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Background: The shaping of the tumor immune microenvironment does not only rely on tumor-infiltrating lymphocytes but on the recruitment of lymphocytes in peripheral blood. Monitoring peripheral blood lymphocyte subsets level (PBLSL) can predict treatment response and prognosis with immune checkpoint inhibitors. This study investigated the heterogeneity of PBLSL in response to chemoradiotherapy (CRT) or combined with immunotherapy (CRIT) in advanced lung cancer patients. Methods: 77 patients with advanced lung cancer receiving CRT or CRIT were divided into treatment-responsive and non-responsive groups based on efficacy. The study analyzed short-term efficacy and progression-free survival (PFS) according to baseline PBLSL and explored the impact under different stratifications, including treatment modality, pathology type, and age. Results: In all patients, higher levels of B cells, higher CD4+/CD8+ T cell ratios, and lower CD8+ T cell levels were associated with better short-term outcomes (P = 0.0035, P = 0.044, P = 0.022). Subgroup analysis revealed that in the CRT group, higher B cell levels correlated with improved efficacy (P = 0.011) and superior PFS (P = 0.048, HR = 0.3886, 95% CI = 0.1696 to 0.8902). In the CRIT group, higher CD4+ T cell levels, lower CD8+ T cell levels, and higher CD4+/CD8+ T cell ratios were linked to better efficacy (P = 0.038, P = 0.047, P = 0.017). For adenocarcinoma patients, higher CD4+/CD8+ T cell ratios and lower CD8+ T cell levels predicted better efficacy (P = 0.0155, P = 0.0119). B cell levels were significant in squamous cell carcinoma (P = 0.0291), while no PBLSL was predictive for small cell lung cancer. Among patients under 65, higher B cell levels were linked to improved efficacy and prolonged PFS (P = 0.0036, P = 0.0332, HR = 0.4111, 95% CI = 0.1973 to 0.8563). For patients over 65, differences in CD4+ T cell levels and CD4+/CD8+ T cell ratios were significant (P = 0.0433, P = 0.0338). Conclusion: PBLSL predicted efficacy and prognosis in various patient stratifications, suggesting PBLSL is a reliable predictor for CRT and CRIT in advanced lung cancer. Detecting different cellular subpopulations helps identify patients with significant treatment responses across different stratifications. [ABSTRACT FROM AUTHOR]

Backgroud: The tumor immune microenvironment influences the efficiency of concurrent chemoradiotherapy (CCRT) in high-grade glioma (HGG). This study investigated peripheral blood T lymphocyte subsets as clinical indicators of therapeutic response and prognosis in pediatric high-grade glioma (pHGG). Methods: This retrospective study included 77 patients with postoperative pHGG who were treated concurrently with temozolomide and external beam radiotherapy between January 1, 2012, and December 31, 2018. The median follow-up was 26 (range: 5-106) months. Peripheral venous blood samples were collected before and after CCRT. The proportions of peripheral blood T lymphocytes and their association with treatment outcome and survival were determined. Results: Sixty-four (83.1%) patients achieved complete remission, partial remission, and stable disease, and 13 (16.9%) patients had progressive disease. Higher CD3+ T cell, CD4+ T cell, and CD8+ CD28+ T cell ratios were predictive of better response, while a higher CD8+ CD28− T cell ratio was predictive of poorer response. Binary logistic regression analysis showed that the CD8+ CD28+ T cell ratio was a significant independent predictor of CCRT response (odds ratio [OR] = 53.521, 95% confidence interval [CI] = 4.294-667.119, P =.002). Univariate and multivariate analysis of prognostic factors associated with survival showed that the CD8+ CD28+ T lymphocyte ratio was a significant independent predictor of progression-free survival (hazard ratio [HR] = 1.80, 95% CI = 1.06-3.08, P =.03), but none of the subsets were significantly associated with overall survival. Conclusion: Peripheral blood T lymphocytes have potential as predictors of CCRT response and prognosis in pHGG. [ABSTRACT FROM AUTHOR]

Background: Tregs are key drivers of immunosuppression in solid tumors. As an important chemokine receptor on Tregs, the regulatory effect of CCR8 on tumor immunity has received more and more attention. However, the current research on CCR8 in the immune microenvironment of ovarian cancer has not been clear. Methods: Bioinformatics analysis was used to compare the transcriptome differences between CD4+ T cells in the peripheral circulation and infiltrated in ovarian tumor tissues. RT-PCR was used to detect the expression levels of chemokine receptor-related differential genes on CD4+ T cells in peripheral blood and ovarian tumor tissues. Multiparameter flow cytometry was used to detect the proportion and phenotypic characteristics of CD4+CCR8+ Tregs and CD4+CCR8− Tregs in different sample types. The expression level of CCR8 ligands was detected at multiple levels. To explore the important role of CCR8-CCL1 and CCR8-CCL18 axis in the migration and invasion of CD4+CCR8+ Tregs into ovarian tumor tissues by establishing a chemotaxis system in vitro. Results: In this study, significantly different gene expression profiles were found between peripheral circulating CD4+ T cells and infiltrating CD4+ T cells in ovarian tumor tissues, in which chemokine-chemokine receptor signaling pathway was significantly enriched in all three groups of differential genes. The expression level of CCR8 in infiltrating CD4+ T cells of ovarian cancer tissue was significantly higher than that in peripheral blood of healthy controls and ovarian cancer patients, and high expression of CCR8 was significantly correlated with advanced tumor stage and poor differentiation. CD4+CCR8+ Tregs are the main type of infiltrating CD4+ Tregs in ovarian tumor tissues, which have stronger immunosuppressive phenotypes, secrete more inhibitory cytokines and have stronger proliferation ability. The ligands CCL1 and CCL18 corresponding to CCR8 were significantly overexpressed in ovarian tumor tissues, and the CCR8-CCL1 and CCR8-CCL18 axis played a key role in the migration and infiltration of CD4+CCR8+ Tregs into ovarian tumor tissues. Conclusions: The results of this study may help to understand the phenotypic characteristics and recruitment process of Tregs in the tumor, and provide new ideas for improving the immunosuppressive status of the ovarian cancer microenvironment. [ABSTRACT FROM AUTHOR]

Objectives: Thymus implantation is a recently FDA‐approved therapy for congenital athymia. Patients receiving thymus implantation develop a functional but incomplete T cell compartment. Our objective was to develop a mouse model to study clinical thymus implantation in congenital athymia and to optimise implantation procedures to maximise T cell education and expansion of naïve T cells. Methods: Using Foxn1nu athymic mice as recipients, we tested MHC‐matched and ‐mismatched donor thymi that were implanted as fresh tissue or cultured to remove donor T cells. We first implanted thymus under the kidney capsule and then optimised intramuscular implantation. Using competitive adoptive transfer assays, we investigated whether the failure of newly developed T cells to expand into a complete T cell compartment was because of intrinsic deficits or whether there were deficits in engaging MHC molecules in the periphery. Finally, we tested whether recombinant IL‐7 would promote the expansion of host naïve T cells educated by the implanted thymus. Results: We determined that thymus implants in Foxn1nu athymic mice mimic many aspects of clinical thymus implants in patients with congenital athymia. When we implanted cultured, MHC‐mismatched donor thymus into Foxn1nu athymic mice, mice developed a limited T cell compartment with notably underdeveloped naïve populations and overrepresented memory‐like T cells. Newly generated T cells were predominantly educated by MHC molecules expressed by the donor thymus, thus potentially undergoing another round of selection once in the peripheral circulation. Using competitive adoptive transfer assays, we compared expansion rates of T cells educated on donor thymus versus T cells educated during typical thymopoiesis in MHC‐matched and ‐mismatched environments. Once in the circulation, regardless of the MHC haplotypes, T cells educated on a donor thymus underwent abnormal expansion with initially more robust proliferation coupled with greater cell death, resembling IL‐7 independent spontaneous expansion. Treating implanted mice with recombinant interleukin (IL‐7) promoted homeostatic expansion that improved T cell development, expanded the T cell receptor repertoire, and normalised the naïve T cell compartment. Conclusion: We conclude that implanting cultured thymus into the muscle of Foxn1nu athymic mice is an appropriate system to study thymus implantation for congenital athymia and immunodeficiencies. T cells are educated by the donor thymus, yet naïve T cells have deficits in expansion. IL‐7 greatly improves T cell development after thymus implantation and may offer a novel strategy to improve outcomes of clinical thymus implantation. [ABSTRACT FROM AUTHOR]

