Identification of CD8+ T cell subsets that normalize in early-treated people living with HIV receiving antiretroviral therapy.

BACKGROUND: Although combined antiretroviral therapy (cART) has decreased the mortality associated with HIV infection, complete immune reconstitution is not achieved despite viral suppression. Alterations of CD8+ T cells and some of their subpopulations, such as interleukin (IL)-17-producing cells, are evidenced in treated individuals and are associated with systemic inflammation and adverse disease outcomes. We sought to evaluate if different CD8+ T cell subsets are differentially normalized during a clinical follow-up of people living with HIV (PLWH) receiving suppressive cART. METHODS: We explored the changes in the frequencies, activation/exhaustion phenotypes (HLA-DR, CD38, PD-1, and TIM-3), and function (total and HIV-specific cells expressing CD107a, perforin, granzyme B, interferon [IFN]-γ and IL-17) of CD8+ T cells from early-treated PLWH receiving cART in a 1-year follow-up, using a multidimensional flow cytometry approach. RESULTS: Despite continuous cART-induced viral suppression and recovery of CD4+ T cells, after a 1-year follow-up, the CD8+ T cell counts, CD4:CD8 ratio, PD-1 expression, and IL-17 production by CD8+ T cells exhibited incomplete normalization compared with seronegative controls. However, the proportion of CD8+ T cells with an exhausted phenotype (co-expressing PD-1 andTIM-3), and cells co-expressing cytotoxic molecules (Perforin and Granzyme B), reached normalization. CONCLUSIONS: Although suppressive cART achieves normalization of CD4+ T cell counts, only particular subsets of CD8+ T cells are more rapidly normalized in PLWH receiving cART, which could be routinely used as biomarkers for therapy efficiency in these patients.

SARS-CoV-2 and the testis: similarity with other viruses and routes of infection.

Since the start of the latest coronavirus (SARS-CoV-2) outbreak, the number of infected individuals and cases of coronavirus disease (COVID-19) has been increasing exponentially worldwide. Of interest is existing evidence that orchitis can develop due coronavirus infection. It is therefore not unreasonable to believe that SARS-CoV-2 could be transmitted by semen. Consequently, it is of paramount importance that individuals who could potentially be infected take all possible care to mitigate the likely risk of passing on the infection through sexual intercourse.

Different phenotypes of non-classical monocytes associated with systemic inflammation, endothelial alteration and hepatic compromise in patients with dengue.

Although dengue can progress to severe stages, the exact causes of this phenomenon are unknown; however, the possibility of monocyte participation is acknowledged. It has been suggested that monocyte subsets (classical, intermediate and non-classical) play differential roles in dengue immunopathology. Therefore, we determined the count of monocyte subsets and obtained the clinical information of patients with dengue. We noted a significant decrease in the count of non-classical monocytes in patients compared with controls. With this finding, we focused on studying the phenotype of non-classical monocytes in the present study. An increase in activation and differentiation markers, such as CD64, CD86, the percentage of tumor necrosis factor-α+ cells and exposure of phosphatidylserine, were recorded in the non-classical monocytes of patients compared with controls. Moreover, a significant decrease in the expression of CX3CR1 with a corresponding increase in the expressions of CCR2, CCR5, CD11b and CD54 was detected in the non-classical monocytes of patients in comparison with that of the controls. Significant increases in the frequency of microparticles from endothelium and in the concentrations of interleukin-6 (IL-6), IL-8 and IL-10 were noted in the plasma of patients. These findings demonstrate that in patients with dengue, non-classical monocytes are activated, exhibiting a phenotype associated with more differentiation, produces tumor necrosis factor-α and has a profile of less endothelial surveillance closer to the cellular migration. These changes were associated with hepatic compromise, endothelial alteration and high concentration of circulating cytokines. Hence, alterations of non-classical monocytes seem to be associated with the immunopathology of dengue infection.

