摘要:

Objectives:HIV-specific CD8 T cells play a central role in the immune control of virus replication. To further understand the role of CD8 T cells in clinical settings, there is a need for a diagnostic assay that quantifies HIV-specific CD8 T cells in all HIV-infected individuals.Designand methods: The CD8VIR (CD8 T cell-mediated virus-specific immune response) assay was designed to mimic viral load reboundin vitroby adding replication defective HIV particles to peripheral blood mononuclear cells. Antigen presenting cells processed the virus and presented most of the viral epitopes to T cells. Activated HIV-specific CD8 T cells were quantified by flow cytometry analysis as CD3CD8 IFNγ producing T cells.Results:The CD8VIR assay reproducibly detected a large proportion of functional HIV-specific CD8 T cells responding to viral load rebound. The whole HIV particle stimulation used in the CD8VIR assay was comparable to the sum of Gag, Pol, Env and Nef stimulations. The percentage of HIV-specific CD8 T cells also significantly correlated with the percentage of Gag-specific cytotoxicity measured by the traditional51Cr release assay. HIV-specific CD8 T cells correlated with immune control of HIV in chronically infected patients.Conclusions:The CD8VIR assay quantifies the majority of HIV-specific CD8 T cells capable of killing HIV-infected cells during viral load rebound. This simple, versatile and reproducible assay can be performed from the specimen submitted for CD4 analysis. Upon clinical validation, the CD8VIR assay can be a new diagnostic tool to predict the control of viral load rebound after treatment interruption.

ISSN:0269-9370    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Objective:To describe the magnitude of immune restoration after long-term control of HIV-1 replication.Design:Prospective study of immune restoration in patients starting highly active antiretroviral therapy (HAART).Methods:Patients with moderately advanced HIV-1 infection (CD4 cells between 100 × 106and 300 × 106/l) who enrolled in a trial of HAART and who had suppression of HIV-1 replication during 3 years of therapy were evaluated for phenotypic and functional indices of immune restoration.Results:Almost all immune restoration achieved occurred during the first year. The median CD4 lymphocyte count increased by 159 × 106cells/l during the first year (P< 0.001); CD4 lymphocyte rises during the second and third years were not significant. Most decreases in activation antigen expression (CD38/HLA-DR) on CD4 and CD8 lymphocytes occurred during the first year, and after 3 years, patient lymphocytes were still abnormally activated. The proportion of CD4 lymphocytes expressing CD28 increased during the first and second years, but even after 3 years, CD28 expression on CD4 cells remained abnormally low. Lymphocyte proliferative responses toCandidanormalized during the first 12 weeks of HAART while responses to tetanus increased only after immunization and enhanced responses to HIV-1 p24 antigen were not observed.Conclusions:Immune restoration was incomplete in patients who started HAART with moderately advanced HIV-1 disease and most changes occurred during the first year. These data suggest that this degree of suppression of HIV-1 replication alone will not suffice to restore immune competence. The clinical significance of incomplete reconstitution of CD4 lymphocyte number, phenotype, and proliferative function in HIV-1 infection remains to be determined.

ISSN:0269-9370    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Objective:To determine the effectiveness of antiretroviral therapy in controlling cerebrospinal fluid (CSF) HIV-1 replication and to assess factors related to virological response in advanced patients.Design:A cross-sectional and longitudinal study.Methods:Consecutive paired CSF and plasma samples from HIV-1-infected patients were collected before starting or changing highly active antiretroviral therapy (HAART).Results:In the cross-sectional analysis 75 patients were included, 55 (73%) with neurological disease, 28 (37%) naive for antiretroviral agents. A significant correlation between plasma and CSF levels at baseline was observed only in antiretroviral-experienced patients. The absence of neurological disease, lower plasma HIV-1 load and a previous exposure to indinavir were all associated with a baseline CSF HIV-1-RNA level less than 80 copies/ml at multivariate analysis. In 29 patients included in the longitudinal study a significant reduction in CSF HIV-1 RNA was observed. Plasma HIV-1-RNA change, CSF HIV-1-RNA level at baseline, overall months of antiretroviral treatment and the magnitude of difference between plasma and CSF HIV-1-RNA levels were all correlated to CSF HIV-1-RNA change during treatment. A significant difference in the magnitude of CSF HIV-1-RNA reduction was observed according to naive status and to the use of three or more drugs penetrating the blood–brain barrier.Conclusion:HAART effectively reduces HIV-1 replication in CSF. A variable response to antiretroviral therapy was observed in CSF, reflecting a different compartmentalization of infection during treatment. Naive status and the use of CNS-penetrating drugs substantially enhance antiviral response. A negative interaction between virological response and the duration of antiretroviral treatment suggests long-term selection of drug-resistant CSF HIV-1 strains.

