Absence of HIV infection in blood donors with indeterminate western blot tests for antibody to HIV-1

Human immunodeficiency virus in cadavers: A review

Millions of people are infected with human immunodeficiency virus (HIV); however, limited research focuses on post-mortem HIV detection. Post-mortem HIV testing is vital because medical records are not always available, and the HIV status can be unknown. The aims of this study were to review the available literature and determine the most efficient HIV test for post-mortem samples, the optimal tissue or bodily fluid to be tested, and the duration that HIV remains reliably detectable. A literature search was conducted using PubMed and Google Scholar. Terms were related to HIV (HIV detection, HIV testing, HIV prevalence) and deceased individuals (post-mortem, cadaver, deceased, organ donor). Inclusion criteria included English studies, or articles with at least an English abstract, while review articles were excluded. From this literature search, 43 studies were applicable. These studies most commonly used enzyme-linked immunosorbent assay and Western blot as screening and confirmation tests, respectively. As for the optimal tissue or bodily fluid, serum remained the golden standard, while testing skin seemed promising. HIV remains detectable in the body up to 58 days after death, although few studies tested samples after 48 h. Knowledge of the HIV status can be beneficial in the case of accidental exposure and can create a range of possible research opportunities on the effects of HIV in different organ systems. This review outlined several gaps in the current literature and future studies should investigate these gaps because this information can be relevant to numerous professions. Clin. Anat. 32:603-610, 2019. © 2019 Wiley Periodicals, Inc.

Prevalence and risk behaviour for human immunodeficiency virus 1 infection in Marajó Island, Northern Brazil

BACKGROUND

Human immunodeficiency virus 1 (HIV-1) infection is a global public health problem, but, so far, there is no published information regarding the epidemiology of HIV-1 in Marajó Archipelago (Pará, Brazil).

AIM

The present study reports the occurrence of infection by HIV-1 in four municipalities of the Marajó Island, Pará, Brazil.

SUBJECTS AND METHODS

A total of 1877 samples were collected from volunteer blood donors (1296 women and 551 men) living in the municipalities of Anajás, Chaves, Portel and São Sebastião da Boa Vista. Information about risk behaviour assessment was obtained from a questionnaire. Plasma samples were tested for the presence of anti-HIV antibodies using serological tests. The infection was confirmed by nucleic acid amplification assays.

RESULTS

Twelve samples were seropositive for HIV by ELISA. Western blot analysis showed four positive samples, eight indeterminate patterns and one found to be negative. Molecular analysis revealed three positive samples. Risk factors for HIV-1 infection included absence of condoms during sexual intercourse (41.3%, São Sebastião da Boa Vista), use of illicit drugs (5.8%, Anajás) and early initiation of sexual activities, from 10-15 years (30.7%).

CONCLUSION

Although the study indicates a low HIV-1 prevalence in Marajó Island, some factors may increase the risk for HIV-1 and these include early sexual initiation, unprotected sexual intercourse and the use of illicit drugs.

HIV testing patterns for United States Air Force personnel, 2008-2012

OBJECTIVE

This study evaluated 3rd generation human immunodeficiency virus (HIV) test patterns and HIV infection rates in the United States Air Force (USAF).

STUDY DESIGN

Retrospective database study.

METHODS

HIV enzyme-linked immunoassay (ELISA) and Western blot tests were analysed for all USAF personnel from 2008 to 2012. For new HIV cases, unadjusted and adjusted annual rates were calculated per 100,000 persons.

RESULTS

In total, 1,608,665 tests were performed in 626,298 individuals, with a reactive ELISA observed in 809 (0.001%) persons. Western blot (n = 1949) results included 378 (19.4%) positive, 1283 (65.8%) negative, and 288 (15.0%) indeterminate (WBi). Unadjusted annual HIV rates were between 16.7 and 20.6 per 100,000 persons during the study period. The overall age-adjusted rate was 14.8 cases per 100,000 persons tested. Blacks/African Americans had the highest risk of HIV (risk ratio 7.9 [95% confidence interval 5.78, 9.95] compared to Whites).

CONCLUSIONS

WBi results, which can cause delays in determining HIV status, were relatively common with the 3rd generation assay. However, this will be mitigated by a planned transition to a 4th generation assay. Although the overall rate of HIV in the USAF is lower than US civilian adults, HIV prevention efforts targeting young Blacks/African Americans may help to reduce HIV incidence in the USAF.

Prevalence and pattern of cross-reacting antibodies to HIV in patients with tuberculosis

In many countries, HIV testing among tuberculosis (TB) patients is recommended so that both infections are appropriately treated. Cross-reacting antibodies to HIV antigens have been reported for several conditions, including TB, leprosy, malaria, and rheumatoid arthritis. To study the pattern and prevalence of cross-reacting antibodies to HIV antigens, we examined sera from 153 HIV-negative TB patients and 40 healthy individuals in Chennai, south India. We also studied the differences in cross-reactivity of various HIV antigens using two different Western blot kits. Of the 153 samples studied, 80 were tested using HIV Western blot and 73 were tested using INNOLIA. Most patients in the study had concordantly negative ELISA and rapid tests, and no subject had a positive Western blot. However, seven TB patients had antibodies that cross-reacted with HIV antigens, giving rise to an indeterminate result. While p51/55 was the most frequently recognized antigen in the Western blot assay, antibodies to sgp120 was most frequently identified in INNOLIA. Sequence similarities between the two organisms could be responsible for eliciting cross-reacting antibodies, since a few related epitopes were identified in HIV and Mycobacterium. These findings could have potential implications for the development of diagnostics and vaccines.

