ISSN:0269-9370    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Objective:This study was performed to determine whether ribonucleases (RNases) contribute to the soluble HIV-1 inhibitory activity that results from the recognition of HLA alloantigens.Design and methods:Supernatants from mixed lymphocyte reactions of peripheral blood mononuclear cells from healthy HLA-discordant individuals exhibited HIV-1 inhibitory activity (alloantigen-stimulated factors; ASF). These supernatants were tested for their sensitivity to heating (90°C for 3 min), and for the presence of three RNases belonging to the RNase A superfamily: eosinophil-derived neurotoxin (EDN); RNase A; and angiogenin. Polyclonal antibodies specific for these RNases were used for Western blot analysis of the ASF, as well as for blocking the HIV-1 inhibitory activity of ASF. In addition, an RNase inhibitor (RI) was used to determine whether the anti-viral activity of ASF was due to RNase activity.Results:HIV-1 inhibitory activity of ASF was: (i) resistant to heat treatment; (ii) blocked by 58% with an antibody specific for EDN, but not with antibodies against RNase A or angiogenin; and (iii) blocked by 65–100% with an RI. Moreover, Western blot analysis with an anti-EDN antibody detected EDN in the ASF.Conclusion:These findings indicate that the majority of the soluble HIV-1 inhibitory activity contained in the supernatants of mixed lymphocyte reactions is due to EDN or a closely related RNase.

ISSN:0269-9370    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Objective:Determine whether natural killer (NK) cells are capable of killing HIV-infected autologous primary T-cell blasts.Design:The ability of NK cells to kill HIV-infected primary T-cell blasts, whose cell surface major histocompatibility complex (MHC) class I molecules was decreased, was evaluated in a lytic assay.Methods:Phytohemagglutinin-treated CD4+ T cells were infectedin vitrowith HIV-1. Infected cells were separated from uninfected cells by removal of CD4+ T cells. The NK cells were isolated from peripheral blood mononuclear cells (PBMC) of the same donor as the CD4+ T cells by immunomagnetic bead separation. The NK cells isolated from PBMC were then used as effector cells and the HIV-infected T-cell blasts were used as target cells in a lytic assay.Results:It was demonstrated that HIV infection of primary CD4+ T cells results in a 61–68% reduction in surface expression of MHC class I molecules. Despite the decreased MHC class I expression the NK cells were incapable of lysing autologous HIV-infected T-cell blasts, yet were effective in the lysis of the NK cell sensitive cell line, K562. The inability of NK cells to lyse HIV-infected T-cell blasts is not dependent on the strain of HIV used to infected the CD4+ T cellConclusion:These studies indicate that despite drastic decreases in MHC class I molecule expression, HIV-infected T-cell blasts can evade destruction by autologous NK cells.

ISSN:0269-9370    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Objective:The percentage and the activity of natural killer (NK) cells are known to be decreased in HIV-infected patients. However, the mechanisms responsible for this NK deficiency are poorly understood. Because of the role of NK cells in the host defence against microbial infections, this defect contributes to the virus-induced immune deficiency. The aim of the present study was to better understand this defect in order to be able to restore NK function in HIV infection.Design and methods:The expression of the cytolytic mediators perforin and granzyme A was analysed by flow cytometry, the lytic activity of peripheral blood NK cells of HIV-infected patients was analysed by cytotoxic assay, and the expression of perforin was followed during administration of interferon (IFN)α attached to polyethylene glycol (PEG)-IFNα.Results:The lytic activity and the expression of perforin and granzyme A was low in NK cells of infected individuals in comparison with normal control volunteers. In both groups NK cytotoxic capacity was linked to perforin expression. The low perforin expression in HIV-infected subjects negatively correlated with HIV RNA plasma level.In vivoadministration of PEG-IFNα restored perforin expression even in patients whose viral load was not reduced by this treatment.Conclusions:These results suggest that HIV-induced NK deficiency could be partly mediated by a defect in perforin and granzyme A expression, and that PEG-IFNα could be used in infected subjects to directly improve their natural immunity in addition to eventually reducing their viraemia.

