Oral fluid as a specimen for detection and confirmation of antibodies to human immunodeficiency virus type 1

Evaluation and diagnostic usefulness of saliva for detection of HIV antibodies: A cross-sectional study

Background:

Use of saliva as a specimen for detection of antibodies to infectious agents has generated particular interest in AIDS research community since 1980s. HIV specific antibodies of immunoglobulin isotypes IgA, IgG, and IgM are readily found in salivary secretions.

Aim and Objectives:

In the present study, HIV specific antibodies were detected in saliva and serum samples of HIV patients by ELISA in confirmed HIV seropositive patients and efficacy of saliva was established in diagnosis of HIV.

Methods:

The 100 saliva and serum samples were collected from age and sex matched confirmed HIV seropositive subjects and 100 Healthy Controls without any infections. HIV antibodies were determined by enzyme-linked immunosorbent assay (ELISA) using Genscreen HIV 1/2 Kit.

Results:

The results were found to be 99% sensitive and 100% specific for saliva samples, while it was 100% sensitive and specific for serum samples.

Conclusion:

Saliva can be used as alternative to blood for detection of HIV antibodies as saliva collection is painless, non-invasive, inexpensive, simple, and rapid. Salivary antibody testing may provide better access to epidemic outbreaks, children, large populations, hard-to-reach risk groups and may thus play a major role in the surveillance and control of highly infectious diseases.

Use of the Bio-Rad Geenius HIV-1/2 supplemental assay for the testing of oral fluids for the presence of HIV antibody

There is currently an absence of products which are cleared by the FDA to provide supplemental testing for oral fluid for HIV antibody. We created a procedure for the use of the BioRad Geenius HIV-1/2 as a supplemental antibody test for oral fluid specimens. The modified procedure was evaluated for its ability to detect HIV-1 antibody in oral fluid in specimens that were found to be repeatedly reactive for HIV-1 antibody by way of the Avioq HIV-1 enzyme immunoassay (EIA). Evaluated were oral fluid specimens analyzed at a local public health laboratory which were stored frozen and oral fluid specimens collected prospectively. Prospectively collected specimens were from patients whose HIV status was subsequently assessed through blood-based testing. For retrospective specimens found repeatedly EIA reactive, and positive by Western blot, the modified Geenius was found positive in 37/38 instances (97.4 %). Those specimens with a mean EIA signal-to-cutoff (S/CO) greater than 3.00 were found to be positive by Geenius in 34/34 (100 %) of instances. For specimens found repeated reactive by EIA and positive by Western blot with mean S/CO less than or equal to 3.00, the Geenius was positive in 4/5 instances (80 %) of instances. For prospectively collected specimens, the Geenius accurately confirmed infection in 22/24 cases (92 %) while prospective specimens found repeatedly reactive by EIA without supplemental Geenius testing were confirmed positive in 29/37 instances (78 %). A modified usage of the Geenius HIV-1/2 Supplemental Assay antibody test may provide utility in the supplementation of testing of oral fluid for the presence of HIV-1 antibody.

Age-related variations of protein carbonyls in human saliva and plasma: is saliva protein carbonyls an alternative biomarker of aging?

Free radical hypothesis which is one of the most acknowledged aging theories was developed into oxidative stress hypothesis. Protein carbonylation is by far one of the most widely used markers of protein oxidation. We studied the role of age and gender in protein carbonyl content of saliva and plasma among 273 Chinese healthy subjects (137 females and 136 males aged between 20 and 79) and discussed the correlation between protein carbonyl content of saliva and plasma. Protein carbonyl content of saliva and plasma were, respectively, 2.391 ± 0.639 and 0.838 ± 0.274 nmol/mg. Variations of saliva and plasma different age groups all reached significant differences in both male and female (all p < 0.05) while both saliva and plasma protein carbonyls were found to be significantly correlated with age (r = 0.6582 and r = 0.5176, all p < 0.001). Gender was discovered to be unrelated to saliva and plasma protein carbonyl levels (all p > 0.05). Saliva and plasma protein carbonyls were positively related (r = 0.4405, p < 0.001). Surprisingly, saliva and plasma protein carbonyls/ferric reducing ability of plasma (FRAP) ratios were proved to be significantly correlated with age (r = 0.7796 and r = 0.6938, all p < 0.001) while saliva protein carbonyls/FRAP ratio and plasma protein carbonyls/FRAP ratio were also correlated (r = 0.5573, p < 0.001). We concluded that saliva protein carbonyls seem to be an alternative biomarker of aging while the mechanisms of protein carbonylation and oxidative stress and the relationship between saliva protein carbonyls and diseases need to be further investigated.

