, but detectable, antibody levels.

GACPAT HIV 1 + 2: a simple, inexpensive assay to screen for, and discriminate between, anti-HIV 1 and anti-HIV 2

A simple and cheap assay suitable for screening for anti-HIV 1 and anti-HIV 2 and discriminating between them was evaluated. In it specimens are incubated in U-bottomed microplate wells coated with anti-human IgG for 30 min at room temperature. After washing, 100 microliters of a 1 in 50 dilution of HIV 1-coated gelatin particles (Serodia-HIV 1/2, Fujirebio) are added. Settling patterns are read on the second day: A positive reaction is indicated by adherence of the particles and a negative by a button. The HIV 1 particles are then washed away and HIV 2 particles added. Anti-HIV 2 reaction patterns are read on the third day. To assess the performance of the modified "GACPAT HIV 1 + 2" assay a panel of 1,621 serum/plasma specimens was used. It comprised validated anti-HIV 1 positive (n = 220), anti-HIV 2 positive (n = 214), dual anti-HIV 1/anti-HIV 2 positive (n = 11), and anti-HIV negative (n = 1,176) serum/plasma specimens. All 434 specimens that contained anti-HIV 1 or anti-HIV 2 reacted positively with the homologous particles. The 11 dually positive specimens reacted positively with both HIV 1 and HIV 2 particles. Five (2.3%) anti-HIV 1 and five (2.3%) anti-HIV 2 positive specimens gave positive reactions with both particle types, but none of the five cross-reactive anti-HIV 2 specimens were dually reactive when the order of particle addition was reversed.(ABSTRACT TRUNCATED AT 250 WORDS)

Salivary antibody detection in epidemiological surveys: a pilot study after a mass vaccination campaign against rubella in São Paulo, Brazil

The sensitivity and specificity of salivary rubella antibody detection was investigated using samples collected from 301 children after a mass vaccination campaign in the state of São Paulo, Brazil. Saliva samples were collected by 2 different methods: directly dribbling into a container or using a commercial collecting device. Corresponding finger-prick blood samples were collected on filter paper. Rubella specific immunoglobulin G (IgG) was measured in saliva by antibody capture radioimmunoassay and in blood samples by indirect enzyme-linked immunosorbent assay. The detection of salivary rubella specific IgG showed good correlation with the detection of rubella antibody in the blood samples. For both collecting techniques the predictive value for a positive saliva test was > 99% compared with the results from the blood tests. However, the predictive value for a negative saliva test was only 58.3% for a dribbled sample, compared to 100% for saliva collected using the commercial device. Moreover, collecting saliva by dribbling from children less than 4 years old was difficult. The detection of rubella specific IgG in saliva collected using a commercial device proved to be sensitive and specific in this epidemiological study, encouraging its more widespread application as a means of surveillance after mass vaccination.

Application of commercial assays to detect IgG antibodies to hepatitis C virus in urine: a pilot study from autopsy cases

Hepatitis C virus (HCV), the main cause of non-A, non-B hepatitis in the United States and possibly in the world, is believed to be transmitted primarily through parenteral exposure. Many screening and supplemental tests are available to detect antibodies to HCV in serum. The ability to use commercial assays to detect antibodies to HCV in urine was investigated in this study. A total of 229 serum/urine matched samples were collected sequentially from forensic autopsy cases examined at the Office of the Chief Medical Examiner, State of Maryland. Testing was performed using the Ortho, Innogenetics, and Abbott second generation HCV screening tests and the INNO-LIA HCV Ab supplemental assay. Sample volumes were increased for urine testing. Forty-six of 229 serum samples were positive by screening and confirmed by supplemental tests. The urine samples produced positive results on 44-45 of the same 46 by screening tests and all 46 positives by the supplemental test. There were no false positive samples using urine when compared with the serum pairs. The one false negative sample using urine was still nonreactive when the urine volume was increased to 200 microliters using the screening tests. Generally, five times the serum volume was required for the screening tests to be optimal for urine samples. The urine samples were stored under different conditions prior to testing to determine the influence on antibody stability in urine.

