摘要:

Objectives:To evaluate the prevalence of the most common cytomegalovirus (CMV) UL97 mutations associated with ganciclovir resistance directly in polymorphonuclear leukocytes (PMNL) of patients with AIDS and CMV retinitis. Also to correlate the presence (or absence) of these mutations with the systemic CMV viral load and the ophthalmologic outcome of these subjects.Methods:Monthly blood samples were obtained from 19 patients with AIDS and CMV retinitis who had been treated with systemic ganciclovir for ≥ 2 months. Detection of CMV UL97 mutations was done using nested PCR amplification followed by restriction enzyme analysis. The viral load was assessed with a polymerase chain reaction-based assay and non-isotopic hybridization detection.Results:CMV UL97 mutations were detected in PMNL of four of 13 (30.8%) patients who had been treated with ganciclovir for ≥ 3 months but in none of six patients who had been treated for < 3 months. All four patients with detectable UL97 mutations were presenting evidence of retinitis progression at the time those mutations were first detected (mean, 145.7 days of ganciclovir) and three of four patients had a viral DNA load > 10 000 copies per 105PMNL contrasting with the copy numbers in the 15 subjects without mutations (mean, 492.9 copies per 105PMNL after a mean of 146.8 days of ganciclovir).Conclusions:The prevalence of the most common CMV UL97 mutations associated with ganciclovir resistance in PMNL of patients with AIDS treated for ≥ 3 months (30.8%) appears to be higher than the rate of emergence of ganciclovir-resistant CMV isolates as previously reported using phenotypic assays (about 8%). Moreover, the detection of these mutations is associated with a considerable increase in the CMV DNA load in the blood as well as with progression of CMV retinitis during ganciclovir therapy.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Objective:We conducted this study to genetically characterize dual infection in individuals demonstrating a dual serological profile.Methods:All subjects were first evaluated by immunoblot for antibody reactivity to the major viral antigens for HIV-1 and HIV-2. Sera were judged to be dual-seropositive if they reacted with strong and equal intensity with the envelope antigens of both HIV-1 and HIV-2 and were confirmed with type-specific recombinant env peptides. We used nested polymerase chain reaction (PCR) to amplify proviral gag and env sequence from peripheral blood mononuclear cell (PBMC) DNA from HIV-1- and HIV-2-infected individuals. Positive amplification was detected after Southern blot hybridization.Results:Plasmid dilution and mixing showed equivalent sensitivity of HIV-1 and HIV-2 primers that was not altered by heterologous target sequences. The DNA PCR showed 100% sensitivity and specificity for detection of monotypic HIV infection. Serologically defined HIV-dual reactives were evaluated by this assay, with 100% detection in female sex workers (21 out of 21), but only 38.5% detection (five out of 13) in hospitalized patients; all being HIV-1 positive only. The lack of HIV-2 proviral signal was significantly correlated with low CD4+ lymphocyte counts (Pvalue = 0.04).Conclusion:The results suggest that HIV dual infection may not be a static condition. Levels of HIV-2 may decrease with disease progression or sequester in tissue reservoirs; our results may also suggest that HIV-1 effectively overgrows HIV-2 in the dually exposed host individual.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Objective:To investigate differences in viral and proviral load between the peripheral blood and the intestinal mucosal immune system in HIV-infected patients.Design:HIV-1 p24 and HIV DNA content were compared in blood samples and intestinal biopsies from HIV-infected patients.Methods:Intestinal biopsies and peripheral blood were simultanously obtained from 27 HIV-infected patients undergoing diagnostic endoscopy. The p24 concentrations were measured in serum and homogenized intestinal biopsies by enzyme-linked immunosorbent assay after acid-dissociation of immune complexes. Proviral load was determined in blood and intestinal biopsies by a quantitative competitive polymerase chain reaction amplifying the HIV-1nefgene from genomic DNA.Results:No significant differences were found in proviral load comparing HIV copies per 1.5 x 105cell equivalents in blood [2650 (600–44 000)] and intestinal biopsies [4200 (1325–19 625)]. Paired analysis revealed a strong positive correlation between serum and mucosal proviral load. In contrast, HIV core protein p24 was detected in intestinal biopsies from 18 patients in much higher concentrations than in