Immunological characterization of compensatory anti-inflammatory response syndrome in patients with severe sepsis: a longitudinal study*.

OBJECTIVES: To perform a complete immunological characterization of compensatory anti-inflammatory response syndrome in patients with sepsis and to explore the relationship between these changes and clinical outcomes of 28-day mortality and secondary infections. DESIGN: Prospective single-center study conducted between April 2011 and December 2012. SETTING: ICUs from Hospital Universitario San Vicente Fundación at Medellin, Colombia. PATIENTS: One hundred forty-eight patients with severe sepsis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: At days 0, 1, 3, 5, 10, and 28, we determined the expression of HLA-DR in monocytes and the apoptosis and the proliferation index in T lymphocytes, as well as the levels of tumor necrosis factor-α, interleukin-6, interleukin-1ß, interleukin-10, and transforming growth factor-ß in both plasma and cell culture supernatants of peripheral blood mononuclear cells. The mean percentage of HLA-DR was 60.7 at enrollment and increased by 0.9% (95% CI, 0.7-1.2%) per day. The mean percentage of CD4 T cells and CD8 T cells AV+/7-AAD- at enrollment was 37.2% and 20.4%, respectively, but it diminished at a rate of -0.5% (95% CI, -0.7% to -0.3%) and -0.3% (95% CI, -0.4% to -0.2%) per day, respectively. Plasma levels of interleukin-6 and interleukin-10 were 290 and 166 pg/mL and decreased at a rate of -7.8 pg/mL (95% CI, -9.5 to -6.1 pg/mL) and -4 pg/mL (95% CI, -5.1 to -2.8 pg/mL) per day, respectively. After controlling for confounders, only sustained plasma levels of interleukin-6 increase the risk of death (hazard ratio 1.003; 95% CI, 1.001-1.006). CONCLUSIONS: We found no evidence to support a two-phase model of sepsis pathophysiology. However, immunological variables did behave in a mixed and time-dependent manner. Further studies should evaluate changes over time of interleukin-6 plasma levels as a prognostic biomarker for critically ill patients.

Multitranscript analysis reveals an effect of 2-deoxy-d-glucose on gene expression linked to unfolded protein response and integrated stress response in primary human monocytes and monocyte-derived macrophages.

BACKGROUND: Glycolytic inhibitor 2-deoxy-d-glucose (2-DG) binds to hexokinase in a non-competitive manner and phosphoglucose isomerase in a competitive manner, blocking the initial steps of the glycolytic pathway. Although 2-DG stimulates endoplasmic reticulum (ER) stress, activating the unfolded protein response to restore protein homeostasis, it is unclear which ER stress-related genes are modulated in response to 2-DG treatment in human primary cells. Here, we aimed to determine whether the treatment of monocytes and monocyte-derived macrophages (MDMs) with 2-DG leads to a transcriptional profile specific to ER stress. METHODS: We performed bioinformatics analysis to identify differentially expressed genes (DEGs) in previously reported RNA-seq datasets of 2-DG treated cells. RT-qPCR was performed to verify the sequencing data on cultured MDMs. RESULTS: A total of 95 common DEGs were found by transcriptional analysis of monocytes and MDMs treated with 2-DG. Among these, 74 were up-regulated and 21 were down-regulated. Multitranscript analysis showed that DEGs are linked to integrated stress response (GRP78/BiP, PERK, ATF4, CHOP, GADD34, IRE1α, XBP1, SESN2, ASNS, PHGDH), hexosamine biosynthetic pathway (GFAT1, GNA1, PGM3, UAP1), and mannose metabolism (GMPPA and GMPPB). CONCLUSIONS: Results reveal that 2-DG triggers a gene expression program that might be involved in restoring protein homeostasis in primary cells. GENERAL SIGNIFICANCE: 2-DG is known to inhibit glycolysis and induce ER stress; however, its effect on gene expression in primary cells is not well understood. This work shows that 2-DG is a stress inducer shifting the metabolic state of monocytes and macrophages.

