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PubMedDate not supplied

HIV antigen, HIV antibody and serum interferon in a patient with encephalopathy.

Acute encephalopathy was associated with the presence of human immunodeficiency virus type I (HIV I) antigen and seroconversion to anti-HIV I in a 27-year-old homosexual man. Examination of consecutive sera from the patient revealed circulating interferon (IFN) alpha which became detectable with the appearance of HIV I antigen but before development of anti-HIV I. Serum IFN was present for only a limited time and was not demonstrable after neurological symptoms resolved. It may be speculated that circulating antiviral activity contributed to the clinical manifestations of acute HIV I infection.

Acquired Immunodeficiency Syndrome↗
PubMed1987

The significance of HIV antigen and HIV antibodies specific against envelope and core proteins in serum of HIV-infected hemophiliacs.

Serial serum samples from the 21 HIV-infected Norwegian hemophiliacs have been assayed for the presence of HIV antigen and antibodies to HIV specific for the core protein p24 and the envelope protein gp41. HIV antigen was detected in 4 patients, of whom 3 have developed AIDS to date. HIV antigen appeared in serum 10 to 24 months before the diagnosis in these patients. Antibodies to gp41 was a constant finding. Antibodies to p24 disappeared from the serum in 1 patient who developed AIDS and from 3 persons free of symptoms related to the HIV infection. The detection of HIV antigen in HIV antibody-positive hemophiliacs appears to be of considerable prognostic significance.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Detection of very early antibody to native HIV antigens by HIV neutralization and live-cell immunofluorescence assays.

Very early detection of HIV infection could help decrease the spread of HIV, improve safety of the blood supply, and permit earlier treatment. Early detection was reported when native gp41 antigen was used to detect antibodies that occurred 2-6 weeks earlier than detection of antibodies to denatured antigens by the current EIA or WB tests or detection by the HIV RNA test. We hypothesized that early antibodies to native gp41/160 could be detected, not only by the reported live-cell immunofluorescence (IFA) but also by a neutralization test, since virions as well as HIV-infected cells contain native gp41/160. To test this hypothesis, we did an initial test of concept study to compare the neutralization test with other tests, using sera from 12 high-risk patients. The neutralization test reproducibly detected early antibodies (characterized) in the sera of 10 of 12 (83%) high-risk subjects. Importantly, the EIA and WB tests that use denatured antigens missed the early diagnosis in 12 of the 13 subjects (92%). The findings support the concept that native HIV antigens can detect polyclonal HIV neutralizing antibodies and live-cell IFA antibodies earlier than currently available tests that use denatured antigens.

Antibody Affinity↗
PubMed1991

HIV antigen variability in ARC/AIDS.

To define the natural variability of human immunodeficiency virus p24 antigen (HIV Ag) over time in untreated HIV-infected patients, we analyzed the percentage change of serum HIV Ag in 40 antigenemic ARC/AIDS subjects receiving placebo in a 24 week clinical trial. When grouped by month of observation, no differences in HIV Ag change were seen among all five 1 month observation periods (p greater than 0.4). After all 105 monthly changes (median of 3 per subject) were pooled, the mean monthly HIV Ag change was 0% change (standard deviation: 77% increase, 44% decrease). Furthermore, HIV Ag changes did not differ among all lengths of observation (from 1 to 5 months using all possible pairwise combinations of HIV Ag levels, p greater than 0.4). CD4 T-cell changes over the whole study did not correlate with HIV Ag changes over the same period. Knowledge of this broad HIV Ag variability should be useful in calculating sample size and in choosing categorical responses unlikely to occur spontaneously in clinical trials of antiviral agents where HIV Ag changes are used as surrogate markers of efficacy.

AIDS-Related Complex↗
PubMed1995

Human immunodeficiency virus (HIV) antigen testing to detect HIV infection in female sex workers in Singapore.

Human immunodeficiency virus (HIV) infection is characterised by seroconversion after a ¿window¿ period of 2 to 3 months. After this period antibodies are usually detectable by screening tests (enzyme immunoassay or particle agglutination) confirmed by Western blot analysis. We studied 1000 newly enrolled female sex workers who had not been previously tested for HIV to assess the usefulness of HIV antigen testing to improve the efficacy of HIV infection detection. Blood was taken at enrollment for HIV antigen and HIV antibody testing. The Abbott HIVAG-1 test was used to detect antigen; antibody detection was by the Abbott recombinant HIV-1/HIV-2 3rd generation enzyme immunoassay (EIA) test, the Fujirebio Serodia-HIV particle agglutination (PA) test for screening, and the Diagnostic Biotechnology HIV Blot 2.2 Western blot (WB) test for antibody confirmation. Of the 1000 samples, 26 were positive for HIV antibody testing (26/26 for EIA, 25/25 for PA, 26/26 for WB), giving a prevalence rate of 2.6%, Of these 26 seropositive samples 1 was positive on HIV antigen testing. There were no samples which were antigen-positive and antibody-negative. HIV antigen testing does not add to increased efficacy of HIV detection among female sex workers in Singapore.