ISSN:0269-9370    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Objective and design:Interferon α (IFNα), which is known to directly inhibit the HIV-1 replicative cycle and to increase the activity of cytotoxic T lymphocytes (CTL), is being tested as an anti-HIV agent. As CTL play a major role in immune defence against HIV, we wanted to further characterize CTL activity and the effect of IFNα on it.Methods:We followed by flow cytometry the intracellular expression of the key mediator of cytotoxicity, perforin, in peripheral blood T cells of patients treated with IFNα.Results:We observed that the percentage of T cells harbouring perforin was higher in infected subjects than in non-infected controls. Administration of IFNα2b attached to polyethylene glycol increased this perforin expression further and reduced viral load (P= 0.010). The increase in the percentage of T cells expressing perforin correlated with IFNα-induced decrease in viral load (r, 0.753;P= 0.003). In addition, the level of perforin expression before IFNα administration was inversely correlated with viral load remaining after IFNα administration (r, −0.647;P= 0.017).Conclusion:The pre-therapeutic percentage of perforin-positive T cells might be a predictive marker of the virological response to IFNα in HIV-1-infected patients.

ISSN:0269-9370    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Background:A high prevalence of bone demineralization occurs in people living with HIV/AIDS. The contribution of HIV itself and its treatment is still unclear. Protease inhibitors (PIs) are potent inhibitors of the cytochrome P450 enzyme system. Three cytochrome P450 mixed function oxygenases control serum levels of 1,25-dihydroxyvitamin D3(1,25(OH)2D3), which is responsible for vitamin D3actions in target tissues including bone. The 25- and 1α-hydroxylases regulate 1,25(OH)2D3synthesis and 24-hydroxylase 1,25(OH)2D3catabolism.Objective:To assess whether HIV-protease inhibitors (ritonavir, indinavir, nelfinavir) impair the activity of the main enzymes involved in 1,25(OH)2D3homeostasis.Design and methods:Studies were conducted in the human hepatocyte (H3B)- and monocyte (THP-1) cell lines, expressing 25-hydroxylase and 1α-hydroxylase, respectively. The 24-hydroxylase expression was induced in macrophages by exposure to 1,25(OH)2D3. Conversion rates of vitamin D3to 25-hydroxyvitamin D3[25(OH)D3]; 25(OH)D3to 1,25(OH)2D3or 24,25(OH)2D3, and 1,25(OH)2D3degradation were quantified in untreated and HIV-PI-treated cells after C18-cartridge extraction and high-performance liquid chromatography purification of 25(OH)D3- 24,25(OH)2D3- and 1,25(OH)2D3fractions.Results:The PIs impair hepatocyte 25(OH)D3- and macrophage 1,25(OH)2D3synthesis in a reversible, dose-dependent manner. Furthermore, PIs inhibit 1,25(OH)2D3-degradation in macrophages with lower potency than that elicited on 1α-hydroxylase. Thus, reduced macrophage 1,25(OH)2D3production is the net effect of PIs action.Conclusions:In intact cellsin vitro, HIV-PIs markedly suppress the activities of 25- and 1α-hydroxylase, which are critical in 1,25(OH)2D3synthesis, while exerting mild inhibition of 24-hydroxylase, responsible for 1,25(OH)2D3catabolism. If PIs elicit a similar potency in inhibiting these critical steps for 1,25(OH)2D3homeostasisin vivo, defective 1,25(OH)2D3production could contribute to the bone demineralization in HIV patients.

ISSN:0269-9370    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Objectives:With regard to the natural history of HIV-1 infection this study investigated whether whole-blood culture cytokine production was associated with mortality in HIV-1-infected patients.Designand methods: One hundred and seven HIV-1-infected patients stratified according to the Centers for Disease Control and Prevention criteria and 65 controls participated. The 24-h phytohaemagglutinin and lipopolysaccharide-stimulated whole-blood culture production of tumour necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL) receptor antagonist (-ra), IL-1β, IL-12, IL-10, IL-2 and soluble (s) IL-2 receptor (-r)α were studied and progression was evaluated using Kaplan–Meier method and Cox proportional-hazards models.Results:Compared with controls, asymptomatic patients had increased production of IL-1β and IL-12 (bothP< 0.05), unchanged production of TNF-α, IFN-γ and IL-1ra and notably reduced production of IL-10, IL-2 and sIL2-rα (allP< 0.05). HIV progression led to a progressive decline in whole-blood culture production of TNF-α, IFN-γ, IL-1ra, IL-1β, IL-12, IL-10 and IL-2 (allP< 0.0001). Low production of these cytokines were all associated with increased mortality risk in the patients (log-rank test, allP< 0.01, univariate Cox, allP< 0.001). Furthermore, low production of TNF-α, IL-1β, IL-12 and IL-10 independently predicted mortality after adjusting for other known prognostic variables (multivariate Cox, allP< 0.05).Conclusions:Preserved capacity of blood cells to produce cytokines was associated with prolonged survival in HIV-1-infected patients indicating a clinical significance of impaired cytokine production in HIV-1 infection.

