Browsing by Author "Ameri, Diego"

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    Expansion of CD25-Negative Forkhead Box P3-Positive T Cells during HIV and Mycobacterium tuberculosis Infection
    (2017-05-09) Angerami, Matías T; Suarez, Guadalupe V; Vecchione, María B; Laufer, Natalia; Ameri, Diego; Ben, Graciela; Perez, Hector; Sued, Omar; Salomon, Horacio ; Quiroga, María F
    Tuberculosis (TB) and HIV alter the immune system, and coinfected (HIV-TB) individuals usually present deregulations of T-lymphocytic immune response. We previously observed an increased frequency of “unconventional” CD4+CD25−FoxP3+ Treg (uTreg) population during HIV-TB disease. Therefore, we aimed to explore the phenotype and function of uTreg and conventional CD4+CD25+FoxP3+ Treg subsets (cTreg) in this context. We evaluated the expression of CD39, programmed cell death protein 1 (PD1), glucocorticoid-induced tumor necrosis factor receptor (GITR), and the effector/memory distribution by flow cytometry in cTreg and uTreg. Also, IL-10, TGF-β, IFN-γ production, and the suppressor capacity of uTregs were analyzed in cocultures with effector lymphocytes and compared with the effect of regulatory T cells (Tregs). We found diminished expression of CD39 and higher levels of PD1 on uTreg compared to cTreg in both HIV-TB and healthy donors (HD). In addition, uTreg and cTreg showed differences in maturation status in both HIV-TB and HD groups, due to the expansion of effector memory uTregs. Interestingly, both HIV-TB and HD showed a pronounced production of IFN-γ in uTreg population, though no significant differences were observed for IL-10 and TGF-β production between uTreg and cTreg. Moreover, IFN-γ+ cells were restricted to the CD39− uTreg population. Finally, when the suppressor capacity was evaluated, both uTreg and cTreg inhibited polyclonal T cell-proliferation and IFN-γ production in a similar extent. These findings suggest that uTregs, which are expanded during HIV-TB coinfection, exert regulatory functions in a similar way to cTregs despite an altered surface expression of Treg characteristic markers and differences in cytokine production.
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    HIV-TB co-infection impairs CD8+ T-cell differentiation and function while dehydroepiandrosterone improves cytotoxic anti-tubercular immune responses
    (2015-9) Suarez, Guadalupe V.; Angerami, Matias; Vecchione, María B.; Laufer, Natalia; Turk, Gabriela; Ruiz, Maria; Mesch, Viviana; Fabre, Bibiana; Maidana, Patricia; Ameri, Diego; Cahn, Pedro; Sued, Omar; Salomon, Horacio; Bottasso, Oscar A.; Quiroga, María F.
    Tuberculosis (TB) is the leading cause of death among HIV-positive patients. The decreasing frequencies of terminal effector (TTE) CD8+T cells may increase reactivation risk in persons latently infected with Mycobacterium tuberculosis (Mtb). We have previously shown that dehydroepiandrosterone (DHEA) increases the protective antitubercular immune responses in HIV–TB patients. Here, we aimed to study Mtb-specific cytotoxicity, IFN-γ secretion, memory status of CD8+T cells, and their modulation by DHEA during HIV–TB coinfection. CD8+T cells from HIV–TB patients showed a more differentiated phenotype with diminished naïve and higher effector memory and TTE T-cell frequencies compared to healthy donors both in total and Mtb-specific CD8+T cells. Notably, CD8+T cells from HIV–TB patients displayed higher Terminal Effector (TTE) CD45RAdim proportions with lower CD45RA expression levels, suggesting a not fully differentiated phenotype. Also, PD-1 expression levels on CD8+T cells from HIV–TB patients increased although restricted to the CD27+ population. Interestingly, DHEA plasma levels positively correlated with TTE in CD8+T cells and in vitro DHEA treatment enhanced Mtb-specific cytotoxic responses and terminal differentiation in CD8+T cells from HIV–TB patients. Our data suggest that HIV–TB coinfection promotes a deficient CD8+ T-cell differentiation, whereas DHEA may contribute to improving antitubercular immunity by enhancing CD8+T-cell functions during HIV–TB coinfection.
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    Immune variations throughout the course of tuberculosis treatment and its relationship with adrenal hormone changes in HIV-1 patients co-infected with Mycobacterium tuberculosis
    (2022-03) Vecchione, María Belén; Angerami, Matias; Suarez, Guadalupe Verónica; Turk, Gabriela; Laufer, Natalia; Ben, Graciela; Ameri, Diego; Gonzalez, Diego; Parodi, Laura M.; Giavedoni, Luis D.; Maidana, Patricia; Fabre, Bibiana; Mesch, Viviana; Sued, Omar; Quiroga, Maria Florencia
    HIV infection is a major risk factor predisposing for Mycobacterium tuberculosis infection and progression to active tuberculosis (TB). As host immune response defines the course of infection, we aimed to identify immuno-endocrine changes over six-months of anti-TB chemotherapy in HIV+ people. Plasma levels of cortisol, DHEA and DHEA-S, percentages of CD4+ regulatory T cell subsets and number of IFN-γ-secreting cells were determined. Several cytokines, chemokines and C-reactive protein levels were measured. Results were correlated with clinical parameters as predictors of infection resolution and compared to similar data from HIV+ individuals, HIV-infected persons with latent TB infection and healthy donors. Throughout the course of anti-TB/HIV treatment, DHEA and DHEA-S plasma levels raised while cortisol diminished, which correlated to predictive factors of infection resolution. Furthermore, the balance between cortisol and DHEA, together with clinical assessment, may be considered as an indicator of clinical outcome after anti-TB treatment in HIV+ individuals. Clinical improvement was associated with reduced frequency of unconventional Tregs, increment in IFN-γ-secreting cells, diminution of systemic inflammation and changes of circulating cytokines and chemokines. This study suggests that the combined anti-HIV/TB therapies result in partial restoration of both, immune function and adrenal hormone plasma levels.