[The detection of the human immunodeficiency virus antigen in the lymphoid cells of seropositive subjects]

Cells from anti-HIV-positive persons were used in experiments for virus isolation. The RT-activity, viral antigen, nucleic acids, electron microscopic morphology, and infectivity were studied. The data presented allow a conclusion that the virus was isolated. These data confirmed the previous diagnosis of HIV infection.

Long-term human immunodeficiency virus infection in asymptomatic homosexual and bisexual men with normal CD4+ lymphocyte counts: immunologic and virologic characteristics

From a prospective cohort study, 24 asymptomatic men were identified who had been antibody positive for human immunodeficiency virus (HIV) for at least 5 years (median = 9.1) with CD4+ lymphocyte counts greater than or equal to 400 cells/mm3. Of these "nonprogressors", 23 (96%) had evidence of HIV infection by either HIV culture or the polymerase chain reaction (PCR) for HIV DNA, although only 1 (4%) had a positive assay for HIV RNA (by PCR) and no one was positive for p24 antigen. Compared with 24 antibody-negative men and 14 men with AIDS, nonprogressors had higher CD8+ counts and lower natural killer cell activity. Nonprogressors had higher beta 2-microglobulin levels than did seronegative controls, suggesting some degree of immune system activation. Compared with men with AIDS, nonprogressors seemed to have a stronger antibody response to six different HIV-related proteins but did not differ significantly in neutralizing antibody or antibody-dependent cellular cytotoxic activity.

High titers of cytopathic virus in plasma of patients with symptomatic primary HIV-1 infection

BACKGROUND

Primary infection with the human immunodeficiency virus (HIV-1) frequently causes an acute, self-limited viral syndrome. To examine the relations among viral replication, the immune response of the host, and clinical illness during this initial phase of infection, we undertook a quantitative, molecular, and biologic analysis of infectious HIV-1 in the blood and plasma of three patients with symptomatic primary infection and of a sexual partner of one of them.

METHODS

During an eight-week period of primary infection, HIV-1 was cultured frequently in dilutions of plasma and peripheral-blood mononuclear cells (PBMC), and levels of HIV-1 antigen and antibody were determined sequentially by enzyme-linked immunosorbent assay and immunoblotting. Replication-competent HIV-1 proviruses were cloned and characterized biologically.

RESULTS

Six to 15 days after the onset of symptoms, high titers of infectious HIV-1 (from 10 to 10(3) tissue-culture-infective doses per milliliter of plasma) and viral p24 antigen were detected in the plasma of all three patients. These titers fell precipitously by day 27, and the decline coincided with an increase in the levels of antiviral antibodies and the resolution of symptoms. Sequential isolates of virus from plasma and PBMC obtained throughout the period of primary infection, as well as virus derived from two molecular proviral clones, were highly cytopathic for normal-donor PBMC and immortalized T cells, despite the marked reduction in the titers of virus in plasma.

CONCLUSIONS

Primary, symptomatic HIV-1 infection is associated with high titers of cytopathic, replication-competent viral strains, and during such infection potential infectivity is enhanced. Effective control of HIV-1 replication during primary infection implies the activation of clinically important mechanisms of immune defense that merit further examination in relation to the development of antiviral therapy and vaccines.

Transient high levels of viremia in patients with primary human immunodeficiency virus type 1 infection

BACKGROUND

The rapidly evolving clinical picture of primary infection with the human immunodeficiency virus type 1 (HIV-1) suggests that a better understanding of the kinetics of viral replication in vivo during the short period before seroconversion may provide insight into the pathogenesis of the acquired immunodeficiency syndrome (AIDS).

METHODS AND RESULTS

Titers of infectious HIV-1 were determined by end-point-dilution culture in sequential samples of plasma and peripheral-blood mononuclear cells from four patients with primary infection, with peak titers of 1000 to 10,000 tissue-culture-infective doses per milliliter of plasma and 100 to 10,000 infective doses per 10(6) peripheral-blood mononuclear cells. The high viral burden in mononuclear cells was confirmed by quantitative studies using a polymerase-chain-reaction method. In as little as 10 days, the high HIV-1 load in both plasma and cells decreased spontaneously and precipitously, at least 100-fold, in all four patients.

CONCLUSIONS

Although p24 core antigenemia and viral isolation have previously been described during primary HIV-1 infection, this report documents the large viral burden during the acute phase of infection. The rapid and spontaneous decline in the viral load suggests an effective immune response in the host that, if understood, may be used to combat AIDS.

