Comparison of different methods for detecting human immune deficiency virus in human immunodeficiency virus-seropositive hemophiliacs

Biosensor technology and surface plasmon resonance for real-time detection of HIV-1 genomic sequences amplified by polymerase chain reaction

BACKGROUND

The recent development of biosensor technologies for biospecific interaction analysis enables the monitoring of a variety of molecular reactions in real time by surface plasmon resonance (SPR). If the ligand is a biotinylated single stranded DNA, this technology could monitor DNA-DNA hybridization. This approach could be of great interest in virology, since the hybridization step is oftenly required to confirm specificity of molecular diagnosis.

OBJECTIVES

To determine whether real-time molecular diagnosis of human immunodeficiency virus type I (HIV-1) could be performed using biosensors and SPR technology.

STUDY DESIGN

Specific hybridization of a biotinylated HIV-1 oligonucleotide probe immobilized on a sensor chip to single stranded DNA obtained by asymmetric polymerase-chain reaction (PCR) was determined using the BIAcore biosensor.

RESULTS

Direct injection of asymmetric PCR to a sensor chip carrying an internal HIV-1 oligonucleotide probe allows detection of hybridization by SPR using biosensor technology. This enabled us to apply a real-time, one-step, non-radioactive protocol to demonstrate the specificity of amplification of HIV-1 genomic sequences by PCR.

CONCLUSION

The procedure described in this study for HIV-1 detection is simple, fast (PCR and SPR analyses take 30 min), reproducible and could be proposed as an integral part of automated diagnostic systems based on the use of laboratory workstations and biosensors for DNA isolation, preparation of PCR reactions and analysis of PCR products.

Prospective study of antigenemia, plasma viremia and lymphocytic viremia in HIV-infected hemophiliacs

A total of 186 blood samples from 24 HIV-1 seropositive hemophiliac patients, monitored every four months for 29 months, were investigated for the presence of viral antigen in plasma. In addition, peripheral blood mononuclear cells (PBMC) were cultured for HIV-1, using normal PBMC as a target for replication. Antigenemia was detected in 51% of the patients and from PBMC in 87.5% of the patients. The incidence of HIV isolation in asymptomatic patients (42.8%) was similar to that found in symptomatic patients (51.4%). Patients with opportunistic infections had a higher incidence of lymphocytic viremia (p < 0.05). Plasma viremia was closely associated (p < 0.05) with low CD4+ counts and infection progression. The persistence of antigenemia was also a marker of a poor clinical course. In treated patients, plasma viremia was the marker that better correlated with the clinical course, and it did not appear during the first nine months of therapy. Zidovudine doses of > 500 mg/day significantly lowered the appearance of antigenemia and lymphocytic viremia (p < 0.05).

Factor VIII, HIV and AIDS in haemophiliacs: an analysis of their relationship

In this review, the association between the Acquired Immune Deficiency Syndrome (AIDS) and haemophilia has been carefully examined, especially the data that have been interpreted as indicating transmission of the human immunodeficiency virus (HIV) to the recipients of purportedly contaminated factor VIII preparations. In our view, the published data do not prove the hypothesis that such transmission occurs, and therefore HIV cannot account for AIDS in haemophiliacs.

Capillary electrophoresis: detection of hybridization between synthetic oligonucleotides and HIV-1 genomic DNA amplified by polymerase-chain reaction

The polymerase chain reaction (PCR) is one of the most efficient techniques for measuring the viral load of HIV-infected samples. Determination of the specificity of PCR products is usually based on Southern blotting and hybridization of the amplified DNA to radioactive oligonucleotide probes specific for sequences comprised between the PCR primers. The recent introduction of capillary electrophoresis (CE) for identification of HIV-1 and HTLV-I PCR products appears interesting in light of its reproducibility, sensitivity and because it is fast and suitable for detection of DNA/DNA and DNA/RNA hybrids. We demonstrate that specific hybridization of a HIV-1 oligonucleotide probe to single-stranded DNA obtained by unbalanced PCR is detectable by capillary electrophoresis. This enabled us the application of a one-step, non-radioactive protocol to demonstrate the specificity of amplification of HIV-1 genomic sequences by PCR. This procedure is simple, reproducible and is suggested as an integral part of automated diagnostic systems based on the use of laboratory work stations for DNA isolation, preparation of PCR reactions and analysis of PCR products.

