Effects of two immunosuppression regimens on T-lymphocyte subsets in elderly kidney transplant recipients.

Background: Despite the growing number of elderly kidney transplant (Ktx) recipients, few studies have examined the effects of immunosuppression on their lymphocyte profiles. Methods: We evaluated the early conversion from mycophenolate sodium (MPS) to everolimus (EVL) after rabbit antithymocyte globulin (rATG) 2 mg/kg induction in elderly kidney recipients. Three groups of KTx patients were compared: (a) Young (n=20, 36 ± 7 y) receiving standard immunosuppression (Group A1) (prednisone, tacrolimus, and MPS), (b) Elderly (n=35, 65 ± 3 y) receiving standard immunosuppression (Group B1), and (c) Elderly (n=16, 65 ± 3 y) with early (mean 30 d) conversion from MPS to EVL (Group B2). Naive, memory, and regulatory peripheral blood TCD4+ lymphocytes were quantified at 0, 30, and 365 d. Results: Results are reported as [mean(p25-p75)]. Young recipients had higher lymphocyte counts at baseline [2,100(1,630-2,400) vs. 1,310 (1,000-1,600)/mm3, p<0.0001] maintained higher counts within 365 d [1,850(1,590-2,120) vs. 1,130(460-1,325)/mm3, p=0.018 and vs. 1,410(805-1,895)/mm3, p=0.268]. Elderly recipients showed a decrease in lymphocytes within 30 d [1,310(1,000-1,600) vs. 910(700-1,198)/mm3, p=0.0012] with recovery within 365 d. The same pattern was observed in total lymphocytes and TCD4+ counts. Rabbit antithymocyte globulin induced a reduction in central memory T-cell percentages at 30 d in both young recipients [6.2(3.77-10.8) vs. 5.32(2.49-7.28)% of CD4+, p=0.036] and in elderly recipients [8.17(5.28-12.88) vs. 6.74(4.36-11)% of CD4+, p=0.05] on standard immunosuppression, returning to baseline at 365 d in elderly recipients but not in young recipients. Regulatory T CD39+ cells (Treg) percentages decreased at 30 d in elderly recipients [2.1(1.23-3.51) vs. 1.69(0.8-2.66)% of CD4+, p=0.0028] and in young recipients [1.29(0.45-1.85) vs. 0.84(0.18-1.82)% of CD4+, p=0.0038], returning to baseline at 365 d in elderly recipients [2.1(1.23-3.51) vs. 2.042(0.88-2.42)% of CD4+], but not in young recipients [1.29(0.45-1.85) vs. 0.86(0.7-1.34) % of CD4+]. The elderly everolimus conversion group did not show significant changes in cell profile over time or compared to elderly recipients with standard immunosuppression. Conclusion: Aging favored the maintenance of Treg during the late transplantation period despite ongoing immunosuppression. Lymphocyte depletion due to rATG was more prominent in elderly recipients and affected memory subsets with a temporary reduction in central memory T cells. However, conversion to everolimus did not impact Treg profile. Reducing the dose of rATG in elderly recipients seems necessary for the expected lymphocyte changes with EVL to occur. Clinical trial registration: nEverOld Trial, identifier NTC01631058.

Obesity Influences T CD4 Lymphocytes Subsets Profiles in Children and Adolescent's Immune Response.

BACKGROUND: Evidence shows that CD4+ T cells are altered in obesity and play a significant role in the systemic inflammation in adults with the disease. OBJECTIVES: Because the profile of these cells is poorly understood in the pediatric population, this study aims to investigate the profile of CD4+ T lymphocytes and the plasma levels of cytokines in this population. METHODS: Using flow cytometry, we compared the expression profile of lymphocyte markers, master transcription factors, cytokines, and molecules involved in the regulation of the immune response in CD4+ T cells from children and adolescents with obesity (OB group, n = 20) with those with eutrophy group (EU group, n = 16). Plasma levels of cytokines in both groups were determined by cytometric bead array (CBA). RESULTS: The OB group presents a lower frequency of CD3+ T cells, as well as a decreased frequency of CD4+ T cells expressing CD28, IL-4, and FOXP3, but an increased frequency of CD4+IL-17A+ cells compared with the EU group. The frequency of CD28 is increased in Th2 and Treg cells in the OB group, whereas CTLA-4 is decreased in all subpopulations compared with the EU group. Furthermore, Th2, Th17, and Treg profiles can differentiate the EU and OB groups. IL-10 plasma levels are reduced in the OB group and negatively correlated with adiposity and inflammatory parameters. CONCLUSIONS: CD4+ T cells have an altered pattern of expression in children and adolescents with obesity, contributing to the inflammatory state and clinical characteristics of these patients.

