Markers of Natural Killer Cell Exhaustion in HIV/HCV Coinfection and Their Dynamics After HCV Clearance Mediated by Direct-Acting Antivirals.

Background: Liver fibrosis is a leading cause of morbimortality in people with HIV/hepatitis C virus (HCV). Natural killer (NK) cells are linked with amelioration of liver fibrosis; however, NK cells from individuals coinfected with HIV/HCV with cirrhosis display impaired functionality and high PD-1 expression. Here, we aimed to study PD-1, TIGIT, and Tim3 as potential exhaustion markers in NK cells from persons coinfected with HIV/HCV with mild and advanced liver fibrosis. We also evaluated the role of PD-1 expression on NK cells after HCV clearance by direct-acting antivirals (DAAs). Methods: Peripheral blood mononuclear cells were isolated from individuals coinfected with HIV/HCV (N = 54; METAVIR F0/F1, n = 27; F4, evaluated by transient elastography, n = 27). In 26 participants, samples were collected before, at the end of, and 12 months after successful DAA treatment. The frequency, immunophenotype (PD-1, TIGIT, and Tim3 expression), and degranulation capacity (CD107a assay) of NK cells were determined by flow cytometry. Results: Unlike PD-1, Tim3 and TIGIT were comparably expressed between persons with mild and advanced fibrosis. Degranulation capacity was diminished in NK/TIGIT+ cells in both fibrosis stages, while NK/PD-1+ cells showed a lower CD107a expression in cirrhotic cases. Twelve months after DAA treatment, those with advanced fibrosis showed an improved NK cell frequency and reduced NK/PD-1+ cell frequency but no changes in CD107a expression. In individuals with mild fibrosis, neither PD-1 nor NK cell frequency was modified, although the percentage of NK/CD107a+ cells was improved at 12 months posttreatment. Conclusions: Although DAA improved exhaustion and frequency of NK cells in cirrhotic cases, functionality was reverted only in mild liver fibrosis, remarking the importance of an early DAA treatment.

Evaluation of the humoral response to the third dose of SARS-COV-2 vaccines in liver transplant recipients.

Solid organ transplant recipients (SOTR) commonly develop an unsatisfactory humoral response to vaccines compared to immunocompetent individuals (IC). We have previously evaluated the humoral response in liver transplant recipients (LTR) who received two-dose vaccines against SARS-CoV-2 and reported that 38 % of LTR did not produce anti-Spike antibodies. Thus, we set out to evaluate the humoral response after the third dose of SARS-CoV-2 vaccines. For this purpose, samples from a cohort of 81 LTR and 27 IC were extracted between 21 and 90 days after the third dose. Serology for anti-Spike IgG antibodies and neutralizing antibodies against Wuhan, Delta and Omicron variants were evaluated. We found that 73.5 % of LTR were responders for anti-Spike IgG, while all the IC mounted a measurable response. LTR who responded to the third dose showed significantly lower anti-Spike IgG levels and neutralizing antibodies than IC. We found that there is less neutralization in LTR compared to IC across all variants. Specifically, the neutralization titers in both groups decrease when encountering the Delta variant, and this decline is even more pronounced with the Omicron variant, compared to the Wuhan variant. Furthermore, we identified that the use of high doses of mycophenolate and advanced age were factors that negatively affected the development of anti-Spike IgG antibodies. Regarding vaccine regimes, the regime viral vector/mRNA/mRNA elicited significantly higher responses in LTR compared to other vaccine schemes. In addition to the recommended and necessary booster doses in this population, strategies that achieve adequate immunization should be evaluated.

COVID-19 Vaccination Responses with Different Vaccine Platforms in Patients with Inborn Errors of Immunity.