serum [858 (262–4111) pg/g versus 34 (9–242) pg/g;P< 0.005]. The p24 concentrations in serum and intestinal biopsies did not correlate and no significant correlation was observed in serum or intestinal biopsies between proviral load and p24 concentrations. No clear correlations were observed between clinical parameters and HIV DNA or HIV p24 levels in blood or biopsies.Conclusions:Our findings demonstrate a homogenous distribution of HIV proviral load in the peripheral blood and the intestinal mucosal immune system. The high viral antigen load in the intestine therefore indicates that mucosal HIV production is upregulated at the transcriptional and/or translational level. The intestinal mucosa is a major reservoir for HIV in HIV-infected patients.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Background:The primary antigenic domain responsible for complement-mediated antibody-dependent enhancement (C′-ADE) of HIV and simian immunodeficiency virus resides in the principal immunodominant sequence of the transmembrane protein.Objective:To identify whether there are amino-acid residues common to the epitopes of the known enhancing human monoclonal antibodies (MAb), and to provide a structural model for this functional region present on the HIV envelope. Since our model predicts that this region is involved in the association of gp120 with gp41, this association was monitored for each mutant.Design:The binding of enhancing human MAb to point and deletion mutations within the enhancing domain was analyzed by two methods. The first analyzed binding to mutants expressed in COS cells: the second quantified the binding of four enhancing human MAb to each mutant gp160 versus wild-type control by enzyme-linked immunosorbent assay (ELISA).Methods:Site-directed mutagenesis was used to produce specific deletions and point mutants, which were expressed in COS cells. Binding of MAb 50–69 and V3-loop MAb 5F7 were visualized in the wild-type and each of the mutant constructs by immunohistochemistry. Quantitative evaluation of enhancing human MAb binding to each mutant versus wild-type was performed by ELISA. A model for the enhancing domain and its relationship to gp120 association with gp41 was provided by molecular dynamics and ligand docking methods.Results:All available enhancing human MAb known to bind to the principal immunodominant region of gp41 were unable to bind to deletions involving the disulfide loop, which in our molecular model provided the primary association site between gp120 and gp41. Point mutations in the loop blocked this association, but had a quantitatively smaller effect on the binding of the enhancing human MAb. A conservative W596Y mutation completely blocked the binding of all human MAb, but had no effect on gp120–gp41 association.Conclusions:A variety of mutations within the primary C′-ADE domain inhibit binding of enhancing human MAb as well as blocking the association of gp120 and gp41. A conservative W596Y mutation blocks binding of all enhancing human MAb with retention of gp120–gp41 association. These data are important to the design of vaccines in which the primary enhancing epitope is disarmed to prevent the subsequent induction of an amnestic response that could lead to viral enhancement of infection. The retention of the gp120–gp41 association is postulated to yield an immunogen similar to natural infection for both subunit and genetic vaccines.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Objectives:To induce recovery of HIV-1-specific immune responses by combining immunization with antiviral chemotherapy.Design:Forty HIV-infected patients entered a double-blind study with recombinant gp160 in combination with zidovudine or placebo. The pretreatment observation period was around 2 years and the treatment period 5 years. Eighty matched HIV-infected patients served as controls.Methods:Immune status was monitored by proliferation assays with HIV-specific antigens, mitogens and recall antigens. Viral load, CD4 cell counts, apoptosis, T-cell clonal analysis and CC-chemokine receptor (CCR)-5 status were determined.Results:All immunized patients showed a strong and HIV-specific T-cell proliferative response. This response was related to the immunizations, and was not enhanced by the zidovudine monochemotherapy given during the first 6 months of the immunizations. The treatments did not significantly alter viral load. Potent antiviral combination therapy given to non-immunized individuals reduced their viral load but did not influence HIV-specific immune responses. There was a trend for an increased frequency of non-progression in the immunized group compared with controls. These individuals had both wild-type and mutantCCR-5genes.Conclusion:The results clearly show that restoration of HIV-specific T-cell immunity occurs after immunization with the HIV gp160 antigen and is not influenced by the addition of antiviral monochemotherapy. Even intensive chemotherapy alone did not restore HIV-specific immunity and immunization alone did not influence viral load. This suggests that combinations of intensive chemotherapy with specific HIV immunization would result both in viral load reduction and improved immune responses to HIV.