Enhanced detection of HIV-1 sequences using polymerase chain reaction and a liquid hybridization technique. Application for individuals with questionable HIV-1 infection

In this report we describe a sensitive HIV-1 detection method which is applicable for confirmation testing of donors whose blood sample gives indeterminate viral-serology results. The method involves performing a polymerase chain reaction (PCR) and detecting the generated fragments using liquid hybridization and gel retardation. We found that it is as specific as blotting on a filter and hybridization with an internal probe but at least tenfold more sensitive. After applying it on DNA samples of a panel of 11 persistent indeterminate anti-p24gag-reactive donors, none was found to be PCR positive. Considering other negative virological and biochemical test results and case-historical data, these donors are not likely to be HIV-1 infected.

Expression of human immunodeficiency virus (HIV) in naturally infected peripheral blood mononuclear cells: comparison of a standard co-culture technique with a newly developed microculture method

Peripheral blood mononuclear cells (PBMCs) from 29 patients infected with human immunodeficiency virus (HIV) were cultured by two different methods. One was the standard co-culture technique, the other a newly developed microculture method. In this assay 10(6) PBMCs were cultivated in 250 microliters medium, no activating agents or allogeneic cells were present. P24 antigen production measured by this method was found in 7 out of 11 PBMC cultures of patients in the Walter Reed (WR) stage 1 or 2, whereas only 4 samples were positive by the co-culture procedure. Cultures from patients in the later stages of the disease (WR 5/6) showed a higher p24 production by the co-culture method than by the microculture assay. It is assumed that rapidly growing HIV strains can be better assessed by the co-culture method which may select for these strains. P24 expression can be more easily obtained by the microculture technique even in cases where slowly replicating strains may be present. In conclusion, results from the microculture procedure described may be a useful supplementation to findings observed by the co-culture method.

Epidemiologically closely related viruses from hemophilia B patients display high homology in two hypervariable regions of the HIV-1 env gene

The diversity of human immunodeficiency virus type 1 (HIV-1) is mainly caused by mutations that affect the gene encoding the gp120 envelope protein. Isolates differ to a large extent in the hypervariable regions of gp120. This study was undertaken to determine the degree of variation of HIV-1 env genes isolated from seven individuals with hemophilia B who became infected in association with administration of a suspected clotting factor lot. Two hypervariable regions and part of a constant region from proviral DNA of the peripheral blood leukocytes of these patients were amplified and the products of the polymerase chain reactions were sequenced. The sequences derived from five of the individuals displayed 100% sequence homology, 1 had two and 1 had six deviations from the consensus sequence. The alignment of the amino acid sequence so deduced revealed no comparable homology to any of these two hypervariable regions from a number of published isolates. The genetic variability of HIV-1 seems to be limited, at least in the early phase of infection, allowing the determination of close relationships between epidemiologically related strains.

Detection of human immunodeficiency virus type 1 DNA by polymerase chain reaction amplification and capture hybridization in microtiter wells

We developed an improved microtiter-based assay for the detection of polymerase chain reaction (PCR)-amplified DNA sequences. The synthetic DNA sequences used to prime the PCR were labeled with biotin at their 5' ends so that the specific PCR product was labeled with biotin. Following amplification, an aliquot of the PCR product was denatured and hybridized to a capture DNA sequence immobilized in a microtiter well. The capture sequence was complementary to a portion of the sequence between the primers, so that only extended primers were captured. The captured PCR product was detected colorimetrically by using a streptavidin-peroxidase conjugate and tetramethylbenzidine substrate.

The polymerase chain reaction for the detection of HIV-1 genomic RNA in plasma from infected individuals

HIV (human immunodeficiency virus) viraemia in serum or plasma of HIV-infected individuals was investigated by the polymerase chain reaction assay (PCR) in combination with reverse transcription to detect HIV-1 genomic RNA. Before PCR, plasma or serum was ultracentrifuged, precipitated virions were then treated with a RNase-free DNase, and a cDNA from the HIV-1 genomic RNA was synthesized. Thirty-three fresh plasma and seven sera from either HIV-1 antibody-positive individuals or patients treated with AZT were tested. Plasma from three patients were assayed 3 or 6 months apart. Twelve sera from HIV-1 antibody-negative individuals were used as negative control. PCR was performed with primers in LTR, gag and env regions: 11 of 40 samples were positive with three primer pairs, 16 with two primer pairs and 11 with only one primer pair. PCR on HIV-1 genomic cDNA was positive in 38 out of the 40 plasma or serum samples (95%), regardless of the clinical stage of the infection: HIV-1 was detected in 14 of the 15 untreated subjects and in 24 of the 25 AZT-treated patients. HIV p24 antigen was detected in the serum of 38% of subjects (15 of 40). The results suggest that this method is suitable for the detection of viral particles in plasma or serum from HIV-1-infected individuals irrespective of antiviral treatment.