Nuclear import of the preintegration complex is blocked upon infection by human immunodeficiency virus type 1 in mouse cells

Mouse cells do not support human immunodeficiency virus type 1 (HIV-1) replication because of host range barriers at steps including virus entry, transcription, RNA splicing, polyprotein processing, assembly, and release. The exact mechanisms for the suppression, however, are not completely understood. To elucidate further the barriers against HIV-1 replication in mouse cells, we analyzed the replication of the virus in lymphocytes from human CD4/CXCR4 transgenic mice. Although primary splenocytes and thymocytes allowed the entry and reverse transcription of HIV-1, the integration efficiency of the viral DNA was greatly reduced in these cells relative to human peripheral blood mononuclear cells, suggesting an additional block(s) before or at the point of host chromosome integration of the viral DNA. Preintegration processes were further analyzed using HIV-1 pseudotyped viruses. The reverse transcription step of HIV-1 pseudotyped with the envelope of murine leukemia virus or vesicular stomatitis virus glycoprotein was efficiently supported in both human and mouse cells, but nuclear import of the preintegration complex (PIC) of HIV-1 was blocked in mouse cells. We found that green fluorescent protein (GFP)-labeled HIV-1 integrase, which is known to be important in the nuclear localization of the PIC, could not be imported into the nucleus of mouse cells, in contrast to human cells. On the other hand, GFP-Vpr localized exclusively to the nuclei of both mouse and human cells. These observations suggest that, due to the dysfunction of integrase, the nuclear localization of PIC is suppressed in mouse cells.

Pediatric HIV infection: immune and viral evaluation

Advances in laboratory methods have driven improvements in the management and treatment of HIV infection. The methods to accurately and rapidly diagnose HIV infection in infants and children have been outlined in the previous article. In this review, the laboratory evaluation of infected children is described and methods to monitor progression of disease and response to therapy outlined.

A combined HIV-1 protein bead array for serology assay and T-cell subset immunophenotyping with a hybrid flow cytometer: a step in the direction of a comprehensive multitasking instrument platform for infectious disease diagnosis and monitoring

BACKGROUND

A new generation of bench-top flow cytometers with digital signal processing to perform suspension array technology (SAT) based bead array assays as well as leukocyte immunophenotyping is now available. These hybrid instruments provide an opportunity for the development of a more cost effective multitasking platform to support infectious disease treatment in resource limited countries.

METHODS

We report the development and testing of two modules compatible with the hybrid flow cytometers. The first module is an eleven HIV-1 protein bead array (PBA) for the detection of circulating antibodies and the second is a cell based T-cell enumeration assay.

RESULTS

The HIV-1 PBA was tested in parallel with two enzyme immunoassays (EIAs) for the detection of plasma antibodies from 4 HIV-1 seroconversion panels and a low antibody titer panel. The PBA as well as the two EIAs performed equally for the detection of antibody positive samples from all seroconversion panels. One antibody positive sample from the low antibody titer panel was missed by the PBA together with one of the two EIAs tested. A parallel analysis of the HIV-1 PBA with Western blot (a confirmatory test for HIV infection) using plasma from nine HIV-1(+) individuals showed that the HIV-1 PBA detected more of the gp41 and gp120 antibody positive samples. Preliminary CD4 T-cell immunophenotyping results from 14 HIV(+) and 10 HIV(-) whole blood specimens with the hybrid flow cytometer platform compared well to conventional flow cytometry data.

CONCLUSION

The successful combination of bead and cell based assays on a single hybrid instrument demonstrated the potential utility of a multitasking platform. The results presented are providing groundwork for future development of more cost effective modular architecture for a flexible flow cytometry based platform.

Detection of low copy numbers of HIV-1 proviral DNA in patient PBMCs by a high-input, sequence-capture PCR (Mega-PCR)

An internally controlled high-input PCR method, termed HIV-1 Mega-PCR was developed to lower the detection limit of HIV-1 DNA polymerase chain reaction (PCR) and to improve its value as a complementary diagnostic test. It is based on PCR amplification of two target sequences in the gag gene of HIV-1 following the selective capture of the targeted sequence and removal of unselected DNA from up to 500 microg of DNA. Efficient selection and amplification was monitored by inclusion of two mimic plasmids. The method was evaluated with buffy coat cells from healthy blood donors which were spiked with blood from 106 different HIV-1-infected individuals, and with 107 HIV-1 seronegative control buffy coats. All specimens from HIV-infected individuals were positive by a PCR protocol using 1 microg of patient DNA. Amplification of 1 microg DNA of the 106 spiked, diluted samples resulted in 68 double positive, 14 single positive, and 24 double negative reactions. In the Mega-PCR, the average input was 260 +/- 84 microg DNA containing an estimated 1.1 +/- 0.6% of spiked patient DNA. Of the 106 samples tested by Mega-PCR, 102 were positive and three negative. One failed to select the mimic plasmid. Among the 107 negative buffy coat controls, none was false-positive and four exhibited a failure of the internal reaction control. Application of HIV-1 Mega-PCR to clinical specimens from seroreverting newborns of HIV-infected mothers and seroindeterminate, PCR-negative specimens revealed no indication for HIV infection, whereas three samples from confirmed, HIV-1-infected but PCR negative individuals showed evidence of the presence of HIV-1 DNA. Mega-PCR lowers the detection limit of an individual analysis to approximately 0.01 HIV-1 DNA copies/microg of applied DNA and may help to confirm or exclude HIV-1-infection in difficult situations diagnostic.