Low HIV-1 proviral DNA burden detected by negative polymerase chain reaction in seropositive individuals correlates with slower disease progression

During 1989, 316 members of a cohort of homosexual men were tested for HIV-specific DNA by the polymerase chain reaction (PCR) using a pair of gag-region primers. Of 125 HIV-seronegative subjects, 123 (98.4%) were PCR-negative while 158 (82.7%) of 191 HIV-seropositive subjects were PCR-positive. Fewer of the 33 subjects who were seropositive and PCR-negative were at Centers for Disease Control (CDC) stage IV than the seropositive, PCR-positive subjects (6 versus 25%; P = 0.030). The seropositive, PCR-negative group had higher mean CD4 counts (640 versus 490 x 10(6) cells/l; P = 0.006), higher CD4: CD8 ratios (0.92 versus 0.64; P = 0.004), lower immunoglobulin (Ig) G levels (1290 versus 1645 mg/dl; P = 0.002), lower IgA levels (168 versus 251 mg/dl; P less than 0.001), and lower C1q binding activity (8 versus 14%; P = 0.010) than the seropositive, PCR-positive subjects. The median rate of CD4 cell decline in the 3 years preceding the PCR sample was less marked in the seropositive, PCR-negative group than the seropositive, PCR-positive group (-58 versus -77 x 10(6) cells/l per year; P = 0.028). To control for duration of infection, we restricted the analysis to the subgroups of 11 seropositive, PCR-negative subjects and 34 seropositive, PCR-positive subjects who had seroconverted earlier in the cohort study. Both subgroups had similar durations of infection, yet the same pattern of differences persisted.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of HIV-1 DNA and infectious virus in cerebrospinal fluid

The polymerase chain reaction (PCR) and a virus culture technique were used to detect human immunodeficiency virus type 1 (HIV-1) DNA in cerebrospinal fluid (CSF) cells and infectious virus in cell-free CSF, respectively, of 28 HIV-1 seropositive homosexual men. Provirus was detected in 24 patients of whom 15 were also culture positive. One subject was virus culture positive but not PCR positive. Two asymptomatic HIV-1 seropositive persons and one individual with persistent generalized lymphadenopathy were negative by both techniques. All of four patients with overt neurological symptoms, but also 20 of 24 patients without such symptoms were PCR positive. The data indicate that viral replication is common, and that the vast majority of HIV-1-infected individuals harbor the virus DNA in CSF, during all stages of infection.

Improved detection of HIV-1 envelope sequences using optimized PCR and inosine-substituted primers

We describe inosine-substituted 'consensus' primers for the detection of HIV-1 envelope sequences by the polymerase chain reaction. The primers, modifications of SK68 and SK69, are highly specific (100%) and sensitive (greater than 94%) and they prevent false-negative results due to variation in the HIV-1 genome. Consensus primers are needed to ensure the detection of most, if not all, variants of HIV-1 including American, African and newly emerging strains.

Detection of human T-cell leukemia virus type I proviral sequences from fixed tissues of seropositive patients

Fixed lymphoma tissues from 11 patients seropositive for human T-cell leukemia virus type I (HTLV-I) antibodies were analyzed for proviral sequences by the polymerase chain reaction. Typical adult T-cell leukemia/lymphomas (ATLLs) from nine patients were positive for HTLV-I sequences. In contrast, one of two lymphomas with immunophenotypes atypical for ATLL was negative for HTLV-I. This HTLV-I DNA-negative lymphoma, although present in an HTLV-I-seropositive patient, was therefore reclassified. The HTLV-I tax gene was always detected in the ATLL tissues, whereas segments of the pol gene were not detected in half the cases. These studies demonstrate that fixed non-ATLL specimens can be distinguished from ATLL specimens.

Interleukin-2 enhances production in 24 hours of infectious human immunodeficiency virus type 1 in vitro by naturally infected mononuclear cells from seropositive donors

When peripheral blood mononuclear cells from HIV-1 seropositive patients were treated with rIL-2 in vitro a rapid increase of 2-12 fold in production of extracellular infectious HIV-1 occurred, in 6 of 9 experiments. Overall, the increase in the 9 experiments was significant (p less than 0.01) and provides more direct evidence for an enhancing role of IL-2 in naturally infected cells.

Trypsin-resistant gp120 receptors are upregulated on short-term cultured human epidermal Langerhans cells

The CD4 molecule is known to be the preferential receptor for the HIV1 envelope glycoprotein. Epidermal Langerhans cells (LC) are dendritic cells which express several surface antigens, among them the CD4 antigens. LC infection was suggested when these cells were seen to present buddings coincident with membrane thickening of roughly 100 nm in size. These buddings were similar in ultrastructural aspect to HIV buddings on in vitro infected promonocytic cells (U937). To clarify the exact role of CD4 molecules in LC infection induced by HIV1, we investigated the possible involvement of between native and recombinant HIV1 gp120 and the LC surface. We also assessed the expression of CD4 molecules on LC membranes dissociated by means of trypsin from their neighbouring keratinocytes. The cellular phenotype was monitored using flow cytometry. We show that human LC can bind the viral envelope protein and that this binding does not depend on CD4 protein expression. The amount of surface bound gp120 was not consistent with the amount of CD4 antigens present on LC membranes. The gp120-binding sites on LC in suspension appear to be typsin-resistant while the CD4 antigens (at least the epitopes known to bind HIV1) are trypsin-sensitive. A burst of gp120 receptor expression was detected on 1-day cultured LC while the CD4 antigens disappeared. These findings lead to the logical conclusion that the binding of gp120 is due to the presence of a LC surface molecule which is different from CD4 antigens.