Simple Summary: Certain cells in people's immune system become inflamed in the lungs of smokers. If they develop emphysema, commonly known as chronic obstructive pulmonary disease (COPD), these inflammatory cells are also present in the blood. The reason why they leave the lungs and enter the blood in COPD patients is currently unknown. When these inflammatory cells enter the blood, they cause further inflammation in other parts of the body, which leads to more medical problems such as cardiovascular disease in patients with COPD. Our studies have shown that due to the increased inflammation in the lungs of COPD patients, these inflammatory cells lose the ability to stay in the lungs due to changes in these cells. We have identified these changes as well as the reasons for these changes. Our studies also show why current medications used to stop inflammation do not work very well on these cells. Now that we know how these cells become resistant to current medications used to prevent inflammation and the reason that they leave the lungs and cause more diseases in patients with COPD, future studies can be planned to target these mechanisms to help improve the health of smokers that develop COPD disease. Introduction: Pro-inflammatory CD8+ T cells are increased in the lungs and also in the peripheral circulation of both smokers and chronic obstructive pulmonary disease (COPD) patients. The reason for this is unclear but has been described as a spillover from cells in the lungs that may cause the systemic inflammation noted in COPD. We have recently shown an increase in steroid-resistant CD28nullCD8+ senescent lymphocytes in the lungs and peripheral blood in COPD. Leukotreine B4 (LB4) receptor 1 (BLTR1) is involved in recruitment of CD8+ T cells to sites of inflammation, and we hypothesized that it may be involved in the migration of these senescent lymphocytes from the lungs in COPD. Methods: Via flow cytometry and Western blot BLTR1, IFNγ, and TNFα expression were measured in peripheral blood, BAL, and large proximal and small distal airway CD28±, CD8± T, and NKT-like cells from COPD patients and healthy control subjects (±prednisolone) following in vitro stimulation. Chemotaxis of leucocyte subsets was determined (±LB4 ± prednisolone). Results: There was an increase in BLTR1-CD28nullCD8+ lymphocytes in the lungs and blood in patients with COPD compared with controls. BLTR1-CD28nullCD8+ T and NKT-like cells produce more IFN/TNF than BLTR+ cells and fail to migrate to LTB4. Treatment with 1 µM prednisolone in vitro resulted in upregulation of BLTR1 expression in pro-inflammatory CD28nullCD8+ cells and migration to LB4. Conclusions: Loss of BLTR1 is associated with an increased inflammatory potential of CD28nullCD8+ T cells and may allow these pro-inflammatory steroid-resistant cells to migrate to peripheral blood. Treatment strategies that upregulate BLTR1 may reduce systemic inflammation and associated co-morbidity in patients with COPD. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is the leading cause of dementia, with the number of patients with AD expected to double in the next quarter‐century. Brain deposition of amyloid‐β (Aβ) and tau proteins is a necessary but insufficient condition for AD pathogenesis. There is also growing evidence to suggest that chronic neuroinflammation due to excessive microglial activation and astrocyte dysfunction exacerbates the pathophysiology of AD, but the factors that disrupt these homeostatic processes remain unclear. Research into AD pathophysiology has shown interest in the changes in adaptive T‐cells, which play a pivotal role in immunity. The immune alterations in the peripheral circulation and increased blood–brain‐barrier permeability observed in patients with AD, even in the initial stages of the disease, require investigation of the immune mechanisms resulting from T‐cell infiltration into the central nervous system (CNS) during disease initiation and exacerbation. Since T‐cells play a two‐faceted role in the CNS immune response, including pathogenic and neuroprotective roles, the role of T‐cells in AD has been debated. Memory T‐cells reside in the brain and communicate with glial cells and neurons. In this review, the role of immune responses in AD is discussed, focusing on the contribution of T‐cells. [ABSTRACT FROM AUTHOR]

Background: Liver cancer is the sixth most common cancer worldwide and the third leading cause of cancer-related death. As a chronic liver disease, many studies have shown that the immune response plays a key role in the progression of liver cancer. Chronic hepatitis B virus (HBV) infection is one of the high-risk factors for HCC, accounting for 50%-80% of HCC cases worldwide, and little is known about the immune status of HBV associated hepatocellular carcinoma (HBV-HCC), therefore, we aimed to explore the changes in peripheral immunity in patients with HBV-HCC. Methods: In this study, patients with HBV-HCC (n=26), patients with hepatitis Brelated cirrhosis (HBV-LC) (n=31) and healthy volunteers (n=49) were included. The lymphocytes and their subpopulation phenotypes in peripheral blood were characterized. In addition, we explored the effect of viral replication on peripheral immunity in patients with HCC and analyzed the circulating immunophenotypic characteristics at different stages of HCC with flow cytometry. Results: Firstly, our results showed that the percentages of total αβ T cells in the peripheral blood of HBV-HCC patients was significantly decreased compared to healthy subjects. Secondly, we found that naïve CD4+ T cells in HBV-HCC patients were significantly reduced, terminally differentiated CD8+ T cells, homing memory CD8+ T cells and Th2 cells were increased in peripheral circulation in HBV-HCC patients. Moreover, in the peripheral blood of HBVHCC patients, expression of TIGIT on CD4+ T cells and PD-1 on the surface of Vd 1 T cells was increased. In addition, we found that sustained viral replication resulted in up-regulation of TIM3 expression on CD4+ T cells, and TIM3+ γδ T cells increased in peripheral circulation in patients with advanced HBV-HCC. Frontiers in. Conclusion: Our study showed that circulating lymphocytes in HBV-HCC patients exhibited features of immune exhaustion, especially in HCC patients with persistent viral replication and in patients with intermediate and advanced HBV-HCC, including decreased frequency of T cells and elevated expression of inhibitory receptors including TIGIT and TIM3 on CD4+ T cells and γδ T cells. Meanwhile, our research suggests that the combination of CD3+ T cell and CD8+HLADR+CD38+ T cell may be a potential diagnostic indicator for HBV-HCC. These findings could help us to better understand the immune characteristics of HBV-HCC and explore the immune mechanisms and immunotherapy strategies for HBV-HCC. [ABSTRACT FROM AUTHOR]

Introduction: Immune dysfunction contributes to the progression of idiopathic nephrotic syndrome (INS), but the details of the pathogenesis of progression remain unknown. This study of children with INS investigated the relationship of activation of the mechanistic target of rapamycin (mTOR) pathway (PI3K/AKT/mTOR/p70S6K) with the levels of T helper 2/regulatory T (Th2/Treg) cells. Materials and Methods: Twenty children with active INS (before steroid treatment), 20 children with remitting INS (INS-R, after steroid treatment), and 20 healthy control children (Ctrl) were enrolled. The levels of Th2/Treg cells in their peripheral circulatory systems were measured using flow cytometry, and the concentration of interleukin (IL)-4 was determined using a cytometric bead array (CBA). The levels of PI3K, AKT, mTOR, p70S6K, and transcription factors associated with Th2/Treg cells were measured using real-time polymerase chain reaction. Results: The INS group had a greater proportion of circulating Th2 cells; level of IL-4 protein; and levels of GATA, PI3K, AKT, mTOR, and p70S6K mRNAs than the Ctrl group (all P < 0.05), but a lower proportion of circulating Tregs and expression of Foxp3 (both P < 0.05). Patients in the INS-R group had normalization of these markers (all P < 0.05). Patients in the INS group had negative correlation in the percentage of Treg cells with Th2 cells and with IL-4 level and a negative correlation in the levels of GATA3 and Foxp3 mRNAs. Conclusions: Patients with active INS had an imbalance of Th2/ Treg cells, which might result from the aberrant signaling of the mTOR pathway (PI3K/AKT/mTOR/ p70S6K). [ABSTRACT FROM AUTHOR]

Introduction: The emergence of SARS-CoV-2, which causes COVID-19, has led to over 400 million reported cases worldwide. COVID-19 disease ranges from asymptomatic infection to severe disease and may be impacted by individual immune differences. Methods: We used multiparameter flow cytometry to compare CD4+ and CD8+ T cell responses in severe (ICU admitted) and non-severe (admitted to observational unit) hospitalized COVID-19 patients. Results: We found that patients with severe COVID-19 had greater frequencies of CD4+ T cells expressing CD62L compared to non-severe patients and greater frequencies of perforin+ CD8+ T cells compared to recovered patients. Furthermore, greater frequencies of CD62L+ CD4+ and CD8+ T cells were seen in severely ill diabetic patients compared to non-severe and non-diabetic patients, and increased CD62L+ CD4+ T cells were also seen in severely ill patients with hypertension. Discussion: This is the first report to show that CD62L+ T cells and perforin+ T cells are associated with severe COVID-19 illness and are significantly increased in patients with high-risk pre-existing conditions including older age and diabetes. These data provide a potential biological marker for severe COVID-19. [ABSTRACT FROM AUTHOR]

Background: A transmembrane glycoprotein called soluble programmed death-1 (sPD-1) is expressed on T cells and is secreted into synovial fluid and peripheral circulation by proteolytic cleavage of membrane-bound protein. Objectives: Assessment of sPD-1 plasma levels in cases with rheumatoid arthritis (RA) and the link with disease activity, laboratory, and clinical parameters. Methods: This research involved 20 active RA cases with DAS score (> 2.6 score), 20 patients in remission (= 2.6 score), and 20 apparently healthy individuals as control group. All studied groups were subjected to obtaining patient histories, doing clinical assessments, and performing laboratory tests in form of CBC, ESR, CRP, RF, and Ant-CCP. Measurements of sPD-1 plasma levels and correlations with clinical, laboratory, and disease activities were made. Results: Regarding demographic information, there were no notable differences across RA patients and controls (P > 0.05). In comparing DAS score of the studied groups, there was a significant increase in active group than remission group. There was a significant increase of SPD-1 levels in active group compared to remission and control groups (P = 0.001), while it was not significant regarding remission and control groups (P=0.054). Positive associations were found between the sPDL-1 and the ESR, Anti-CCP, CRP, and DAS score. Conclusion: Plasma sPD-1 in RA cases was significantly raised, and they correlate with DAS28, demonstrating that sPD-1 could be a useful indicator of the degree of RA disease activity. SPD-1 might be a new biomarker or target for RA immunomodulatory treatment. [ABSTRACT FROM AUTHOR]