TCF1-positive and TCF1-negative TRM CD8 T cell subsets and cDC1s orchestrate melanoma protection and immunotherapy response.

BACKGROUND: Melanoma, the most lethal form of skin cancer, has undergone a transformative treatment shift with the advent of checkpoint blockade immunotherapy (CBI). Understanding the intricate network of immune cells infiltrating the tumor and orchestrating the control of melanoma cells and the response to CBI is currently of utmost importance. There is evidence underscoring the significance of tissue-resident memory (TRM) CD8 T cells and classic dendritic cell type 1 (cDC1) in cancer protection. Transcriptomic studies also support the existence of a TCF7+ (encoding TCF1) T cell as the most important for immunotherapy response, although uncertainty exists about whether there is a TCF1+TRM T cell due to evidence indicating TCF1 downregulation for tissue residency activation. METHODS: We used multiplexed immunofluorescence and spectral flow cytometry to evaluate TRM CD8 T cells and cDC1 in two melanoma patient cohorts: one immunotherapy-naive and the other receiving immunotherapy. The first cohort was divided between patients free of disease or with metastasis 2 years postdiagnosis while the second between CBI responders and non-responders. RESULTS: Our study identifies two CD8+TRM subsets, TCF1+ and TCF1-, correlating with melanoma protection. TCF1+TRM cells show heightened expression of IFN-γ and Ki67 while TCF1- TRM cells exhibit increased expression of cytotoxic molecules. In metastatic patients, TRM subsets undergo a shift in marker expression, with the TCF1- subset displaying increased expression of exhaustion markers. We observed a close spatial correlation between cDC1s and TRMs, with TCF1+TRM/cDC1 pairs enriched in the stroma and TCF1- TRM/cDC1 pairs in tumor areas. Notably, these TCF1- TRMs express cytotoxic molecules and are associated with apoptotic melanoma cells. Both TCF1+ and TCF1- TRM subsets, alongside cDC1, prove relevant to CBI response. CONCLUSIONS: Our study supports the importance of TRM CD8 T cells and cDC1 in melanoma protection while also highlighting the existence of functionally distinctive TCF1+ and TCF1- TRM subsets, both crucial for melanoma control and CBI response.

Effector CD4+ T-cell subsets in Takayasu arteritis-differences between the peripheral blood and the aorta.

Takayasu arteritis (TAK) is a granulomatous vasculitis that affects large arteries. T cells are important in TAK pathophysiology as these cells orchestrate granulomatous infiltration in arteries. This study aims to evaluate effector CD4+ T cells in the peripheral blood and the aortic wall of TAK patients and to analyze associations with disease activity and therapy. We performed a longitudinal study including 30 TAK patients and 30 controls. CD3+ T cells, CD3+CD4- T cells, CD4+ T cells, and Th1, Th2, and Th17 cells were evaluated in peripheral blood by flow cytometry, and the expression of CD4, CD8, Tbet, GATA-3, and RORγT was analyzed in the aorta of six patients by immunohistochemistry. TAK patients presented lower CD3+ T cells and CD4+ T cells (P = 0.031 and P = 0.039, respectively) than controls. Patients with active disease and those in remission had higher proportions of Th17 cells than controls (P = 0.016 and P = 0.004, respectively). Therapy for TAK did not result in significant differences concerning CD4+ effector T-cell subpopulations. Disease duration correlated with the number and percentage of Th2 cells (rho = -0.610 and rho = -0.463, respectively) and with Th17 cells (rho = -0.365 and rho = -0.568). In the aorta, the expression of CD8 was higher than CD4, whereas GATA-3, Tbet, and RORγT were expressed in this order of frequency. In conclusion, TAK patients present an increased Th17 response in the peripheral blood regardless of disease activity, whereas in the aortic tissue CD8 cells and the Th2 response were predominant.

Phenotypic and Functional Characterization of Memory CD4+ and CD8+ T Cells After Antigenic Stimulation.

The encounter of T cells with the antigen through the interaction of T cell receptors with peptides and major histocompatibility complex (MHC) molecules on the surface of antigen-presenting cells (APCs) can generate effector response and memory T cells. Memory T cells developed following infections or vaccination may persist, leading to the generation of a specific immune response upon reexposure to the same pathogen through rapid clonal proliferation and activation of effector functions. T cell memory subsets can be identified based on the expression of several membrane markers such as CCR7, CD27, and CD45RA. Using fluorescent antibodies against these markers and a flow cytometer, it is possible to perform immunophenotyping via the analysis of cell surface expression of proteins by different subpopulations such as the subsets of naïve, effector, and memory T cells as well as via the analysis of functional markers that further characterize each sample. Intracellular cytokine staining allows for the evaluation of intracellular proteins expressed in T cells in response to antigenic stimulation. This chapter presents the phenotypic and functional characterization of memory T cells after antigenic stimulation, detailing the procedures for identifying intracellular and surface protein markers. Herein, we review and present a reproducible standardized protocol using antibodies for specific markers and applying flow cytometry.