Latent infection of epidermal Langerhans cells in HIV-positive individuals

Epidermal cell suspensions obtained from 3 symptom-free HIV-positive individuals were cultured and marked with monoclonal antibodies for the HIV proteins p15, p24 and gp120 in the alkaline phosphatase anti-alkaline phosphatase staining technique. For 2 individuals, cells were positive after 3 days in culture, and for the third, after 4 days. Supernatant from one of the cultures infected allogeneic peripheral blood mononuclear cells. We conclude that epidermal Langerhans cells from symptom-free HIV-positive individuals are latent-infected and are able to produce and release HIV.

Correlation between CD4 cell counts and cellular and plasma viral load in HIV-1-seropositive individuals

We conducted a study of 152 HIV-1-seropositive individuals in order to evaluate the possible correlations between the isolation of HIV from peripheral blood mononuclear cells or from plasma and CD4 cell counts. HIV was isolated from only 36% of plasma samples, and the isolation rate was closely related to CD4 cell counts, increasing gradually from 0% in subjects with greater than 800 x 10(6)/l CD4 cells to 88% in those with less than 100 x 10(6)/l CD4 cells. In contrast, HIV was isolated from 92% of cell samples (99% in subjects with less than 900 x 10(6)/l CD4 cells, 46% in those with CD4 counts greater than or equal to 900 x 10(6)/l). Since most cell samples were positive, a scoring method was designed to quantify the cellular viral load. The results obtained demonstrated that the cellular viral load was closely related to CD4 counts. We also found that the cellular viral load was higher in subjects with either positive plasma isolation or positive p24 antigenaemia. The measurement of the cellular viral load by this scoring method appears to be useful for the management of HIV-seropositive individuals and for the evaluation of therapeutic trials.

Postmortem viability of the human immunodeficiency virus

In 1989 blood samples from 2581 fatalities investigated at the Institute of Forensic Medicine in Hamburg were screened for HIV-1-antibodies. Sera from 13 corpses were confirmed positive for HIV-1 (prevalence rate approx 0.5%).-Viable HIV was found in blood cultures of 4 cadavers stored under non-refrigerated conditions up to 36 hours after death.

Assessment of HIV status using the polymerase chain reaction in antibody-positive patients and high-risk antibody-negative haemophiliacs

The polymerase chain reaction (PCR) was used to identify the presence of DNA sequences homologous to HIV-1 in the buffy-coat leukocytes of antibody-positive and antibody-negative individuals in a haemophiliac population. The presence of HIV sequences was demonstrated in all of the antibody-positive haemophiliacs with the exception of one patient who was repeatedly negative. None of the seronegative haemophiliacs gave an overall positive result, although there were clear differences between this population and the negative controls who were examined. We conclude that, in our hands, PCR represents a reliable test which represents a useful diagnostic advance in HIV medicine.

[Virologic diagnosis of human immunodeficiency]

The reference tests for HIV diagnosis are the ELISA and Western-Blot assays. Their rapid development has made it possible to obtain a reliable, specific and highly sensitive diagnosis. The follow-up of HIV-infected subjects includes HIV-p24 antigenaemia, but viral culture and PCR will perhaps permit a quantification of viral load in order to evaluate the results of antiviral therapy.

[Isolation of human immunodeficiency virus type 1 (HIV-1) from seropositive hemophiliac Japanese]

We reported some biological properties of HIV-1 isolated from 16 hemophiliac Japanese and accidentally infected one mother. Peripheral mononuclear cells (PMCs) were obtained from them, one with AIDS, one with lymphadenopathy and the others were asymptomatic carriers. CD 8 depleted PMCs were obtained by panning methods. They were cocultivated with PHA-stimulated PMCs from seronegative donors. Fifteen HIV-1 isolates were obtained from 17 cases. Recovery rate was 87.5%. The replication rate of HIV-1 from AIDS patient was faster than other isolates from asymptomatic carriers. They did not from plaques on MT 4 cells. The host range study showed that all fifteen isolates infected primary macrophages and only two simultaneously infected human T cell line (MT 2). None of them showed infectivity to other T cell, B cell or monocytic cell lines. Although our study population was rather small, these results suggested that the majority of seropositive hemophiliac Japanese were already infected by HIV-1 and had the risk for the development of AIDS. Moreover, we recognized that HIV-1 from hemophiliac Japanese showed characteristic biological features, i,e, such as 1) weak cytopathic effects, 2) narrow host range and 3) tropism to primary macrophages. It is suggested that they may belong to a unique subtype of HIV-1 and their selective infectivity to primary macrophages have some relation to the clinical status of seropositive hemophiliacs. Further study is necessary to clarify these points.