Finger-stick whole blood HIV-1/-2 home-use tests are more sensitive than oral fluid-based in-home HIV tests

Background

Several countries have recently recommended the expansion of anti-human immunodeficiency virus (HIV) antibody testing, including self-testing with rapid tests using oral fluid (OF). Several tests have been proposed for at-home use, but their diagnostic accuracy has not been fully evaluated.

Objective

To evaluate the performance of 5 rapid diagnostic tests for the detection of anti-HIV-1/2 antibodies, with 4 testing OF and 1 testing whole blood.

Methods

Prospective multi-center study in France. HIV-infected adults and HIV-uninfected controls were systematically screened with 5 at-home HIV tests using either OF or finger-stick blood (FSB) specimens. Four OF tests (OraQuick Advance Rapid HIV-1/2, Chembio DPP HIV 1/2 Assay, test A, and test B) and one FSB test (Chembio Sure Check HIV1/2 Assay) were performed by trained health workers and compared with laboratory tests.

Results

In total, 179 HIV-infected patients (M/F sex ratio: 1.3) and 60 controls were included. Among the HIV-infected patients, 67.6% had an undetectable HIV viral load in their plasma due to antiretroviral therapy. Overall, the sensitivities of the OF tests were 87.2%, 88.3%, 58.9%, and 28% (for OraQuick, DPP, test A, and test B, respectively) compared with 100% for the FSB test Sure Check (p<0.0001 for all comparisons). The OraQuick and DPP OF tests' sensitivities were significantly lower than that of the FSB-based Sure Check (p<0.05). The sensitivities of the OF tests increased among the patients with a detectable HIV viral load (>50 copies/mL), reaching 94.8%, 96.5%, 90%, and 53.1% (for OraQuick, DPP, test A, and test B, respectively). The specificities of the four OF tests were 98.3%, 100%, 100%, and 87.5%, respectively, compared with 100% for the FSB test.

Conclusion

An evaluation of candidates for HIV self-testing revealed unexpected differences in performance of the rapid tests: the FSB test showed a far greater reliability than OF tests.

Using conventional HIV tests on oral fluid

There is need for more evaluations of non-invasive tests in order to broaden the reach of testing programs and to perform large scale epidemiological studies. In this study, three different human immunodeficiency virus (HIV) enzyme linked immunosorbent assays (ELISAs) and one line immunoassay were evaluated to detect HIV antibodies in oral fluid samples. Specimens were collected, after informed consent was obtained, with the Oracol (MMD, Worcester, England) device. A total IgG quantitation test was performed to demonstrate the quality of the sample. Assessment of a modified protocol of the Vironostika HIV Ag/Ab, Enzygnost Anti-HIV 1/2 Plus Genscreen HIV-1/2 Version 2 and a line immune confirmatory assay the INNO-LIA HIV I/II score was done, using oral fluid specimens of 325 HIV positive and negative individuals. For the ELISAs, the addition of an extra internal oral fluid control was evaluated as well as different cut-offs, time between sampling and testing and the effect of drinking water just before sampling. Finally, the confirmatory test and some testing algorithms and combination of tests were discussed. The results obtained from the oral fluid specimens were compared with the gold standard on paired serum specimens. Firstly, there was no significant difference observed between the use of the kit controls and the oral fluid controls. New protocols and calculation of cut-offs were defined for two of the three ELISAs. High sensitivities and specificities were obtained with all three ELISAs without any statistical difference between the three tests. Secondly, no statistically significant difference was observed when samples were stored for different time periods between sampling and testing, meaning that a period of seven days at room temperature before testing is still acceptable. Thirdly, drinking water before sample collection did not interfere with the testing, although lower optical densities were observed. None of the positive samples were missed. In addition, the line immunoassay INNO-LIA HIV I/II score test is a promising test for confirmation of reactive oral fluid specimen, but more samples need to be validated in order to adapt the interpretation rules specifically for oral fluid specimens. Different choices/algorithms adapted for the purpose of testing can be proposed. In conclusion, it can be said that the commercial ELISAs with adapted protocol and cut-off values are suitable tools for making HIV test performance accessible to people. With this non-invasive sampling method, more eligible individuals can and will be selected for further HIV test on blood.