Blotting, Western↗
PubMed1990

Removal of HIV antigens and HIV-infected cells in vitro using immunomagnetic beads.

Human anti-HIV antibody-coated magnetic beads and magnetic particle concentrators were used to eliminate HIV antigens and the infected cells in vitro. Fifty micrograms/ml of the antibody coated on 30 mg/ml of tosyl-activated beads, and 10 min of reaction time between the antigens and the immunobeads were sufficient to eliminate the virus antigens from phosphate buffered saline, serum and peripheral blood. HIV-infected cells were eliminated in vitro, but not completely. This method will be useful in eliminating viral antigens and infected cells from clinical material such as blood and blood products.

Cell Separation↗
PubMed1987

Detection of HIV antigen and specific antibodies to HIV core and envelope proteins in sera of patients with HIV infection.

The sera of well-characterized populations were examined for three markers of human immunodeficiency virus (HIV) infection; HIV antigen (HIV Ag), and antibodies to HIV envelope (gp41) and core (p24) proteins. Of 563 serum samples tested, 251 were from HIV-infected patients diagnosed as having AIDS manifested by opportunistic infections (AIDS-OI), AIDS-associated Kaposi's sarcoma (AIDS-KS), or AIDS-related complex (ARC). One hundred seventy-six specimens tested were from asymptomatic high-risk individuals, and 136 were from heterosexual control subjects or patients with non-AIDS-related disease. None of the 136 control individuals tested had HIV Ag or HIV antibodies to either p24 or gp41. Of the 427 HIV-seropositive individuals, 99% to 100% were positive for gp41 antibodies to HIV. In contrast, the seroprevalence of p24 antibodies to HIV varied from 23% to 83% and appeared to be inversely associated with the severity of the patients' clinical symptoms. When specimens were analyzed for the presence of HIV Ag, in seropositive individuals the prevalence rate for this marker was lowest (1.4%) in asymptomatic individuals and highest (50%) in the AIDS-OI diagnosed group. Also, 240 cases with AIDS-KS, AIDS-OI, and ARC and the group of asymptomatic high-risk individuals were analyzed for T helper/T lymphocytes (T4) cell number and T4/T8 ratio; only one (2.0%) HIV Ag-positive case showed a T4 cell number greater than 400 and a normal T4/T8 ratio. These studies appear to demonstrate a direct correlation between the presence of HIV Ag and the severity of clinical complications of HIV infection.

Antibodies, Viral↗
PubMed1989

Independent clinical significance of HIV antigen determination and CD4 counts in anti-HIV positive patients.

HIV antigenemia was found in 52/243 HIV antibody positive individuals attending 2 AIDS-screening clinics, giving a prevalence of 13, 25 and 76% in CDC groups II, III and IV, respectively. No correlation was found to decreased CD4 lymphocyte values in the individual groups. HIV antigen therefore identified a separate subpopulation. For 138 asymptomatic patients followed prospectively both laboratory parameters predicted HIV-related events, the relative risk factor being 4 for low CD4 value and 6 for presence of HIV antigen. Individuals presenting with HIV antigen and decreased CD4 count all developed disease within 18 months, the relative risk factor being 24. Thus the 2 markers, when measured together, effectively separated asymptomatic HIV-infected patients into 1 of 3 risk categories.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1998

Lymphocyte-proliferative responses to HIV antigens as a potential measure of immunological reconstitution in HIV disease.

Lymphocyte-proliferative responses (LPRs) to HIV antigens are absent or of low magnitude in the majority of HIV-infected individuals, even early in the disease. However, lymphocytes from 2% to 3% of individuals proliferate very strongly to HIV Env or Gag antigens, and these individuals remain well clinically, without antiretroviral therapy. In established HIV infection, suppression of HIV-replication with potent antiretroviral therapy does not result in the development of strong LPRs to HIV antigens. Large LPRs to HIV antigens can be induced by HIV vaccines in patients with established infection, even though they were not formed in response to infection. Studies must be designed to determine whether large LPRs induced by vaccines administered in conjunction with potent antiretroviral therapy are associated with long-term control of HIV infection.

Animals↗
PubMed1988

Acid hydrolysis of serum samples to increase detection of HIV antigen.

Sera from 32 HIV-infected patients and 20 controls were assayed for HIV antigen (HIV-Ag) and antibodies following acid hydrolysis. Acid hydrolysis, followed by neutralization immediately prior to the assay, was found to be a simple means to solubilize immune complexes and allowed recovery of 40-50% of complexed antigen. Following acid hydrolysis, HIV-Ag levels rose or became detectable in 22/32 patients and HIV IgG1-4 levels rose in 17/20 patients studied. The results show that complexed HIV-Ag may evade detection in HIV-infected patients.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Absence of HIV antigens in renal tissue from patients with HIV-associated nephropathy.