Type 1 Diabetes Brazilian patients exhibit reduced frequency of recent thymic emigrants in regulatory CD4+CD25+Foxp3+T cells.

To control immune responses, regulatory CD4+CD25+Foxp3+ T cells (Treg) maintain their wide and diverse repertoire through continuous arrival of recent thymic emigrants (RTE). However, during puberty, the activity of RTE starts to decline as a natural process of thymic involution, introducing consequences, not completely described, to the repertoire. Type 1 diabetes (T1D) patients show quantitative and qualitative impairments on the Treg cells. Our aim was to evaluate peripheral Treg and RTE cell frequencies, in T1D patients from two distinct age groups (young and adults) and verify if HLA phenotypes are concomitant associated. To this, blood samples from Brazilian twenty established T1D patients (12 young and 8 adults) and twenty-one healthy controls (11 young and 10 adults) were analyzed, by flow cytometry, to verify the percentages of CD4, Treg (CD4+CD25+Foxp3+) and the subsets of CD45RA+ (naive) and CD31+(RTE) within then. Furthermore, the HLA typing was also set. We observed that the young established T1D patients feature decreased frequencies in total Treg cells and naive RTE within Treg cells. Significant prevalence of HLA alleles, associated with risk, in T1D patients, was also identified. Performing a multivariate analysis, we confirmed that the cellular changes described offers significant variables that distinct T1D patients from the controls. Our data collectively highlight relevant aspects about homeostasis imbalances in the Treg cells of T1D patients, especially in young, and disease prognosis; that might contribute for future therapeutic strategies involving Treg cells manipulation.

Effects of low-dose rapamycin on lymphoid organs of mice prone and resistant to accelerated senescence.

Aging is a complex, natural, and irreversible phenomenon that subjects the body to numerous changes in the physiological process, characterized by a gradual decline in the organism's homeostatic mechanisms, closely related to immunosenescence. Here, we evaluated the regulation of immunosenescence in lymphoid organs of senescence-accelerated prone 8 (SAM-P8) and senescence-accelerated resistant 1 (SAM-R1) mice treated with a low dose of rapamycin (RAPA). Mice were treated with a dose of 7.1 µg/kg RAPA for 2 months and had body mass and hematological parameters analyzed prior and during treatment. Cellular and humoral parameters of serum, bone marrow, thymus, and spleen samples were evaluated by ELISA, histology, and flow cytometry. Changes in body mass, hematological parameters, cell number, and in the secretion of IL-1ß, IL-6, TNF-α, IL-7, and IL-15 cytokines were different between the 2 models used. In histological analyses, we observed that SAM-P8 mice showed faster thymic involution than SAM-R1 mice. Regarding the T lymphocyte subpopulations in the spleen, CD4+ and CD8+ T cell numbers were higher and lower, respectively, in SAM-P8 mice treated with RAPA, with the opposite observed in SAM-R1. Additionally, we found that the low dose of RAPA used did not trigger changes that could compromise the immune response of these mice and the administered dose may have contributed to changes in important lymphocyte populations in the adaptive immune response and the secretion of cytokines that directly collaborate with the maturation and proliferation of these cells.

Landscape of unconventional γδ T cell subsets in cancer.

T cells are broadly categorized into two groups, namely conventional and unconventional T cells. Conventional T cells are the most prevalent and well-studied subset of T cells. On the other hand, unconventional T cells exhibit diverse functions shared between innate and adaptive immune cells. During recent decades, γδ T cells have received attention for their roles in cancer immunity. These cells can detect various molecules, such as lipids and metabolites. Also, they are known for their distinctive ability to recognize and target cancer cells in the tumor microenvironment (TME). This feature of γδ T cells could provide a unique therapeutic tool to fight against cancer. Understanding the role of γδ T cells in TME is essential to prepare the groundwork to use γδ T cells for clinical purposes. Here, we provide recent knowledge regarding the role γδ T cell subsets in different cancer types.

Valganciclovir modulates the tumor necrosis factor axis molecules expression and CD4+ T-cell subsets in disseminated Kaposi Sarcoma patients.