Assessment of sensitivity and specificity of first, second, and third generation EIA for the detection of antibodies to HIV-1 in oral fluid

The performances of three blood-based immunoassays test kits were compared with regard to their ability to detect HIV-1 antibody in oral fluid. It was found that these three kits differ in their ability to detect HIV-1 antibody. Notably, a third generation EIA which has been shown to possess superior sensitivity for antibody detection in plasma appears to possess no sensitivity advantage for detecting HIV-1 antibody in oral fluid.

Performance of a Western immunoblot assay to detect specific anti-Toxoplasma gondii IgG antibodies in human saliva

Toxoplasma gondii represents the most prominent infectious parasitic organism found in humans. While normally asymptomatic in healthy individuals, toxoplasmosis can cause abortion in patients during pregnancy, or can be fatal in immunosupressed individuals such as persons suffering from acquired immunodeficiency syndrom (AIDS). Toxoplasma gondii infection in humans is routinely assesssed by serological means. Here, we show that detection of anti-T. gondii IgG is also possible using a non-invasive methodology employing saliva. Sera and saliva of 201 healthy volunteers were investigated for the presence of anti-T. gondii-IgG antibodies by immunoblotting. The sera of 59 (29.4%) individuals showed IgG antibodies against T. gondii by ELISA, Vidas, and immunoblotting; 58 (98.3%) of these were also positive for anti-T. gondii IgG in the saliva immunoblot, with diagnostic relevant bands of Mr of 32-35 kDa and 40-45 kDa. The saliva immunoblot test exhibits a specificity of 100% and a sensitivity of 98.5%. Thus, saliva could be used as an alternative, non-invasive means for the detection of specific anti-T. gondii IgG in humans.

Effects of sample collection and storage methods on antipneumococcal immunoglobulin A in saliva

Saliva contains components of both the mucosal and systemic immune systems. Variable flow rates, immunoglobulin proteases, and variation in collection and storage methods all introduce differences in the estimated concentrations of antibodies. We evaluated the effect of four collection methods and three storage protocols on the concentrations of immunoglobulin A (IgA) antibodies to pneumococcal capsular antigens 1, 5, 6B, and 14 and to pneumococcal surface adhesin A (PsaA) in saliva. Specimens were collected from 30 healthy Kenyan adults by collecting drool, by pipette suction, and with two commercial kits, OraSure and Oracol. Aliquots from each specimen were snap-frozen with glycerol in liquid nitrogen or stored for 4 to 8 h at +4 degrees C either with or without the addition of protease enzyme inhibitors prior to storage at -70 degrees C. Anticapsular IgA concentrations were not significantly different with different collection methods, but snap-freezing the specimens in liquid nitrogen led to concentrations 41 to 47% higher than those of specimens stored by the other methods (P < 0.0005).