Detection of antibodies to human immunodeficiency virus in vaginal secretions by immunoglobulin G antibody capture enzyme-linked immunosorbent assay: application to detection of seminal antibodies after sexual intercourse

In order to evaluate a commercial immunoglobulin G (IgG) antibody capture enzyme-linked immunoassay (ELISA) (Wellcozyme HIV1 + 2 Gacelisa; Murex Diagnostics Limited, Dartford, United Kingdom) for the detection of antibodies to human immunodeficiency virus (HIV) in vaginal secretion samples (VS) from HIV-seropositive and -seronegative women, serum samples (S) and VS were obtained from 129 African women living in the Central African Republic, a country of high HIV prevalence. Sera were tested for HIV by routine second-generation ELISA with confirmatory Western blot (immunoblot) (WB). By the Gacelisa IgG immuno-capture assay, 45 VS were positive and 84 were negative, whereas by WB, 44 VS were confirmed positive and 85 were confirmed negative. Considering WB as a reference, the IgG immunocapture assay in VS was 97.7% sensitive (43 of 44 positive samples) and 97.6% specific (83 of 85 negative samples). Of 42 HIV-seropositive women, 41 (97.6%) had S and VS that both were HIV positive (S+ VS+), and of 87 HIV-seronegative women, 83 (95.4%) had S and VS that both were HIV negative (S- VS-). Five women had discordant results for S and VS. One (S+ VS-) possibly had a false-negative VS result. Two (S- VS+) had similar indeterminate patterns for S and VS in WB. Two (S- VS+) had a typical HIV-positive pattern on WB of VS, whereas S results in WB were indeterminate in one case and negative in the other case; for both women, detection of prostatic acid-phosphatase was positive in VS, strongly suggesting recent sexual intercourse with an HIV-positive man. Because all HIV-infected men have detectable IgG antibodies to HIV in the seminal fluid, an HIV-seronegative rape victim with HIV-positive VS (S- VS+) should receive short-term antiviral therapy to prevent possible HIV transmission.

Detection of anti-human immunodeficiency virus type 1 (HIV-1) immunoglobulin G in urine by an ultrasensitive enzyme immunoassay (immune complex transfer enzyme immunoassay) with recombinant reverse transcriptase as an antigen

Anti-human immunodeficiency virus type 1 immunoglobulin G in urine was detected by an immunoassay with reverse transcriptase as the antigen and beta-D-galactosidase as the label; this immunoassay was 30-fold more sensitive than the previous immunoassay with peroxidase as the label. The sensitivity and specificity were both 100%. The lowest signal for asymptomatic carriers was 20-fold higher than the highest signal for seronegative subjects.

Diagnosis of HIV-1 infection by detection of antibody IgG to HIV-1 in urine with ultrasensitive enzyme immunoassay (immune complex transfer enzyme immunoassay) using recombinant proteins as antigens

Anti-HIV-1 IgG in urine was detected by an ultrasensitive enzyme immunoassay (immune complex transfer enzyme immunoassay) using recombinant reverse transcriptase (RT), p17 and p24 as antigens, and beta-D-galactosidase from Escherichia coli as label. Anti-HIV-1 IgG in urine was reacted simultaneously with 2,4-dinitrophenyl-bovine serum albumin-recombinant protein conjugate and recombinant protein-beta-D-galactosidase conjugate. The immune complex formed, consisting of the three components, was trapped onto polystyrene balls coated with affinity-purified (anti-2,4-dinitrophenyl group) IgG. After washing, the immune complex was eluted from the polystyrene balls with excess of epsilon N-2,4-dinitrophenyl-L-lysine and transferred to clean polystyrene balls coated with affinity-purified (anti-human IgG gamma-chain) IgG. Finally, the enzyme activity bound to the last solid phase was assayed by fluorometry. Using recombinant RT as antigen, the sensitivity and specificity for 83 seropositives and 100 seronegatives were both 100%, and the lowest signal for 60 asymptomatic carriers was 8.2-fold higher than the highest signal for the seronegatives. The positivity with recombinant RT as antigen could be confirmed by using recombinant p17 and p24 as antigens. The sensitivity could be improved by a longer assay of bound beta-D-galactosidase activity by using concentrated urine samples and by the combined use of recombinant RT, p17, and p24. Thus, reliable diagnosis of HIV-1 infection was possible for asymptomatic carriers.