Valganciclovir (VGC) was used in a randomized clinical trial in patients with disseminated Kaposi Sarcoma/human immunodeficiency virus (DKS/HIV) as add-on therapy to evaluate the proinflammatory axis tumor necrosis factor (TNF) and its receptors (TNFRs) in T cells. Two treatment schedules were used: an experimental regime (ER) and a conventional treatment (CT). Mononuclear cells from patients with DKS/HIV were obtained at baseline (W0), 4 (W4), and 12 weeks (W12). Ten DKS/HIV patients received CT (antiretroviral therapy [cART]) and 10 ER (valganciclovir [VGC] initially, plus cART at the fourth week). HIV+ without KS and HIV- patient groups were included as controls. Correlation between T-cell subsets and HHV-8 viral load (VL) and a multivariate linear regression was performed. Data showed that DKS/HIV patients have an increased frequency of CD8+ T cells, which display a high density of CD8 expression. The ER scheme increases naïve and central memory CD4+ T cells at W4 and W12 of follow-up and induces a balanced distribution of activated CD4+ T-cell subsets. Moreover, ER decreases solTNFR2 since W4 and CT decreased the transmembrane forms of TNF axis molecules. Although CT induces a positive correlation between HHV-8 VL and TNFRs, the use of ER positively correlates with TNF and TNFRs levels through follow-up and a moderate correlation with HHV-8 VL and TNF soluble levels. In conclusion, VGC, as an add-on therapy in DKS/HIV patients, gradually modulates the activation of CD4+ T-cell subsets and the TNF/TNFRs axis, suggesting a better regulation of the inflammatory status.

Subpoblaciones de linfocitos T en adultos mayores cubanos con leucemia linfoide crónica / Subpopulations of T lymphocytes in Cuban older adults with chronic lymphoid leukemia

Introducción: la inmunosenescencia está asociada con un mayor riesgo de desarrollo de cáncer. Dentro de las hemopatías malignas que afectan a este grupo de edad, está la leucemia linfoide crónica (LLC), caracterizada por trastornos en la inmunidad adaptativa que incluye las subpoblaciones de linfocitos T. Objetivo: Determinar la frecuencia de las subpoblaciones de linfocitos T en los pacientes adultos mayores con leucemia linfoide crónica evaluados en el Instituto de Hematología e Inmunología de Cuba. Métodos: Se realizó un estudio transversal en 30 adultos mayores con leucemia linfoide crónica. Se cuantificaron los linfocitos TCD3+CD4+ y TCD3+CD8+ en sangre periférica por citometría de flujo. Para la lectura y el análisis de los datos se empleó un citómetro de flujo Beckman Coulter Gallios. Se utilizaron los valores porcentuales, la media y la desviación estándar. Se consideró estadísticamente significativo si p≤0.05. Resultados: Hubo un predominio de hombres que representaron el 56,7 por ciento y del grupo de 70-79 años de edad. No se reportó ningún adulto mayor con LLC con valores altos ni normales de linfocitos TCD3+CD4+. Predominaron los hombres con valores bajos porcentuales de linfocitos TCD3+CD4+, TCD3+CD8+ e inversión del índice CD4/CD8 en relación con las mujeres. Conclusiones: Los adultos mayores con LLC presentan alteraciones en el número de las subpoblaciones de linfocitos T. La acción de estas células en relación al crecimiento de células B malignas aún es desconocido y resulta importante determinar si esto puede reflejar un intento de evasión de las células tumorales al control inmunológico(AU)

Introduction: Immunosenescence is associated with an increased risk of cancer development. Among the malignant hemopathies that affect this age group, it is chronic lymphoid leukemia (CLL), characterized by disorders in adaptive immunity, which include subpopulations of T lymphocytes. Objective: To determine frequency of T lymphocyte subpopulations in older adult patients with chronic lymphoid leukemia evaluated at the Institute of Hematology and Immunology of Cuba. Methods: A cross-sectional study was conducted in 30 older adults with chronic lymphoid leukemia. TCD3+CD4+ and TCD3+CD8+ lymphocytes were quantified in peripheral blood by flow cytometry. A Beckman Coulter Gallios flow cytometer was used to read and analyze the data. The percentage values, the mean and the standard deviation were used. It was considered statistically significant if p≤0.05. Results: There was a predominance of men who represented 56.7 percent and the age group of 70-79 years. No older adults with CLL with high or normal values of TCD3+CD4+ lymphocytes were reported. Men predominated with low percentage values of TCD3+CD4+, TCD3+CD8+ lymphocytes and inversion of the CD4/CD8 ratio in relation to women. Conclusions: Older adult with CLL present alterations in the number of T lymphocyte subpopulations. The role of these cells in relation to the growth of malignant B cells it is unknown and it turns out important to determine if this may reflect an attempt to evade tumor cells from immune control(AU)

Rhythmic profile of memory T and B-cells along childhood and adolescence.