Patients with inborn errors of immunity (IEI) in Argentina were encouraged to receive licensed Sputnik, AstraZeneca, Sinopharm, Moderna, and Pfizer vaccines, even though most of the data of humoral and cellular responses combination on available vaccines comes from trials conducted in healthy individuals. We aimed to evaluate the safety and immunogenicity of the different vaccines in IEI patients in Argentina. The study cohort included adults and pediatric IEI patients (n = 118) and age-matched healthy controls (HC) (n = 37). B cell response was evaluated by measuring IgG anti-spike/receptor binding domain (S/RBD) and anti-nucleocapsid(N) antibodies by ELISA. Neutralization antibodies were also assessed with an alpha-S protein-expressing pseudo-virus assay. The T cell response was analyzed by IFN-γ secretion on S- or N-stimulated PBMC by ELISPOT and the frequency of S-specific circulating T follicular-helper cells (TFH) was evaluated by flow cytometry.No moderate/severe vaccine-associated adverse events were observed. Anti-S/RBD titers showed significant differences in both pediatric and adult IEI patients versus the age-matched HC cohort (p < 0.05). Neutralizing antibodies were also significantly lower in the patient cohort than in age-matched HC (p < 0.01). Positive S-specific IFN-γ response was observed in 84.5% of IEI patients and 82.1% presented S-specific TFH cells. Moderna vaccines, which were mainly administered in the pediatric population, elicited a stronger humoral response in IEI patients, both in antibody titer and neutralization capacity, but the cellular immune response was similar between vaccine platforms. No difference in humoral response was observed between vaccinated patients with and without previous SARS-CoV-2 infection.In conclusion, COVID-19 vaccines showed safety in IEI patients and, although immunogenicity was lower than HC, they showed specific anti-S/RBD IgG, neutralizing antibody titers, and T cell-dependent cellular immunity with IFN-γ secreting cells. These findings may guide the recommendation for a vaccination with all the available vaccines in IEI patients to prevent COVID-19 disease.

Respuesta inmune contra SARS-CoV-2 en personas con VIH convalecientes de COVID-19 / SARS-CoV-2 immunity in PWH

Desde principios de la pandemia de SARS-CoV-2 se ha debatido el curso de la enfermedad COVID-19 en personas con VIH. Por un lado, la inmunodeficiencia derivada de la infección por VIH y la mayor prevalencia de comorbilidades estarían asociadas al desarrollo de enfermedad grave. Por otro lado, la disfunción inmunológica podría evitar una respuesta inflamatoria exacerbada. En este trabajo de revisión analizamos la evidencia disponible en cuanto a la relación entre la manifestación clínica de COVID-19 y la respuesta inmune humoral y celular contra SARS-CoV-2 en el contexto de la coinfección con VIH. La bibliografía sugiere que las personas con VIH que reciben tratamiento antirretroviral logran respuestas eficaces contra SARS-CoV-2, a pesar de presentar algunas de las funciones celulares alteradas. Esto sugiere un impacto significativo de la terapia antirretroviral, no solo en el control del VIH sino en potenciar la inmunidad para restringir otras infecciones.

Since the beginning of SARS-CoV-2 pandemic, the course of COVID-19 in people with HIV has been debated. On the one hand, the immunodeficiency derived from HIV infec-tion and the higher prevalence of comorbidities would be associated with severe disease. On the other hand, due to its immunological dysfunction, an exacerbated inflam-matory response might be avoided.In this review, we analyzed the evidence regarding the clinical manifestation of COVID-19 and the humoral and cellular immune response against SARS-CoV-2 during HIV coinfection. The literature suggests that people with HIV on antiretroviral treatment achieved effective responses against SARS-CoV-2, despite having altered cell func-tions. This indicates a remarkable impact of antiretroviral therapy, not only in controlling HIV but also in boosting immunity to restrict other infections

Immune Response to SARS-CoV-2 Third Vaccine in Patients With Rheumatoid Arthritis Who Had No Seroconversion After Primary 2-Dose Regimen With Inactivated or Vector-Based Vaccines.