SARS-CoV-2 Vaccine Effects on Semen Parameters: A Systematic Review and Meta-Analysis.

OBJECTIVE: Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epitomizes the best preventative SARS-CoV-2 infection strategy to counteract the severe consequences of infection. However, concerns have been raised that the vaccines could have an adverse effect on sperm function and overall reproductive health. This combined systematic review and meta-analysis aimed to investigate the effects of different available SARS-CoV-2 vaccines on semen parameters. METHODS: A systematic PubMed, Scopus, Google Scholar, ScienceDirect, LILACS (Literatura Latinoamericana y del Caribe en Ciencias de la Salud), and Scilit database literature search until mid-June 2022 was conducted. Prospective and retrospective studies were eligible. No limitation was placed on language. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were thereafter obtained. RESULTS: Upon search completion, 122 studies were identified and retrieved and 110 were excluded, while the remaining 12 independent studies evaluating the effects of coronavirus disease 2019 (COVID-19) vaccines on semen parameters were included in this review. The total number of men included was 1551, aged 22.4-48 years. Following meta-analysis, the SMD summary measure with 95% CI for each semen parameter included a concentration of 0.22 (0-0.22); Total sperm count of 0.11 (0.18-0.24); Total motility of 0.02 (0.05-0.09); Volume of 0.02 (-0.1-0.14); Vitality of 0.55 (-0.19-0.29), progressive motility of -0.43 (-0.54 to -0.32); Total motile sperm count of -0.38 (-0.44 to -0.31); And normal morphology of 0.42 (-0.54 to -0.3). In brief, the total sperm count was slightly increased post-vaccination, while progressive motility, total motile sperm count, and normal morphology were marginally reduced post-vaccination, according to the meta-analysis. CONCLUSIONS: No effects were observed regarding sperm viability and semen volume since the results of all the studies crossed the line of no effect. All seminal parameters analyzed showed a negligible or small change in relation to the vaccination effect. Furthermore, the parameters remained within the normal World Health Organization reference ranges, making the clinical significance unclear. Therefore, based on these results, it appears that vaccination does not have negative effects on semen quality. The individual study findings suggested that COVID-19 vaccines are not associated with decreased semen parameters.

Antibody Responses in COVID-19: A Review.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to spread worldwide as a severe pandemic. Although its seroprevalence is highly variable among territories, it has been reported at around 10%, but higher in health workers. Evidence regarding cross-neutralizing response between SARS-CoV and SARS-CoV-2 is still controversial. However, other previous coronaviruses may interfere with SARS-CoV-2 infection, since they are phylogenetically related and share the same target receptor. Further, the seroconversion of IgM and IgG occurs at around 12 days post onset of symptoms and most patients have neutralizing titers on days 14-20, with great titer variability. Neutralizing antibodies correlate positively with age, male sex, and severity of the disease. Moreover, the use of convalescent plasma has shown controversial results in terms of safety and efficacy, and due to the variable immune response among individuals, measuring antibody titers before transfusion is mostly required. Similarly, cellular immunity seems to be crucial in the resolution of the infection, as SARS-CoV-2-specific CD4+ and CD8+ T cells circulate to some extent in recovered patients. Of note, the duration of the antibody response has not been well established yet.