HIV-1 infection in a cohort of haemophilic patients

The course of HIV infection in 53 haemophilic patients aged 5-20 years was evaluated by clinical examination and laboratory tests. During the evaluation time (median 30 months) two patients died of AIDS and 32 patients (60%) deteriorated when assessed by the Brodt-Helm classification. Nineteen patients (37%) had decreased absolute helper cell counts (less than 500 CD4 positive cells/microliters), and 45 patients (87%) had reduced helper cell to lymphocyte ratios (less than 0.35). HIV-1 was isolated from peripheral lymphocytes in 29 of 46 patients. As the disease progressed the number of positive viral cultures increased. Considerable progression of the HIV infection was seen in haemophilic children and adolescents during the median evaluation period of 30 months. The transition from symptomless HIV infection to immunodeficiency was easily recognised. A lowered ratio of helper cells to lymphocytes seems to be a useful marker of the beginning of the deterioration of the immune system.

Graded cytopathogenicity of the human immunodeficiency virus (HIV) in the course of HIV infection

To determine whether the biological variability of HIV-1 has any clinical significance, the highly variable cytopathogenicity of 153 HIV-1 strains, isolated from 119 hemophiliacs, was related to the number of CD4+ lymphocytes present in the patient's blood at the time of virus isolation. It was shown that the cytopathogenicity of the HIV-1 isolates was inversely correlated with the number of CD4+ lymphocytes. The highest CD4+ cell number were observed in 34 latently infected patients characterized by HIV seropositivity, failure of virus isolation, and detection of viral DNA by the polymerase chain reaction. Cytopathogenicity of the HIV-1 isolates was a reliable prognostic marker and correlated well with other less-sensitive prognostic parameters, including the detection of infectious virus and p24 antigen in the plasma, and the decline of p24 antibody in the serum. The results suggest that the viral isolates - if not subjected to extensive passage - represent in vivo variants selected from a heterogeneous viral population according to the particular immunological conditions of the host.

Detection of human immunodeficiency virus-1 by polymerase chain reaction and virus cultivation

Peripheral blood of 57 patients with antibodies to human immunodeficiency virus 1 (HIV-1) and of five HIV-1 seronegative subjects at risk for HIV-1 infection were analysed by polymerase chain reaction (PCR) and virus isolation. The virus was recovered from peripheral blood cells in 89% and from plasma in 75% of the HIV-1 seropositive cases. In contrast, proviral HIV-1 DNA was detected in all HIV-1 seropositive patients by dot blot hybridization of the amplified fragments. The intensities of the dot blot reactions were less pronounced in asymptomatic HIV-1 seropositive individuals than in patients with acquired immunodeficiency syndrome (AIDS) or AIDS-related complex (ARC), suggesting an increase in proviral DNA with advancing disease. Three of five seronegative patients with signs or symptoms suggesting HIV-1 infection, but none of the controls, were positive for HIV-1 DNA by one or two primer pairs. These results show a high sensitivity of the PCR for detecting HIV-1 DNA in patients of all stages of HIV-1 infection. Proviral DNA can also be detected in some individuals without detectable antibodies to the virus. The virus load in peripheral blood, as determined by virus cultivation and PCR, seems to increase with progression of the infection.

Natural history of HIV-infection in hemophiliacs: clinical, immunological, and virological findings

At our institution 686 hemophiliacs are being treated. Of them 402 (59%) are anti-HIV-seropositive. The general use of heat-treated clotting factor products was begun in July 1983, and from May 1984 all patients exclusively used heat-treated clotting factors. Thus, one can assume that infection occurred no later than early 1984 in our patients. Since December 1985 HIV-positive hemophiliacs have regularly been clinically and immunologically examined. Most of the 306 patients who could be investigated were clinically symptom-free at the time of their first visit. However, 45 patients have developed AIDS from 1982 through August 1988. The mean survival time of hemophiliacs with AIDS is less than 6 months. In 36% of those 274 patients who have been followed for a mean period of 14 months the clinical stage of the disease worsened by at least one stage according to the classification system proposed by the Centers for Disease Control. We did not find a correlation between clotting-factor consumption during the years 1984-1986 and the actual clinical stage of the patients. Virus isolation from peripheral blood lymphocytes (PBIs) answered the question whether anti-HIV seropositive hemophiliacs are not only immunized but really infected in many more cases than those revealed by detection of p24 antigen or decline of p24 antibody. Positive viral culture correlated strongly with a drop in CD4+ lymphocytes under the level of 400/microliters. However, HIV could not be cultured regularly in advanced cases, suggesting that virus replication in PBLs is not necessarily the cause of depletion of T-helper cells.(ABSTRACT TRUNCATED AT 250 WORDS)