OBJECTIVE: The aim of this study was to assess the immune response after a third dose of SARS-CoV-2 vaccine in patients with rheumatoid arthritis (RA) with undetectable antibody titers after the primary regimen of 2 doses. METHODS: Patients with RA with no seroconversion after 2 doses of SARS-CoV-2 vaccine and who received a third dose of either an mRNA or vector-based vaccine were included. Anti-SARS-CoV-2 IgG antibodies, neutralizing activity, and T cell responses were assessed after the third dose. RESULTS: A total of 21 nonresponder patients were included. At the time of vaccination, 29% were receiving glucocorticoids and 85% biologic disease-modifying antirheumatic drugs (including 6 taking abatacept [ABA] and 4 taking rituximab [RTX]). The majority (95%) received the BNT162b2 vaccine and only one of them received the ChAdOx1 nCoV-19 vaccine. After the third dose, 91% of the patients presented detectable anti-SARS-CoV-2 IgG and 76% showed neutralizing activity. Compared to other treatments, ABA and RTX were associated with the absence of neutralizing activity in 4 out of 5 (80%) patients and lower titers of neutralizing antibodies (median 3, IQR 0-20 vs 8, IQR 4-128; P = 0.20). Specific T cell response was detected in 41% of all patients after the second dose, increasing to 71% after the third dose. The use of ABA was associated with a lower frequency of T cell response (33% vs 87%, P = 0.03). CONCLUSION: In this RA cohort, 91% of patients who failed to seroconvert after 2 doses of SARS-CoV-2 vaccine presented detectable anti-SARS-CoV-2 IgG after a third dose. The use of ABA was associated with a lower frequency of specific T cell response.

Macrophage Migration Inhibitory Factor (MIF) Promotes Increased Proportions of the Highly Permissive Th17-like Cell Profile during HIV Infection.

In this study, we evaluate the role of the MIF/CD74 axis in the functionality of CD4+ T lymphocytes (CD4TL) during HIV infection. MDMs from healthy donors were infected with a R5-tropic or Transmitted/Founder (T/F) HIV strain. At day 11 post-MDM infection, allogeneic co-cultures with uninfected CD4TLs plus MIF stimulus were performed. Cytokine production was evaluated by ELISA. MIF plasma levels of people with HIV (PWH) were evaluated by ELISA. The phenotype and infection rate of CD4TLs from PWH were analyzed after MIF stimulus. Intracellular cytokines and transcription factors were evaluated by flow cytometry. Data were analyzed by parametric or non-parametric methods. The MIF stimulation of HIV-infected MDMs induced an increased expression of IL-6, IL-1ß and IL-8. In CD4TL/MDM co-cultures, the MIF treatment increased IL-17A/RORγt-expressing CD4TLs. Higher concentrations of IL-17A in supernatants were also observed. These results were recapitulated using transmitted/founder (T/F) HIV-1 strains. The MIF treatment appeared to affect memory CD4TLs more than naïve CD4TLs. MIF blocking showed a negative impact on IL17A+CD4TL proportions. Higher MIF concentrations in PWH-derived plasma were correlated with higher IL-17A+CD4TL percentages. Finally, MIF stimulation in PWH-derived PBMCs led to an increase in Th17-like population. MIF may contribute to viral pathogenesis by generating a microenvironment enriched in activating mediators and Th17-like CD4TLs, which are known to be highly susceptible to HIV-1 infection and relevant to viral persistence. These observations establish a basis for considering MIF as a possible therapeutic target.

Phenotypic and functional analysis of γδ T cells in the pathogenesis of human T-cell lymphotropic virus type 1 infection.

The human T-cell leukemia virus type 1 (HTLV-1) is the cause of serious malignant and inflammatory diseases, including adult T-cell leukemia and lymphoma and tropical spastic paraparesis. The potential protective role of γδ T cells in HTLV-1 infection remains unclear. Here, demonstrate that there is a decrease in the amount of Vγ9Vδ2 T cells in patients with HTLV-1, especially in those with HTLV-1 associated pathologies. This suggests that γδ T cells could be involved in controlling the virus. Indeed, we found that Vγ9Vδ2 T cells, expanded from non-infected individuals, can kill cells expressing the viral proteins HBZ and Tax and this phenotype is reversed in the presence of mevastatin. Cytotoxicity by Vγ9Vδ2 T cells was not associated with an increase of INF-γ production. In sharp contrast, killing by NK cells was reduced by Tax expression. Thus, our study provides initial evidence for a potential protective role of Vγ9Vδ2 T cells against HTLV-1 infection. Therapeutic exploitation of these insights is feasible with current technologies of T-cell therapies and could provide novel tools to prevent and treat HTLV-1-associated malignancies and neurologic complications.