Latent HIV-1 infection in enriched populations of blood monocytes and T cells from seropositive patients

The extent of latent HIV-1 infection in blood T cells and monocytes of 23 seropositive individuals was examined using DNA amplification (PCR) of HIV-1 sequences. Amplified DNA was found in at least one cell type in all seropositives tested, including 13 asymptomatic, 5 ARC, and 5 AIDS patients. Amplification with two or more primer sets from the gag, env, LTR occurred in 21 (91%) patients' T cells and 17 (74%) patients' monocytes. However, amplification with the LTR primers in monocytes was uncommon. Among four patients tested, amplified DNA continued to be detected after a greater than one thousand-fold dilution (less than 500 cells) of both T cell and monocyte lysates. Repeat analysis after 7-9 mo in five seropositives yielded similar findings in T cells and monocytes, but some variation in the efficacy of amplification with individual primers occurred. There was no difference in those 10 patients who were taking AZT, compared to those who were untreated. Our results indicate that a fraction (less than 1%) of both T cells and monocytes in blood carry a latent infection in all stages of HIV-1 disease and can serve as reservoirs throughout AZT therapy.

Antibody reactivity to deletion mutants of the HIV-1 SF2 envelope

In human immunodeficiency virus type 1 (HIV-1) infected individuals, the antibody response to the external envelope (gp120) is associated with in vitro neutralization. To further characterize the anti-gp120 response, we examined the IgG reactivity of 75 HIV-1-seroconverted and 200 HIV-1-seropositive individuals to deletion mutants of gp120 in an enzyme immunoassay. We used yeast-derived, non-glycosylated recombinant HIV-1 SF2 gp120 equivalent and-variants deleted in variable regions. We observed two distinctive response patterns: IgG non-responders (SF2-V3-restricted responders) and IgG responders to conserved regions of gp120. This divergence in response pattern occurred soon after gag/env HIV-1 antibody seroconversion and persisted in time within an individual. In addition, the SF2-V3-restricted responders had a higher frequency of HIV-1 core antigen positivity and HIV-1 core antibody negativity than the non-restricted responders. These results suggest that specific and persistent host antibody response patterns to gp120 develop early in HIV-1 infection and that these patterns are associated with differences in HIV-1 expression.

Human immunodeficiency virus isolates from asymptomatic homosexual men and from AIDS patients have distinct biologic and genetic properties

Human immunodeficiency virus type 1 (HIV-1) isolates from asymptomatic homosexual men and AIDS patients were compared for their in vitro biologic and genetic properties. Most of the HIV-1 isolates from asymptomatic men, but not from AIDS patients, failed to infect CD4+ H9 cells and phytohemagglutinin-stimulated peripheral blood lymphocytes. In a longitudinal study, serial HIV-1 isolates obtained from men who seroconverted to HIV-1 and later developed AIDS were able to infect H9 cells. In contrast, longitudinal isolates from men who remained asymptomatic did not infect H9 cells. HIV-1 isolates from AIDS patients in general exhibited increased production of intracellular viral DNA, RNA, and protein as compared to isolates from asymptomatic men. Cells infected with HIV-1 isolates from asymptomatic men produced very little gp120, p24, and p55 proteins as compared to those from AIDS patients. The overall restriction patterns of HindIII, Sac-1, Pst-1, EcoR1, and BamH1 were very similar between HIV-1 isolates from asymptomatic men and those from AIDS patients. However, the restriction endonuclease pattern of BglII was quite distinct for isolates from asymptomatic men as compared to AIDS patients. Preliminary studies mapped a unique BglII site in the gag region of most of the isolates from asymptomatic men, approximately 2.0 kb from the 5' end. Thus, HIV-1 isolates from asymptomatic subjects and from AIDS patients have distinct biologic and genetic properties which may be related to the various clinical outcomes of HIV-1 infection.

Isolation of HIV-1 from seropositive people living in Cotonou, Benin

Benin is located in West Africa and is situated between HIV-2 and HIV-1-endemic zones. The first cases of HIV-1 infection in Benin were reported in 1987. Since then, AIDS cases have been diagnosed there and the number of known HIV-seropositive people has rapidly increased. Blood samples were collected from 14 seropositive and 11 seronegative patients living in the main city, Cotonou, and their peripheral blood mononuclear cells were cultured. In seven of the seropositive cases, a retrovirus was detected by measurement of Mg2(+)-dependent reverse transcriptase activity and electron microscopy. HIV-1 antigen assay and genomic analysis indicated that the isolated viruses belong to the first serotype. In each positive case, an HIV-1 DNA probe hybridized to the RNA extracted from the virus and six isolates were found positive by the polymerase chain reaction using HIV-1-specific primers.

Rapid and quantitative detection of enzymatically amplified HIV-1 DNA using chemiluminescent oligonucleotide probes

A hybridization protection assay (HPA) that uses acridinium ester (AE) labeled oligonucleotide probes which are specific for a conserved gag gene region of human immunodeficiency virus type 1 (HIV-1) was developed to measure the amount of HIV-1 nucleic acid. Hybridization of the single-stranded probes with their target HIV-1 sequences protected the chemiluminescent AE group from subsequent alkaline hydrolysis. The chemiluminescence from the residual AE could be easily quantitated in a luminometer. The entire process comprising template dissociation, hybridization, alkaline hydrolysis, and chemiluminescence measurement can be completed in less than one hour and does not require the separation of hybridized probe from unhybridized probe. We demonstrated that HPA could quantitatively measure the amount of DNA amplified by polymerase chain reaction. A comparative study using amplified DNA from the peripheral blood mononuclear cells (PBMC) of HIV seropositive and seronegative persons showed that HPA was as sensitive as the previous methods using 32P-labeled DNA probes.

