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Peripheral CD4 T-cell depletion has been observed in human immunodeficiency virus (HIV)-negative patients with pulmonary tuberculosis (TB). To investigate more accurately this alteration, we studied peripheral blood CD45RA+ and CD29high CD4 subsets in 79 TB patients with (HIV+TB+) or without (HIV-TB+) HIV infection, 85 HIV-infected patients without TB (HIV+TB-), and 43 healthy controls, all living in West Africa. The high proportion of CD4+CD29high T cells observed in controls was dramatically decreased in CDC-A stage HIV+TB- patients. CD45RA+ CD4+ T cells were depleted during the CDC-B stage. Both the percentage and the absolute count of CD29highCD4+ T cells were decreased in HIV-TB+ and HIV+TB+ patients versus controls, but CD45RA+CD4+ T cells were not decreased in TB patients without HIV-infection. Although distinct alterations in the CD4+ T-cell homeostasis are involved in TB- versus HIV-infected subjects, our data suggest that the CD29+CD4+ T-cell depletion observed during the early HIV disease contributes to the risk of active TB, by reducing the pool of T cells able to relocalize to the sites of the M. tuberculosis multiplication. [ABSTRACT FROM AUTHOR]

In the developed word, monitoring HIV-infected patients is routinely determined by CD4+ T lymphocyte absolute counts. The reference procedure, flow cytometry, is expensive, requires sophisticated instrumentation and operators with specific training. Due to these limitations, CD4 counting is often unavailable in developing countries. The Capcellia assay is an enzyme-linked immunoassay for quantitative determination of CD4 and CD8 molecules. We evaluated this method in West Africa on blood samples collected from 39 HIV-uninfected and 44 HIV-infected adult subjects. CD4 concentration ranges were determined according to the clinical stages of the disease. We then studied the relationship between the two methods in the HIV-infected patients. The Spearman's rank correlation was 0.61 (95% confidence interval: 0.38-0.76, P < 0.0001). Nevertheless, determination of limits of agreement revealed discrepancies between the two methods, especially for CD4 counts > 0.4 x 10(9)/l, which are discussed. We conclude that the Capcellia assay is a convenient means to determine the immunodepression level where flow cytometric instrumentation is unavailable, and can be complementary to CD4 T lymphocyte enumeration. [ABSTRACT FROM AUTHOR]

T cells from peripheral blood of hymenoptera sensitive patients were studied before and after venom desensitization. Before treatment, T cells showed a variable but higher proliferative response to allergen than T cells of treated patients or controls. While before desensitization, T cell products, specifically released after in vitro allergen stimulation, were able to amplify the IgE-dependent platelet activity, we showed that after treatment of the same patients, T cell products strongly reduced platelet activation. Considering the modifications in platelet activation previously observed in patients treated by specific immunotherapy, the present results suggest that, through a modification of T cell reactivity to allergen. T cell functions are modulated by desensitization, and emphasize the involvement of T cell products in the desensitization mechanisms. [ABSTRACT FROM AUTHOR]

The actions of IGFs are regulated at various levels. One mechanism involves binding to IGF-binding protein-3 (IGFBP-3) for transport, thus governing bioavailability. IGFBP3 transcription is modulated by many hormones and agents that stimulate or inhibit growth. We have previously shown in pediatric and adult cohorts a correlation between IGFBP-3 serum levels and two single-nucleotide polymorphisms (SNPs) located within the minimal promoter (-202 A/C and -185 C/T). Functionality of these SNPs was further explored in hepatic adenocarcinoma-derived SK-HEP-1 cells using transient transfections of luciferase constructs driven by different haplotypes of the IGFBP3 promoter. Basal luciferase activity revealed a significant haplotype-dependent transcriptional activity (at nucleotides -202 and -185, AC > CC, P < 0.001; AC > CT, P < 0.001; AC > AT, P < 0.001). Insulin treatment produced a similar haplotype dependence of luciferase activity (AC > CC, P = 0.002; AC > CT, P < 0.001; AC > AT, P = 0.011). However, induction ratios (insulin/control) for CC and AT were significantly higher compared with AC and CT (CC > AC, P = 0.03; CC > CT, P = 0.03; AT > AC, P = 0.03; AT > CT, P = 0.04). Gel retardation assays were used to identify upstream stimulatory factor (USF-1 and USF-2) methylation-dependent binding to E-box motifs located between the SNPs. Mutation of the USF binding site resulted in a significant loss of insulin stimulation of luciferase activity in the transfection assay. Chromatin immunoprecipitation with anti-USF-1/-2 showed an enrichment of IGFBP3 promoter in insulin-treated cells compared with unstimulated cells. Bisulfite sequencing of genomic DNA revealed that CpG methylation in the region of USF binding was haplotype dependent. In summary, we report a methylation-dependent USF binding site influencing the basal and insulin-stimulated transcriptional activity of the IGFBP3 promoter.