Comparison of murex single-use diagnostic system with traditional enzyme immunoassay for detection of exposure to human immunodeficiency virus

Because a retrospective study detected 13 negative Western blots out of 38 single-use diagnostic system (SUDS)-positive cases over a 1-year period, we performed a prospective study to compare the performance of the SUDS test with that of enzyme immunoassay (EIA). Of 888 SUDS-tested sera, 875 (98.4%) were both SUDS and EIA negative and 5 (0.6%) were SUDS, EIA, and Western blot positive. The rate of SUDS-positive samples decreased from 3.16/month in the retrospective study to 1.33/month in the prospective study. The immunoassays had sensitivities and specificities of 100 and 99.7 (SUDS) and 100 and 99.4% (traditional EIA), respectively. In laboratories with experienced personnel, the SUDS test performs as well as the EIA as a screen for infection with the human immunodeficiency virus.

Anti-HIV indeterminate western blot in dialysis patients: a long-term follow-up

In a group of 520 patients undergoing chronic hemodialysis, 23 (4. 4%) were enzyme immunoassay (EIA) positive for human immunodeficiency virus (HIV) and indeterminate by Western blot (IWB) analysis. The antibodies were mostly directed against p24 and p55 antigens. A comparison between hemodialysis patients with and without IWB showed significant differences between the two groups with respect to number of units of blood transfused, history of renal transplant rejection, and Rh status. No significant differences were observed with respect to ethnic group, nature of renal disease, duration of hemodialysis, associated diseases, and ABO blood group. The HIV IWB phenomenon may represent abnormal immune reactivity as a result of transplantation antigens and/or autoantibody formation. Five-year follow-up of the HIV EIA-positive IWB patients showed that none had seroconverted to HIV-positive status.

HIV-(1/2) indeterminate western blot results: follow-up of asymptomatic blood donors in belo horizonte, minas gerais, brazil

The clinical and public health importance of indeterminate results in HIV-(1/2) testing is still difficult to evaluate in volunteer blood donors. At Fundacao Hemominas, HIV-(1/2) ELISA is used as the screening test and, if reactive, is followed by Western blot (WB). We have evaluated 84 blood donors who had repeatedly reactive ELISA tests for HIV-(1/2), but indeterminate WB results. Sixteen of the 84 donors (19.0%) had history of sexually transmitted diseases; 18/84 (21.4%) informed receiving or paying for sex; 3/84 (3.6%) had homosexual contact; 2/26 women (7.6%) had past history of multiple illegal abortions and 3/84 (3.6%) had been previously transfused. Four out of 62 donors (6.5%) had positive anti-nuclear factor (Hep2), with titles up to 1:640. Parasitological examination of the stool revealed eggs of S. mansoni in 4/62 (6.4%) donors and other parasites in 8/62 (12.9%). Five (5.9%) of the subjects presented overt seroconversion for HIV-(1/2), 43/84 (51.2%) had negative results on the last visit, while 36/84 (42.9%) remained WB indeterminate. Although some conditions could be found associated with the HIV-(1/2) indeterminate WB results and many donors had past of risky behavior, the significance of the majority of the results remains to be determined.

Optimizing the delivery of HIV counseling and testing services: the Uganda experience using rapid HIV antibody test algorithms

The AIDS Information Center (AIC) was established in Kampala, Uganda in 1990 in response to increasing interest by members of the general public who wished to know their HIV serostatus. By 1996, >300,000 clients had been seen. HIV serologic testing was performed at a central laboratory and results reported back to AIC after 2 weeks. Approximately 25% of clients failed to learn their HIV serostatus as a result of failure to return or late arrival of results. To address these issues, AIC carried out an evaluation of 3 rapid HIV assays, Sero-Strip, SeroCard, and Capillus, against a standard criterion to identify a testing algorithm that could be used as an on-site confirmatory testing strategy. The study was carried out over a period of 5 working days and 325 clients were seen. An algorithm was identified, which gave no indeterminate results with unambiguously positive or negative specimens, which was 100% sensitive and specific, and which could be integrated with minimal disruption into existing counseling procedures. All clients left AIC knowing their HIV serostatus and having spent <2 hours at the Center. The results of this evaluation demonstrate that "same-day" results can be provided in counseling and testing settings without compromising the quality of counseling or the accuracy of HIV testing.

Evaluation of epidemiological and serological predictors of human immunodeficiency virus type-1 (HIV-1) infection among high risk professional blood donors with western blot indeterminate results

BACKGROUND

Indeterminate pattern of results in Western blot (WBI) for human immunodeficiency virus type-1 (HIV-1) infection may represent early HIV-1 infection or may be non-specific in origin. This issue can be resolved by follow up testing upto at least 6 months resulting in psychological distress as well as in high drop out rates among those undergoing investigation pointing out the need for additional parameters that could help in determining the status of HIV-1 infection at the time of initial testing itself in individuals with WBI pattern.

OBJECTIVE

The objectives of the present study were: (i) to determine the frequency of HIV-1 infected individuals in a group of professional donors showing WBI patterns in initial testing on the basis of follow up serological studies; (ii) to find out if any HIV related epidemiological or serological characteristics recorded at the time of initial testing could be considered as predictor for HIV-1 infection in WBI specimens; and (iii) to evaluate two alternative serodiagnostic strategies for HIV-1 infection viz. multiple EIAs based on different antigen preparations/principles and a line immunoassay (LIA) employing recombinant antigens in resolving status of HIV-1 infection in specimens showing WBI results at initial testing.