[HIV isolation and clinical markers on the seropositive subjects]

We investigated 18 anti-HIV seropositive subjects with respect to the isolation of HIV from peripheral blood mononuclear cells (PBMC) and cellular and serologic markers for progression to AIDS. The subjects included homosexuals and recipients of blood products. Three had AIDS, an asymptomatic subject developed AIDS during the study and 14 of the remaining have remained asymptomatic. HIV was isolated from all AIDS patients and 7 asymptomatic subjects. Moreover HIV was detected significantly sooner in symptomatic patients than in asymptomatic subjects. The reductions in CD4 lymphocytes number and CD4/CD8 ratio, as well as anti-HIV core (p24, p17) antigens negativity correlated with deterioration of clinical symptoms and successful HIV isolation. The isolates from AIDS patients and from an asymptomatic subject who 9 months later developed AIDS were infective and cytotoxic to MT-4 cells, however isolates from asymptomatic subjects were not infective. These findings indicate that disease progression correlates with the appearance of variant viruses that are more infective and cytopathic.

A semiquantitative microassay for measurement of relative number of blood mononuclear cells infected with human immunodeficiency virus

A simple semiquantitative microassay was developed for the measurement of relative number of infected peripheral blood mononuclear cells (PBMC) from individuals infected with human immunodeficiency virus (HIV). The assay is based on cocultivation of serially diluted PBMC of a seropositive person with phytohemagglutinin-stimulated normal PBMC. The microassay has comparable sensitivity with the standard virus culture method in detecting positive HIV cultures. Since the microassay uses only 2-3 x 10(5) patients' PBMC, the assay is also most suitable for HIV isolation from HIV-infected infants or from AIDS patients with extremely low T-cell counts. The microassay can also be used to measure antiviral effects of a drug on persistent HIV infection in vitro. Because the microassay measures the relative number of infected PBMC, it can be readily used for following the quantitative antiviral effect of a drug in a clinical trial.

Polymerase chain reaction (PCR) amplification demonstrates the absence of human T-cell lymphotrophic virus (HTLV)-I specific pol sequences in peripheral T-cell lymphomas

HTLV-I seronegative patients in nonendemic areas have been described with T-cell proliferations the DNA of which contains specific HTLV-I viral sequences. We have looked for the presence of HTLV-I DNA sequences in 27 HTLV-I seronegative patients with peripheral T-cell lymphomas, distinct from adult T-cell leukemia (ATL), and four HTLV-I seropositive patients, three with an ATL and one with a tropical spastic paraparesis. Using HTLV-I pol specific primers, the genomic DNA from peripheral blood mononuclear cells and lymph nodes massively infiltrated by tumor cells was analyzed by the enzymatic gene amplification procedure. In contrast to the peripheral blood lymphocytes from the four HTLV-I seropositive patients, the peripheral T-cell lymphoma samples did not harbor HTLV-I pol sequences. The data show that the detection of HTLV-I nucleotide sequences by the polymerase chain reaction correlates with serologic analysis in this series.

Pneumococcal bacteremia as a marker for human immunodeficiency virus infection in patients without AIDS

We retrospectively reviewed medical records of all adult patients with blood cultures positive for Streptococcus pneumoniae to determine the number of HIV seropositive patients in whom S pneumoniae bacteremia was the presenting manifestation. We also compared the clinical presentation, laboratory data, and outcome of pneumococcal bacteremia in patients who were HIV seropositive with patients with no risk factors for HIV infection. All adult patients with blood cultures positive for S pneumoniae from January 1987 through April 1989 at two acute care general hospitals in northern California were identified by review of microbiology data. One hospital served veterans, the other the indigent of a suburban area. Six (15%) of 41 patients with pneumococcal bacteremia were HIV seropositive; five were not known to be HIV seropositive before the onset of bacteremia, and the sixth was asymptomatic with respect to HIV infection. No patient with AIDS had pneumococcal bacteremia. HIV seropositive patients were significantly younger, had significantly fewer underlying diseases, and had fewer complications of pneumococcal bacteremia than bacteremic patients with no risk factors for HIV infection. Patients with pneumococcal bacteremia should be evaluated for HIV infection, especially in the absence of other underlying diseases that predispose to pneumococcal bacteremia.

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.