Detection of antibody IgG to HIV-1 in urine by ultrasensitive enzyme immunoassay (immune complex transfer enzyme immunoassay) using recombinant p24 as antigen for diagnosis of HIV-1 infection

Anti-HIV-1 IgG in urine was detected by an ultrasensitive enzyme immunoassay (immune complex transfer enzyme immunoassay) using recombinant p24 gag protein (p24) of HIV-1 as antigen and beta-D-galactosidase from Escherichia coli as label. Anti-HIV-1 IgG in urine was reacted simultaneously with 2,4-dinitrophenyl-bovine serum albumin-recombinant p24 conjugate and recombinant p24-beta-D-galactosidase conjugate. The complex formed, consisting of the three components, was trapped onto polystyrene balls coated with affinity-purified (anti-2,4-dinitrophenyl group) IgG, eluted with epsilon N-2,4-dinitrophenyl-L-lysine, and transferred to polystyrene balls coated with affinity-purified (anti-human IgG gamma-chain) IgG. Bound beta-D-galactosidase activity was assayed by fluorometry. This assay was at least 3,000-fold more sensitive than conventional methods. The lowest signal among 49 asymptomatic carriers was 3.1-fold higher than the highest nonspecific signal among 100 seronegative subjects. The sensitivity and specificity were both 100%. The positivity could be confirmed by preincubation of urine samples with excess of the antigen. Thus, this assay would be a powerful tool for detecting IgG antibody to HIV-1 in urine.

Detection of anti-HIV in saliva and urine at the time of seroconversion

To determine whether there is a delay between the appearance of anti-HIV in serum/plasma and its detection in saliva and urine, salivary and urine specimens were collected from nine individuals who, on the basis of increasing IgG anti-HIV reactivity, Western blot band patterns and presence of strong IgM anti-HIV reactivity in their serum specimens, were believed to have recently become anti-HIV-positive. Serum from 8 of these patients and 3 commercial panels of plasma specimens collected during seroconversion were diluted to mimic the low immunoglobulin concentrations present in saliva and urine and tested in Wellcozyme HIV 1 + 2 GACELISA and four commercial EIAs intended for testing serum specimens. The 9 pairs of saliva and urine specimens were collected between 4 and 43 days (median 24 days) after the first evidence of seroconversion. All were reactive by Wellcozyme HIV 1 + 2 GACELISA and gave optical density/cut off (OD/CO) ratios in the range 3.8 to 9.8 (median 5.2) for dribbled saliva and 2.4 to 10.1 (median 6.3) for urine. Salivary specimens taken with commercial collection devices gave OD/CO ratios in the range 1.6 to 10.6 (median 5.9). In the serum/plasma specimens Wellcozyme HIV 1 + 2 GACELISA detected anti-HIV at higher dilutions than the other assays, often with a 100-fold or more difference. Saliva and urine specimens were all strongly reactive by Wellcozyme HIV 1 + 2 GACELISA. We therefore predict that it would first detect anti-HIV in salivary and urine specimens at about the same time as it becomes detectable in serum/plasma but that other commercial EIAs would not.

Novel assay for the detection of immunoglobulin G antihuman immunodeficiency virus in untreated saliva and urine

Epidemiological evidence and laboratory studies indicate that human immunodeficiency virus type 1 (HIV 1) is rarely, if ever, transmitted in saliva or urine. In that both specimens are easy to collect, each may be a useful alternative to serum specimens for anti-HIV screening. A rapid, simple, and robust IgG-capture enzyme-linked immunosorbent assay (GACELISA) suitable for the detection of anti-HIV 1 and 2 in saliva and urine was developed. Following optimisation of the assay, 177 salivary and 568 urine specimens collected from individuals of known serostatus were investigated. The assay was 100% sensitive on 50 salivary (median OD/CO = 8.9) and 126 urinary (median OD/CO = 8.6) specimens collected from anti-HIV-positive patients. The specificity was 100% on 127 salivary specimens (median OD/CO = 0.37) and 422 urinary specimens (median OD/CO = 0.39) collected from anti-HIV-negative individuals. These findings demonstrate that GACELISA HIV 1 + 2 tests on saliva or on urine are an accurate alternative to a conventional anti-HIV test of blood. This assay is satisfactory for surveillance purposes and, with appropriate precautions, could be used clinically.