Creación de la colección COVID-19 del Biobanco de Enfermedades Infecciosas en Argentina / Establishment of a COVID-19 collection within the Biobank of Infectious Diseases in ArgentinaEsta obra está bajo una licencia de CreativeCommons Reconocimiento-NoComercial 4.0Internacionalhttps://creativecommons.org/licenses/by-nc/4.0/i

La pandemia de COVID-19 ha puesto en jaque a los sistemas de salud en el mundo; la vinculación entre la investigación biomédica y la práctica asistencial ha probado ser un requisito fundamental para dar respuesta a la misma de manera eficiente y rápida. En este sentido, los biobancos se constituyen como un componente clave ya que favorecen el almacenamiento de grandes volúmenes de muestras biológicas gestionadas en base a criterios que garanticen su óptima calidad, armonización y seguridad, respetando requisitos éticos y legales que aseguran los derechos de los ciudadanos. La cesión de estas muestras a distintos grupos de investigación promueve el desarrollo de nuevas herramientas diagnósticas y terapéuticas y vacunas. Frente a la llegada del SARS-CoV-2 a la Argentina, el Biobanco de Enfermedades Infecciosas estableció rápidamente la colección COVID-19 constituida por muestras de plasma, suero y células mononucleares de sangre periférica de personas cursando la enfermedad o recuperadas. En solo seis meses se enrolaron 825 donantes, lo que significa alrededor de 14.000 viales de material biológico almacenados y a disposición de los investigadores que lo soliciten. A tal efecto, se realizaron seis actos de cesión a diversos grupos pertenecientes a instituciones de investigación, mientras que tres se encuentran en evaluación. Las muestras cedidas han permitido, por ejemplo, el desarrollo de kits serológicos de producción nacional; lo que pone de manifiesto que el rápido establecimiento de esta colección, bajo un sistema de gestión eficiente, constituye una herramienta muy valiosa en la respuesta a esta nueva enfermedad

The COVID-19 pandemic has driven an unprecedented health crisis. Cooperation between biomedical research and healthcare practice has been shown to be a fundamental requirement to provide an efficient and timely response. In this regard, biobanks are key components since they allow the storage of large volumes of biological samples with guaranteed optimum quality, harmonization and safety, ensuring ethical and legal requirements which protect citizen rights. The transfer of these samples to different research groups fosters the development of new diagnostic and therapeutic tools as well as vaccines. Upon SARS-CoV-2 arrival to Argentina, the Biobank of Infectious Diseases rapidly established the COVID-19 collection comprised by plasma, serum and peripheral blood mononuclear cells samples obtained from people within the acute phase of the infection or who have already recovered. In only 6 months, 825 donors were enrolled, representing around 14,000 vials of biological material stored and available to researchers who might require it. In this line, 6 transfer agreements have been already performed to different groups belonging to national research institutions, while 3 are under evaluation. The transferred samples have allowed, for instance, the development of nationally produced serologic kits, which shows that the rapid establishment of this collection, under an efficient management system, represents a highly valuable tool in the response to this new disease.

Immune variations throughout the course of tuberculosis treatment and its relationship with adrenal hormone changes in HIV-1 patients co-infected with Mycobacterium tuberculosis.

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.