Immune characterization of a Colombian family cluster with SARS-CoV-2 infection. / Caracterización inmunológica de un grupo familiar colombiano con infección por SARS-CoV-2

INTRODUCTION: Immunological markers have been described during COVID-19 and persist after recovery. These immune markers are associated with clinical features among SARSCoV-2 infected individuals. Nevertheless, studies reporting a comprehensive analysis of the immune changes occurring during SARS-CoV-2 infection are still limited. OBJECTIVE: To evaluate the production of proinflammatory cytokines, the antibody response, and the phenotype and function of NK cells and T cells in a Colombian family cluster with SARS-CoV-2 infection. MATERIALS AND METHODS: Proinflammatory cytokines were evaluated by RT-PCR and ELISA. The frequency, phenotype, and function of NK cells (cocultures with K562 cells) and T-cells (stimulated with spike/RdRp peptides) were assessed by flow cytometry. Anti-SARS-CoV-2 antibodies were determined using indirect immunofluorescence and plaque reduction neutralization assay. RESULTS: During COVID-19, we observed a high proinflammatory-cytokine production and a reduced CD56bright-NK cell and cytotoxic response. Compared with healthy controls, infected individuals had a higher frequency of dysfunctional CD8+ T cells CD38+HLA-DR-. During the acute phase, CD8+ T cells stimulated with viral peptides exhibited a monofunctional response characterized by high IL-10 production. However, during recovery, we observed a bifunctional response characterized by the co-expression of CD107a and granzyme B or perforin. CONCLUSION: Although the proinflammatory response is a hallmark of SARS-CoV-2 infection, other phenotypic and functional alterations in NK cells and CD8+ T cells could be associated with the outcome of COVID-19. However, additional studies are required to understand these alterations and to guide future immunotherapy strategies.

Introducción. Se han descrito diferentes marcadores inmunológicos durante la COVID-19, los cuales persisten incluso después de la convalecencia y se asocian con los estadios clínicos de la infección. Sin embargo, aún son pocos los estudios orientados al análisis exhaustivo de las alteraciones del sistema inmunológico en el curso de la infección. Objetivo. Evaluar la producción de citocinas proinflamatorias, la reacción de anticuerpos, y el fenotipo y la función de las células NK y los linfocitos T en una familia colombiana con infección por SARS-CoV-2. Materiales y métodos. Se evaluaron las citocinas proinflamatorias mediante RT-PCR y ELISA; la frecuencia, el fenotipo y la función de las células NK (en cocultivos con células K562) y linfocitos T CD8+ (estimulados con péptidos spike/RdRp) mediante citometría de flujo, y los anticuerpos anti-SARS-CoV-2, mediante inmunofluorescencia indirecta y prueba de neutralización por reducción de placa. Resultados. Durante la COVID-19 hubo una producción elevada de citocinas proinflamatorias, con disminución de las células NK CD56bright y reacción citotóxica. Comparados con los controles sanos, los individuos infectados presentaron con gran frecuencia linfocitos T CD8+ disfuncionales CD38+HLA-DR-. Además, en los linfocitos T CD8+ estimulados con péptidos virales, predominó una reacción monofuncional con gran producción de IL-10 durante la fase aguda y una reacción bifuncional caracterizada por la coexpresión de CD107a y granzima B o perforina durante la convalecencia. Conclusión. Aunque la reacción inflamatoria caracteriza la infección por SARS-CoV-2, hay otras alteraciones fenotípicas y funcionales en células NK y linfocitos T CD8+ que podrían asociarse con la progresión de la infección. Se requieren estudios adicionales para entender estas alteraciones y guiar futuras estrategias de inmunoterapia.

Functional regulatory T cells accumulate in aged hosts and promote chronic infectious disease reactivation.