Detection of antibodies to HIV in homologous sets of plasma, urine and oral mucosal transudate samples using rapid assays in Tanzania

The aim of this study was to evaluate the performance of commercially available anti-HIV assays when testing plasma, urine and oral mucosal transudate (OMT) samples for the presence of antibodies to HIV. Homologous sets of plasma, urine and oral mucosal transudate specimens were collected from 288 hospitalized patients in northern Tanzania and tested for antibodies to HIV using a routine enzyme immunoassay (Recombinant 3rd Generation EIA, Abbott) and two rapid assays (Testpack HIV-1/HIV-2; Abbott and SUDS HIV-1, Murex). Incubation times and/or sample volumes when testing OMT or urine were increased as compared to those recommended for plasma. The corresponding plasma specimens from all repeatedly reactive samples and samples presenting discordant results were subjected to confirmational testing by an HIV-1/2 Western blot. A total of 15.3% (44/288) of the plasma samples were anti-HIV-1 positive by Western blot. The sensitivity using plasma was 100% by all assays, 69.7-97.7% using urine, and 92.7-100% using oral transudate specimens. The sensitivity of both rapid assays was excellent and higher than the EIA when testing OMT. Specificities ranged from 98.8-100% for plasma, 99-100% for urine and were 100% by all assays using oral samples. The results obtained using oral mucosal transudate specimens and rapid assays were at least comparable to those obtained with plasma, while the use of urine specimens produced suboptimal sensitivities with two of the three assays. The testing of alternative body fluids for antibodies to HIV is yet another strategy that may be applicable, particularly in developing countries.

Reducing the cost of HIV antibody testing

Available tests to detect antibody to human immunodeficiency virus (HIV) have a range of applications, and injudicious selection and inappropriate use can add a significant financial burden to budgets for AIDS programmes in developing countries. There are several ways by which the cost of HIV antibody testing can be reduced; they include use of tests appropriate for existing laboratory capabilities; adoption of cost-effective testing strategies; pooling of serum samples before testing; and ensuring best possible purchase prices. Each approach can significantly reduce the cost of HIV antibody testing alone or in combination, which increases the potential sustainability of antibody testing programmes, even in settings of limited resources.

Human immunodeficiency virus: GACPAT and GACELISA as diagnostic tests for antibodies in urine

Testing for antibodies to human immunodeficiency virus (HIV) in urine may be of use in epidemiological studies. We collected 336 paired urine and serum samples from subjects in Karonga District, northern Malawi: 86 (25.6%) of the serum samples were HIV positive. Serum results were compared with those from immunoglobulin (Ig) G antibody-capture particle adherence tests (GACPAT) and IgG antibody-capture enzyme-linked immunosorbent assay (GACELISA) on the corresponding urine samples performed independently in 2 laboratories. The minimum observed relative sensitivity and specificity of GACPAT were 96.5% and 98.8% respectively; the specificity could be raised by using a protocol involving re-testing of reactive samples to determine end-point titre. For GACELISA, the observed relative sensitivity and specificity were 98.8% and 99.2% respectively. Such assays may be useful either as a primary screen in populations where urine samples are considerably easier to obtain than serum samples, or as an alternative test for individuals unwilling to provide a serum sample.

Detection of antibody IgG to HIV-1 in urine by sensitive enzyme immunoassay (immune complex transfer enzyme immunoassay) using recombinant proteins as antigens for diagnosis of HIV-1 infection

For diagnosis of HIV-1 infection, attempts were made to detect anti-HIV-1 IgG in urine by sensitive enzyme immunoassay (immune complex transfer enzyme immunoassay) using recombinant reverse transcriptase (RT) and p17 as antigens. Anti-HIV-1 IgG in urine was reacted simultaneously with 2,4-dinitrophenyl-bovine serum albumin-recombinant protein conjugate and recombinant protein-enzyme conjugate. The enzymes used as labels were horseradish peroxidase for RT and Escherichia coli beta-D-galactosidase for p17. The complex formed, consisting of the three components, was trapped onto polystyrene balls coated with affinity-purified (anti-2,4-dinitrophenyl group) IgG, eluted with epsilon N-2,4-dinitrophenyl-L-lysine and transferred to polystyrene balls coated with affinity-purified (anti-human IgG gamma-chain) IgG. Finally, bound enzyme activity was assayed by fluorometry. Urine samples were collected from 100 seronegative subjects and 70 seropositive subjects. The sensitivity and specificity were both 100% with unconcentrated urine samples. The positivity was confirmed by preincubation of urine samples with excess of the antigens. The positivity and negativity with one of the two antigens could be confirmed with the other antigen. The positivity with low signals could be confirmed by concentration of urine samples. Detection of anti-HIV-1 IgG in urine by the immune complex transfer enzyme immunoassay using different antigens would make diagnosis of HIV-1 infection possible.