We report the detection of an interleukin-4 (IL-4) variant whose expression is tightly associated with deprivation apoptosis. It is detected with the 8D4 anti-IL-4 monoclonal antibody (mAb) not only in T helper-2 (Th2) but also in Th1 clones, and primary T cells, and it is a nonsecreted molecule. It is not expressed during primary necrosis. Our data suggest that de novo IL-4 transcription of an alternative IL-4 mRNA (IL-4 delta(13)) is induced during deprivation apoptosis. In HIV-infected patients, increased expression of IL-4 in T cells is highly correlated to increased apoptosis, restricted to 8D4 reactivity (r(2) = 0.84 between % 8D4-8(+) and % 7- amino-actinomycin D-positive [7-AAD(+)] peripheral T cells, P <.0001), and associated with disease progression. The particular reactivity of apoptotic T cells to 8D4 mAb may explain some discordances among studies analyzing the Th1/Th2 balance in HIV infection and questions the function of this intracellular type 2 signal.

Background: Increased and premature T cell apoptosis is recognized as a feature of HIV infection, and its normalization during highly active antiretroviral therapy (HAART) is thought to contribute to quantitative CD4 T cell restoration., Design: Cross-sectional study of spontaneous, CD3- and CD95-mediated apoptosis in lymphocytes from 53 HIV-infected individuals taking HAART., Methods: Overnight stimulation of peripheral blood mononuclear cells (PBMC) with coated anti-CD3 or anti-CD95 monoclonal antibodies or incubation overnight in medium. Apoptosis in CD4 and CD8 T cells was measured by flow cytometry. For in vitro assay of antiretroviral drugs, normal PBMC were prestimulated with anti-CD3 monoclonal antibodies and apoptosis was induced by ligation of CD95. The expression of active caspase-8 and caspase-3 was examined by flow cytometry., Results: We report for the first time that important levels of T cell apoptosis may persist under HAART, in spite of a rise in CD4 T cells from baseline and a sustained suppression of plasmatic viral load. Spontaneous CD3- or CD95-induced apoptosis levels were inversely correlated with the in vivo number of CD4 T cells and the CD4/CD8 ratio, but not with the viral load or duration of antiretroviral therapy. Regimens including lamivudine are associated with persistent T cell apoptosis, particularly following CD95 ligation. Lamivudine was also found to stimulate in vitro CD95-induced apoptosis and caspase activation in pre-activated T lymphocytes from healthy donors., Conclusion: The immunomodulatory effect of lamivudine may be one of the contributing factor to increased levels of T cell apoptosis under HAART. The data suggest that there is a requirement for physiological apoptosis during HAART.

Background: A key factor leading to impaired immunity in HIV infection is an alteration of the pattern of cytokine response, although its precise nature remains controversial, particularly the in vivo influence of HIV on interleukin (IL)-12 synthesis., Design: A cross-sectional study in 73 HIV-infected persons (28 of them receiving highly active antiretroviral therapy) and 18 HIV-seronegative healthy donors., Methods: The frequency of monocytes/macrophages (M/M) synthesizing IL-12, IL-10 and tumour necrosis factor alpha (TNF-alpha) was determined in peripheral blood mononuclear cells. The cells were cultured in medium or were stimulated with lipopolysaccharide; proportions of CD64 M/M producing IL-12, TNF-alpha or IL-10 was determined by cytofluorometric analysis. The influence of exogenous interferon gamma (IFN-gamma), IL-10 or IL-15 on IL-12 synthesis was tested., Results: Chronic HIV disease is associated with increased priming of M/M for IL-12 (involving both p40 and p70 molecules) and TNF-alpha synthesis; this was associated with cosynthesis of both cytokines by a fraction of M/M. Priming for IL-12 was physiologically enhanced by IFN-gamma and decreased by IL-10; IL-15 had no effect. The proportion of IL-10-producing CD64 M/M was not altered in patients compared with controls but there was an inverse correlation between IL-10-producing M/M and viral load. IL-12 production was not correlated with viral load but was increased following antiretroviral therapy. Following LPS stimulation, IL-12 and TNF-alpha responses were not altered in HIV-positive patients; however, the IL-10 response was decreased but restored by antiretroviral therapy., Conclusion: These observations argue for a preserved intrinsic CD64 M/M of IL-12 production in HIV pathogenesis.