Declines in immune function are well described in the elderly and are considered to contribute significantly to the disease burden in this population. Regulatory T cells (T(regs)), a CD4(+) T cell subset usually characterized by high CD25 expression, control the intensity of immune responses both in rodents and humans. However, because CD25 expression does not define all T(regs), especially in aged hosts, we characterized T(regs) by the expression of FOXP3, a transcription factor crucial for T(reg) differentiation and function. The proportion of FOXP3(+)CD4(+) T(regs) increased in the blood of the elderly and the lymphoid tissues of aged mice. The expression of functional markers, such as CTLA-4 and GITR, was either preserved or increased on FOXP3(+) T(regs) from aged hosts, depending on the tissue analyzed. In vitro depletion of peripheral T(regs) from elderly humans improves effector T cell responses in most subjects. Importantly, T(regs) from old FoxP3-GFP knock-in mice were suppressive, exhibiting a higher level of suppression per cell than young T(regs). The increased proportion of T(regs) in aged mice was associated with the spontaneous reactivation of chronic Leishmania major infection in old mice, likely because old T(regs) efficiently suppressed the production of IFN-gamma by effector T cells. Finally, in vivo depletion of T(regs) in old mice attenuated disease severity. Accumulation of functional T(regs) in aged hosts could therefore play an important role in the frequent reactivation of chronic infections that occurs in aging. Manipulation of T(reg) numbers and/or activity may be envisioned to enhance the control of infectious diseases in this fragile population.

NK Cell Activity and CD57+/NKG2Chigh Phenotype Are Increased in Men Who Have Sex With Men at High Risk for HIV.

Introduction: The HIV-exposed seronegative (HESN) status is for individuals who remain seronegative despite repeated exposure to HIV. One of the main cohorts within this group is men who have sex with men (MSM). Studies of this cohort have revealed different immunological and genetic mechanisms that can explain the phenomenon of natural HIV resistance. NK cells' higher effector capacity is related to natural resistance to HIV. Besides, a new population of NK cells with adaptive features was described recently. These cells are increased in some HESN cohorts and appear to be involved in better control of viral replication in primarily HIV-infected subjects. The present study evaluated the role of NK cells in the natural resistance to HIV-1 infection in MSM. Methodology: Phenotypic and functional features were evaluated in NK cells from two groups of MSM, at different risks of HIV infection, according to the number of sexual partners. The production of IFN-γ and ß-chemokines was included in the analysis, as well as the cytotoxic capacity and adaptive NK cell frequency. Genetic features, such as HLA and KIR allele frequencies, were also explored. Results: High-risk MSM exhibit an increased frequency of fully mature and CD57+/NKG2Chigh NK cells. These individuals also show higher cytotoxic capacity and IFN-γ production in response to K562 stimuli. NK cells with a CD107a+/IFN-γ+ functional profile were found more frequently and displayed higher IFN-γ production capacity among high-risk MSM than among low-risk MSM. The protective allele HLA-B∗18 was only present in the high-risk MSM group as well as HLA-B∗ 39. The protective phenotype KIR3DL1/S1-HLA-B∗Bw4, in a homozygous state, was particularly abundant in the high-risk population. Notably, some of these functional features were related to higher frequencies of mature and CD57+/NKG2Chigh NK cells, which, in turn, were associated with a higher number of sexual partners. Conclusion: The changes observed in the NK cell compartment can be driven by the magnitude of sexual exposure and immunological challenges of high-risk individuals, which could influence their resistance/susceptibility to HIV infection.

Polyfunctional CD8+ T-Cell Response to Autologous Peptides from Protease and Reverse Transcriptase of HIV-1 Clade B.

BACKGROUND: The diversity of the HIV proteome influences the cellular response and development of an effective vaccine, particularly due to the generation of viral variants with mutations located within CD8+ T-cell epitopes. These mutations can affect the recognition of the epitopes, that may result in the selection of HIV variants with mutated epitopes (autologous epitopes) and different CD8+ T-cell functional profiles. OBJECTIVE: To determine the phenotype and functionality of CD8+ T-cell from HIV-infected Colombian patients in response to autologous and consensus peptides derived from HIV-1 clade B protease and reverse transcriptase (RT). METHODS: By flow cytometry, we compared the ex vivo CD8+ T-cell responses from HIV-infected patients to autologous and consensus peptides derived from HIV-1 clade B protease and RT, restricted by HLA-B*35, HLA-B*44 and HLA-B*51 alleles. RESULTS: Although autologous peptides restricted by HLA-B*35 and HLA-B*44 did not show any differences compared with consensus peptides, we observed the induction of a higher polyfunctional profile of CD8+ T-cells by autologous peptides restricted by HLA-B*51, particularly by the production of interferon-γ and macrophage inflammatory protein-1ß. The response by different memory CD8+ T-cell populations was comparable between autologous vs. consensus peptides. In addition, the magnitude of the polyfunctional response induced by the HLA-B*51-restricted QRPLVTIRI autologous epitope correlated with low viremia. CONCLUSION: Autologous peptides should be considered for the evaluation of HIV-specific CD8+ Tcell responses and to reveal some relevant epitopes that could be useful for therapeutic strategies aiming to promote polyfunctional CD8+ T-cell responses in a specific population of HIV-infected patients.