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Objectives:Triple combination treatment of HIV-1 infection using two reverse transcriptase inhibitors and a protease inhibitor can result in significant and sustained decreases in the quantity of viral RNA in peripheral blood. Lymphoid tissue, however, constitutes the major reservoir of HIV in infected patients. Study of the viral burden in these tissues has provided additional insight in the efficacy of antiretroviral treatment.Design:Patients were randomized into two groups in order to study differences in the development of resistance to reverse transcriptase inhibitors. Group I started treatment with all three drugs simultaneously. Group II started with ritonavir monotherapy, aiming at initial reduction in virus production before the addition of lamivudine and zidovudine 3 weeks later.Methods:Changes in the amount of HIV in plasma and tonsillar lymphoid tissue during 24 weeks of treatment with ritonavir, lamivudine and zidovudine were studied by reverse transcriptase polymerase chain reaction.Results:Thirty-three antiretroviral-naive HIV-infected patients were included for analysis. After 24 weeks, median CD4+ cell count increased by 152 × 106/l and median plasma viral RNA levels decreased by at least 2.87 log10copies/ml. In 88% of the patients remaining on treatment, plasma RNA levels were below the quantification limit of the assay used (mean, 2.4 log10copies/ml). The lymphoid tissue viral burden, ranging from 9.16 to 8.52 log10copies/g at baseline, was markedly reduced with at least 2.1 log10copies/g by week 24 in the five patients analysed. Eight patients (24%) withdrew because of side-effects. In one patient in group II, ritonavir and lamivudine resistance-associated mutations developed.Conclusions:Treatment with this triple antiretroviral drug combination produced a durable and strong decrease of HIV-1 RNA burden in both plasma and lymphoid tissue.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Objectives:To evaluate the impact of therapeutic immunization with p24 virus-like particle (VLP) and zidovudine (ZDV) on p24 antibody titre (primary endpoint), CD4+ cell counts, cellular responses to the immunogen and recall antigens, and viral load (secondary endpoints) in subjects with asymptomatic HIV infection and CD4+ counts greater than 400 × 106cells/l.Design:A double dummy, double-blind randomized placebo-controlled Phase II trial of the therapeutic vaccine p24-VLP, with or without ZDV.Methods:ZDV-naive subjects were randomized to one of three groups for 6 months: group A, ZDV 200 mg three times daily plus intramuscular administration of alum adjuvant monthly; group B, ZDV 200 mg three times daily plus p24-VLP (500 µg) in intramuscular alum monthly; group C, placebo capsules plus p24-VLP (500 µg) in intramuscular alum monthly. Subjects were followed for a further 6 months.Results:Sixty-one patients received vaccinations. The mean CD4+ cell counts pretherapy for groups A, B, and C were 605 ± 25, 668 ± 43, and 583 ± 30 × 106cells/l, respectively. Treatment was well tolerated. At both 24 and 52 weeks there were no significant differences between the treatment groups in terms of antibody responses to p24, CD4+ or CD8+ cell counts, viral load, T-cell responses to p24, p17, recall antigen or mitogen, or markers of immune activation, despite induction of antibody and proliferative responses to the carrier protein of the vaccine.Conclusion:Vaccination with p24-VLP was well tolerated. p24-VLP either alone or in combination with ZDV did not significantly alter either antibody or proliferative responses to p24, or CD4+ cell number, immune activation or viral load over 12 months.