Seroprevalencia de COVID 19 en personas viviendo con VIH en el Area Metropolitana / COVID-19 Seroprevalence and PLHIV

Se desconoce si las personas que viven con el VIH (PVV) tienen un mayor riesgo de contraer la infección por SARS-CoV-2. Los estudios serológicos prospectivos pueden permitir análisis de seroincidencia. Este estudio prospectivo incluyó a PVV sin antecedentes de vacunación contra SARS-CoV-2 de la Ciudad Autónoma de Buenos Aires (CABA) y Gran Buenos Aires (GBA) que concurrieron entre marzo y junio de 2021 a realizar sus controles al instituto INBIRS. La tasa de seroprevalencia de anticuerpos contra la proteína espiga del SARS-CoV-2 fue del 33,3% (IC 24,9-42,5%) para la población estudiada. Esta prevalencia fue significativamente mayor a la reportada previamente para la población general de la misma región geográfica. No se observó una asociación entre el recuento de linfocitos T CD4+ con los niveles de IgG específica. En conclusión, el hallazgo de una alta seroprevalencia de anticuerpos contra SARS-CoV-2 entre las PVV en CABA y GBA puede sugerir una mayor susceptibilidad a la infección por este virus; sin embargo, puede ser también un marcador subrogante que indica la tasa de seroprevalencia en población general se encuentra subestimada

It is not known whether people living with HIV (PLHIV) are at increased risk of acquiring SARS-CoV-2 infection. Prospective serological studies can allow seroincidence analysis. This prospective study included PLHIV, without a history of vaccination against SARS-CoV-2, from the Autonomous City of Buenos Aires (CABA) and Buenos Aires surroundings (GBA), who attended INBIRS Institute between March and June 2021 to carry out their controls. The seroprevalence rate of antibodies against the SARS-CoV-2 spike protein was 33.3% (CI 24.9-42.5%) for the study population. This prevalence was significantly higher than that previously reported for the general population of the same geographic region. No association was found between CD4+ T-cell counts with levels of SARS-CoV-2 specific IgG. In conclusion, the finding of a high seroprevalence of antibodies against SARS-CoV-2 among PLHIV in CABA and GBA may suggest a greater susceptibility to infection; however, it can also be a surrogate marker that the seroprevalence rate in the general population is underestimated.

Hepatitis C Virus (HCV) Clearance After Treatment With Direct-Acting Antivirals in Human Immunodeficiency Virus (HIV)-HCV Coinfection Modulates Systemic Immune Activation and HIV Transcription on Antiretroviral Therapy.

BACKGROUND: Hepatitis C virus (HCV) coinfection among people with human immunodeficiency virus (HIV) might perturb immune function and HIV persistence. We aimed to evaluate the impact of HCV clearance with direct-acting antivirals (DAAs) on immune activation and HIV persistence in HIV/HCV-coinfected individuals on antiretroviral therapy (ART). METHODS: In a prospective observational study, ART-treated participants with HIV/HCV coinfection received sofosbuvir/daclatasvir ±â€…ribavirin (n = 19). Blood samples were collected before DAA therapy, at the end of treatment, and 12 months after DAA termination (12MPT). T- and natural killer (NK)-cell phenotype, soluble plasma factors, cell-associated (CA)-HIV deoxyribonucleic acid (DNA) forms (total, integrated, 2LTR), CA-unspliced (US) and multiple-spliced ribonucleic acid (RNA), and plasma HIV RNA were evaluated. RESULTS: Hepatitis C virus clearance was associated with (1) a downmodulation of activation and exhaustion markers in CD4+, CD8+ T, and NK cells together with (2) decreased plasma levels of Interferon gamma-induced protein 10 (IP10), interleukin-8 (IL-8), soluble (s)CD163 and soluble intercellular adhesion molecule (sICAM). Cell-associated US HIV RNA was significantly higher at 12MPT compared to baseline, with no change in HIV DNA or plasma RNA. CONCLUSIONS: Elimination of HCV in HIV/HCV-coinfected individuals alters immune function and the transcriptional activity of latently infected cells. This report provides insights into the effects of HCV coinfection in HIV persistence and regards coinfected subjects as a population in which HIV remission might prove to be more challenging.