STUDY DESIGN

Professional donors with WBI patterns belonging to EIA reactive and EIA nonreactive groups were subjected to study of epidemiological profile, prevalence of sexually transmitted diseases (STD) markers and follow up serological testing for HIV-1 at 6, 12, 24 and 48 weeks intervals to record any seroconversion. The initial and follow up specimens from the donors with initial WBI results were subjected to two EIAs (one based on dot immunoassay using synthetic HIV-1 antigens and other based on microwell EIA using recombinant HIV-1 proteins) as well as to LIA.

RESULTS

Professional donors with initial WBI results, from the EIA reactive group had higher proportion of unmarried individuals (90.3%), with history of heterosexual promiscuity (75%) and visit to STD clinics (36.1%) compared with the WBI donors from the EIA nonreactive group (72.7, 42.4 and 12.1%, respectively, P values < 0.001). Prevalence of antitreponemal antibodies was higher in the former group (16.7%) compared with the later group (1.5%, P value < 0.002). Seroconversion was recorded in 4 (7.3%) out of 55 EIA reactive WBI donors from the EIA reactive group that were characterised by high optical density (OD) values in EIA, 'p24 only' pattern of band in WB and positivity by LIA at the time of initial testing. LIA was found to be more reliable test compared with combination of EIAs to determine status of HIV-1 infection in WBI specimens at the time of initial testing.

CONCLUSION

The present study points out that parameters like history of heterosexual promiscuity, prevalence of STD markers, high OD values in screening EIA, 'p24' only pattern of bands in WB and positivity by LIA could have individual predictive values for HIV-1 infection in specimens showing WBI pattern of results at initial testing.

Screening for human immunodeficiency virus type 1 and 2 in a Turkish blood donor population

OBJECTIVES

To determine the prevalence of human immunodeficiency virus-1 and -2 infection in voluntary blood donors at a university hospital in the third largest city of Turkey and to evaluate the HIV testing strategy for notifying blood donors.

METHODS

Between July 1995 and August 1997, 36,373 voluntary blood donors who met the criteria for donating blood were tested for the presence of HIV-1 and -2 antibodies by using an automated enzyme-linked fluorescent immunoassay. Repeatedly reactive samples were subjected to a different enzyme-linked immunosorbent assay (ELISA) and a line immunoassay (LIA) for the detection of antibodies.

RESULTS

Of the 36,373 samples tested 72 were found to be repeatedly reactive or borderline by the first screening enzyme immunoassay (EIA). None of the 72 samples was reactive by the second EIA. These samples were further tested by LIA: 64 were negative on the line immunoassay and 8 were indeterminate. Three of eight donors who had indeterminate results by LIA were tested for HIV-1 DNA by polymerase chain reaction (PCR) and were found to be negative. One additional donor with an indeterminate LIA was found to be negative by EIA and LIA during the 6-month follow-up period.

CONCLUSION

Donor questioning, repeat EIA testing, LIA testing, and HIV-1 DNA analysis did not confirm evidence for HIV infection among this blood donor population. Blood donor notification of test results according to the World Health Organization (WHO) strategy III was found to be an appropriate approach.

Synthetic-peptide-based enzyme-linked immunosorbent assay for screening human serum or plasma for antibodies to human immunodeficiency virus type 1 and type 2

A synthetic-peptide-based enzyme-linked immunosorbent assay (EIA) capable of screening for antibodies to both human immunodeficiency virus type 1 (HIV-1) and HIV-2 has been developed for use in blood banks and diagnostic laboratories. Microtiter wells are coated with two synthetic peptides, one corresponding to the highly conserved envelope region of HIV-1 and another corresponding to the conserved envelope region of HIV-2. Overall, sensitivity was 100% in 303 individuals diagnosed with AIDS and 96 individuals diagnosed with AIDS-related complex, 14.8% in a study of 500 high-risk group members, 99.9% in 600 EIA repeatedly reactive (RR)-HIV-1 Western blot (WB)-positive repository specimens, and 100% for 222 geographically diverse HIV-1 specimens and 216 confirmed HIV-2-positive specimens evaluated. The specificity was determined to be 99.72% for a total of 13,004 serum and plasma samples from random volunteer donors evaluated across five blood banks. Forty donors who were found to be EIA RR-WB indeterminate but nonreactive on the United Biomedical, Inc., test (UBI HIV 1/2 EIA) were prospectively followed as an additional measure of specificity. None of the 40 low-risk cases evolved into a positive WB pattern at follow-up. The sensitivity and specificity of this new assay are comparable to those of other Food and Drug Administration-licensed HIV-1 and HIV-1-HIV-2 assays that are currently available in the United States. The UBI HIV 1/2 EIA affords laboratories another choice in the detection of antibodies for HIV-1 and HIV-2 with a test based on an alternative antigen format.

A multicentre quality assessment study to monitor the performance of HIV-1 PCR

Eleven German laboratories and one Swiss laboratory initiated a quality assessment study to evaluate the specificity and sensitivity of their polymerase chain reaction (PCR) for detection of HIV-1 DNA. Following its own PCR protocols, each laboratory tested a panel of ten coded samples consisting of cell pellets containing 0, 0.1, 1, 10, 10(2), 10(3) and 10(4) ACH-2 cells per 1.5 x 10(5) uninfected peripheral blood mononuclear cells. Of the twelve participating laboratories, three reported correct results for the dilution series as well as for uninfected specimens. One or more classification errors were recorded for 12% of the samples for which the diagnosis was expected to be positive or negative. Samples containing 10 copies of the target template were correctly reported by eleven of the twelve participants. The average sensitivity was 97%. The results of the study revealed no significant differences between the Amplicor kit and in-house procedures. Most of the classification errors occurred in specimens from HIV-negative samples. Out of 36 negative samples, 5 were reported false positive, showing that contamination remains a problem for some laboratories, regardless of the PCR test performed. Careful laboratory techniques and internal as well as external quality control procedures will help avoiding carryover contamination.