An altered cytotoxic program of CD8+ T-cells in HIV-infected patients despite HAART-induced viral suppression.

Despite the suppression of viral replication induced by the highly active anti-retroviral therapy (HAART), an increased immune activation and inflammatory state persists in HIV-infected patients, contributing to lower treatment response and immune reconstitution, and development of non-AIDS conditions. The chronic activation and inflammation affect the functionality and differentiation of CD8+ T-cells, particularly reducing their cytotoxic capacity, which is critical in the control of HIV replication. Although previous studies have shown that HAART induce a partial immune reconstitution, its effect on CD8+ T-cells cytotoxic function, as well as its relationship with the inflammatory state, is yet to be defined. Here, we characterized the functional profile of polyclonal and HIV-specific CD8+ T cells, based on the expression of cell activation and differentiation markers, in individuals chronically infected with HIV, under HAART. Compared with seronegative controls, CD8+ T-cells from patients on HAART exhibited a low degranulation capacity (surface expression of CD107a), with consequent low secreted levels and high intracellular expression of granzyme B and perforin. This degranulation defect was particularly observed in those cells expressing the activation marker HLA-DR, which were further characterized as effector memory cells with high expression of CD57. The expression of CD107a, but not of granzyme B and perforin, in CD8+ T-cells from HIV-infected patients on HAART reached levels similar to those in seronegative controls when the treatment duration was higher than 25 months. In addition, the expression of CD107a was negatively correlated with the expression of exhaustion markers on CD8+ T-cells and the plasma inflammatory molecule sCD14. Thus, despite HAART-induced viral suppression, CD8+ T-cells from HIV-infected patients have an alteration in their cytotoxic program. This defect is associated with the cellular activation, differentiation and exhaustion state, as well as with the inflammation levels, and can be partially recovered with a long and continuous treatment.

Cytotoxic CD4+ T-cells during HIV infection: Targets or weapons?

Classically, CD4+ T-cells have been referred as cytokine-producing cells and important players in immune responses by providing soluble factors that potentiate several effector immune functions. However, it is now evident that CD4+ T-cells can also elaborate cytotoxic responses, inducing apoptosis of target cells. Cytotoxic CD4+ T cells (CD4+ CTLs), exhibit cytolytic functions that resemble those of CD8+ T-cells; in fact, there is evidence suggesting that they may have a role in the control of viral infections. In this article, we discuss the role of CD4+ CTLs during HIV infection, where CD4+ CTLs have been associated with viral control and slow disease progression. In addition, we address the implication of CD4+ CTLs in the context of antiretroviral therapy and the partial reconstitution of CD8+ T-cells effector function.

Potential immune escape mutations under inferred selection pressure in HIV-1 strains circulating in Medellín, Colombia.