ISSN:0269-9370    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Background:Despite multiple, repeated exposures to HIV-1, some individuals never seroconvert. Mucosal and systemic immune correlates of this condition have been analysed in HIV-1-exposed women but no data are available concerning mucosal immunity and HIV-1-specific immune responses in exposed but uninfected men.Design:We analysed cellular and humoral immune parameters in peripheral lymphocytes, seminal fluid and urethral swabs of 14 recently HIV-1-exposed seonegative (ESN) heterosexual men, seven HIV-seropositive patients and seven healthy controls.Results:HIV-1-specific IgA were detected in urethral swabs of 11 out of 14 ESN and of six out of seven HIV-seropositive patients; Env- and Gag-specific IFNγ-producing CD4 and CD8 peripheral lymphocytes were present in ESN and HIV-seropositive patients; seminal lymphocytes, but not peripheral blood lymphocytes, of ESN were enriched in activated populations (CD8CD38RO and CD4CD25). p24-specific cytotoxic T lymphocytes were correlated with the percentage of CD4 in the HIV-seropositive partners. High urethral concentrations of HIV-1-specific IgA were seen in those ESN with the most recent unprotected sexual episode.Conclusions:This is the first report of HIV-specific mucosal immunity in ESN men. These data add to the body of knowledge of the immune correlates present in exposed, uninfected individuals and might be important in vaccine design.

ISSN:0269-9370    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Objective:To assess the usefulness of total lymphocyte count (TLC) for monitoring HIV-infected patients receiving highly active antiretroviral therapy.Design:Observational cohort study.Methods:Correlation between difference (Δ) from baseline at week 4, 8, 12 and 48 in TLC, CD4 cell count and viral load was determined in patients initiating HAART in phase III clinical trials between 1995 and 2001 at the HIV Clinical Research Unit, Somerset Hospital, Cape Town.Results:The study included 266 patients. At weeks 4, 8, 12 and 48, median increase in TLC was 30, 52, 139 and 219 cells × 106/l, median increase in CD4 cell count was 8, 48, 88, and 145 cells × 106/l, and median decrease in viral load was −1.6, −2.2, −2.5 and −2.7 log10copies/ml, respectively. The correlation between all pairs of ΔTLC and ΔCD4 cell counts was significant (r, 0.61;P< 0.0001), but between ΔTLC and Δ viral load it was not (r, −0.014;P= 0.73). However, the correlation between median viral load reduction and median increase in both ΔCD4 cell count (r, −0.96;P< 0.0001) and ΔTLC (r, −0.89;P< 0.0001) was significant. The slope of ΔCD4 cell count was [52.493 + 0.14(ΔTLC)]. Sensitivity and specificity of an increase or decrease from baseline in TLC for similar trend in CD4 cell count during follow-up were 83.4% and 87.3% respectively.Conclusion:TLC correlated well with changes in CD4 cell count and at a group level with viral load changes. TLC may have a role in inexpensive monitoring of the immunological response to highly active antiretroviral therapy in a resource-constrained setting.

ISSN:0269-9370    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Objective:To evaluate the safety, tolerability, and trough levels of three pre-exposure prophylaxis regimens of nevirapine among HIV-1-uninfected subjects at high risk for HIV-1 infection.Methods:A phase I/II trial (HIVHOP 101) in which 33 such uninfected subjects received a 200 mg tablet of nevirapine once weekly (cohort A, n = 12), twice weekly (cohort B, n = 12), or every other day (cohort C, n = 9) for 12 weeks. Clinical signs/symptoms, laboratory parameters, and nevirapine trough levels were assessed at entry and at 1, 2, 4, 6, 9, and 12 weeks, with a follow-up sample at 16 weeks.Results:No subject experienced clinical symptoms attributed to nevirapine, including rash. There were no significant changes in liver enzyme levels from baseline to week 12 in the three cohorts, except for glutamyl transpeptidase in cohort B. Median nevirapine trough levels at weeks 1 and 12 were 119 ng/ml (range, < 25–205) and 135 ng/ml (range, < 25–1065), respectively, for cohort A, 569 ng/ml (range, 135–2641) and 431 ng/ml (range, 42–2454) for cohort B, and 1942 ng/ml (range, 1214–2482) and 943 ng/ml (range, 262–5281) for cohort C. No subject became HIV-1 antibody positive by week 16.Conclusions:A single dose of nevirapine taken once weekly, twice weekly, or every other day for 12 weeks was safely tolerated by the subjects in this small study, and resulted in nevirapine levels well above the IC50(inhibitory concentration of 50%: 10 ng/ml) over the 12-week period in nearly all evaluable subjects.

ISSN:0269-9370    

出版商:OVID    

年代:2003

数据来源: OVID