T cells play a pivotal role in reducing disease severity during SARS-CoV-2 infection and formation of long-term immune memory. We studied 50 COVID-19 convalescent patients and found that T cell response was induced more frequently and persisted longer than circulating antibodies. We identified 756 clonotypes specific to nine CD8+ T cell epitopes. Some epitopes were recognized by highly similar public clonotypes. Receptors for other epitopes were extremely diverse, suggesting alternative modes of recognition. We tracked persistence of epitope-specific response and individual clonotypes for a median of eight months after infection. The number of recognized epitopes per patient and quantity of epitope-specific clonotypes decreased over time, but the studied epitopes were characterized by uneven decline in the number of specific T cells. Epitopes with more clonally diverse TCR repertoires induced more pronounced and durable responses. In contrast, the abundance of specific clonotypes in peripheral circulation had no influence on their persistence. The clonotypes of CD8+ T cells specific to 9 SARS-CoV-2 epitopes are identified from COVID-19 convalescent patients and the longitudinal study of these clonotypes reveals that T cell persistence correlates with TCR diversity. [ABSTRACT FROM AUTHOR]

Once regarded as an experimental artefact, cytotoxic CD4+ T cells (CD4 CTL) are presently recognized as a biologically relevant T cell subset with important functions in anti-viral, anti-tumor, and autoimmune responses. Despite the potentially large impact on their micro-environment, the absolute cell counts of CD4 CTL within the peripheral circulation are relatively low. With the rise of single cell analysis techniques, detection of these cells is greatly facilitated. This led to a renewed appraisal of CD4 CTL and an increased insight into their heterogeneous nature and ontogeny. In this review, we summarize the developmental path from naïve CD4+ T cells to terminally differentiated CD4 CTL, and present markers that can be used to detect or isolate CD4 CTL and their precursors. Subsets of CD4 CTL and their divergent functionalities are discussed. Finally, the importance of local cues as triggers for CD4 CTL differentiation is debated, posing the question whether CD4 CTL develop in the periphery and migrate to site of inflammation when called for, or that circulating CD4 CTL reflect cells that returned to the circulation following differentiation at the local inflammatory site they previously migrated to. Even though much remains to be learned about this intriguing T cell subset, it is clear that CD4 CTL represent interesting therapeutic targets for several pathologies. [ABSTRACT FROM AUTHOR]

The epidermal growth factor receptor variant III (EGFRvIII) has been investigated as a therapeutic target for chimeric antigen receptor (CAR) T cell therapy in glioblastoma. Earlier research demonstrated that phenotypic and genotypic characteristics in T cells and CAR T product predicted therapeutic success in hematologic malignancies, to date no determinants for clinical response in solid tumors have been identified. We analyzed apheresis and infusion products from the first-in-human trial of EGFRvIII-directed CAR T for recurrent glioblastoma (NCT02209376) by flow cytometry. Clinical response was quantified via engraftment in peripheral circulation and progression-free survival (PFS), as determined by the time from CAR T infusion to first radiographic evidence of progression. The CD4+CAR T cell population in patient infusion products demonstrated PD1 expression which positively correlated with AUC engraftment and PFS. On immune checkpoint inhibitor analysis, CTLA-4, TIM3, and LAG3 did not exhibit significant associations with engraftment or PFS. The frequencies of PD1+GZMB+ and PD1+HLA-DR+ CAR T cells in the CD4+ infusion products were directly proportional to AUC and PFS. No significant associations were observed within the apheresis products. In summary, PD1 in CAR T infusion products predicted peripheral engraftment and PFS in recurrent glioblastoma. [ABSTRACT FROM AUTHOR]

B cells interact with T follicular helper (Tfh) cells in germinal centers (GCs) to generate high-affinity antibodies. Much less is known about how cognate T–B-cell interactions influence Th cells that enter circulation and peripheral tissues. Therefore, we generated mice lacking MHC-II expressing B cells and, by thoracic duct cannulation, analyzed Th cells in the efferent lymph at defined intervals post-immunization. Focusing on gut-draining mesenteric lymph nodes (MLNs), we show that antigen-specific α4β7+ gut-homing effector Th cells enter the circulation prior to CXCR5+PD-1+ Tfh-like cells. B cells appear to have no or limited impact on the early generation and egress of gut-homing Th cells but are critical for the subsequent appearance of Tfh-like cells that peak in the lymph before GCs have developed. At this stage, antigen-presenting B cells also reduce the proportion of α4β7+ Th cells in the MLN and efferent lymph. Furthermore, cognate B-cell interaction drives a broad transcriptional program in Th cells, including IL-4 that is confined to the Tfh cell lineage. The IL-4-producing Tfh-like cells originate from Bcl6+ precursors in the LNs and have gut-homing capacity. Hence, B cells program the efferent lymph Th cell response within a limited window of time after antigenic challenge. [ABSTRACT FROM AUTHOR]

Background: Coronavirus disease 2019 (COVID-19) patients with severe disease had a high mortality rate. It's imperative to identify risk factors associated with disease progression and prognosis. Immune responses played an important role in the host's defense against the virus. We studied the dynamics of peripheral blood lymphocytes (PBLs) in relation to the clinical outcome in COVID-19 patients in intensive care unit (ICU). Design: This cohort included 342 COVID-19 patients who were admitted to ICU between February 1 and May 30, 2020, with 178 having follow-up PBL analysis. The patients were divided into a group that survived and an expired group. PBL analysis was performed by flow cytometry. Results: At time of initial flow analysis, there were no statistically significant differences in lymphocyte, T-cell and subsets, B-cell or natural killer (NK) cell counts between the 2 groups. However, during the ICU course, the surviving group demonstrated a full recovery of CD3+ T-cells, CD4+ T-cells, and CD8+ T-cells, with no significant change in B-cells, and a slight upward trend in NK-cells. In contrast, the expired group showed no recovery in T-cells (and subsets) and no significant changes in B-cells and NK-cells. We identified the earliest time points and cut-off values for T-cell subsets that predict clinical outcomes. Conclusion: The results of this study suggest that evaluation of PBL in COVID-19 patients could be valuable in the study of the immune responses to the disease and the prognostication of outcome. [ABSTRACT FROM AUTHOR]

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Objective To assess the potential diagnostic utility of advanced lymphocyte profiling to differentiate between primary Sjögren's Syndrome (pSS) and non-Sjögren Sicca syndrome. Methods Distribution of peripheral lymphocyte subpopulations was analysed by flow cytometry in 68 patients with pSS, 26 patients with sicca syndrome and 23 healthy controls. The ability to discriminate between pSS and sicca syndrome was analysed using the area under the curve (AUC) of the receiver operating characteristic curve of the different lymphocyte subsets. Results The ratio between naïve/memory B cell proportions showed an AUC of 0.742 to differentiate pSS and sicca syndrome, with a sensitivity of 76.6% and a specificity of 72% for a cut-off value of 3.4. The ratio of non-switched memory B cells to activated CD4+ T cells percentage (BNSM/CD4ACT) presented the highest AUC (0.840) with a sensitivity of 83.3% and specificity of 81.7% for a cut-off value <4.1. To differentiate seronegative pSS patients from sicca patients, the BNSM/CD4ACT ratio exhibited an AUC of 0.742 (sensitivity 75%, specificity 66.7%, cut-off value <4.4), and the number of naïve CD4 T cells had an AUC of 0.821 (sensitivity 76.9%, specificity 88.9%, cut-off value <312/mm3). Conclusion Patients with pSS show a profound imbalance in the distribution of circulating T and B lymphocyte subsets. The ratio BNSM/CD4ACT is useful to discriminate between pSS and sicca syndrome. [ABSTRACT FROM AUTHOR]