Expression of IL-33 Receptor Is Significantly Up-Regulated in B Cells During Pregnancy and in the Acute Phase of Preterm Birth in Mice.

Interleukin-33 (IL-33) is a mucosal alarmin belonging to the IL-1 cytokine family and is now recognized to have a key role in innate and adaptive immunity, contributing to tissue homeostasis and response to environmental stresses. In addition, IL-33 has also been shown to work as a positive regulator that initiates and maintains a Th2 immune response. In the context of pregnancy, it has been recently demonstrated that upon certain stress conditions, such as an infection induced inflammation, IL-33 is released from the uterine mucosa and triggers decidual B cells to produce anti-inflammatory molecules, which in turn restore immune homeostasis and prevents the development of preterm birth. In this study we therefore performed a detailed characterization of IL-33 receptor (Il1rl1 or ST2) expression in B cells during normal pregnancy, as well as in a mouse model of preterm birth. We observed that splenic B cells significantly up-regulate the expression of Il1rl1 during pregnancy and identified the B1 B cell population as the main ST2-expressing B cell subset. A further kinetic analysis showed that percentages of ST2-expressing B1 B cells are significantly augmented on days 12 and 14 of pregnancy, both in the spleen and peritoneal cavity of pregnant mice, and then drop toward the end of pregnancy to the levels observed in non-pregnant animals. Furthermore, using a mouse model of LPS-induced preterm birth, we demonstrated that not only are the percentages of ST2-expressing B1 B cells significantly enlarged in the spleen during the acute phase of preterm birth, but decidual B cells also significantly up-regulate ST2 expression as compared to term-pregnant mice. Overall, our results suggest a functional role of ST2 expression in B cells during pregnancy and reinforce the importance of the IL-33/ST2 axis in B cells as a critical mechanism to control inflammation-induced preterm birth.

7-oxo-DHEA enhances impaired M. tuberculosis-specific T cell responses during HIV-TB coinfection.

BACKGROUND: Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis (TB), affecting approximately one third of the world's population. Development of an adequate immune response will determine disease progression or progress to chronic infection. Risk of developing TB among human immunodeficiency virus (HIV)-coinfected patients (HIV-TB) is 20-30 times higher than those without HIV infection, and a synergistic interplay between these two pathogens accelerates the decline in immunological functions. TB treatment in HIV-TB coinfected persons is challenging and it has a prolonged duration, mainly due to the immune system failure to provide an adequate support for the therapy. Therefore, we aimed to study the role of the hormone 7-oxo-dehydroepiandrosterone (7-OD) as a modulator of anti-tuberculosis immune responses in the context of HIV-TB coinfection. METHODS: A cross-sectional study was conducted among HIV-TB patients and healthy donors (HD). We characterized the ex vivo phenotype of CD4 + T cells and also evaluated in vitro antigen-specific responses by Mtb stimulation of peripheral blood mononuclear cells (PBMCs) in the presence or absence of 7-OD. We assessed lymphoproliferative activity, cytokine production and master transcription factor profiles. RESULTS: Our results show that HIV-TB patients were not able to generate successful anti-tubercular responses in vitro compared to HD, as reduced IFN-γ/IL-10 and IFN-γ/IL-17A ratios were observed. Interestingly, treatment with 7-OD enhanced Th1 responses by increasing Mtb-induced proliferation and the production of IFN-γ and TNF-α over IL-10 levels. Additionally, in vitro Mtb stimulation augmented the frequency of cells with a regulatory phenotype, while 7-OD reduced the proportion of these subsets and induced an increase in CD4 + T-bet+ (Th1) subpopulation, which is associated with clinical data linked to an improved disease outcome. CONCLUSIONS: We conclude that 7-OD modifies the cytokine balance and the phenotype of CD4 + T cells towards a more favorable profile for mycobacteria control. These results provide new data to delineate novel treatment approaches as co-adjuvant for the treatment of TB.

PD-1/PD-L1 Pathway Modulates Macrophage Susceptibility to Mycobacterium tuberculosis Specific CD8+ T cell Induced Death.