Immunobiography describes the life-long effects of exogenous or endogenous stimuli on remodeling of immune cell biology, including the development of memory T and B-cells. The present study aimed at investigating the rhythms of changes in phenotypic features of memory T and B-cells along childhood and adolescence. A descriptive-observational investigation was conducted including 812 healthy volunteers, clustered into six consecutive age groups (9Mths-1Yr; 2Yrs; 3-4Yrs; 5-7Yrs; 8-10Yrs; 11-18Yrs). Immunophenotypic analysis of memory T-cell (CD4+ and CD8+) and B-cell subsets were performed by flow cytometry. The results pointed out that memory-related biomarkers of T and B-cells displayed a bimodal profile along healthy childhood and adolescence, regardless of sex. The first stage of changes occurs around 2Yrs, with predominance of naive cells, while the second and more prominent wave occurs around the age 8-10Yrs, with the prevalence of memory phenotypes. The neighborhood connectivity profile analysis demonstrated that the number of correlations reaches a peak at 11-18Yrs and lower values along the childhood. Males presented higher and conserved number of correlations when compared to females. Altogether, our results provide new insights into immunobiography and a better understanding of interactions among the cellular subsets studied here during childhood and adolescence.

CXCR5 and TIM-3 expressions define distinct exhausted T cell subsets in experimental cutaneous infection with Leishmania mexicana.

T-cell exhaustion is a key stage in chronic infections since it limits immunopathology, but also hinders the elimination of pathogens. Exhausted T (Tex) cells encompass dynamic subsets, including progenitor cells that sustain long-term immunity through their memory/stem like properties, and terminally-differentiated cells, resembling the so-called Tex cells. The presence of Tex cells in chronic leishmaniasis has been reported in humans and murine models, yet their heterogeneity remains unexplored. Using flow cytometry, we identified Tex cells subtypes based on PD-1, CXCR5 and TIM-3 expressions in draining lymph nodes (dLNs) and lesion sites of C57BL/6 mice infected with L. mexicana at 30-, 60- and 90-days post-infection. We showed that infected mice developed a chronic infection characterized by non-healing lesions with a high parasite load and impaired Th1/Th2 cytokine production. Throughout the infection, PD-1+ cells were observed in dLNs, in addition to an enhanced expression of PD-1 in both CD4+ and CD8+ T lymphocytes. We demonstrated that CD4+ and CD8+ T cells were subdivided into PD-1+CXCR5+TIM-3- (CXCR5+), PD-1+CXCR5+TIM-3+ (CXCR5+TIM-3+), and PD-1+CXCR5-TIM-3+ (TIM-3+) subsets. CXCR5+ Tex cells were detected in dLNs during the whole course of the infection, whereas TIM-3+ cells were predominantly localized in the infection sites at day 90. CXCR5+TIM-3+ cells only increased at 30 and 60 days of infection in dLNs, whereas no increase was observed in the lesions. Phenotypic analysis revealed that CXCR5+ cells expressed significantly higher levels of CCR7 and lower levels of CX3CR1, PD-1, TIM-3, and CD39 compared to the TIM-3+ subset. CXCR5+TIM-3+ cells expressed the highest levels of all exhaustion-associated markers and of CX3CR1. In agreement with a less exhausted phenotype, the frequency of proliferating Ki-67 and IFN-γ expressing cells was significantly higher in the CXCR5+ subset within both CD4+ and CD8+ T cells compared to their respective TIM-3+ subsets, whereas CD8+CXCR5+TIM-3+ and CD8+TIM-3+ subsets showed an enhanced frequency of degranulating CD107a+ cells. In summary, we identified a novel, less-differentiated CXCR5+ Tex subset in experimental cutaneous leishmaniasis caused by L. mexicana. Targeting these cells through immune checkpoint inhibitors such as anti-PD-1 or anti PD-L1 might improve the current treatment for patients with the chronic forms of leishmaniasis.

CD4 T lymphocyte subsets display heterogeneous susceptibility to apoptosis induced by serum from patients with systemic lupus erythematosus.