While Salmonella enterica is seen as an archetypal facultative intracellular bacterial pathogen where protection is mediated by CD4+ T cells, identifying circulating protective cells has proved very difficult, inhibiting steps to identify key antigen specificities. Exploiting a mouse model of vaccination, we show that the spleens of C57BL/6 mice vaccinated with live-attenuated Salmonella serovar Typhimurium (S. Typhimurium) strains carried a pool of IFN-γ+ CD4+ T cells that could adoptively transfer protection, but only transiently. Circulating Salmonella-reactive CD4+ T cells expressed the liver-homing chemokine receptor CXCR6, accumulated over time in the liver and assumed phenotypic characteristics associated with tissue-associated T cells. Liver memory CD4+ T cells showed TCR selection bias and their accumulation in the liver could be inhibited by blocking CXCL16. These data showed that the circulation of CD4+ T cells mediating immunity to Salmonella is limited to a brief window after which Salmonella-specific CD4+ T cells migrate to peripheral tissues. Our observations highlight the importance of triggering tissue-specific immunity against systemic infections. Author summary: Helper T cells are essential for controlling infections by bacterial pathogens, such as Salmonella enterica var Typhimurium (S. Typhimurium). While it is well-established that this role is related to their provision of IFN-γ, when and where helper T cells elicit their protective function in vivo remains unresolved. We identified a protective helper T cell population in the circulation of mice early after inoculation with growth-attenuated S. Typhimurium strains; this population waned overtime. We observed that circulating helper T cell immunity can adoptively protect naïve recipient mice against lethal S. Typhimurium infection when harvested from a short time-window. In comparing helper T cell responses between spleen and liver in Salmonella-infected mice, we have observed a previously uncharacterized trafficking of helper T cells to the liver followed by the residence of S. Typhimurium-specific T cell memory in the organ. Taken together these findings identify that protective immunity to Salmonella infections is transient in the circulation and the liver as a preferential site of helper T memory cells. [ABSTRACT FROM AUTHOR]

keyimage.jpg Activating γδ T cells: Gamma delta T (γδ T) cells exhibit potent cytotoxic properties that can be activated against both solid and liquid tumors. Here, De Gassart et al. have developed a humanized monoclonal antibody, ICT01, which targets BTN3A, a plasma membrane receptor responsible for Vγ9Vδ2 T cell activation. Treatment with ICT01 prolonged survival of xenograft mouse models adoptively transferred with human Vγ9Vδ2 T cells and was well tolerated in cynomolgus macaques. In addition, treatment in a first-in-human, phase 1/2a clinical study of ICT01 showed tolerance and pharmacodynamic results in patients. ICT01 represents a promising clinical strategy to activate circulating Vγ9Vδ2 T cells for efficient killing of tumors. Gamma delta T (γδ T) cells are among the most potent cytotoxic lymphocytes. Activating anti–butyrophilin 3A (BTN3A) antibodies prime diverse tumor cell types to be killed by Vγ9Vδ2 T cells, the predominant γδ T cell subset in peripheral circulation, by mechanisms independent of tumor antigen–major histocompatibility complex (MHC) complexes. In this report, we describe the development of a humanized monoclonal antibody, ICT01, with subnanomolar affinity for the three isoforms of BTN3A. We demonstrate that ICT01-activated Vγ9Vδ2 T cells kill multiple tumor cell lines and primary tumor cells, but not normal healthy cells, in an efficient process requiring approximately 20% target occupancy. We show that ICT01 activity is dependent on BTN3A and BTN2A but independent of the phosphoantigen (pAg)–binding B30.2 domain. ICT01 delays the growth of hematologic and solid tumor xenografts and prolongs survival of NOD/SCID/IL2rγnull (NSG) mice adoptively transferred with human Vγ9Vδ2 T cells. In single- and multiple-dose safety studies in cynomolgus macaques that received up to 100 mg/kg once weekly, ICT01 was well tolerated. With respect to pharmacodynamic endpoints, ICT01 selectively activated Vγ9Vδ2 T cells without affecting other BTN3A-expressing lymphocytes such as αβ T or B cells. A first-in-human, phase 1/2a, open-label, clinical study of ICT01 was thus initiated in patients with advanced-stage solid tumors (EVICTION: NCT04243499; EudraCT: 2019-003847-31). Preliminary results show that ICT01 was well tolerated and pharmacodynamically active in the first patients. Digital pathology analysis of tumor biopsies of a patient with melanoma suggests that ICT01 may promote immune cell infiltration within the tumor microenvironment. [ABSTRACT FROM AUTHOR]

Head and neck squamous cell carcinoma (HNSCC) is a common type of cancer worldwide. Strong connections have been revealed between immune cells and the pathogenesis of HNSCC. Important differences regarding the levels of immune cell subpopulations in both peripheral circulation and tumor microenvironment were emphasized, with some of them having prognostic significance. In our study, we performed an analysis of immune changes in the tumor tissue and the peripheral blood of untreated HNSCC patients, investigating the proportions of different immune cell populations in these two compartments. The local infiltrating lymphocytes were mainly cytotoxic T cells (CD8+). We have also revealed an increased level of B lymphocytes (CD19+) in the tumor microenvironment. In peripheral blood, the most important lymphocyte subtype was represented by the helper T lymphocytes (CD4+). We also found an increased proportion of circulating NK cells (CD56+). Our results showed significant differences between all investigated lymphocyte subtypes in the peripheral blood and the tumor tissue of untreated HNSCC patients, suggesting that the local and systemic expressions of antitumor immune responses are different and that investigation of immune cell proportions in peripheral circulation has different cues that do not reflect the immune infiltrate pattern within the tumor microenvironment. Further studies are necessary to unveil the complex interplay involving local and systemic events in the immune system's fight against cancer. [ABSTRACT FROM AUTHOR]

Overview : Long-term survival of T lymphocytes in quiescent state is essential to maintain their cell numbers in secondary lymphoid organs and in peripheral circulation. In the BioBreeding diabetes-prone strain of rats (BB-DP), loss of functional GIMAP5 (GTPase of the immune associated nucleotide binding protein 5) results in profound peripheral T lymphopenia. This discovery heralded the identification of a new family of proteins initially called Immune-associated nucleotide binding protein (IAN) family. In this review we will use 'GIMAP' to refer to this family of proteins. Recent studies suggest that GIMAP proteins may interact with each other and also be involved in the movement of the cellular cargo along the cytoskeletal network. Here we will summarize the current knowledge on the characteristics and functions of GIMAP family of proteins. [ABSTRACT FROM AUTHOR]

Autologous chimeric antigen receptor (CAR) T cells targeted to epidermal growth factor receptor variant III (CAR T-EGFRvIII) have been developed and administered experimentally to treat patients with IDH1 wildtype recurrent glioblastoma (rGBM) (NCT02209376). We report the case of a 59-year-old patient who received a single peripheral infusion of CAR T-EGFRvIII cells and survived 36 months after disease recurrence, exceeding expected survival for recurrent glioblastoma. Post-infusion histopathologic analysis of tissue obtained during a second stage surgical resection revealed immunosuppressive adaptive changes in the tumor tissue as well as reduced EGFRvIII expression. Serial brain imaging demonstrated a significant reduction in relative cerebral blood volume (rCBV), a measure strongly associated with tumor proliferative activity, at early time points following CAR T treatment. Notably, CAR T-EGFRvIII cells persisted in her peripheral circulation during 29 months of follow-up, the longest period of CAR T persistence reported in GBM trials to date. These findings in a long-term survivor show that peripherally administered CAR T-EGFRvIII cells can persist for years in the circulation and suggest that this cell therapy approach could be optimized to achieve broader efficacy in recurrent GBM patients. [ABSTRACT FROM AUTHOR]

The inflammatory immune response has evolved to protect the host from different pathogens, allergens, and endogenous death or damage-associated molecular patterns. Both innate and adaptive immune components are crucial in inducing an inflammatory immune response depending on the stimulus type and its duration of exposure or the activation of the primary innate immune response. As the source of inflammation is removed, the aggravated immune response comes to its homeostatic level. However, the failure of the inflammatory immune response to subside to its normal level generates chronic inflammatory conditions, including autoimmune diseases and cancer. Innate lymphoid cells (ILCs) are newly discovered innate immune cells, which are present in abundance at mucosal surfaces, including lungs, gastrointestinal tract, and reproductive tract. Also, they are present in peripheral blood circulation, skin, and lymph nodes. They play a crucial role in generating the pro-inflammatory immune response during diverse conditions. On the other hand, adaptive immune cells, including different types of T and B cells are major players in the pathogenesis of autoimmune diseases (type 1 diabetes mellitus, rheumatoid arthritis, psoriasis, and systemic lupus erythematosus, etc.) and cancers. Thus the article is designed to discuss the immunological role of different ILCs and their interaction with adaptive immune cells in maintaining the immune homeostasis, and during inflammatory autoimmune diseases along with other inflammatory conditions (excluding pathogen-induced inflammation), including cancer, graft-versus-host diseases, and human pregnancy. [ABSTRACT FROM AUTHOR]

Malaria can cause life-threatening complications which are often associated with inflammatory reactions. More subtle, but also contributing to the burden of disease are chronic, often subclinical infections, which result in conditions like anemia and immunologic hyporesponsiveness. Although very frequent, such infections are difficult to study in endemic regions because of interaction with concurrent infections and immune responses. In particular, knowledge about mechanisms of malaria-induced immunosuppression is scarce. We measured circulating immune cells by cytometry in healthy, malaria-naïve, adult volunteers undergoing controlled human malaria infection (CHMI) with a focus on potentially immunosuppressive cells. Infectious Plasmodium falciparum (Pf) sporozoites (SPZ) (PfSPZ Challenge) were inoculated during two independent studies to assess malaria vaccine efficacy. Volunteers were followed daily until parasites were detected in the circulation by RT-qPCR. This allowed us to analyze immune responses during pre-patency and at very low parasite densities in malaria-naïve healthy adults. We observed a consistent increase in circulating polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) in volunteers who developed P. falciparum blood stage parasitemia. The increase was independent of preceding vaccination with a pre-erythrocytic malaria vaccine. PMN-MDSC were functional, they suppressed CD4+ and CD8+ T cell proliferation as shown by ex-vivo co-cultivation with stimulated T cells. PMN-MDSC reduced T cell proliferation upon stimulation by about 50%. Interestingly, high circulating PMN-MDSC numbers were associated with lymphocytopenia. The number of circulating regulatory T cells (Treg) and monocytic MDSC (M-MDSC) showed no significant parasitemia-dependent variation. These results highlight PMN-MDSC in the peripheral circulation as an early indicator of infection during malaria. They suppress CD4+ and CD8+ T cell proliferation in vitro. Their contribution to immunosuppression in vivo in subclinical and uncomplicated malaria will be the subject of further research. Pre-emptive antimalarial pre-treatment of vaccinees to reverse malaria-associated PMN-MDSC immunosuppression could improve vaccine response in exposed individuals. [ABSTRACT FROM AUTHOR]