CD8+T cells contribute to tuberculosis (TB) infection control by inducing death of infected macrophages. Mycobacterium tuberculosis (Mtb) infection is associated with increased PD-1/PD-L1 expression and alternative activation of macrophages. We aimed to study the role of PD-1 pathway and macrophage polarization on Mtb-specific CD8+T cell-induced macrophage death. We observed that both PD-L1 on CD14+ cells and PD-1 on CD8+T cells were highly expressed at the site of infection in pleurisy TB patients' effusion samples (PEMC). Moreover, a significant increase in CD8+T cells' Mtb-specific degranulation from TB-PEMC vs. TB-PBMC was observed, which correlated with PD-1 and PDL-1 expression. In an in vitro model, M1 macrophages were more susceptible to Mtb-specific CD8+T cells' cytotoxicity compared to M2a macrophages and involved the transfer of cytolytic effector molecules from CD8+T lymphocytes to target cells. Additionally, PD-L1 blocking significantly increased the in vitro Ag-specific CD8+T cell cytotoxicity against IFN-γ-activated macrophages but had no effect over cytotoxicity on IL-4 or IL-10-activated macrophages. Interestingly, PD-L1 blocking enhanced Mtb-specific CD8+ T cell killing of CD14+ cells from human tuberculous pleural effusion samples. Our data indicate that PD-1/PD-L1 pathway modulates antigen-specific cytotoxicity against M1 targets in-vitro and encourage the exploration of checkpoint blockade as new adjuvant for TB therapies.

Interaction Between Macrophage Migration Inhibitory Factor and CD74 in Human Immunodeficiency Virus Type I Infected Primary Monocyte-Derived Macrophages Triggers the Production of Proinflammatory Mediators and Enhances Infection of Unactivated CD4+ T Cells.

Understanding the mechanisms of human immunodeficiency virus type I (HIV-1) pathogenesis would facilitate the identification of new therapeutic targets to control the infection in face of current antiretroviral therapy limitations. CD74 membrane expression is upregulated in HIV-1-infected cells and the magnitude of its modulation correlates with immune hyperactivation in HIV-infected individuals. In addition, plasma level of the CD74 activating ligand macrophage migration inhibitory factor (MIF) is increased in infected subjects. However, the role played by MIF/CD74 interaction in HIV pathogenesis remains unexplored. Here, we studied the effect of MIF/CD74 interaction on primary HIV-infected monocyte-derived macrophages (MDMs) and its implications for HIV immunopathogenesis. Confocal immunofluorescence analysis of CD74 and CD44 (the MIF signal transduction co-receptor) expression indicated that both molecules colocalized at the plasma membrane specifically in wild-type HIV-infected MDMs. Treatment of infected MDMs with MIF resulted in an MIF-dependent increase in TLR4 expression. Similarly, there was a dose-dependent increase in the production of IL-6, IL-8, TNFα, IL-1ß, and sICAM compared to the no-MIF condition, specifically from infected MDMs. Importantly, the effect observed on IL-6, IL-8, TNFα, and IL-1ß was abrogated by impeding MIF interaction with CD74. Moreover, the use of a neutralizing αMIF antibody or an MIF antagonist reverted these effects, supporting the specificity of the results. Treatment of unactivated CD4+ T-cells with MIF-treated HIV-infected MDM-derived culture supernatants led to enhanced permissiveness to HIV-1 infection. This effect was lost when CD4+ T-cells were treated with supernatants derived from infected MDMs in which CD74/MIF interaction had been blocked. Moreover, the enhanced permissiveness of unactivated CD4+ T-cells was recapitulated by exogenous addition of IL-6, IL-8, IL-1ß, and TNFα, or abrogated by neutralizing its biological activity using specific antibodies. Results obtained with BAL and NL4-3 HIV laboratory strains were reproduced using transmitted/founder primary isolates. This evidence indicated that MIF/CD74 interaction resulted in a higher production of proinflammatory cytokines from HIV-infected MDMs. This caused the generation of an inflammatory microenvironment which predisposed unactivated CD4+ T-cells to HIV-1 infection, which might contribute to viral spreading and reservoir seeding. Overall, these results support a novel role of the MIF/CD74 axis in HIV pathogenesis that deserves further investigation.