BACKGROUND: Serum from systemic lupus erythematosus (SLE) patients has been shown to induce T-lymphocyte (TL) apoptosis. Given that different cells of the immune system display different sensitivity to apoptosis, we set to evaluate the in vitro effect of SLE serum on regulatory T-cells (Treg), Th17, Th1 and Th2 from SLE patients and healthy controls. METHODS: Peripheral blood mononuclear cells from SLE patients or normal controls were exposed to a pool of sera from SLE patients or normal controls. Annexin V was used to label cells in apoptosis or necrosis. Annexin V-labeled Treg, Th17, Th1 and Th2 cells were determined using flow cytometry. RESULTS: Total CD3 + and CD4 + cells from SLE patients showed higher frequency of spontaneous apoptosis/necrosis, whereas Th1 cells from SLE patients presented reduced spontaneous apoptosis/necrosis rate as compared with cells from controls. Incubation with SLE serum induced increased frequency of apoptotic/necrotic CD3 + , CD4 + and Th2 cells from normal controls or from SLE patients as compared with cultures incubated with normal human serum (NHS) or without human serum at all. Incubation with SLE serum did not increase the apoptosis/necrosis rate in Th1 or Th17 cells. Treg cells from SLE patients were more prone to apoptosis/necrosis induced by SLE serum than Treg cells from normal individuals. Th1, Th2, and Th17 cells presented increased apoptosis rates in cultures without human serum. CONCLUSION: Our findings indicate that the serum of patients with active SLE stimulates apoptosis of CD4 + T cells in general and exhibit differentiated effects on CD4 + T-cell subsets.

SUV39H1 is a prognosis and immune microenvironment-related biomarker in diffuse large B-cell lymphoma.

BACKGROUND: The tumor microenvironment plays a crucial role in the oncogenesis and treatment of diffuse large B-cell lymphoma (DLBCL). The H3K9me3-specific histone methyltransferase Suppressor of variegation 3-9 homolog 1 (SUV39H1) is a significant gene that promotes the progression of various malignancies. However, the specific expression of SUV39H1 in DLBCL remains unclear. METHODS: By retrieving data from GEPIA, UCSC XENA and TCGA public databases, we observed the high expression of SUV39H1 in DLBCL. Combined with an immunohistochemical validation assay, we analyzed our hospital's clinical characteristics and prognosis of 67 DLBCL patients. The results showed that high SUV39H1 expression was closely associated with age over 50 years (P = 0.014) and low albumin levels (P = 0.023) of patients. Furthermore, the experiments in vitro were deployed to evaluate the regulation of SUV39H1 on the DLBCL immune microenvironment. RESULTS: The results showed that high SUV39H1 expression was closely associated with age over 50 years (P = 0.014) and low albumin levels (P = 0.023) of patients. The prognostic analysis showed that the high SUV39H1 expression group had a lower disease-free survival (DFS) rate than the low SUV39H1 expression group (P < 0.05). We further discovered that SUV39H1 upregulated the expression of CD86+ and CD163+ tumor-associated macrophages by DLBCL patients' tissues and cell experiments in vitro (P < 0.05). And SUV39H1-associated T lymphocyte subsets and cytokines IL-6/CCL-2 were downregulated in DLBCL (P < 0.05). CONCLUSIONS: In summary, SUV39H1 might be not only a potential target for treating DLBCL but also a clinical indicator for doctors to evaluate the trend of disease development.

O efeito do tratamento com rapamicina em órgãos linfoides de camundongos propensos à senescência acelerada / The effect of rapamycin treatment on lymphoid organs of senescence accelerated mice prone

Envelhecer compreende um fenômeno complexo, natural e irreversível, que submete o organismo a inúmeras alterações nos processos biológicos, fisiológicos, ambientais, psicológicos, comportamentais e sociais. Esse processo é caracterizado por um declínio gradual dos mecanismos homeostáticos do organismo, intimamente relacionados com o estado senescente. A senescência, quando diz respeito ao sistema imunológico, é denominada de imunossenescência, que pode ser definida como uma parada estável do ciclo celular associada a mudanças, com uma resposta que limita a proliferação de células envelhecidas ou danificadas. A autofagia está diretamente relacionada com a manutenção do fenótipo senescente, em que a atividade autofágica exerce um papel essencial e ativo na influência da biossíntese de proteínas e organelas. Essa via é regulada naturalmente pela proteína mTOR e quimicamente pelo fármaco rapamicina. Assim, pretendemos investigar: (1) as alterações no perfil corporal e hematimêtrico dos animais ao longo do tratamento com rapamicina; (2) avaliar o perfil de citocinas; (3) observar as modificações histológicas em órgãos linfoides primários e secundário; (4) analisar as populações de células linfoides e mieloides; e (5) avaliar a capacidade proliferativa de linfócitos in vitro. Camundongos SAMP-8 e SAMR-1 foram tratados com rapamicina durante dois meses. A mensuração da massa corporal e análises hematológicas foram realizadas antes e durante o tratamento. Amostras de soro, medula óssea, timo e baço foram analisados em ensaios de ELISA, histologia, população e subpopulações de células. Alterações na massa corporal, parâmetros hematológicos e celularidade de células foram nítidas entre os dois modelos utilizados. Diferenças também foram percebidas na detecção de citocinas IL-1ß. IL-6 e TNF-α, com resultados significantes nas amostras de baço, timo e medula óssea. As citocinas IL-7 e IL-15 apresentaram diferenças de secreção entre os grupos, sendo a primeira maior detectada em camundongos com senescência acelerada tratados com rapamicina. Em nossa análise histológica observamos que os camundongos SAM-P8 apresentaram involução tímica. E nas subpopulações de linfócitos T do baço, células TCD4+ e TCD8+ estavam, respectivamente, em maior e menor quantidade nos camundongos SAM-P8 tratados com rapamicina. Dessa forma, o camundongo da linhagem SAM-P8 é um excelente modelo para se estudar as alterações da senescência, em que o mesmo apresenta características fisiológicas distintas dos camundongos utilizados como controle (SAM-R1). Além disso, verificamos que a dose de rapamicina empregada não desencadeou alterações que pudessem comprometer a resposta imunológica desses camundongos, bem como na possibilidade de atuar na resposta contra os efeitos complexos do envelhecimento