HIV-associated nephropathy (HIV-N) is considered a distinctive disease, the pathogenesis of which is still undefined. Direct virus-induced renal cell damage has been postulated. The numerous cytolytic ultrastructural changes and a few studies by immunoperoxidase support this hypothesis, but there has been no demonstration of virus by electron-microscopy (EM) or by tissue culture. In seven out of 12 cases with histological characteristics of HIV nephropathy, with proteinuria (five cases) or with nephrotic syndrome (two cases), we tested renal tissue for HIV antigens: core p18 and p25; envelope gp45 and gp110, by means of immunoperoxidase avidin-biotin complex monoclonal antibodies (MoAbs). Light-microscopy (LM) showed in five patients a focal and segmental glomerular sclerosis, and in two a mesangial hyperplasia with vacuolisation of visceral epithelium and protein inclusions. Electron-microscopy, performed in five of seven patients, showed several protein inclusions in podocyte cytoplasm, tubuloreticular inclusions in endothelial cell cytoplasm in all cases, nuclear degranulation of tubular cells in four cases and nuclear bodies in two. HIV antigens by MoAbs on renal tissue were negative in all cases, in both glomeruli and tubules. These results do not confirm the presence of HIV proteins in renal tissue of patients with HIV nephropathy. A possible explanation, apart from no direct HIV in the disease, may be the low viral load in tissues, because of the early phases of renal damage in most cases.

AIDS-Associated Nephropathy↗
PubMed1989

Detection of antibodies against myelin basic protein and increased levels of HIV-IgG antibodies and HIV antigen after solubilization of immune complexes in sera and CSF of HIV infected patients.

Fifteen HIV seropositive patients were studied. It was possible to enhance detection of HIV antigen and HIV and myelin basic protein (MBP) antibodies after dissociation of immune complexes by acid hydrolysis. HIV p24 antigen was then detected in four patients, three of whom were previously antigen negative. In 14 patients the treatment resulted in increased anti-HIV IgG subclass levels. Anti-MBP IgG was detected in 12 patients. Intrathecal synthesis of anti-MBP IgG subclasses was found in eight patients, five of whom had symptoms from the central nervous system.

Acquired Immunodeficiency Syndrome↗
PubMed1988

[Diagnostic value of the determination of HIV antigen in enzyme immunoassay].

Enzyme-immunoassays (EIA) for HIV antigen and antibodies were performed on 33,076 serum samples during an 11-month period. Prospective analysis involved samples from 21,496 blood donors, 11,086 samples sent in as coming from "high-risk" persons and 101 samples from AIDS patients, while retrospectively samples from 393 high-risk persons, including a group of homosexuals from New York, were tested. No HIV antigen was found among blood donors, although during the test period seroconversion of one blood donor had been noted. Among 297 persons infected with HIV, 82 sera were positive for HIV antigen, always in combination with HIV antibodies: there was no case positive for HIV antigen but negative for HIV antibodies. The results suggests that at present it is not necessary routinely to test blood donors for HIV antigen by EIA.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Evaluation of four HIV antigen tests.

A direct comparison of different HIV antigen assays is very helpful in making an informed choice, not only for the testing laboratories but also for healthcare workers in the developing world who are looking for reliable and inexpensive tests/methods in the follow-up of their treated patients. As a follow-up to the study published previously [Fransen K., Martens G., Stynen D., Goris A., Nys P., Nkengasong J., Heyndrickx L., Janssens W., van der Groen G., 1997. J. Med. Virol. 53, 31--35] where only two tests have been compared, four different commercial methods for HIV antigen determination in plasma and supernatant of cell cultures have now been evaluated on a limited sample size (88): COULTER HIV-1 p24 Antigen Assay (Coulter), (Test 1) INNOTEST HIV Antigen mAb (Innogenetics) (Test 2), Genetic Systems HIV-1 Ag EIA (Sanofi-Pasteur(1)) (Test 3) and VIDAS HIV P24 II (bioMérieux) (Test 4). Of the four tests used in this study, Test 2 was by far the most sensitive test. In a population of 88 follow-up samples from 35 different patients representing all stages of infection, the test detected confirmed p24 antigen at least once in 85.7% (30/35) of these patients, versus Test 3 in 74.3% (26/35), Test 4 in 71.4% (25/35), and Test 1 in 48.6% (17/35) of the patients. Test 2 detected confirmed p24 antigen in 84.9% of the follow-up samples, followed by Test 4 (65.9%), Test 3 (64.8%) and Test 1 (39.8%). Finally, Test 2 also proved best for detecting genetically diverse isolates.

Evaluation Studies as Topic↗