The oppositely-imprinted genes insulin-like growth factor-II (IGF2) and H19, a putative tumor suppressor, often show coordinate, reciprocal regulation and are believed to play a role in carcinogenesis. To explore the possible interactions between these genes, we stably transfected diHepG2 cells with a plasmid containing either the sense or the antisense H19 cDNA sequences and verified their expression by Northern analysis and by RNase protection analysis. Levels of H19, IGF2 and gamma-actin mRNA were quantified by competitive RT-PCR analysis. Although H19 sense transgene overexpression (n = 24 clones) did not decrease the low, basal levels of IGF2 mRNA compared to control cells, levels of IGF2 mRNA were positively correlated with the levels of H19 antisense mRNA (P < 0.0001, n = 40 clones). Furthermore, the increase in IGF2 mRNA level was accompanied by an elevation of IGF-II peptide in conditioned media. To see if H19 mRNA had a specific effect on transcription, we also performed transient transfections with reporter gene constructs containing IGF2 promoter 3 in the presence of sense or antisense H19 cDNA sequences under control of a cytomegalovirus promoter. We show a lower reporter gene activity from reporter gene constructs in the presence of sense H19 cDNA than from those with antisense or neomycin. Our results suggest that H19 participates in the repression of IGF2, at least in part through effects on IGF2 transcription, an effect which may contribute to its action as a tumor suppressor.

Highly-active antiretroviral therapy (HAART) has lead to a dramatic decrease in the morbidity of patients infected with the human immunodeficiency virus (HIV). However, metabolic side effects, including lipodystrophy-associated (LD-associated) dyslipidemia, have been reported in patients treated with antiretroviral therapy. This study was designed to determine whether successful HAART was responsible for a dysregulation in the homeostasis of tumor necrosis factor-alpha (TNF-alpha), a cytokine involved in lipid metabolism. Cytokine production was assessed at the single cell level by flow cytometry after a short-term stimulation of peripheral blood T cells from HIV-infected (HIV(+)) patients who were followed during 18 months of HAART. A dramatic polarization to TNF-alpha synthesis of both CD4 and CD8 T cells was observed in all patients. Because it was previously shown that TNF-alpha synthesis by T cells was highly controlled by apoptosis, concomitant synthesis of TNF-alpha and priming for apoptosis were also analyzed. The accumulation of T cells primed for TNF-alpha synthesis is related to their escape from activation-induced apoptosis, partly due to the cosynthesis of interleukin-2 (IL-2) and TNF-alpha. Interestingly, we observed that LD is associated with a more dramatic TNF-alpha dysregulation, and positive correlations were found between the absolute number of TNF-alpha CD8 T-cell precursors and lipid parameters usually altered in LD including cholesterol, triglycerides, and the atherogenic ratio apolipoprotein B (apoB)/apoA1. Observations from the study indicate that HAART dysregulates homeostasis of TNF-alpha synthesis and suggest that this proinflammatory response induced by efficient antiretroviral therapy is a risk factor of LD development in HIV(+) patients.

HIV infection is marked by the progressive destruction of the CD4 T lymphocyte subset, an essential component of the immune system and a vital source of cytokines required for differentiation of natural killer (NK) and gamma delta T cells, for maturation of B lymphocytes into plasmocytes, and for differentiation of CD8+ T cells into virus-specific cytotoxic T lymphocytes. CD4 T lymphocytes are also a source of chemokines which control migration of lymphocytes to the site of infection and which also inhibit HIV entry into CD4-expressing targets. Continuous production of viral proteins leads to an unbalanced immune activation and to the triggering of apoptotic programs, turning mononuclear cells, including CD4 T cells, CD8 T cells and APC, into effectors of apoptosis, leading to fratricidal destruction of healthy uninfected cells expressing the death receptors. Inappropriate PCD is also responsible for the disappearance of T helper cells primed for type-1 cytokine synthesis, thus contributing to the lack of survival factors which could prevent spontaneous lymphocyte apoptosis. Under potent anti-retroviral therapies, a significant decrease in spontaneous, TCR- and CD95-induced lymphocyte apoptosis is observed, concomitant with a partial quantitative and qualitative restoration of the immune system in treated patients. However, owing to the suppressive effect of anti-retroviral drugs on physiological apoptosis, these therapies are associated with alteration of TNF-alpha-regulated T cell homeostasis, leading to an accumulation in the blood of T cells primed for TNF-alpha synthesis, and contributing to the development of a new syndrome associated with these treatments, the lipodystrophy syndrome.