Aging comprises a complex, natural, and irreversible phenomenon, which subjects the organism to countless alterations in biological, physiological, environmental, psychological, behavioral, and social processes. This process is characterized by a gradual decline in the organism's homeostatic mechanisms, closely related to senescence effects. Senescence, when it concerns the immune system, is called immunosenescence, which can be defined as a stable cell cycle arrest associated with changes and is a response that limits the proliferation of aged or damaged cells. Autophagy is a genetically regulated, conserved cellular process and a metabolic pathway essential for maintaining cellular homeostasis, which plays a constitutive and active role in controlling the biosynthesis of proteins and organelles. This pathway is regulated naturally by mTOR or chemically by the drug rapamycin, having a direct relationship with cellular homeostasis and maintenance of the senescent phenotype. Thus, we intend to investigate: (1) the changes in the body and hematimetic profile of the animals throughout the rapamycin treatment; (2) evaluate the cytokine profile; (3) observe histological changes in primary and secondary lymphoid organs; (4) analyze lymphoid and myeloid cell populations; and (5) evaluate the proliferative capacity of lymphocytes in vitro. SAMP-8 and SAMR-1 mice were treated with rapamycin for two months. Body mass measurement and hematological analyses were performed before and during treatment. Serum, bone marrow, thymus and spleen samples were analyzed in ELISA assays, histology, cell population and subpopulations. Changes in body mass, hematological parameters, and cellularity were clear between the two models used. Differences were also noticed in the detection of cytokines IL-1ß. IL-6 and TNF-α, with significant results in the spleen, thymus and bone marrow samples. The cytokines IL-7 and IL-15 showed differences in secretion between groups, the former being higher detected in mice with accelerated senescence treated with rapamycin. In our histological analysis we observed that SAM-P8 mice showed thymic involution. And in the spleen T-lymphocyte subpopulations, TCD4+ and TCD8+ cells were, respectively, in higher and lower quantities in SAM-P8 mice treated with rapamycin. Thus, the SAM-P8 mouse is an excellent model to study the changes of senescence, since it presents physiological characteristics different from the control mice (SAM-R1). Furthermore, we verified that the dose of rapamycin used did not trigger changes that could compromise the immune response of these mice, as well as the possibility of acting in the modulatory response against the complex effects of aging

Evaluation of Atypical Chemokine Receptor Expression in T Cell Subsets.

Chemokines are molecules that pertain to a family of small cytokines and can generate cell chemotaxis through the interaction with their receptors. Chemokines can trigger signaling via conventional G-protein-coupled receptors or through atypical chemokine receptors. Currently, four atypical chemokine receptors have been are described (ACKR1, ACKR2, ACKR3 and ACKR4). ACKRs are expressed in various cells and tissues, including T lymphocytes. These receptors' main function is related to the internalization and degradation of chemokines, as well as to the inflammation control. However, the expression of these receptors in human T lymphocytes is unclear in the literature. The objective of this study was to evaluate the expression of ACKRs in different subpopulations of T lymphocytes. For this, peripheral blood from healthy donors was used to analyze the expression of ACKR2, ACKR3 and ACKR4 by immunophenotyping CD4, CD8 T lymphocytes and, in their subsets, naive, transition and memory. Results obtained in this study demonstrated that ACKR2, ACKR3 and ACKR4 receptors were expressed by T lymphocytes subsets in different proportions. These receptors are highly expressed in the cytoplasmic milieu of all subsets of T lymphocytes, therefore suggesting that their expression in plasma membrane is regulated after transcription, and it must be dependent on a stimulus, which was not identified in our study. Thus, regarding ACKRs function as scavenger receptors, at least for the ACKR3, this function does not impair the chemotaxis exert for their ligand compared to the typical counterpart receptor.

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.

Where do T cell subsets stand in SARS-CoV-2 infection: an update.