Low hepatitis B prevalence among pre-school children in Denmark: saliva anti-HBc screening in day care centres

Although Denmark has a low hepatitis B virus (HBV) prevalence, HBV transmission has been reported in Danish day-care centres. The aim of this study was to validate saliva anti-HBc testing as a method for HBV screening, the applicability of saliva sampling to pre-school children, and to determine the HBV prevalence in Danish day-care centres with a high proportion of immigrants. For validation, paired saliva and plasma samples were obtained from blood donors and injecting drug users. Employees and children in day-care centres with a high proportion of immigrant children were offered saliva screening followed by blood test if positive. The specificity and sensitivity of anti-HBc tests on saliva was 100% (102 blood donors and four injecting drug users) and 85.9% (61 of 71 anti-HBc-positive injecting drug users), respectively. In all samples from HBsAg (n = 7) or anti-HBc IgM-positives (n = 9), anti-HBc was detected in saliva. Adequate saliva samples were obtained from 93% (588/634) of children and 100% (166/166) of employees participating in the day-care centre survey. Among children 55% were of non-Scandinavian origin and only one (0.2%, 95% CI [0.0; 1.0]) was HBV positive. Among employees the corresponding values were 22% and 7 (4.2%). The positive predictive value of the saliva test was 25% (1/4) among children and 88% (7/8) among adults. In conclusion, saliva testing is feasible for HBV screening among children in low prevalence populations, but any anti-HBc reactivity should be confirmed by plasma analysis. The HBV prevalence in pre-school children in Denmark is low even among immigrants from endemic areas.

Inhibitory effects of whole and parotid saliva on immunomodulators

Based on the presence of cytokines in whole saliva and their association with resistance and susceptibility to infectious disease, the present study was designed to evaluate the diagnostic potential of a large panel of cytokines and chemokines in saliva. Despite the endogenous presence of Th1/Th2 and pro-inflammatory cytokines and several chemokines in whole and parotid saliva of most individuals tested, the detection of known concentrations of several recombinant cytokines and chemokines was inhibited immediately following their addition to each type of saliva. In contrast, purified immunoglobulins were unaffected by either whole or parotid saliva. Further studies revealed that the inhibition of immunoreactivity involved sequestration of the majority of cytokines affected and degradation of chemokines. These results suggest that absolute concentrations of cytokines/chemokines may not be fully detectable in saliva. Therefore, the diagnostic value of any cytokine/chemokine is questionable and should be evaluated independently as such.

Human saliva as a diagnostic specimen

Human saliva can be easily obtained by noninvasive techniques and contains many analytes of interest for screening, diagnosis and monitoring. These include steroid and other nonpeptide hormones, therapeutic drugs, drugs of abuse and antibodies. Numerous studies in the past 40 y have shown correlations between serum and saliva levels. Both diurnal and monthly profiles of hormone levels parallel traditional serum patterns. Multiple specimens for steroid hormone analysis can be easily collected by the patient, at home, to monitor fertility cycles, menopausal fluctuations, stress and other diurnal variations. Drug doses can be monitored without inconvenient and costly visits to blood-drawing facilities. Antibody levels can be determined to screen for infectious diseases. Saliva can be collected directly by spitting into a tube or with one of several devices, each of which has its own special advantages and disadvantages. Salivary levels of steroid hormones and other analytes that are protein bound in serum reflect the unbound and active concentration of the hormone. Saliva can be used as a diagnostic specimen not only to obtain information more inexpensively and efficiently than serum, but also to provide information not readily available from serum testing.

A simple saliva-based test for detecting antibodies to human immunodeficiency virus