Setting: The study was conducted in Bobo-Dioulasso, Burkina Faso, where Mycobacterium tuberculosis infection and human immunodeficiency virus type 1 (HIV-1) infection are prevalent., Objective: To identify proportions of representative (test) populations who are reactive to the tuberculin skin test, and to study the relationship between CD4 T-lymphocyte counts and the induration size of the tuberculin skin test in these groups., Design: A group of 435 healthy students was tuberculin skin tested in order to evaluate the intensity of skin testing in a 'normal' population. The study group consisted of 195 subjects with or without tuberculosis, and with or without HIV-1 infection, who received a tuberculin skin test and a CD4 T lymphocyte count on the same day., Results: In total, 90% of the control (nontuberculous, HIV negative) subjects, 32% of the HIV-1 seropositive subjects, 76.5% of the tuberculous patients and 57% of the tuberculous HIV-1 seropositive patients were tuberculin positive. There was no direct correlation between the induration size of reactions to the tuberculin skin test and CD4 T-lymphocyte count in these study groups using linear regression analysis., Conclusion: In vivo skin testing using tuberculin yields clinically significant information on the degree of immunodeficiency which is different from that of CD4 T-lymphocyte counts. The tuberculin skin test should therefore be used as an independent marker of the weakened immunological status of HIV-1 seropositive subjects.

It has been proposed that HIV infection is associated with an imbalance in Th1 and Th2 subsets. Recent reports indicate that Th1 and Th2 effectors differ in their susceptibility to activation-induced apoptosis. To determine whether increased T cell apoptosis in HIV-infected patients contributes to alterations in cytokine synthesis, we performed single-cell analysis of type 1 and type 2 cytokine production by CD4 and CD8 T cells, simultaneously with detection of apoptosis. We demonstrate that a differential alteration in representation of Th1 subsets, rather than commitment of T cells to secrete Th2 cytokines, occurs throughout HIV infection. A significant decrease in the number of IL-2- or TNF-alpha-producing T cells was observed, whereas those producing IFN-gamma remained preserved. Furthermore, there is a gradient of susceptibility to activation-induced apoptosis (IL-2 < IFN-gamma < TNF-alpha) among the different Th1 subsets. This gradient was detected in both CD4 and CD8 subsets, as well as in control donors and HIV-infected patients, in whom the susceptibility to apoptosis of IL-2 and IFN-gamma producers was increased compared with controls. This differential intrinsic apoptosis susceptibility of Th1 effectors was found to be tightly regulated by Bcl-2 expression. In HIV-infected persons, disappearance of IL-2-producing T cells was a good indicator of disease progression and was correlated with the progressive shrinkage of the CD4+ CD45RA+ T cell compartment and a gradual increased susceptibility to activation-induced apoptosis of the IL-2-producing subset. This close relationship between the CD45RA/CD45R0 ratio, the level of type 1 cytokine production, and susceptibility to apoptosis should be considered in HIV-infected patients under antiviral or immune-based therapies.

CD4+ lymphocyte count (CD4+ LC) is a widely used marker of Human Immunodeficiency Virus (HIV) immune impairment. Physiological lymphocytosis is frequently encountered in Africans. Therefore, we tried to determine if given CD4+ LC levels are of similar significance in European versus African HIV-infected individuals. Lymphocyte phenotyping of 750 HIV-infected adults was retrospectively analyzed. Three hundred and seventy patients were consecutively selected in Paris, France; 185 in Abidjan, Côte d'Ivoire; and 195 in Bobo-Dioulasso, Burkina Faso. In the three settings, lymphocyte phenotyping was performed by flow cytometry using similar protocols. Data from Abidjan and Bobo-Dioulasso were combined on the basis of geographic proximity and contrasted with those from Paris. Geometric mean levels of Total Lymphocyte Count (TLC), CD4+ LC, CD8+ lymphocyte count (CD8+ LC), and CD4:CD8 ratio, adjusted for percentage of CD4+ T-cells (%CD4+), were compared between Africans and Europeans. For a given %CD4+, TLC and CD4+ LC but not CD8+ LC tended to be about one third higher in West African than in French adults (p < 0.0001). Approximate equivalencies of absolute CD4+ counts in French and West African HIV-infected adults suggest that where thresholds of 200 and 500 CD4+ cells/microliter are applied in Europe, it might be appropriate to apply a threshold of approximately 250 and 700 CD4+ cells/microliter in West Africa, respectively. Establishing indicators of progression of HIV infection with locally appropriate thresholds may represent important steps toward improvement of HIV disease management in Africa.

During and after the Rift Valley Fever epidemic in southern mauritania, we conducted epidemiological inquiries in order to determine epidemic and epizootic areas. The epidemic area was divided into two different zones. The first was located along the right bank of the Senegal River, around the town of Rosso. The second was located near the town of Kaedi. This epidemic area was included within the epizootic area, which stretched to the south, between Rosso and Saint-Louis. Several ecological changes had occurred in the recent past including erection of dams on the Senegal River for irrigation, and heavier rainfall than during previous years.