Antibodies to the HIV-1 p17 protein cross-react with human superoxide dismutase-2

Antibodies reacting with the gag protein p17 of the human immunodeficiency virus type 1 (HIV-1) can occasionally be found in the serum of non-HIV-1-infected individuals. Conversely, anti-p17 antibodies can also react with human tissues from non-infected individuals. Here we report on the isolation from human liver of a molecule that is immunoreactive with anti-p17 antibodies. This molecule was purified to homogeneity and identified as superoxide dismutase-2 (manganese type SOD). Both human SOD-2 and HIV-1 p17 contain the LQPALK hexapeptide which may serve as a common antigenic determinant. This study indicates that human SOD-2 is a target for anti-p17 antibodies and suggests that HIV-1-negative individuals may possess SOD-2 auto-antibodies that cross-react with HIV-1 p17.

Interactions between Exogenous and Endogenous Retroviruses

Retroviruses are distinguished from other viruses by several features. Notably, some retroviruses are present as normal elements in the genomes of virtually all vertebrates (endogenous proviruses). Others are exogenous, i.e. horizontally transmitted agents, many of which cause fatal diseases. The endogenous retroviruses are genetically transmitted and to a large extent their significance is uncertain. However, there is evidence suggesting that they contribute to the development of diseases in several animal species. Most importantly, some endogenous retroviruses are capable of interacting with exogenous counterparts through a variety of different mechanisms with serious consequences to the host. Conversely, others are advantageous in that they protect against exogenous retroviruses. In this review various types of interactions between endogenous and exogenous retroviruses are discussed, including receptor interference, recombination, phenotypic mixing, immunological interactions and heterologous trans-activation. Copyright 1997 S. Karger AG, Basel

Human immunodeficiency virus testing and counseling: nuts and bolts

The human immunodeficiency virus poses an increasing health hazard to women. Physicians must recognize this risk and evaluate their patients for human immunodeficiency virus. Because of general increased awareness and the recommendations that all prenatal patients be offered human immunodeficiency virus testing and counseling, more and more women will be tested, yet counseling has not become a routine aspect in the evaluation of patients. This article reviews the key components of human immunodeficiency virus testing and counseling, including test interpretation, risk assessment, risk reduction, and pretest and posttest counseling. Familiarity with these areas should enable the practitioner to feel comfortable in providing this service.

The diagnosis and management of HIV infection

In the past 15 years HIV infection and AIDS have become pandemic in the world. Infectious and neoplastic complications have evolved in response to medical advances and to the appearance of HIV infection in different populations. Because AIDS patients live longer with severe immunosuppression and new treatments have controlled opportunistic infections, the spectrum of complications of AIDS has changed. New and more effective antiretroviral drugs are being developed, and physicians are learning how to use them more effectively. Currently, medical management of HIV-infected patients focuses on the appropriate use of antiretrovirals and the prevention, early diagnosis, and treatment of complicating illnesses. A coordinated continuum of care and patient education and involvement are also key elements of effective management of HIV infection.

Evaluation of Chiron HIV-1/HIV-2 recombinant immunoblot assay

In a study to determine the reliability, sensitivity, and specificity of the Chiron RIBA HIV-1/HIV-2 Strip Immunoblot Assay (RIBA HIV-1/2 SIA) for confirmation of human immunodeficiency virus type 1 (HIV-1) and HIV-2 antibodies, 1,263 serum samples from various populations in the United States, Caribbean, Africa, India, and Thailand were evaluated by RIBA HIV-1/2 SIA, and the results were compared with those obtained by an HIV-1 Western blot (immunoblot) assay. All sera were tested by HIV enzyme immunoassay, RIBA HIV-1/2 SIA, and Western blotting. Samples with discrepant results were further tested by an HIV-1 and/or HIV-2 immunofluorescent-antibody assay and HIV-1 p24 antigen assay. The RIBA HIV-1/2 SIA detected all 17 HIV-1 and HIV-2 dually reactive serum samples, all 215 HIV-2-positive serum samples, and 480 of 481 HIV-1-positive serum samples for a sensitivity of 99.8%. Of 548 negative samples, 523 were RIBA HIV-1/2 SIA negative, for a specificity of 95.4%, with 22 (4%) samples interpreted as indeterminate and 3 (0.6%) interpreted as falsely positive. Western blotting detected 391 of 548 negative samples (specificity, 71.4%), with 152 (27.7%) samples interpreted as indeterminate and 5 (0.9%) interpreted as falsely positive. In conclusion, the RIBA HIV-1/2 SIA had a sensitivity comparable to that of Western blotting and could discriminate HIV-1 from HIV-2 in one blot, providing a cost advantage. Because of its high degree of specificity, the RIBA HIV-1/2 SIA further reduced the number of indeterminate results found by Western blotting, providing a more accurate means of assessing seronegative individuals.