This study was performed to determine the feasibility of using saliva as a diagnostic medium for the detection of antibodies to human immunodeficiency virus type 1 (HIV-1) and HIV-2 under nonlaboratory conditions and to evaluate the performance characteristics of such a test. We developed for this purpose a self-contained kit (Saliva. Strip [ST]), which combines the collection and processing, as well as the analysis, of the specimen. The kit's performance was evaluated in a blinded study. Saliva collection was facilitated with a specially designed device that contains a sample adequacy indicator, and immunochromatography test strips were used for the analysis. A total of 1,336 matched serum and saliva specimens (684 reactive and 652 nonreactive specimens) were tested. We tested sera using an enzyme immunoassay (EIA) and a rapid strip test. Sera reactive in one of the assays were also analyzed by Western blotting. Sensitivity and specificity were 99.4 and 99.4%, respectively, for ST, 100 and 99.1%, respectively, for EIA, and 99.7 and 100%, respectively, for the serum strip test. The saliva test performed well when HIV-2-positive sera or a low-titer performance panel (HIV-1) of serum or plasma specimens were diluted (1:2,000) in nonreactive saliva. Because the methodology we present here uses a noninvasively obtained medium, the methodology may be suitable for use in the field where laboratory support and personnel are limited, such as community outreach programs, doctors' offices, surveillance studies, and community hospitals.

Detection of antibodies to human immunodeficiency virus type 1 in oral fluids: a large-scale evaluation of immunoassay performance

Paired serum and oral-fluid (OF) specimens (n = 4,448) were collected from blood donors and patients attending local sexually transmitted disease clinics in Trinidad and Tobago and the Bahamas and were tested for the presence of human immunodeficiency virus type 1 (HIV-1) antibodies. Sera were tested by Abbott AB HIV-1/HIV-2 (rDNA) enzyme immunoassay (EIA), and positive specimens were confirmed by Cambridge HIV-1 and HIV-2 Western blotting (WB). OF specimens were collected with the OraSure collection device and were tested by Murex GACELISA and by two EIAs from Organon Teknika (the Oral Fluid Vironostika HIV-1 Microelisa System [OTC-L] and the Vironostika HIV-1 Microelisa System [OTC-M]). EIA-reactive OF specimens were confirmed by miniaturized WB (OFWB). GACELISA detected all 474 HIV-1 seropositive specimens (sensitivity, 100%). OTC-L detected 470 positive specimens (sensitivity, 99.2%), while OTC-M detected 468 positive specimens (sensitivity, 98.8%). Specificities ranged from 99.2 to 100% for the three assays. Concordance of OFWB with serum WB was 99.4%, and banding patterns determined by the two methods were similar. The immunoglobulin G (IgG) concentration of OF specimens ranged from 0.21 to 100 microg/ml, with a mean of 17.1 microg/ml. Significant differences in OF IgG concentrations were observed between HIV antibody-positive and HIV antibody-negative persons (31.94 versus 15.28 microg/ml, respectively [P < 0.0001]). These data further confirm the suitability of OF specimens for detection of HIV-1 antibodies. Currently available HIV-1 antibody assays provide sensitivities and specificities with OF specimens comparable to those achieved with serum specimens.

Evaluation of two novel immunoassays designed to detect HIV antibodies in oral fluids

The testing of oral fluid samples for the detection of HIV antibodies offers several advantages over the testing of blood. Our objective was to evaluate a new generation of rapid and simple assays designed specifically to detect HIV-1 and HIV-2 antibodies in oral fluids (saliva). Serum and oral fluid pairs were collected from 615 high- and low-risk individuals in the United States, Peru, and the ivory Coast. Two different oral fluid collection devices and rapid assay systems included: (1) the Orapette/SalivaCard HIV-1/ HIV-2 and (2) the Omni-Sal/ImmunoCcmb II HIV-1 and HIV-2. The corresponding serum pairs were analyzed by conventional ELISAs, and all reactive sera were confirmed with HIV-1 and HIV-2 Western blots. The results indicated a 100% sensitivity for both rapid oral fluid assays, including successful detection of HIV-2 antibodies. Specificities ranged from 99.8% to 100%. One sample produced a reactive result by the SalivaCard while being nonreactive by the other assays including the Western blots. Both assays performed excellently, indicating that antibodies to HIV can be detected reliably in oral fluids by simple and rapid assays. This combination of rapid testing technology and the use of easily collected oral fluid samples offers an efficient and accurate alternative to conventional testing and can be appropriately applied to a variety of testing situations for the laboratory diagnosis of HIV infection.