An outbreak of coronavirus disease 2019 (COVID-19) emerged in China in December 2019 and spread so rapidly all around the globe. It's continued and spreading more dangerously in India and Brazil with higher mortality rate. Understanding of the pathophysiology of COVID-19 depends on unraveling of interactional mechanism of SARS-CoV-2 and human immune response. The immune response is a complex process, which can be better understood by understanding the immunological response and pathological mechanisms of COVID-19, which will provide new treatments, increase treatment efficacy, and decrease mortality associated with the disease. In this review we present a amalgamate viewpoint based on the current available knowledge on COVID-19 which includes entry of the virus and multiplication of virus, its pathological effects on the cellular level, immunological reaction, systemic and organ presentation. T cells play a crucial role in controlling and clearing viral infections. Several studies have now shown that the severity of the COVID-19 disease is inversely correlated with the magnitude of the T cell response. Understanding SARS-CoV-2 T cell responses is of high interest because T cells are attractive vaccine targets and could help reduce COVID-19 severity. Even though there is a significant amount of literature regarding SARS-CoV-2, there are still very few studies focused on understanding the T cell response to this novel virus. Nevertheless, a majority of these studies focused on peripheral blood CD4+ and CD8+ T cells that were specific for viruses. The focus of this review is on different subtypes of T cell responses in COVID-19 patients, Th17, follicular helper T (TFH), regulatory T (Treg) cells, and less classical, invariant T cell populations, such as δγ T cells and mucosal-associated invariant T (MAIT) cells etc that could influence disease outcome.

Differentiation of Memory CD8 T Cells Unravel Gene Expression Pattern Common to Effector and Memory Precursors.

Long-term immunological protection relies on the differentiation and maintenance of memory lymphocytes. Since the knowledge of memory generation has been centered on in vivo models of infection, there are obstacles to deep molecular analysis of differentiating subsets. Here we defined a novel in vitro CD8 T cell activation and culture regimen using low TCR engagement and cytokines to generate differentiated cells consistent with central memory-like cells, as shown by surface phenotype, gene expression profile and lack of cytotoxic function after challenge. Our results showed an effector signature expressed by in vitro memory precursors and their plasticity under specific conditions. Moreover, memory CD8 T cells conferred long-term protection against bacterial infection and slowed in vivo tumor growth more efficiently than effector cells. This model may allow further understanding of CD8 T cell memory molecular differentiation subsets and be suited for generating cells to be used for immunotherapy.

Frequency of CXCR3+ CD8+ T-Lymphocyte Subsets in Peripheral Blood Is Associated With the Risk of Paradoxical Tuberculosis-Associated Immune Reconstitution Inflammatory Syndrome Development in Advanced HIV Disease.

Background: Tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) is a clinical aggravation of TB symptoms observed among a fraction of HIV coinfected patients shortly after the start of antiretroviral therapy (ART). Of note, TB-IRIS is characterized by exacerbated inflammation and tissue damage that occurs in response to the elevated production of CD4+ T cell-derived IFN-γ. Nevertheless, the possible participation of CD8+ T cells in TB-IRIS development remains unclear. Methods: We performed a comprehensive assessment of the composition of CD8+ T cell memory subsets and their association with circulating inflammation-related molecules in TB-HIV coinfected patients initiating ART. Results: We found that TB-IRIS individuals display higher frequencies of Antigen-experienced CD8+ T cells during the onset of IRIS and that the levels of these cells positively correlate with baseline mycobacterial smear grade. TB-IRIS individuals exhibited higher frequencies of effector memory and lower percentages of naïve CD8+ T cells than their Non-IRIS counterparts. In both TB-IRIS and Non-IRIS patients, ART commencement was associated with fewer significant correlations among memory CD8+ T cells and cells from other immune compartments. Networks analysis revealed distinct patterns of correlation between each memory subset with inflammatory cytokines suggesting different dynamics of CD8+ T cell memory subsets reconstitution. TB-IRIS patients displayed lower levels of memory cells positive for CXCR3 (a chemokine receptor that plays a role in trafficking activated CD8+ T cells to the tissues) than Non-IRIS individuals before and after ART. Furthermore, we found that CXCR3+ naïve CD8+ T cells were inversely associated with the risk of TB-IRIS development. On the other hand, we noticed that the frequencies of CXCR3+ effector CD8+ T cells were positively associated with the probability of TB-IRIS development. Conclusion: Our data suggest that TB-IRIS individuals display a distinct profile of memory CD8+ T cell subsets reconstitution after ART initiation. Moreover, our data point to a differential association between the frequencies of CXCR3+ CD8+ T cells and the risk of TB-IRIS development. Collectively, our findings lend insights into the potential role of memory CD8+ T cells in TB-IRIS pathophysiology.