T-cell-induced expression of human immunodeficiency virus in macrophages

Macrophages are major reservoirs of human immunodeficiency virus (HIV) in the tissues of infected humans. As monocytes in the peripheral blood do not show high levels of infection, we have investigated the expression of HIV in T-cell-activated, differentiated macrophages. Peripheral blood mononuclear cells were isolated from HIV-seropositive individuals and stimulated with antigens or mitogens, and the nonadherent fraction was removed. Macrophages were cultured alone for 2 weeks, and HIV expression was assessed. Results from p24 antigen capture assays demonstrated that the presence of autologous T cells and concanavalin A or autologous T cells and allogeneic cells for the initial 24 h of culture induced HIV expression in 35 of 47 (74%) HIV-seropositive patients tested. The macrophage monolayers could be immunostained with anti-HIV antibodies to reveal discrete infectious centers, indicating that complete virus replication was occurring in the macrophages and that infection of adjacent cells was mediated by cell-cell contact. Time course studies of the interval of coculture of the adherent and nonadherent cells indicated that 24 h (but not 2 h) was sufficient for induction of HIV in the macrophages. Direct contact between the adherent cells and activated T cells was required as well. Since the presence of autologous T cells also appeared to be necessary, induction of HIV expression in macrophages may be genetically restricted. HIV-seronegative nonadherent cells were able to induce HIV expression in macrophages from HIV-seropositive donors, demonstrating that the virus originated in the monocytes and was reactivated in the context of a classic T-cell-mediated immune reaction. The high percentage of monocytes from HIV-seropositive donors which can be induced to replicate HIV by activated T cells suggests that infection of monocytes may be critical to the pathogenesis of this lentivirus infection.

In vivo T lymphocyte origin of macrophage-tropic strains of HIV. Role of monocytes during in vitro isolation and in vivo infection

Previously published isolation techniques with T cell blasts and monocyte-derived macrophages (MDM) were used to recover HIV from the PBMC of a group of 23 asymptomatic seropositive individuals. Viral isolation was more readily accomplished by MDM coculture resulting in 9 isolates being obtained exclusively by this method (macrophage tropic strains). To determine the in vivo cellular source of these isolates we separated PBMC from 5 of these 9 patients into T lymphocyte and monocyte fractions by flow microfluorometry. These fractions were then analyzed by polymerase chain reaction (PCR) for the presence of HIV-1 proviral DNA. In 4 out of these 5 patients HIV-1 proviral DNA could be detected exclusively in T lymphocytes but not in monocytes, although the virus could be isolated only by MDM coculture. In the remaining patient HIV could be amplified in both T lymphocytes and monocytes. Further phenotypic analysis revealed that, among T lymphocytes, only the CD4+ subset was infected with HIV. We conclude that among PBMC the most common in vivo source of HIV strains which preferentially infect macrophages in vitro is the CD4+ T lymphocyte. These data also suggest that the macrophage tropism characteristic of some HIV strains reflects predominantly an in vitro phenomenon.

High levels of Epstein-Barr virus in the oropharynx: a predictor of disease progression in human immunodeficiency virus infection

The role of Epstein-Barr virus (EBV) on the progression of human immunodeficiency virus (HIV) infection is not well defined. The objective of this prospective study was to determine the prevalence of EBV excretion and the role that EBV might have on HIV disease progression. Fifty-two homosexual males were studied, all of whom had positive EBV serology. Twenty-four of the 27 HIV-seropositive and 14 of the 25 HIV-seronegative subjects had detectable levels of EBV DNA in oropharyngeal cells. In addition to a greater prevalence of detectable EBV, the level of excretion was higher among HIV-seropositives than among HIV-seronegatives, and higher among group III than among group II HIV-seropositive men. These results are consistent with earlier studies showing a relationship between immunosuppression and EBV reactivation. The EBV excretion levels in a control group of 52 age-matched heterosexual males were substantially lower than those found in the homosexual group. In a proportional hazards regression analysis EBV excretion was found to be the best single predictor of progression of HIV infection (P less than 0.001). HIV p24 core antigenemia (P = 0.048) and low EBNA (P = 0.024) were significant predictors independent of EBV excretion. Whether EV directly accelerates the time to progression or is merely a marker of underlying subclinical immunosuppression remains an open question.

[Cultivation of HIV-1 virus on mononuclear peripheral blood cells of HIV-1 seropositive individuals]

Using the method of co-cultivation with phytohaemagglutinin-stimulated lymphocytes from healthy donors, the author isolated the HIV-1 virus from peripheral mononuclear blood cells of three patients with the AIDS symptomatology and one patient with the ARC symptomatology. The presence of the virus in infected cells was proved by detection of the viral antigen p 24 in enzymatic immunoassays and in the immunofluorescence test. Three of the isolated strains were adapted to sensitive continual tissue cultures, where the isolates caused chronic infection of the cells associated with the development of a cytopathic effect. In the investigated patients no relationship was proved between viraemia and antigenaemia. The author discusses the importance of virus cultivation for laboratory diagnosis, epidemiology and research of HIV infection and AIDS.

Gonococcal arthritis caused by auxotype P in a man with HIV infection

The development of gonococcal arthritis is reported in a man with HIV infection and CDC Stage IVC2 disease. The diagnosis of disseminated Neisseria gonorrhoeae was facilitated by microbiological examination of a joint aspirate. The auxotype identified by culture was moderately resistant to penicillin, a characteristic which is highly unusual for an organism causing disseminated gonococcal infection. This case serves as an example of the role of HIV infection in the modification of host response to common pathogens and the need for clinicians to modify their management of disseminated gonococcal infection especially in immunosuppressed persons.

Scrotal ulceration in HIV-positive patients

Four patients with scrotal ulceration were seen during a period of 9 months. All of them were HIV-positive homosexual men with coexisting skin conditions. Herpes simplex virus was not isolated from any of the ulcers, but a variety of bacteria was recovered. It is suggested that multiple factors peculiar to HIV-positive individuals may account for the development of such ulcers.

Search for early lesions following human immunodeficiency virus type 1 infection. A study of six individuals who died a violent death after seroconversion

Histologic studies supplemented by in situ hybridization for human immunodeficiency virus type 1 (HIV-1), Epstein-Barr virus, cytomegalovirus, and human herpesvirus type 6 were performed on tissues obtained from the autopsy of six patients who died either by homicide or suicide shortly after learning of their seroconversion. Except for mild nonspecific lymphoid tissue reactions, no lesions were noted that would indicate HIV-1 infection. DNA from all viruses was detected in some lymphoid cells. The amount of DNA for Epstein-Barr virus, cytomegalovirus, and human herpesvirus type 6 corresponded to that observed for clinically occult latent infection. Lymphoid cells carrying HIV-1 DNA were even less frequent. Cells positive for HIV-1 were noted in the lamina propria of the large intestine in three male homosexuals and in one female prostitute. The cells were arranged similar to antigen-presenting cells. The present findings are consistent with current theories regarding the pathogenesis of HIV-1-associated disease.

Isolation of HIV-1 from monocytes of individuals negative by conventional culture

To improve isolation of human immunodeficiency virus (HIV) from purified monocytic cell populations, a differential culture technique was applied to blood from HIV-seropositive individuals, culture-negative for HIV by routine culture. When 206 individuals were grouped by percentage of CD4+ lymphocytes, increases in viral isolation rates were significantly associated with declines in percentage of CD4+ cells (P less than .0001). Of 158 asymptomatic individuals, 78% had greater than 400 CD4+ lymphocytes/mm3. Only 19% were culture-positive using routine methods. Separation of peripheral blood mononuclear cells (PBMC) into purified lymphocyte and monocyte subpopulations for 12 asymptomatic patients and subsequent HIV culture of each purified subpopulation using three different indicator cell lines resulted in 100% virus recovery from purified monocytes cultured in the U-937 promonocytic cell line. Culture of purified lymphocytes in U-937 cells did not increase the isolation rate, whereas culture of patient PBMC in U-937 indicator cells and in allogeneic monocytes resulted in a 50% increase in HIV isolation. A monocytic indicator cell line added to routine culture methods may improve virus recovery from asymptomatic individuals.

Replication of HIV-1 in primary monocyte cultures

A subpopulation of human monocytes began to express surface CD4 during its in vitro cultivation in the presence of recombinant M-CSF and became susceptible to infection with an isolate of HIV-1 [AD-87(M)], originally recovered from a seropositive individual by cocultivation with primary monocytes. Approximately 10% of the adherent cells synthesized CD4; a similar fraction was infectable with AD-87(M) and produced high levels of progeny particles. An interesting feature of the HIV-1 infection of primary monocytes was the detection of gp 160/120 inside but not on the surface of virus-producing cells. The implication of these results on HIV infection in vivo will be discussed.

Presence of HBV-DNA in peripheral blood mononuclear cells from anti-HIV symptomless carriers

The presence of hepatitis B virus DNA (HBV-DNA) in the peripheral blood mononuclear cells (PBMC) of 29 anti-HIV symptomless carriers (eleven HBeAg positive, eleven anti-HBe positive and seven HBsAg negative) and of 40 anti-human immunodeficiency virus (HIV)-negative patients (15 HBeAg positive, 15 anti-HBe positive and ten HBsAg negative) has been studied by dot-blot and Southern blot hybridization. HBV-DNA has been found in similar proportions in both anti-HIV-positive and negative patients (36% and 46%, respectively, in the HBeAg positive group and 27% and 37% in the anti-HBe positive group). No HBV-DNA was detected in the PBMC of the HBsAg-negative patients. No relation has been observed between the presence of HBV-DNA in the PBMC of the anti-HIV-positive patients and the detection of HIV antigen (HIV Ag), number of CD4 cells or the CD4/CD8 ratio. In summary, the presence of HBV-DNA in the PBMC of anti-HIV symptomless carriers does not seem to imply that the patient's clinical state has worsened.