The classical liver-derived and serum-effective complement system is well appreciated as a key mediator of host protection via instruction of innate and adaptive immunity. However, recent studies have discovered an intracellularly active complement system, the complosome, which has emerged as a central regulator of the core metabolic pathways fueling human immune cell activity. Induction of expression of components of the complosome, particularly complement component C3, during transmigration from the circulation into peripheral tissues is a defining characteristic of monocytes and T cells in tissues. Intracellular complement activity is required to induce metabolic reprogramming of immune cells, including increased glycolytic flux and OXPHOS, which drive the production of the pro-inflammatory cytokine IFN-γ. Consequently, reduced complosome activity translates into defects in normal monocyte activation, faulty Th1 and cytotoxic T lymphocyte responses and loss of protective tissue immunity. Intriguingly, neurological research has identified an unexpected connection between the physiological presence of innate and adaptive immune cells and certain cytokines, including IFN-γ, in and around the brain and normal brain function. In this opinion piece, we will first review the current state of research regarding complement driven metabolic reprogramming in the context of immune cell tissue entry and residency. We will then discuss how published work on the role of IFN-γ and T cells in the brain support a hypothesis that an evolutionarily conserved cooperation between the complosome, cell metabolism and IFN-γ regulates organismal behavior, as well as immunity. [ABSTRACT FROM AUTHOR]

Summary: Administration of chemotherapeutics as direct injections into tumors offers increased anti-tumor activity and reduced systemic toxicity. In this study, the Renca syngeneic murine xenograft model of renal cancer was used to evaluate the effects of intratumoral (IT) submicron particle docetaxel (NanoDoce®) on tumor growth and immunomodulation. Tumor volume (TV) was compared to controls, including intravenous (IV) chemotherapy. Flow cytometry of peripheral bloods and tumors was used to evaluate immune cell populations. Groups of animals were inoculated with a second Renca tumor at a site distant from the primary tumor. IT NanoDoce significantly reduced primary TV and reduced the growth rates of untreated secondary tumors. CD4+, CD8+ and Treg populations were increased in peripheral bloods from animals administered IT NanoDoce. Additional evaluation of the effect of IT NanoDoce on peripheral and local immune cell populations as well as the impact on sites of distant tumor growth are warranted. [ABSTRACT FROM AUTHOR]

To investigate the polymorphism of T cell receptor β chain variable region (TCRV β) in peripheral blood of clinically isoiated syndrome (CIS) patients. To preliminarily predict the specific TCRV β fragment of CIS and its diagnostic value for CIS. Methods Hospitalized patients of Beijing Xuanwu Hospital from September 2012 to March 2014, were divided into 2 groups including CIS group (experimental pateints, n = 30) and normal control group (healthy volunteers, n = 30). The routine immune indexes and expression of TCRVβ subfamilies were detected by flow cytometry. CELL Quest Pro 5.1 software was used to analyze 24 subfamilies of TCRVβ. Calculated the statistic of amplification rate, amplification number and amplification fraction of the total 24 subfamilies of TCRVβ. Results Compared to the normal control group, the quantitative expression of CD4+ TCRVβ2, 4, 5.2, 5.3, 7.1, 8, 14, 17, 20, 21.3 and CD8+TCRVβ4, 14 were significantly expanded in CIS group, CD4+TCRVβ11 and CD8+TCRVβ9, 11 were significantly reduced in CIS group (P < 0.05 or P < 0.01). The amplification rate of CD4+TCRVβ2 (P = 0.002) and CD8+TCRVβ14 (P = 0.010) in CIS group were higher than those in normal control group, but there was no significant difference in the other subfamilies. There was no statistical difference in the expansion rate of the TCRVβ between CIS group and normal control group. The amplification number (P = 0.001) and amplification fraction (P = 0.006) of the TCRVβ in CIS group were significantly higher than the normal control group. Receiver operating characteristic curve (ROC) analysis indicated that the area under the curve (AUC) of CD4+TCRVβ4 in the diagnosis of CIS was 0.719 (95%CI: 0.592-0.851, P = 0.003). The sensitivity was 83.33%, the specificity was 56.67%. The AUC of CD4+TCRVβ14 in the diagnosis of CIS was 0.713 (95%CI: 0.581-0.845, P = 0.005). The sensitivity was 70%, the specificity was 56.23%. The AUC of CD8+TCRVβ4 in the diagnosis of CIS was 0.727 (95%CI: 0.600-0.854, P = 0.002). The sensitivity was 93.33%, the specificity was 50%. The three fragments have medium diagnostic value for CIS. Conclusions Although the expression levels of CD4+TCRV β4, CD4+TCRV β14 and CD8+TCRV β4 in peripheral blood are increased in CIS group, their diagnostic value is limited. [ABSTRACT FROM AUTHOR]

Background: The establishment of adaptive immune responses to neoplasms involves not only the tumour tissue, but also the peripheral blood. We aimed to conduct a preliminary exploration to understand the immune response of T lymphocytes of peripheral blood mononuclear cells (PBMC‐Ts) in oral squamous cell carcinoma (OSCC). Methods: A total of 103 blood samples from OSCC patients and 18 blood samples from healthy donors (HD) were analysed by flow cytometry. Results: Compared to those in HD, a series of unique features of PBMC‐Ts were observed in OSCC patients including a significant increase in CD4+ T cells, a shift from naïve to memory/effector phenotype, an increased frequency of exhausted phenotypes (programmed death‐1 [PD‐1], T cell Ig and mucin protein‐3 [Tim‐3] and Tregs), an abundance of Th17s and Tc17s and an imbalance in Th17/Tc17 and Th17/Treg ratios. Furthermore, in OSCC patients, we also found that CD4+ T cells were significantly increased in patients with larger tumours than smaller tumours, memory/effector phenotype and exhausted phenotypes were significantly associated with advanced clinical stage and lymph node metastasis, and the Th17/Treg ratio was associated with early clinical stage and no lymph node metastasis. Conclusion: PBMC‐Ts may be involved in the development and progression of OSCC, which suggested to be a manifestation of an immune response between host and tumour neoantigens. [ABSTRACT FROM AUTHOR]

Interaction between B and CD4 T cells is crucial for their optimal responses in adaptive immunity. Immune responses augmented by their partnership promote chronic inflammation. Here we report that interaction between B and CD4 T cells augments their atherogenicity to promote lipid-induced atherosclerosis. Genetic deletion of the gene encoding immunoglobulin mu (μ) heavy chain (μMT) in ApoE−/− mice resulted in global loss of B cells including those in atherosclerotic plaques, undetectable immunoglobulins and impaired germinal center formation. Despite unaffected numbers in the circulation and peripheral lymph nodes, CD4 T cells were also reduced in spleens as were activated and memory CD4 T cells. In hyperlipidemic μMT−/− ApoE−/− mice, B cell deficiency decreased atherosclerotic lesions, accompanied by absence of immunoglobulins and reduced CD4 T cell accumulation in lesions. Adoptive transfer of B cells deficient in either MHCII or co-stimulatory molecule CD40, molecules required for B and CD4 T cell interaction, into B cell-deficient μMT−/− ApoE−/− mice failed to increase atherosclerosis. In contrast, wildtype B cells transferred into μMT−/− ApoE−/− mice increased atherosclerosis and increased CD4 T cells in lesions including activated and memory CD4 T cells. Transferred B cells also increased their expression of atherogenic cytokines IL-1β, TGF-β, MCP-1, M-CSF, and MIF, with partial restoration of germinal centers and plasma immunoglobulins. Our study demonstrates that interaction between B and CD4 T cells utilizing MHCII and CD40 is essential to augment their function to increase atherosclerosis in hyperlipidemic mice. These findings suggest that targeting B cell and CD4 T cell interaction may be a therapeutic strategy to limit atherosclerosis progression. [ABSTRACT FROM AUTHOR]