Difficulties and strategies of HIV diagnosis

HIV infection is commonly diagnosed by detection of antibodies (anti-HIV) by ELISA or agglutination. Reactive results are confirmed by western blot (immunoblot) or further specific tests such as competitive ELISA, which, when evaluated quantitatively, allow the differentiation of HIV types and partially subtypes. Detection of infection of newborn babies, characterisation of individual strains for subtyping and forensic identification, and therapeutic monitoring are the domain of nucleic-acid-based assays. Nucleic-acid-based assays narrow the serological diagnostic window period in early HIV infection and, when quantified, give some indication of clinical status.

B cell epitopes of HIV type 1 p24 capsid protein: a reassessment

The objective of the present study was to identify p24 antigenic domains recognized during natural human immunodeficiency virus type 1 (HIV-1) infection, the determination of the major epitopes of p24 having significant applications for both the improvement of diagnostic approaches and the development of vaccines. Reactivity of 20 HIV-1-infected patients and 8 HIV-1-negative patients was analyzed using an enzyme-linked immunosorbent assay (ELISA) developed with 45 overlapping synthetic pentadecapeptides, spanning amino acids 133 to 363 of HIV-1 p55gag precursor. Two peptides covering aa 178-192 and 288-302 of p55 were recognized by 40 and 45% of HIV-1 antibody-positive human samples, respectively. A peptide covering aa 272-322 of p55 was synthesized and recognized by most human sera in indirect ELISA. However, inhibition assays indicated that this sequence does not contain all of the immunodominant domains of p24 since it was not sufficient to block binding of human sera to whole p24. A three-dimensional model of p24 derived from the Mengovirus VP2 suggests that the two distant sequences recognized by human sera containing antibodies to HIV-1 could possibly be a part of a conformational epitope built up by two loops corresponding to aa 183-186 and 289-292.

The influence of CD4+ T cells, HIV disease stage and zidovudine on HIV isolation in Bahia, Brazil

HIV-1 isolation was attempted on 72 individuals, including persons with known HIV infection and five without proven HIV infection but with indeterminate Western blot patterns, as well as on low-risk HIV seronegative persons. The ability to detect HIV-1 from culture supernatant by p24 antigen capture assay was evaluated by segregating patients by absolute CD4+ cell counts, clinical stage of disease, p24 antigenemia and zidovudine use. The likelihood of a p24 positive HIV culture was highest among patients with CD4+ T-cell counts below 200/ul and patients with advanced clinical disease. Use of zidovudine did not affect the rate of HIV positivity in cultures.

Estimated risk of transmission of the human immunodeficiency virus by screened blood in the United States

BACKGROUND

In the United States, transmission of the human immunodeficiency virus (HIV) by blood transfusion occurs almost exclusively when a recently infected blood donor is infectious but before antibodies to HIV become detectable (during the "window period"). We estimated the risk of HIV transmission caused by transfusion on the basis of the window period associated with the use of current, sensitive enzyme immunosorbent assays and recent data on HIV incidence among blood donors.

METHODS

We analyzed demographic and laboratory data on more than 4.1 million blood donations obtained in 1992 and 1993 in 19 regions served by the American National Red Cross, as well as the results of HIV-antibody tests of 4.9 million donations obtained in an additional 23 regions.

RESULTS

We estimated that, in the 19 study regions, 1 donation in every 360,000 (95 percent confidence interval, 210,000 to 1,140,000) was made during the window period. In addition, it is estimated that 1 in 2,600,000 donations was HIV-seropositive but was not identified as such because of an error in the laboratory. We estimated that 15 to 42 percent of window-period donations were discarded because they were seropositive on laboratory tests other than the HIV-antibody test. When these results were extrapolated to include the additional 23 Red Cross service regions, there was a risk of one case of HIV transmission for every 450,000 to 660,000 donations of screened blood. If the Red Cross centers are assumed to be representative of all U.S. blood centers, among the 12 million donations collected nationally each year an estimated 18 to 27 infectious donations are available for transfusion.

CONCLUSIONS

The estimated risk of transmitting HIV by the transfusion of screened blood is very small and nearly half that estimated previously, primarily because the sensitivity of enzyme immunosorbent assays has been improved.

Detection of human immunodeficiency virus type 1 proviral DNA by PCR using an electrochemiluminescence-tagged probe

We have developed a rapid, pseudohomogeneous assay for the detection of PCR amplicons, based on the use of electrochemiluminescence generated from a Tris-bipyridine ruthenium(II) label. PCR amplification of highly conserved human immunodeficiency virus type 1 (HIV-1) gag gene sequences was performed with SK38 and SK39 primers, the latter of which was 5' biotinylated. Post-PCR reaction mixtures were combined with 10(12) copies of the SK19 probe-Tris-bipyridine ruthenium(II) conjugate, denatured by heating at 100 degrees C for 5 min, and hybridized at 55 degrees C for an additional 15 min. Hybridization to the biotinylated strand of the amplified DNA was determined by the addition of streptavidin-conjugated magnetic particles and analyzed by using an Origen-1 electrochemiluminescence analyzer. Our results demonstrated a sensitivity of fewer than five copies of HIV-1 (pre-PCR), by using either purified plasmid DNA containing one complete copy of the HIV-1 cDNA genome or lysed, proteinase K-treated 8E5 cells as the starting material. In an evaluation of actual clinical specimens (peripheral blood monocytes from both healthy and HIV-1-infected children), the electrochemiluminescent detection assay correlated 100% with both our standard method (solution hybridization with a radiolabeled probe followed by polyacrylamide gel electrophoresis [PAGE] and autoradiography) and a commercial method (Roche Amplicor). The electrochemiluminescent method was substantially easier to perform than either the PAGE or microtiter plate assays and was considerable faster to perform than either of these alternative formats.