ISSN:0269-9370    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Objective:To study virologic and immunologic factors associated with discordant treatment response in HIV-infected patients receiving highly active antiretroviral therapy (HAART).Design:Study participants included a total of 27 patients: (a) 10 discordant patients (mean CD4+ cell count, 396.1 × 106cells/l; mean HIV-RNA, 5.4 log10copies/ml); (b) seven responder patients (mean CD4+ cell count, 997.5 × 106cells/l); and (c) 10 failing patients (mean CD4+ cell count 66.5 × 106cells/l; mean HIV-RNA, 5.4 log10copies/ml).Methods:The HIV-1 isolation rate and biological phenotype, drug resistance genotypic mutations of HIV-1 strains, recall and HIV-1-specific antigen lymphocyte proliferation (LP), and interleukin (IL)-15 production were studied.Results:Virus isolation was obtained in 30% of discordant patients, and in 100% of failing patients. A higher replication constant was reported in discordant patients. No difference in the number of drug resistance mutations and biological phenotypes of HIV-1 was found in discordant patients with respect to failing patients. Discordant patients developed positive LP responses toCandida albicansand HIV-1 p24. LP in response toC. albicans, HIV-1 p24 and gp160 was positive in responder patients. No significant LP was found in failing patients. Increased levels of IL-15 after stimulation with lipopolysaccaride (LPS) andC. albicanswere found in both discordant patients and responder patients. Conversely, a strong reduction of IL-15 levels was observed in failing patients.Conclusion:The present results suggest that decreased virus isolation rate, restoration of both lymphocyte proliferation and IL-15 production are factors involved in the discordant antiretroviral therapy response of HIV-infected patients.

ISSN:0269-9370    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Background:Specific mutations in VPR and V2 potentially restrict HIV-1 replication in macrophages. Such restriction could potentially limit HIV replication in long-term non-progressors (LTNP), thus accounting for low viral load and delayed progression to AIDS.Objective:To examine whether a specific VPR phenotype (truncated versus non-truncated) correlates with disease progression and whether elongated V2 restricts viral replication in macrophages or alters viral tropism.Methods:Sequence analysis was carried for VPR and V1-V3 env from four rapid progressors (RPs), six late progressors (LPs), and three LTNPs in cohort of HIV-1-infected homosexual men. The replication kinetics of sequential isolates was examined in primary CD4 cells and macrophages and coreceptor usage was determined by GHOST infection assays.Results:No differences were found in the VPR protein from RP and LTNP isolates. Analysis of the V2 region revealed that all RPs maintained similar V2 lengths (40 aa), whereas LPs and LTNPs acquired additional amino acids (2-13 aa) in the V2 region. Coreceptor specificity revealed that RP switch from CCR5 to multiple coreceptor usage, whereas LTNPs maintained R5 viruses. Sequential isolates from each group revealed comparable replication efficiencies in both T-cells and macrophages, regardless of the V2 length or coreceptor utilization. In addition, cross-section analysis of six LTNPs from Australia revealed extended V2 with consistent usage of CCR5 coreceptor.Conclusion:The present results suggest that acquisition of a V2 extension over time in HIV-1-infected LPs/LTNPs appears to correlate with maintenance of CCR5 usage among LTNPs. These findings may be important for a better understanding of the host interactions and disease progression.