Opportunistic agents in bronchoalveolar lavage in 99 HIV seropositive patients

During a ten month period, 117 fibreoptic bronchoscopies and bronchoalveolar lavages (BAL) were performed in human immunodeficiency virus (HIV) infected patients suspected of having opportunistic pulmonary infections. The BAL were classified into 3 groups, according to clinical manifestations related to HIV infection at the time of fibreoptic bronchoscopy: pre-acquired immunodeficiency syndrome (AIDS) (n = 54), AIDS with Kaposi's sarcoma (n = 37), AIDS without Kaposi's sarcoma (n = 26). On chest X-ray, diffuse infiltrates were most common (54%), followed by normal X-rays (24%) and localized infiltrates (18%). Amongst the 117 BAL, 68 (58%) yielded at least one opportunistic agent. In 28 BAL performed for pulmonary signs or unexplained fever with normal chest X-rays, one or several opportunistic agents were isolated in 17 samples of BAL fluid. The most frequently identified opportunistic agents were Pneumocystis carinii (in 38% of BAL) and cytomegalovirus (35%); these were associated in 17% of BAL. There was no statistically significant difference in opportunistic agents among the 3 groups of BAL (pre-AIDS, AIDS with Kaposi's sarcoma, AIDS without Kaposi's sarcoma). In particular, cytomegalovirus was found in BAL with the same frequency in these 3 groups.

Macrophage-HIV interaction: viral isolation and target cell tropism

Viral isolates were recovered by cocultivation on macrophage colony-stimulatingfactor (MCSF)-treated monocyte target cells from peripheral blood mononuclear cells (PBMCs) in 25 out of 27 patients seropositive or at risk for HIV infection. Frequency of virus recovery was independent of the patient's age, sex, numbers of CD4+ T cells, clinical stage or zidovudine (azidothymidine) therapy. Sixteen out of 19 HIV isolates were serially passaged in MCSF- treated monocytes. Five out of five virus isolates were also passaged in phytohemagglutinin/interleukin-2 (PHA/IL-2)-treated lymphoblasts. In lymphoblasts, no qualitative or quantitative differences were observed between these isolates and human T-cell leukemia virus IIIB (HTLV-IIIB) for (1) release of p24 antigen reverse transcriptase, and infectious virus, (2) induction of typical cytopathic effects (cell syncytia in 3-10% of cells) and cell lysis, (3) frequency of infected cells (5-20% of PBMC) as detected by in situ hybridization for HIV RNA, (4) down-modulation of T cell plasma membrane CD4, and (5) site of progeny virion assembly and budding (plasma membrane only with no intracytoplasmic accumulation of virus). Progeny virus recovered from infected lymphoblasts was fully infectious for other lymphoblasts, but failed to infect MCSF-treated monocytes. Detailed analysis of target cell tropism among HIV isolates showed that HIV isolated in monocytes infected both monocytes and lymphoblasts; progeny virus isolated in lymphoblasts infected only T cells. HIV interacts differently with monocytes and T cells. Understanding this interaction may more clearly define both the pathogenesis of HIV disease and strategies for therapeutic intervention.

Human immunodeficiency virus-infected individuals contain provirus in small numbers of peripheral mononuclear cells and at low copy numbers

In human immunodeficiency virus (HIV)-infected individuals, the proportion of circulating mononuclear cells (PBMCs) which carry HIV provirus and the number of HIV proviral sequences per infected PBMC have been matters for conjecture. Using a double polymerase chain reaction which allows the detection of single molecules of provirus and a method of quantifying the provirus molecules, we have measured provirus frequencies in infected individuals down to a level of one molecule per 10(6) PBMCs. As a general rule, only a small proportion of PBMCs contain provirus (median value of samples from 12 patients, one per 8,000 cells), and most if not all of the infected cells carry a single provirus molecule. The frequency of provirus-carrying cells correlated positively both with the progression of the disease and with the success with which virus could be isolated from the same patients by cocultivation methods. Of seven asymptomatic (Centers for Disease Control stage II) patients, all but one contained one provirus molecule per 6,000 to 80,000 cells; of five Centers for Disease Control stage IV patients, all but one contained one provirus molecule per 700 to 3,300 cells. When considered in conjunction with estimates of the frequency of PBMCs that express viral RNA, our results suggest that either (i) the majority of provirus-containing cells are monocytes or (ii) most provirus-containing lymphocytes are transcriptionally inactive. We also present nucleotide sequence data derived directly from provirus present in vivo which we show is not marred by the in vitro selection of potential virus variants or by errors introduced by Taq polymerase. We argue from these data that, of the provirus present in infected individuals, the proportion which is defective is not high in the regions sequenced.

Detection of HIV RNA by in situ hybridization in peripheral blood mononuclear cells of seronegative children born to HIV-infected mothers

Of 44 children born to human immunodeficiency virus (type 1) (HIV)-infected mothers, 11 have become seronegative. After the loss of maternal antibodies all children were analysed for several immunological functions and virological parameters in order to determine their HIV status. All children to date are clinically healthy and have normal immune functions. HIV-1 was detected by p24 antigen in one child, by in situ hybridization in nine children while viral cultures were all negative. These data suggest that the rate of vertical transmission of HIV-1 may be underestimated if seronegative children are considered to be not infected. They also suggest that molecular biological techniques are more sensitive than HIV antigen assay or viral cultures.