Objectives PD-1+CXCR5−CD4+T peripheral helper (Tph) cells, a recently identified T cell subset, are proven to promote B cell responses and antibody production in rheumatoid arthritis, but their role in the pathogenesis of SLE is unknown. We explored the role of Tph in lupus disease development. Methods This cohort study included 68 patients with SLE and 41 age- and sex-matched healthy individuals. The frequency of PD-1+CXCR5−CD4+T cells was analysed in peripheral blood by flow cytometry. Inducible T-cell costimulator, CD38, MHC-II, IL-21, CXCR3 and CCR6 expression were measured in Tph cells. Comparisons between the two groups were performed, and correlations between Tph cells and other parameters were investigated. Results We revealed a markedly expanded population of Tph cells (8.31 ± 5.45 vs 2.86 ± 1.31%, P < 0.0001) in the circulation of patients with SLE (n = 68), compared with healthy controls (n = 41). Tph cells were much higher in the active group than in the inactive group (14.21 ± 5.21 vs 5.49 ± 2.52%, P < 0.0001). Tph cells were significantly associated with SLEDAI score (r = 0.802), ESR (r = 0.415), IgG (r = 0.434), C3 (r = −0.543), C4 (r = −0.518) and IL-21 level (r = 0.628), and ANA titre (r = 0.272). Furthermore, Tph cells were much higher in lupus patients with arthritis, nephritis, rash, alopecia, pleuritis, pericarditis and haematological involvement. Tph cells were associated with CD138+/CD19+ plasma cells (r = 0.518). Furthermore, MHC-II, inducible T-cell costimulator, CD38, and IL-21 expression were all higher in Tph cells from SLE patients compared with healthy controls. CXCR3+CCR6−Tph (Tph1) cells were expanded in the SLE patients. Conclusion Our data show that relative number of Tph cells is correlated with disease measures in patients with SLE, suggesting an important role in lupus disease development. [ABSTRACT FROM AUTHOR]

Highlights • mVEGF165b as an immunization adjunct was able to induce high titers of anti-VEGF antibody. • High anti-VEGF antibody titers decrease immunosuppression by reducing the proportion of Tregs in the spleen or in peripheral circulation. • The decrease immunosuppression augments the immune response induced by peptide vaccine from Mucin-1. • mVEGF165b can be used as a potential adjunct with other tumor vaccines to increase anti-tumor efficacy and also promote the T cell infiltration into tumor. Abstract Compelling evidence has shown that blocking VEGF via monoclonal antibodies may be beneficial in that it not only inhibits tumor angiogenesis but also reduces immune suppression and promotes T cell infiltration into tumors. Herein, we determined whether our recently generated VEGF165b mutant could be used as a co-immunization adjunct to augment the peptide cancer-vaccine- induced immune response in a mouse model of breast cancer. When co-immunized mVEGF165b with the peptide-based cancer vaccine (MUC1, a T-cell epitope dominant peptide vaccine from Mucin1), the VEGF antibody titers increased approximately 600,000-fold in mice. Moreover, the anti-VEGF antibody also reduced the frequency of regulatory T cells (Tregs) in both preventive and therapeutic scenarios. Mechanistically, the decrease of the Tregs population was associated with a remarkably increased MUC-1-specific IFN-γ-producing CD8+ T cells and anti-MUC1 humoral response. Finally, this combination co-immunization produced a superior antitumor response and significantly prolonged survival of tumor-bearing mice. In conclusion, our findings suggest that mVEGF165b may be an ideal immunization adjunct to enhance the immune efficacy of peptide-based tumor vaccines by overcoming immune tolerance. [ABSTRACT FROM AUTHOR]

DNA methyltransferase inhibitors (DNMTis) have found widespread application in the management of cancer. Zebularine (Zeb), functioning as a demethylating agent, has exhibited notable advantages and enhanced therapeutic efficacy in the realm of tumour immunotherapy. Nevertheless, due to its lack of targeted functionality, standalone Zeb therapy necessitates the administration of a substantially higher dosage. In this investigation, we have devised an innovative nanodrug formulation, comprising the DNA methyltransferase inhibitor Zeb and pH-responsive chitosan (CS), hereinafter referred to as CS-Zeb nanoparticles (NPs). Our findings have unveiled that CS-Zeb NPs manifest heightened drug release within an acidic milieu (pH 5.5) in comparison to a neutral environment (pH 7.4). Furthermore, in vivo studies have conclusively affirmed that, in contrast to equivalent quantities of Zeb in isolation, the nanocomplex significantly curtailed tumour burden and protracted the survival duration of the B16F10 tumour-bearing murine model. Additionally, CS-Zeb NPs elicited an augmentation of CD8+ T cells within the peripheral circulation of mice and tumour-infiltrating lymphocytes (TILs). Notably, the dosage of CS-Zeb NPs was reduced by a remarkable 70-fold when juxtaposed with Zeb administered in isolation. To summarise, our study underscores the potential of CS-Zeb NPs as an alternative chemotherapeutic agent for cancer treatment. [Display omitted] • We designed an innovative Nano Zebs (CS-Zeb NPs) that greatly enhance the use of Zebularine. • CS-Zeb NPs possess potent demethylation and tumour suppressive abilities. • CS-Zeb NPs enhances anti-tumour immune response in B16F10 tumour-bearing mice. [ABSTRACT FROM AUTHOR]

• Tissue resident T cells (T RM) express adhesion molecules and embed within tissues. • T RM promotion in tumors leads to sequestration of T cells out of circulation. • Definitive surgery or tumor ablation may remove most tumor-specific T cells. • Neoadjuvant immunotherapy promotes egress of T RM from tumors into circulation. • This effect may underlie the clinical benefit observed with neoadjuvant immunotherapy. Resident memory T (T RM) cells are embedded in peripheral tissue and capable of acting as sentinels that can respond quickly to repeat pathogen exposure as part of an endogenous anti-microbial immune response. Recent evidence suggests that chronic antigen exposure and other microenvironment cues may promote the development of T RM cells within solid tumors as well, and that this T RM phenotype can sequester tumor-specific T cells into tumors and out of circulation resulting in limited systemic antitumor immunity. Here, we perform a review of the published English literature and describe tissue-specific mediators of T RM cell differentiation in states of infection and malignancy with special focus on the role of TGF-β and how targeting TGF-β signaling could be used as a therapeutical approach to promote tumor systemic immunity. The presence of T RM cells with antigen specificity to neoepitopes in tumors associates with positive clinical prognosis and greater responsiveness to immunotherapy. Recent evidence indicates that solid tumors may act as reservoirs for tumor specific T RM cells and limit their circulation – possibly resulting in impaired systemic antitumor immunity. T RM cells utilize specific mechanisms to egress from peripheral tissues into circulation and other peripheral sites, and emerging evidence indicates that immunotherapeutic approaches may initiate these processes and increase systemic antitumor immunity. Reversing tumor sequestration of tumor-specific T cells prior to surgical removal or radiation of tumor may increase systemic antitumor immunity. This finding may underlie the improved recurrence free survival observed with neoadjuvant immunotherapy in clinical trials. [ABSTRACT FROM AUTHOR]

Background: Research with primary human white blood cell (WBC) subpopulations requires high quantity, quality, and functionality of peripheral blood mononuclear cells (PBMCs) as a source to further characterize cellular subpopulations such as T and B lymphocytes, monocytes, or natural killer cells. Apart from buffy coats derived from whole blood, residual blood from preparative hemapheresis kits are used as a source for PBMCs, but knowledge on the yield and functionality of cells from different devices is limited.Study Design and Methods: We evaluated quantity and quality of PBMCs isolated from apheresis kits of two apheresis devices (AMICUS, Fenwal; and Trima Accel, Terumo BCT), the latter being our standard source for many years. PBMCs derived from Trima or AMICUS were tested for yield and subtype composition by flow cytometry. Functionality was assessed by cytokine induction of CD4+ and CD8+ T cells and by degranulation. Moreover, cytotoxic activity of natural killer cells was quantified by a real-time killing assay.Results: Mean numbers of isolated cells were 5.5 ± 2.4 × 108 for AMICUS, and 10.3 ± 6.4 × 108 for Trima Accel, respectively. The proportion of WBC subtypes corresponded to well-known numbers from whole blood, with minor differences between the two apheresis systems. Likewise, minor differences in cytokine induction were found in stimulated CD4+ or CD8+ T cells. Finally, PBMCs derived from the two systems showed comparable cytotoxic activity.Conclusion: PBMC derived from residual blood of the AMICUS and Trima Accel apheresis devices serve as an economic and easily accessible source for functional PBMCs with comparable quantity and quality to PBMCs derived from whole blood. [ABSTRACT FROM AUTHOR]