The introduction of highly active antiretroviral therapy (HAART) has significantly improved life expectancy of HIV-infected patients; nevertheless, it does not eliminate the virus from hosts, so a cure for this infection is crucial. Some strategies have employed the induction of anti-HIV CD8+ T cells. However, the high genetic variability of HIV-1 represents the biggest obstacle for these strategies, since immune escape mutations within epitopes restricted by Human Leukocyte Antigen class I molecules (HLA-I) abrogate the antiviral activity of these cells. We used a bioinformatics pipeline for the determination of such mutations, based on selection pressure and docking/refinement analyses. Fifty HIV-1 infected patients were recruited; HLA-A and HLA-B alleles were typified using sequence-specific oligonucleotide approach, and viral RNA was extracted for the amplification of HIV-1 gag, which was bulk sequenced and aligned to perform selection pressure analysis, using Single Likelihood Ancestor Counting (SLAC) and Fast Unconstrained Bayesian Approximation (FUBAR) algorithms. Positively selected sites were mapped into HLA-I-specific epitopes, and both mutated and wild type epitopes were modelled using PEP-FOLD. Molecular docking and refinement assays were carried out using AutoDock Vina 4 and FlexPepDock. Five positively selected sites were found: S54 at HLA-A*02 GC9, T84 at HLA-A*02 SL9, S125 at HLA-B*35 HY9, S173 at HLA-A*02/B*57 KS12 and I223 at HLA-B*35 HA9. Although some mutations have been previously described as immune escape mutations, the majority of them have not been reported. Molecular docking/refinement analysis showed that one combination of mutations at GC9, one at SL9, and eight at HY9 epitopes could act as immune escape mutations. Moreover, HLA-A*02-positive patients harbouring mutations at KS12, and HLA-B*35-positive patients with mutations at HY9 have significantly higher plasma viral loads than patients lacking such mutations. Thus, HLA-A and -B alleles could be shaping the genetic diversity of HIV-1 through the selection of potential immune escape mutations.

Role of CD8+ T Cells in the Selection of HIV-1 Immune Escape Mutations.

Human immunodeficiency virus type-1 (HIV-1) infection represents one of the biggest public health problems worldwide. The immune response, mainly the effector mechanisms mediated by CD8+ T cells, induces the selection of mutations that allows the virus to escape the immune control. These mutations are generally selected within CD8+ T cell epitopes restricted to human leukocyte antigen class I (HLA-I), leading to a decrease in the presentation and recognition of the epitope, decreasing the activation of CD8+ T cells. However, these mutations may also affect cellular processing of the peptide or recognition by the T cell receptor. Escape mutations often carry a negative impact in viral fitness that is partially or totally compensated by the selection of compensatory mutations. The selection of either escape mutations or compensatory mutations may negatively affect the course of the infection. In addition, these mutations are a major barrier for the development of new therapeutic strategies focused on the induction of specific CD8+ T cell responses.

Variants in LTA, TNF, IL1B and IL10 genes associated with the clinical course of sepsis.

The aim of this study was to explore the association between some SNPs of the TNF, LTA, IL1B and IL10 genes with cytokine concentrations and clinical course in Colombian septic patients. We conducted a cross-sectional study to genotype 415 septic patients and 205 patients without sepsis for the SNPs -308(G/A) rs1800629 of TNF; +252 (G/A) rs909253 of LTA; -511(A/G) rs16944 and +3953(C/T) rs1143634 of IL1B; and -1082(A/G) rs1800896, -819(C/T) rs1800871 and -592(C/A) rs1800872 of IL10. The association of theses SNPs with the following parameters was evaluated: (1) the presence of sepsis; (2) severity and clinical outcomes; (3) APACHE II and SOFA scores; and (4) procalcitonin, C-reactive protein, tumor necrosis factor, lymphotoxin alpha, interleukin 1 beta and interleukin 10 plasma concentrations. We found an association between the SNP LTA +252 with the development of sepsis [OR 1.29 (1.00-1.68)]; the SNP IL10 -1082 with sepsis severity [OR 0.53 (0.29-0.97)]; the TNF -308 with mortality [OR 0.33 (0.12-0.95)]; and the IL10 -592 and IL10 -1082 with admission to the intensive care unit (ICU) [OR 3.36 (1.57-7.18)] and [OR 0.18 (0.04-0.86)], respectively. None of the SNPs were associated with cytokine levels, procalcitonin and C-reactive protein serum concentrations, nor with APACHE II and SOFA scores. Our results suggest that these genetic variants play an important role in the development of sepsis and its clinical course.