Detection of HIV-1 proviral sequences in lymphocytes using a qualitative polymerase chain reaction assay

The performance and clinical relevance of a qualitative PCR-based assay for the detection of HIV-1 DNA sequences in peripheral blood mononuclear cells (PBMCs) was evaluated by two different laboratories. Four hundred and one samples were obtained from 397 individuals from different risk populations. All blood donors tested had negative results; positive signals were obtained from all infected patients. HIV-1 DNA was detected in 3 of 17 infants born to seropositive mothers; Western blot indeterminate blood donors and exposed health-care workers had negative results. Our results demonstrate that this PCR assay provides both sensitive and specific results and is suitable for testing large numbers of samples and for rapid identification of HIV-1 infection.

Antibodies to human immunodeficiency virus (HIV-1) in autoimmune diseases: primary Sjögren's syndrome, systemic lupus erythematosus, rheumatoid arthritis and autoimmune thyroid diseases

The aetiology of autoimmune diseases remains unknown. The relationship between virus, and more recently retrovirus, has been suggested with this group of diseases. Immunoblotting is a useful method for determining the presence of proteins coded by different retrovirus genes. Since the prevalence of these types of proteins in patients with primary Sjögren's syndrome (SS), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and autoimmune thyroid diseases has not been fully established, the aim of this work was to determine the prevalence of antibodies to immunodeficiency human virus type 1 (HIV-1) proteins in these diseases and their possible relationship with the presence of anti-nuclear, anti-DNA, anti-SSA (Ro) and anti-SSB (La) autoantibodies. Antibodies to human immunodeficiency virus (HIV-1) were studied in a group of 341 patients with autoimmune diseases (77 SS, 98 SLE, 75 RA, 91 autoimmune thyroid diseases) and 126 blood donors as a control group. A Western blot was used to detect antibodies to HIV-1, and a double polymerase chain reaction (PCR) using nested primers in the gag and pol gene of HIV-1. Antinuclear antibodies, anti-DNA, anti-SSA (Ro) and anti-SSB (La) were determined by enzyme-linked immunosorbent assays. At least one band was shown on immunoblotting in 26% of patients with autoimmune diseases and 35% of controls. The presence of antibodies to p55 or p68 proteins in patients with SS or SLE proved to be the only statistically significant difference between the other autoimmune diseases studied and the control group. These antibodies were not associated with autoantibodies ANA, DNA, SSA (Ro) or SSB (La).(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-human immunodeficiency virus type 1 antibodies of noninfected subjects are not related to autoantibodies occurring in systemic diseases

Indeterminate Western blot (WB) (immunoblot) patterns for anti-human immunodeficiency virus type 1 (HIV-1) antibodies are often observed when testing serum samples from noninfected individuals. We investigated here the possible involvement of some frequently occurring autoantibodies (anti-SmB/B', U1snRNP [68 kDa, A, and C], Ro/SS-A [60 and 52 kDa], and Jo-1) in the generation of such indeterminate HIV-1 WB. In particular, the role of a reported sequence homology between p24 gag and the SmB/B' autoantigen was investigated. Serum samples were obtained from 50 healthy controls, 51 patients with systemic lupus erythematosus (SLE), 46 with systemic sclerosis, 6 with Sjögren's disease, 3 with mixed connective tissue disease, and 41 healthy subjects with persistent indeterminate HIV-1 WB. Reactivity to HIV-1 p24 gag was slightly but not significantly more frequent in patients with SLE than in controls (25.5% versus 14.0%; P > 0.1), whereas reactivity to HIV-1 p17 gag was significantly more frequent in the former subjects (23.5% versus 8.0%; P = 0.03). Simultaneous reactivity to p17 and p24 was observed in patients with SLE (11.8%; P = 0.014) or systemic sclerosis (8.7%; P = 0.049) but not in controls. There was no association found between the presence of any autoantibody and the occurrence of indeterminate HIV-1 WB nor between the presence of p24-reactive antibodies and anti-SmB/B'; this indicates that most p24-reactive antibodies are directed to epitopes other than the proline-rich sequences shared by p24 gag and SmB/B'.

Evaluation of HIV type 1 western blot-indeterminate blood donors for the presence of human or bovine retroviruses

From 1985 through 1990, 1100 of 500,000 human blood donations in Syracuse, New York were repeatedly reactive by ELISA for antibodies to the human immunodeficiency virus type 1 (HIV-1). Nine hundred of the ELISA-reactive samples were confirmed as negative by Western blot (WB), 40 were confirmed as positive, and the remaining 160 sera were indeterminate, reacting mainly with HIV-1 gag gene products. Twenty donors with the most reactive indeterminate WB were selected for follow-up studies. Four of these 20 donors admitted to retroviral risk factors and, interestingly, 12 (60%) had exposure to dairy cattle and drank unpasteurized milk. These 20 donors were analyzed over a 3-year period for the presence of the pathogenic human retroviruses HIV-1, HIV-2, human T cell lymphoma/leukemia virus types I and II (HTLV-I and HTLV-II), as well as bovine immunodeficiency virus (BIV) and leukemia virus (BLV). Retroviral analyses included serology, plasma antigen capture, virus culture, and the polymerase chain reaction. Only one donor seroconverted and was clearly infected with HIV-1. None of the other 19 donor serological reactivities to HIV-1 changed, nor were they positive for any of the above-mentioned retroviruses. Although we cannot ascertain whether these latter 19 HIV-1 WB-indeterminate donors were exposed to human or bovine retroviral proteins, it is unlikely that their HIV-1 seroreactivity was caused by infection with HIV-1, HIV-2, HTLV-I, HTLV-II, BLV, or BIV.