At home in the pancreas: Type 1 diabetes (T1D) is associated with enrichment of autoreactive CD8+ T cells that target destruction of pancreatic islets. Culina et al. studied islet-reactive CD8+ T cells reactive to the zinc transporter 8186–194 (ZnT8186–194) and other islet epitopes in healthy individuals and T1D patients, which showed similar functionality and similar frequencies and naïve phenotypes in the peripheral circulation across both groups. In contrast, ZnT8186–194-reactive CD8+ T cells were enriched in the pancreas of T1D patients relative to healthy controls and showed cross-reactivity to an epitope from the commensal Bacteroides stercoris. These results indicate that incomplete central tolerance may allow the survival of these islet-reactive CD8+ T cells in the periphery, and that proinflammatory conditions in the islets can contribute to T1D progression. The human leukocyte antigen–A2 (HLA-A2)–restricted zinc transporter 8186–194 (ZnT8186–194) and other islet epitopes elicit interferon-γ secretion by CD8+ T cells preferentially in type 1 diabetes (T1D) patients compared with controls. We show that clonal ZnT8186–194-reactive CD8+ T cells express private T cell receptors and display equivalent functional properties in T1D and healthy individuals. Ex vivo analyses further revealed that CD8+ T cells reactive to ZnT8186–194 and other islet epitopes circulate at similar frequencies and exhibit a predominantly naïve phenotype in age-matched T1D and healthy donors. Higher frequencies of ZnT8186–194-reactive CD8+ T cells with a more antigen-experienced phenotype were detected in children versus adults, irrespective of disease status. Moreover, some ZnT8186–194-reactive CD8+ T cell clonotypes were found to cross-recognize a Bacteroides stercoris mimotope. Whereas ZnT8 was poorly expressed in thymic medullary epithelial cells, variable thymic expression levels of islet antigens did not modulate the peripheral frequency of their cognate CD8+ T cells. In contrast, ZnT8186–194-reactive cells were enriched in the pancreata of T1D patients versus nondiabetic and type 2 diabetic individuals. Thus, islet-reactive CD8+ T cells circulate in most individuals but home to the pancreas preferentially in T1D patients. We conclude that the activation of this common islet-reactive T cell repertoire and progression to T1D likely require defective peripheral immunoregulation and/or a proinflammatory islet microenvironment. [ABSTRACT FROM AUTHOR]

Individuals exposed to Mycobacterium tuberculosis (Mtb) may be infected and remain for the entire life in this condition defined as latent tuberculosis infection (LTBI) or develop active tuberculosis (TB). Among the multiple factors governing the outcome of the infection, dendritic cells (DCs) play a major role in dictating antibacterial immunity. However, current knowledge on the role of the diverse components of human DCs in shaping specific T-cell response during Mtb infection is limited. In this study, we performed a comparative evaluation of peripheral blood circulating DC subsets as well as of monocyte-derived Interferon-α DCs (IFN-DCs) from patients with active TB, subjects with LTBI and healthy donors (HD). The proportion of circulating myeloid BDCA3+ DCs (mDC2) and plasmacytoid CD123+ DCs (pDCs) declined significantly in active TB patients compared to HD, whereas the same subsets displayed a remarkable activation in LTBI subjects. Simultaneously, the differentiation of IFN-DCs from active TB patients resulted profoundly impaired compared to those from LTBI and HD individuals. Importantly, the altered developmental trait of IFN-DCs from active TB patients was associated with down-modulation of IFN-linked genes, marked changes in molecular signaling conveying antigen (Ag) presentation and full inability to induce Ag-specific T cell response. Thus, these data reveal an important role of IFN-α in determining the induction of Mtb-specific immunity. [ABSTRACT FROM AUTHOR]

Background: Multiorgan dysfunction syndrome contributes to adverse outcomes in advanced heart failure (AdHF) patients after mechanical circulatory support (MCS) implantation and is associated with aberrant leukocyte activity. We tested the hypothesis that preoperative peripheral blood mononuclear cell (PBMC) gene expression profiles (GEP) can predict early postoperative improvement or non-improvement in patients undergoing MCS implantation. We believe this information may be useful in developing prognostic biomarkers. Methods & design: We conducted a study with 29 patients undergoing MCS-surgery in a tertiary academic medical center from 2012 to 2014. PBMC samples were collected one day before surgery (day -1). Clinical data was collected on day -1 and day 8 postoperatively. Patients were classified by Sequential Organ Failure Assessment score and Model of End-stage Liver Disease Except INR score (measured eight days after surgery): Group I = improving (both scores improved from day -1 to day 8, n = 17) and Group II = not improving (either one or both scores did not improve from day -1 to day 8, n = 12). RNA-sequencing was performed on purified mRNA and analyzed using Next Generation Sequencing Strand. Differentially expressed genes (DEGs) were identified by Mann-Whitney test with Benjamini-Hochberg correction. Preoperative DEGs were used to construct a support vector machine algorithm to predict Group I vs. Group II membership. Results: Out of 28 MCS-surgery patients alive 8 days postoperatively, one-year survival was 88% in Group I and 27% in Group II. We identified 28 preoperative DEGs between Group I and II, with an average 93% prediction accuracy. Out of 105 DEGs identified preoperatively between year 1 survivors and non-survivors, 12 genes overlapped with the 28 predictive genes. Conclusions: In AdHF patients following MCS implantation, preoperative PBMC-GEP predicts early changes in organ function scores and correlates with long-term outcomes. Therefore, gene expression lends itself to outcome prediction and warrants further studies in larger longitudinal cohorts. [ABSTRACT FROM AUTHOR]

Systemic immune defects that are associated with disease progression exist in a variety of malignancies. γδ T cells are innate‑like lymphocytes that do not require self‑major histocompatibility complex‑restricted priming. Ex vivo‑expanded circulating γδ T cells exhibit promising antitumor activity and are a potential candidate for the treatment of various malignancies, including non‑small cell lung cancer (NSCLC). In the present study, flow cytometry was used as a method to study the phenotypes and characteristics of γδ T cells. A lower frequency of circulating γδ T cells was observed in NSCLC patients than in healthy controls. In advanced NSCLC patients, γδ T cells were also detected in the pleural effusion, but the frequency of γδ T cells here was significantly lower than in the peripheral blood. Vδ1+and Vδ1‑Vδ2‑ T cells represented the most enriched subsets in the pleural effusion. Moreover, the present study demonstrated that Vδ1+ T cells are a type of γδ T cells characterized by a cluster of differentiation (CD)3dim T‑cell receptor (TCR)γδbright phenotype, whereas Vδ2+ T cells represent a CD3brightTCRγδdim phenotype, according to the fluorescence intensity of CD3 and γδTCR using flow cytometry. Finally, the present study reported a decrease in the expression of CD27 and CD28 molecules on the surface of circulating γδ T cells in NSCLC. The present data suggest the existence of a dysregulated repertoire of γδ T cells in NSCLC, which exhibit impaired activation and a reformed cytokine‑releasing profile. Although the ex vivo expansion of γδ T cells may be a prospective therapeutic strategy in NSCLC patients, it remains necessary to clarify which subsets (Vδ1 or Vδ2) should be expanded and the sources from which γδ T cells should be generated. [ABSTRACT FROM AUTHOR]

Myeloid derived suppressor cells (MDSCs), which suppress anti-tumor or anti-viral immune responses, are expanded in the peripheral blood and tissues of patients/animals with cancer or viral infectious diseases. We here show that in chronic SIV infection of Indian rhesus macaques, the frequency of MDSCs in the bone marrow (BM) was paradoxically and unexpectedly decreased, but increased in peripheral blood. Reduction of BM MDSCs was found in both CD14+MDSC and Lin-CD15+MDSC subsets. The reduction of MDSCs correlated with high plasma viral loads and low CD4+ T cell counts, suggesting that depletion of BM MDSCs was associated with SIV/AIDS disease progression. Of note, in SHIVSF162P4-infected macaques, which naturally control viral replication within a few months of infection, the frequency of MDSCs in the bone marrow was unchanged. To investigate the mechanisms by which BM MDSCs were reduced during chronic SIV infection, we tested several hypotheses: depletion due to viral infection, alterations in MDSC trafficking, and/or poor MDSC replenishment. We found that the possible mobilization of MDSCs from BM to peripheral tissues and the slow self-replenishment of MDSCs in the BM, along with the viral infection-induced depletion, all contribute to the observed BM MDSC reduction. We first demonstrate MDSC SIV infection in vivo. Correlation between BM CD14+MDSC reduction and CD8+ T cell activation in tissues is consistent with decreased immune suppression by MDSCs. Thus, depletion of BM MDSCs may contribute to the pathologic immune activation during chronic SIV infection and by extension HIV infection. [ABSTRACT FROM AUTHOR]

Problem Vγ9Vδ2 T cells (γ9δ2) are involved in antibacterial immune responses. The aim of this study was to look for associations between peripheral blood (PB) γ9δ2 T cells and cervix/vaginal Chlamydia trachomatis ( Ct) infection in women with recurrent spontaneous abortions ( RSA). Method of study Peripheral blood samples were obtained from 201 RSA women within 10 days after they experienced a new miscarriage. γ9δ2 T cells and their percentage in total γδ T cells were compared between women who had been found and women who had not been found infected with Ct (last 6 months). Fertile women (82) served as control subjects. Results The difference of mean percentages of γ9δ2 T cells between the abortion and control groups, and the Chlamydia (+) and Chlamydia (−) groups was highly statistically significant ( P<.00001). Significant difference was also found between the Chlamydia (+) and Chlamydia (−) group and the control group ( ANOVA). Conclusion The measurement of γ9δ2T cells may be useful to suspect possibly undiagnosed chlamydial infection in RSA women. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the hypothesis of increased mobilization of senescent T cells to the peripheral blood induced by exercise. The systematic survey of indexed empirical studies was conducted in PubMed and ScienceDirect databases using the keywords: "exercise", "exercise-induced mobilization of T lymphocytes", "exercise-induced mobilization of CD8", "immune space", "senescent T-cell mobilization", "naive T-cell repertoire", "senescent T-cell repertoire". The main criterion was the mobilization of senescent T lymphocytes after exercise. After search, 442 studies (PUBMED = 99 studies; ScienceDirect = 343 studies) were found and six met all the criteria for inclusion in the meta- analysis. The studies that met the inclusion criteria were assessed for methodological quality with the PEDro scale. Data were analyzed using Comprehensive Meta-analysis software. The difference between the standard errors of the mean (Std diffin means), the confidence interval (95 % CI), and P and Z scores (Z-value and P-value) were calculated. In conclusion, acute exercise mobilizes a population of CD8 + T-cells exhibiting a senescent phenotype into the peripheral blood compartment. It is possible that this mobilization induces apoptosis of these cells and create a vacant space for the production of naive T cells. [ABSTRACT FROM AUTHOR]