Determination of dehydroepiandrosterone and its biologically active oxygenated metabolites in human plasma evinces a hormonal imbalance during HIV-TB coinfection.

An estimated one third of the world's population is affected by latent tuberculosis (TB), which once active represents a leading cause of death among infectious diseases. Human immunodeficiency virus (HIV) infection is a main predisposing factor to TB reactivation. Individuals HIV-TB co-infected develop a chronic state of inflammation associated with hypothalamic-pituitary-adrenal (HPA) axis dysregulation. This results in a hormonal imbalance, disturbing the physiological levels of cortisol and dehydroepiandrosterone (DHEA). DHEA and its oxygenated metabolites androstenediol (AED), androstenetriol (AET) and 7-oxo-DHEA are immunomodulatory compounds that may regulate physiopathology in HIV-TB co-infection. In order to study possible changes in plasma levels of these hormones, we developed an approach based on high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). To our knowledge, this represents the first report of their simultaneous measurement in HIV-TB individuals and the comparison with healthy donors, obtaining statistically higher plasma levels of DHEA, AET and 7-oxo-DHEA in patients. Moreover, we found that concentrations of 7-oxo-DHEA positively correlated with absolute CD4+ T cell counts, nadir CD4+ T cell values and with individuals who presented TB restricted to the lungs. This research contributes to understanding the role of these hormones in HIV-TB and emphasizes the importance of deepening their study in this context.

Immunoendocrine interactions during HIV-TB coinfection: implications for the design of new adjuvant therapies.

Worldwide, around 14 million individuals are coinfected with both tuberculosis (TB) and human immunodeficiency virus (HIV). In coinfected individuals, both pathogens weaken immunological system synergistically through mechanisms that are not fully understood. During both HIV and TB infections, there is a chronic state of inflammation associated to dramatic changes in immune cytokine and endocrine hormone levels. Despite this, the relevance of immunoendocrine interaction on both the orchestration of an effective immune response against both pathogens and the control of the chronic inflammation induced during HIV, TB, or both infections is still controversial. The present study reviews immunoendocrine interactions occurring during HIV and TB infections. We also expose our own findings on immunoendocrine cross talk in HIV-TB coinfection. Finally, we evaluate the use of adrenal hormones and their derivatives in immune-therapy and discuss the use of some of these compounds like the adjuvant for the prevention and treatment of TB in HIV patients.

Modulation of the phenotype and function of Mycobacterium tuberculosis-stimulated dendritic cells by adrenal steroids.

Cell-mediated immunity, cytokines induced during the specific immune response and T-cell populations are crucial factors for containing Mycobacterium tuberculosis infection. Recent reports suggest a cross-regulation between adrenal steroids (glucocorticoids and dehydroepiandrosterone, DHEA) and the function of antigen-presenting cells (APCs). Therefore, we investigated the role of adrenal hormones on the functional capacity of M. tuberculosis-induced dendritic cells (DCs). Cortisol significantly inhibited the functions of M. tuberculosis-induced DCs. Interestingly, the presence of DHEA enhanced the M. tuberculosis-induced expression of MHC I, MHC II and CD86 and also increased ERK1/2 phosphorylation. Moreover, DHEA improved the production of IL-12 in response to M. tuberculosis stimulation, diminished IL-10 secretion and could not modify TNF-α synthesis. Importantly, we observed that DHEA enhanced the antigen-specific T-cell proliferation and IFN-γ production induced by M. tuberculosis-stimulated DC. These data show for the first time the relevance of the adrenal axis (especially of DHEA) in the modulation of DC function in the context of tuberculosis, a disease where the induction of a Th1 environment by APCs is crucial for the development of an effective immune response to the mycobacteria.