Molecular methods: applications for clinical infectious diseases

The application of molecular biology to microbiology has led to a surge of new information about most infectious microorganisms, the pathogenesis of the infections they cause, and the specific microbial antigens involved in the immune response to these infections. The simultaneous application of the same techniques to diagnosis and epidemiology has also shown great promise, but these developments have not yet had a major effect on the routine practice of medicine. For some purposes, direct probe tests perform as well as other available methods. However, for most infections, these methods have not been proven sufficiently sensitive. The latest generation of highly sensitive diagnostics based on the polymerase chain reaction will overcome this technical obstacle and may revolutionize the management of many infections. Difficulties inherent in performing these tests will require special procedures and training in clinical laboratories to ensure that they are performed reliably. Nucleic acid-based methods for epidemiologic typing of microorganisms and for identification of noncultivatable pathogens are particularly useful for analysis of poorly cultivatable, dangerous, or otherwise untypeable microorganisms.

Detection of human immunodeficiency virus type 1 by PCR before seroconversion in high-risk individuals who remain seronegative for prolonged periods

HIV-1 seronegative patients at high risk for HIV infection were followed up. In 1990 PCR was positive for HIV DNA sequences in samples of 17 seronegative patients who continued to report for surveillance of HIV infection. There was clear evidence of seroconversion in four of these 17 seronegative patients, while in one patient an indeterminate result for HIV was repeatedly obtained in different samples. The other 12 patients continue to be seronegative without any evidence of HIV infection except the presence of provirus in peripheral blood mononuclear cells. It is important to apply the PCR technique together with tests to detect other virological and immunological markers, in order to identify seronegative carriers and thus avoid HIV transmission by them.

Host-virus interaction as defined by amplification of viral DNA and serology in lentivirus-infected sheep

To correlate the presence of ovine lentivirus (OvLV) as detected by polymerase chain reaction (PCR) with detection of antibody, 42 sheep from a flock with enzootic OvLV infection were studied. The results of agar gel immunodiffusion (AGID), ELISA, and immunoblotting assays were compared, and leukocytes (blood, bone marrow, lymph node, and lung cells) were assessed for viral DNA by PCR using pol and LTR primers; amplified products were detected by specific DNA and RNA probes. Based on the number of animals that had detectable viral DNA, the specificities of AGID, ELISA, and immunoblotting were 77%, 92%, and 95 or 100% (depending on which criterion was used to interpret immunoblot results), respectively. Only in animals with OvLV-associated disease was OvLV DNA detected in leukocyte DNA prior to the amplification of virus in culture and only in this group was high titer antibody detected to the OvLV major surface (gp 105) and transmembrane (gp 55) antigens. Animals that were both antibody and PCR-negative lacked histopathologic evidence of disease. From this study there was no indication that OvLV infection without the development of antibody occurs, and detection of OvLV DNA in animals with weak or partial serological reactions likely indicates early OvLV infection rather than false-positive PCR results.

Comparative humoral responses to human immunodeficiency virus type 1-p24gag linear B-cell epitopes among individuals showing atypical western immunoblotting reactions and implications for diagnosis

Serum specimens from 25 individuals with an isolated human immunodeficiency virus type 1 (HIV-1) core antigen reactivity in a Western immunoblot test were examined for their reactivities with HIV-1 virions, control cellular antigens, HIV-1-Bru p24gag recombinant protein (p24gag), and a panel of 22 p24gag-derived peptides. The results were as follows: (i) serum specimens from eight HIV-1-uninfected subjects did bind to virions but failed to bind to p24gag; (ii) sera from 13 HIV-1-uninfected subjects and from one HIV-2-infected patient reacted with HIV-1 virions and p24gag but failed to bind to any of the peptides expressing major p24gag epitopes, and (iii) 3 serum specimens obtained from one neonate carrying anti-HIV-1 maternal antibody and from two HIV-1-infected subjects who had seroconverted during the study reacted with HIV-1 virions, p24gag, and one or more peptides containing the major p24gag epitopes. Our data suggest that the combination of p24gag and appropriate peptides could be useful for resolution when atypical Western immunoblot results are encountered.

HIV and adolescents

Human immunodeficiency virus has entered the adolescent population, and pediatricians will be caring for youngsters who are HIV positive or at risk of being infected. We should remember that it is risky sexual behavior and injection drug use that places a teen at risk for HIV infection, not their sexual orientation, ethnicity, or gender. Parents and their teenagers desire and expect their pediatricians to provide care and guidance for the diseases and problems that adolescents face. A screening psychosocial assessment of teenagers can identify those who need more in-depth counseling. Although the subjects of sex and drug use initially may be uncomfortable for a physician, practice using the HEADSS assessment will rapidly lead to comfort in discussing these important subjects. An understanding of HIV testing and pre- and post-test counseling will prepare the physician for the inevitable patient who wishes testing or who is HIV positive. Much of the treatment of HIV-positive adolescents involves patience and support while the adolescent grapples with the serious implications of being HIV positive. The initial history and physical exam establishes baselines regarding previous infections and illnesses that may bear on HIV infection, as well as determining which symptoms and signs of HIV infection are present. The initial laboratory tests further define the patient's current clinical state and will determine what therapies are immediately needed. Human immunodeficiency virus continues to evolve toward a manageable chronic illness that responds most favorably to early intervention.