ISSN:0269-9370    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Objectives:To investigate HLA class I allele frequencies in a Kenyan commercial sex worker (CSW) cohort, and to examine HIV-1 specific cytotoxic T lymphocyte (CTL) responses directed against epitopes derived from locally prevalent clade A virus.Methods:PCR–single strand polymorphism HLA class I typing. Sequencing of novel alleles and examination of their distribution in the CSW cohort, and a low risk HIV uninfected cohort. The peptide-binding motif of a novel class I allele was predicted, and a panel of candidate CTL epitopes was synthesized whose functional significance was examined using ELISpot and51Cr release assays.Results:Class I HLA-A and B frequencies within the cohort are presented. Two novel class I alleles were found, HLA-B*4415 and HLA-Cw*0407. These two class I alleles were relatively common, both in the CSW cohort (2.1% and 3.3% respectively) and in a cohort of lower risk women (1.9% and 3.8% respectively). Allele HLA-B*4415 restricted CTL responses against a novel epitope (EEKAFSPEV) derived from p24 of clade A HIV-1, and HLA-Cw0407 restricted CTL against a predefined HLA-Cw*0401 gp120 epitope.Conclusions:Multi-epitope vaccine design requires knowledge of HLA class I distribution and HIV CTL epitope characterization in potential target populations. The description of two novel HLA class I alleles at high frequency in this high risk Kenyan CSW cohort suggests that HLA mapping of vaccine cohorts and subsequent characterization of local CTL epitopes will be warranted prior to vaccine trials.

ISSN:0269-9370    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Objectives:To examine the relationship between the humoral immune response and viral envelope diversity among HIV/AIDS patients with or without HIV-associated dementia (HAD).Methods:Whole blood and sera were collected from age- and disease-progression matched AIDS-defined patients with and without neuro-cognitive impairment at two centers. Peripheral blood mononuclear cells were isolated from whole blood and separated into monocyte/macrophage and peripheral blood lymphocyte (PBL) preparations. Genomic DNA, isolated from the PBL population, was used as template to amplify HIV-1 C2V3 envelope sequences in a nested PCR protocol. The resulting fragments were sequenced and subjected to a phylogenetic analysis.Results:Sera from non-demented (ND; n = 21) patients neutralized infection of CCR5-dependent, but not CXCR4-dependent viruses, more efficiently than sera from HAD patients (n = 15) (P< 0.05). A recombinant virus containing a brain derived C2V3 sequence was also neutralized less efficiently by sera from HAD patients (P< 0.05). C2V3 envelope sequences amplified from PBL revealed significantly greater diversity within the V3 region from HAD compared with ND patients (P< 0.001). The number of non-synonymous substitutions was positively correlated with the severity of neuro-cognitive impairment of patients (P< 0.005). Similarly, brain derived V3 sequences exhibited significantly increased diversity among HAD patients (P< 0.001).Conclusion:Our findings imply that HAD patients exhibited impaired serological responses that may lead to the emergence of viral mutants that potentially could infect the brain and mediate neurodegeneration.

ISSN:0269-9370    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Objectives:The impact of highly active antiretroviral therapy (HAART) on hepatitis C virus (HCV) is unknown. We analysed changes in HCV RNA and the frequency of hepatotoxicity in co-infected patient enrolling in AIDS Clinical Trials Group trials, and determined whether HCV impairs successful immune reconstitution in these populations.Design/methods:In a prospective analysis of co-infected patients completing at least 16 weeks of HAART in four trials, and co-infected patients with available stored plasma from two other completed HAART trials, HCV RNA was measured at baseline and to week 48. A retrospective analysis of immune recovery in 40 HCV-RNA-positive and 129 HCV-RNA-negative patients from a single trial was performed.Results:Prospective analysis: 60 patients completed at least 16 weeks of HAART. The mean HCV-RNA level increased 0.35 log10IU/ml at week 16 and 0.43 log10IU/ml at week 48. When stratified by baseline CD4 cell count, subjects’ HCV-RNA levels increased 0.43 and 0.59 log10IU/ml at weeks 16 and 48 for entry CD4 cell counts < 350 cells/mm3, but only 0.26 and 0.1 log10IU/ml at weeks 16 and 48 for entry CD4 cell counts > 350 cells/mm3. Severe alanine aminotransferase elevations occurred in only 3.3%. Retrospective analysis: HCV co-infection had no effect on the overall mean CD4 cell increase at weeks 16 or 48 compared with uninfected controls.Conclusion:In HCV-co-infected patients undergoing HAART, immune recovery is associated with a persistent increase in HCV RNA, especially with baseline CD4 cell counts < 350 cells/mm3. HCV co-infection did not antagonize the CD4 cell response to HAART.