Immune characterization of a Colombian family cluster with SARS-CoV-2 infection / Caracterización inmunológica de un grupo familiar colombiano con infección por SARS-CoV-2

Abstract | Introduction: Immunological markers have been described during COVID-19 and persist after recovery. These immune markers are associated with clinical features among SARS- CoV-2 infected individuals. Nevertheless, studies reporting a comprehensive analysis of the immune changes occurring during SARS-CoV-2 infection are still limited. Objective: To evaluate the production of proinflammatory cytokines, the antibody response, and the phenotype and function of NK cells and T cells in a Colombian family cluster with SARS-CoV-2 infection. Materials and methods: Proinflammatory cytokines were evaluated by RT-PCR and ELISA. The frequency, phenotype, and function of NK cells (cocultures with K562 cells) and T-cells (stimulated with spike/RdRp peptides) were assessed by flow cytometry. Anti-SARS-CoV-2 antibodies were determined using indirect immunofluorescence and plaque reduction neutralization assay. Results: During COVID-19, we observed a high proinflammatory-cytokine production and a reduced CD56bright-NK cell and cytotoxic response. Compared with healthy controls, infected individuals had a higher frequency of dysfunctional CD8+ T cells CD38+HLA-DR-. During the acute phase, CD8+ T cells stimulated with viral peptides exhibited a monofunctional response characterized by high IL-10 production. However, during recovery, we observed a bifunctional response characterized by the co-expression of CD107a and granzyme B or perforin. Conclusion: Although the proinflammatory response is a hallmark of SARS-CoV-2 infection, other phenotypic and functional alterations in NK cells and CD8+ T cells could be associated with the outcome of COVID-19. However, additional studies are required to understand these alterations and to guide future immunotherapy strategies.

Resumen | Introducción. Se han descrito diferentes marcadores inmunológicos durante la COVID-19, los cuales persisten incluso después de la convalecencia y se asocian con los estadios clínicos de la infección. Sin embargo, aún son pocos los estudios orientados al análisis exhaustivo de las alteraciones del sistema inmunológico en el curso de la infección. Objetivo. Evaluar la producción de citocinas proinflamatorias, la reacción de anticuerpos, y el fenotipo y la función de las células NK y los linfocitos T en una familia colombiana con infección por SARS-CoV-2. Materiales y métodos. Se evaluaron las citocinas proinflamatorias mediante RT-PCR y ELISA; la frecuencia, el fenotipo y la función de las células NK (en cocultivos con células K562) y linfocitos T CD8+ (estimulados con péptidos spike/RdRp) mediante citometría de flujo, y los anticuerpos anti-SARS-CoV-2, mediante inmunofluorescencia indirecta y prueba de neutralización por reducción de placa. Resultados. Durante la COVID-19 hubo una producción elevada de citocinas proinflamatorias, con disminución de las células NK CD56 bright y reacción citotóxica. Comparados con los controles sanos, los individuos infectados presentaron con gran frecuencia linfocitos T CD8+ disfuncionales CD38+HLA-DR-. Además, en los linfocitos T CD8+ estimulados con péptidos virales, predominó una reacción monofuncional con gran producción de IL-10 durante la fase aguda y una reacción bifuncional caracterizada por la coexpresión de CD107a y granzima B o perforina durante la convalecencia. Conclusión. Aunque la reacción inflamatoria caracteriza la infección por SARS-CoV-2, hay otras alteraciones fenotípicas y funcionales en células NK y linfocitos T CD8+ que podrían asociarse con la progresión de la infección. Se requieren estudios adicionales para entender estas alteraciones y guiar futuras estrategias de inmunoterapia.