Our previous studies showed that α7 nicotinic acetylcholine receptor (nAchR) agonist nicotine has stimulatory effects on murine bone marrow-derived semimature DCs, but the effect of nicotine on peripheral blood mononuclear cell- (PBMC-) derived human semimature dendritic cells (hu-imDCs) is still to be clarified. In the present study, hu-imDCs (cultured 4 days) were conferred with ex vivo lower dose nicotine stimulation and the effect of nicotine on surface molecules expression, the ability of cross-presentation, DCs-mediated PBMC priming, and activated signaling pathways were determined. We could demonstrate that the treatment with nicotine resulted in increased surface molecules expression, enhanced hu-imDCs-mediated PBMC proliferation, upregulated release of IL-12 in the supernatant of cocultured DCs-PBMC, and augmented phosphorylation of Akt and ribosomal protein S6. Nicotine associated with traces of LPS efficiently enhanced endosomal translocation of internalized ovalbumin (OVA) and increased TAP-OVA colocalization. Importantly, the upregulation of nicotine-increased surface molecules upregulation was significantly abrogated by the inhibition of Akt kinase. These findings demonstrate that ex vivo nicotine stimulation augments hu-imDCs surface molecules expression via Akt-S6 pathway, combined with increased Ag-presentation result in augmented efficacy of DCs-mediated PBMC proliferation and Th1 polarization. [ABSTRACT FROM AUTHOR]

Drug resistance and immune deficiency are important factors for the poor prognosis of lung carcinoma. The present study explored the possible protective effect of immune reconstitution from peripheral blood mononuclear cells (PBMCs) on multi-drug-resistant human lung carcinoma Am1010 cells in non-obese diabetic/severe combined immunodeficient (NOD/SCID) mice. The inoculated tumor fragments grew rapidly in the NOD/SCID mice. The growth was significantly inhibited by intraperitoneal injection of PBMCs. In the mice injected with PBMCs, numerous CD3+ and CD8+ cells, but less CD4+ cells, were found in spleen and tumor tissues. These data suggest that PBMC transplantation inhibits lung carcinoma progression via the reconstitution of the immune system, particularly of cytotoxic T lymphocytes. [ABSTRACT FROM AUTHOR]

This prospective cohort study is to verify the hypothesis that the balance of Th17 and Treg cells frequencies in the peripheral circulation is disturbed in patients with varying degrees of connective tissue diseases-associated pulmonary arterial hypertension (CTD-aPAH) and to prove the influence ofTh17/Treg imbalance on prognosis.We detected the frequencies and absolute counts of Th17 and Treg cells and related serumcytokines secretion and expressions of key transcription factors in 117 patients with connective tissue diseases (CTD), 53 patients with CTD-aPAH, and 48 healthy volunteers. Moreover, the median value according to levels of Th17/Treg ratios in patients with CTD-aPAH was chosen as basis of group division for survival analysis. CTD-aPAH patients revealed significant increase in peripheral Th17 cells, Th17-related cytokines, and ROR γt mRNA levels.They also presented a significant decrease in Treg cells, Treg-related cytokines, and Foxp3 mRNA levels as compared with CTD patients and healthy controls. More importantly, the Th17/Treg ratio was significantly related to the severity and prognosis of CTD-aPAH. This study indicated that theTh17/Treg axis disorder plays a critical role in CTD-aPAH. Furthermore, the dynamic balance between Th17 and Treg cells was likely to influence prognosis of patients with CTD-aPAH. [ABSTRACT FROM AUTHOR]

Abstract: The proportions of CD4+, CD8+ and WC1+ T lymphocytes from peripheral blood using flow cytometry were investigated in goats infected with Fasciola hepatica and previously immunised with recombinant Cathepsin-L1 (rCL1) and Glutathione-S-transferase sigma class (GST). The immunisation trial did not induce protective responses, and no significant differences were recorded between immunised and non-immunised groups. However, there was a significant decrease in the proportion of CD4+ T lymphocytes in the infected groups both at 5 weeks post-infection (wpi), coinciding with the migratory stage of the infection, and at 12wpi in the biliary stage of the infection. The proportional decrease in this circulating population may be related to the recruitment of CD4+ T cells in liver and hepatic lymph nodes and also to the immunomodulatory effect of the parasite through the interaction of F. hepatica excretory–secretory products (FhESP) with this cell population. To date, this is the first report about the effect of F. hepatica infection in peripheral lymphocyte subsets in goats. [Copyright &y& Elsevier]

T lymphocytes expressing the CLA antigen constitute a subset of effector memory lymphocytes that are functionally involved in T-cell-mediated cutaneous diseases. Skin-seeking lymphocytes recirculate between inflamed skin and blood during cutaneous inflammation. Many studies in different T-cell-mediated inflammatory cutaneous diseases have clearly related their pathologic mechanisms to CLA+ T cells. Based on common features of these cells in different cutaneous disorders mediated by T cells, we propose that circulating CLA+T cells could constitute very useful peripheral cellular biomarkers for T-cell-mediated skin diseases. [ABSTRACT FROM AUTHOR]

This study aims to explore the changes and clinical significances of T helper 17 (Th17) cells in the peripheral blood of patients with acute cerebral hemorrhage. The percentage of Th17 cells were assessed by flow cytometry. The mRNA levels of retinoid-related orphan receptor γt (RORγt) were detected by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). The serum levels of interleukin-17 (IL-17) were measured by enzyme-linked immunosorbent assay (ELISA). According to the examination results, the percentage of Th17 cells, the mRNA expression of RORγt and the serum levels of IL - 17 at 24 h, 3 d and 7 d increased significantly in patients with acute cerebral hemorrhage than in normal controls (P = 0.000, for all). Although the patients with acute cerebral hemorrhage had no significant differences in the percentage of Th17 cells, the mRNA expression of ROR γ t comparable with normal controls (P = 0.058, 0.239), the serum levels of IL-17 in patients were statistically higher than those in normal controls at 14 d (P = 0.000). The percentage of Th17 cells and the serum levels of IL-17 increase in the peripheral blood of patients with acute cerebral hemorrhage, suggesting Th17 cells may participate in the occurrence and development of cerebral hemorrhage. [ABSTRACT FROM AUTHOR]

Abstract: The therapeutic efficacy of allogeneic peripheral blood stem cell transplantation (PBSCT) for hematological malignancies relies largely on the graft-versus-leukemia (GVL) effects exerted by the donor CD3 cells, but there is a risk of onset of uncontrolled graft-versus-host disease (GVHD). Regulatory T cells (Tregs) (CD4+CD25high Foxp3+) are believed to maintain tolerance and to inhibit acute GVHD (aGVHD) after allogeneic PBSCT. Nevertheless, when looking at post-allotransplantation patient outcomes, although the impact of aGVHD on survival is amply documented, so far there is no evidence that the donor graft CD3/Tregs ratio may affect overall survival (OS), nonrelapse mortality (NRM), disease-free survival (DFS), and relapse rates. Our aim was to study the possible impact of the gCD3/Tregs ratio on survival after myeloablative allogeneic PBSCT. We analyzed 74 consecutive patients diagnosed with acute myeloid leukemia (n = 62), acute lymphoblastic leukemia (n = 10), and chronic myeloid leukemia (n = 2) who underwent transplantation with unmanipulated PBSCs from a human leukocyte antigen–identical related donor (n = 48) or a human leukocyte antigen–identical unrelated donor (n = 26). Patients were subdivided into a high gCD3/Tregs ratio (≥36) group (HR group, n = 30) and a low gCD3/Tregs ratio (<36) group (LR group, n = 44). The OS, DFS, NRM, and relapse rates at 3 years were 53%, 51%, 29%, and 34%, respectively. Comparing the LR and HR groups, a statistically significant difference was demonstrated for the 3-year OS, DFS, and NRM rates (65% vs 31%, P = .0001; 67 versus 26%, P = .0001; 5% versus 71%, P < .0001, respectively) but not for relapse (30% vs 25%, P = ns). By multivariate analysis, LR significantly predicted better OS (P = .019), DFS (P = .003), and NRM (P = .05), whereas there was no statistically significant association between LR and relapse (P = .155). Overall, our data may suggest that LR preserves GVL effects but is also protective against aGVHD in allotransplantation patients. [Copyright &y& Elsevier]