ISSN:0269-9370    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Objective:To evaluate the prevalence of HIV-related central nervous system (CNS) lesions (HIV-encephalitis and/or HIV-leukoencephalopathy: HIV-E/L) with and without concomitant opportunistic diseases in a large autopsy series, and to correlate it with the changes in antiretroviral treatment that have occurred since the beginning of the epidemic.Methods:We reviewed 1597 consecutive autopsies of HIV-positive patients performed between 1984 and 2000, and divided into four time periods on the basis of the therapeutic regimens available: 1984–1987, no therapy; 1988–1994, monotherapy (zidovudine); 1995–1996, dual combination therapy with nucleoside reverse transcriptase inhibitors (NRTI); and 1997–2000, triple combination therapy including two NRTI and at least one protease inhibitor or non-NRTI. The data concerning the treatment actually received were collected only for the patients who died during the last period. The χ2-test was used to assess the significance of the differences in prevalence.Results:The CNS of 1210 patients (76%) was affected by opportunistic diseases, HIV-related lesions or both. The prevalence of HIV-related lesions in the four periods was respectively 54%, 32%, 18% and 15%; this reduction was statistically significant (P< 0.000001). During the last period, however, differences in HIV-E/L between treated and untreated patients were not statistically significant, although there were fewer than expected cases among the treated patients (six instead of eight) and more than expected among the untreated patients (10 instead of eight).Conclusions:These neuropathological data from a large autopsy series confirm clinical observations concerning the efficacy of antiretroviral treatment in reducing the frequency of HIV-related CNS lesions in AIDS patients.

ISSN:0269-9370    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Introduction:Co-infection with GBV-C (`Hepatitis G’ virus) appears to be associated with slower disease progression in HIV-infected, untreated individuals. We wished to determine whether detection of GBV-C RNA was associated with differential response to HIV therapy in a population-based cohort of 461 individuals initiating antiretroviral therapy between June 1996 and August 1998, in British Columbia, Canada.Methods:The presence of GBV-C RNA in plasma was identified by nested RT–PCR, using detection of HIVgagRNA as a positive control. Time to virological success [achieving HIV plasma viral load (pVL) ⩽ 500 copies/ml], virological failure (subsequent confirmed pVL > 500 copies/ml) and immunological failure (confirmed CD4 cell count below baseline) were assessed by Kaplan–Meier methods and Cox proportional hazard regression.Results:Of the 441 individuals for whom results were available, 90 (20.4%) had detectable plasma GBV-C RNA. GBV-C RNA was significantly associated with a lower HIV pVL at baseline (P= 0.004). In univariate and multivariate Cox models, GBV-C RNA positive and negative individuals did not differ with respect to time to virological success [risk ratio (RR), 0.98; 95% confidence interval (CI), 0.75–1.27], time to virological failure (RR, 1.10; 95% CI, 0.74–1.65), or time to immunological failure (RR, 1.09; 95% CI, 0.73–1.63). There was no correlation between detection of GBV-C RNA and mutations in the human chemokine receptors CCR5 and CX3CR1, or HIV viral tropism as predicted by the HIV envelope sequence (P> 0.1).Conclusion:GBV-C viremia is relatively common in individuals seeking treatment for HIV infection; however, it does not appear to have any effect on initial antiretroviral therapy response.

ISSN:0269-9370    

出版商:OVID    

年代:2002

数据来源: OVID