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Objective and design:To study, in T-lymphoid cells, the effects of macrophage inflammatory protein (MIP)-1α, MIP-1β and RANTES β-chemokines on the replication of T-cell-tropic HIV-1 strains, since it has been reported that β-chemokines interfere with the replication of macrophage-tropic HIV-1 strains, but not T-cell-tropic strains.Methods:Freshly phytohaemagglutinin (PHA)-activated peripheral blood lymphocytes (PBL) and cultured PHA-activated T cells from healthy volunteers, as well as the C8166 T-cell line, were treated overnight with β-chemokines before infection with T-cell-tropic HIV-1 isolates, or human T-lymphotropic virus type IIIB. HIV replication was followed by detecting the production of infectious particles, p24 antigen, and viral sequences. CXC-chemokine receptor (CXCR)-4 expression was followed by detection and quantification of specific transcripts.Results:Pretreatment of T cells with MIP-1α, MIP-1β and RANTES affected T-cell-tropic strains, increased the replication of HIV-1P1and HIV-1RPdTstrains dose-dependently, as well as virus absorption and provirus DNA accumulation. These findings were associated with increased accumulation of CXCR-4 transcripts, and mediated by the protein tyrosine kinase signalling. Moreover, β-chemokines stimulated PBL proliferation.Conclusions:β-Chemokines increase the adsorption and replication of at least some T-cell-tropic HIV-1 strains, and this is related to stimulated expression of the CXCR-4 coreceptor.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Objective:To compare the prevalence of drug-resistant tuberculosis disease among patients with and without HIV infection.Design:An historical prospective evaluation of patients with culture-proven tuberculosis reported between January 1988 and December 1995.Setting:A major metropolitan county public health department.Patients:A total of 802 consecutive culture-positive tuberculosis patients were eligible for inclusion in the study. HIV serologic testing and drug susceptibilities were completed on 741 (92%) eligible patients. Of these patients, 646 tested HIV-negative and 95 (12.8%) tested HIV-positive. Patients not tested for HIV (n = 59) and without drug susceptibilities (n = 2) were excluded from the analyses. Outpatient management was based on a policy of universal directly observed therapy.Main outcome measures:Patient HIV status, initial drug resistance and acquired drug resistance. Isolates were characterized for resistance to isoniazid, rifampin, rifabutin, ethambutol, streptomycin, capreomycin, kanamycin and ethionamide. Determination of initial resistance was based on the first available susceptibility study and acquired resistance on subsequent susceptibility studies.Results:Initial drug resistance was found in 55 (8.5%) HIV-negative patients and four (4.2%) HIV-positive patients. Acquired drug resistance occurred in five (0.8%) HIV-negative patients and one (1.1%) HIV-positive patient. These differences were not statistically significant.Conclusions:HIV infection is not a risk factor for drug-resistant tuberculosis. Increased drug resistance in HIV infected tuberculosis patients reflects a failure of tuberculosis control in the underlying population.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Objectives:To examine rates of HIV-1 and sexually transmitted disease (STD) among pregnant and postpartum women in urban Malawi, Africa.Design:Serial cross-sectional surveys and a prospective study.Methods:Three major surveys were conducted in 1990, 1993 and 1994/1995. Consecutive first-visit antenatal women and women giving birth at the Queen Elizabeth Central Hospital were tested for HIV and STD after counseling and obtaining informed consent. Unlinked, anonymous HIV testing was also conducted on smaller samples of antenatal women in the same hospital to provide annual prevalence data. HIV-seronegative postpartum women from the 1990 and 1993 surveys were enrolled in a prospective study to determine HIV incidence.Results:HIV seroprevalence rose from 2.0% in 1985 to 32.8% in 1996, a 16-fold increase. The highest age-specific HIV prevalence was in the following age-groups: 20–24 years during 1990, 25–29 years during 1993, and 30–34 years during 1996. Among 1173 women followed for a median of 30.9 months, HIV incidence was 5.98 per 100 person-years in women aged < 20 years and declined steadily in older women. The prevalence of STD significantly declined among both HIV-positive and negative women. This decline in STD prevalence, however, was not accompanied by increased condom use over time.Conclusions:Among urban childbearing women in Malawi, incidence of HIV is highest among young women while, currently, prevalence is highest among older women. Recent declines in STD prevalence suggest that HIV prevention programs are having an impact either through improved STD diagnosis and treatment or reduced risk behaviors. Sequential cross-sectional STD prevalence measures may be useful in monitoring effectiveness of STD and HIV prevention activities.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID