Lymphocyte Populations Research Articles

Fecal microbiota transplantation from protozoa-exposed donors downregulates immune response in a germ-free mouse model, its role in immune response and physiology of the intestine.

Intestinal parasites are part of the intestinal ecosystem and have been shown to establish close interactions with the intestinal microbiota. However, little is known about the influence of intestinal protozoa on the regulation of the immune response. In this study, we analyzed the regulation of the immune response of germ-free mice transplanted with fecal microbiota (FMT) from individuals with multiple parasitic protozoans (P) and non-parasitized individuals (NP). We determined the production of intestinal cytokines, the lymphocyte populations in both the colon and the spleen, and the genetic expression of markers of intestinal epithelial integrity. We observed a general downregulation of the intestinal immune response in mice receiving FMT-P. We found significantly lower intestinal production of the cytokines IL-6, TNF, IFN-γ, MCP-1, IL-10, and IL-12 in the FMT-P. Furthermore, a significant decrease in the proportion of CD3+, CD4+, and Foxp3+ T regulatory cells (Treg) was observed in both, the colon and spleen with FMT-P in contrast to FMT-NP. We also found that in FMT-P mice there was a significant decrease in tjp1 expression in all three regions of the small intestine; ocln in the ileum; reg3γ in the duodenum and relmβ in both the duodenum and ileum. We also found an increase in colonic mucus layer thickness in mice colonized with FMT-P in contrast with FMT-NP. Finally, our results suggest that gut protozoa, such as Blastocystis hominis, Entamoeba coli, Endolimax nana, Entamoeba histolytica/E. dispar, Iodamoeba bütschlii, and Chilomastix mesnili consortia affect the immunoinflammatory state and induce functional changes in the intestine via the gut microbiota. Likewise, it allows us to establish an FMT model in germ-free mice as a viable alternative to explore the effects that exposure to intestinal parasites could have on the immune response in humans.

Functional genomics implicates natural killer cells in the pathogenesis of ankylosing spondylitis

Multiple lines of evidence indicate that ankylosing spondylitis (AS) is a lymphocyte-driven disease. However, which lymphocyte populations are critical in AS pathogenesis is not known. In this study, we aimed to identify the key cell types mediating the genetic risk in AS using an unbiased functional genomics approach. We integrated genome-wide association study (GWAS) data with epigenomic and transcriptomic datasets of human immune cells. To quantify enrichment of cell type-specific open chromatin or gene expression in AS risk loci, we used three published methods - LDSC-SEG, SNPsea, scDRS - that have successfully identified relevant cell types in other diseases. Natural killer (NK) cell-specific open chromatin regions are significantly enriched in heritability for AS, compared to other immune cell types such as T cells, B cells, and monocytes. This finding was consistent between two AS GWAS. Using RNA-seq data, we validated that genes in AS risk loci are enriched in NK cell-specific gene expression. Using the human Space-Time Gut Cell Atlas, we also found significant upregulation of AS-associated genes predominantly in NK cells. We performed co-localization analyses between GWAS risk loci and genetic variants associated with gene expression (eQTL) to find putative target genes. This revealed four AS risk loci affecting regulation of candidate target genes in NK cells: two known loci, ERAP1 and TNFRSF1A, and two under-studied loci, ENTR1 (aka SDCCAG3) and B3GNT2. Our findings suggest that NK cells may play a crucial role in AS development and highlight four putative target genes for functional follow-up in NK cells.

The myocardium of human dilated nonischemic cardiomyopathy harbors unique tissue-resident lymphocyte subsets

Abstract Purpose The etiology of dilated nonischemic cardiomyopathy (NICM) is often unclear, but thought to be multifactorial, involving an interplay between genetic factors and direct myocardial damage caused by infection, autoimmunity, or toxins. Tissue-resident lymphocytes are non-circulating immune cells which are retained within various tissues and play integral roles in maintaining homeostasis, responding to infection, regulating inflammation, and mediating tissue repair. Despite their likely involvement in various cardiac pathologies, the presence of tissue-resident lymphocytes in the human heart has not yet been well-characterized, neither in health nor in disease. Methods Human left ventricular tissue and paired peripheral blood samples were obtained from six adult organ donors with normal heart function who died of noncardiac causes and from the explants of six adult patients with end-stage nonischemic cardiomyopathy. Heart tissue was processed using mechanical and enzymatic digestion. Mononuclear cells were isolated from both heart and paired blood by density centrifugation. Isolated mononuclear cells were surface stained with an antibody cocktail and interrogated using multidimensional flow cytometry. Results The adult human heart contains a diverse immune cell population (Fig 1A). Both healthy and NICM cardiac lymphocytes express distinct phenotypic profiles which resemble those of resident lymphocytes found across various tissues, distinct from those isolated from paired blood. Frequencies of effector memory T (Tem) cells (CD45RA- CCR7-) were higher in heart than in blood among both CD4+ and CD8+ T-cells. In heart compared to blood, significantly more Tem expressed CD69, a canonical marker of tissue-resident memory T (Trm) cells (Fig 1B). Cardiac Trm, especially CD8+ Trm, expressed classical Trm signature markers including integrins CD103 (epithelial binding) and CD49a (collagen binding). NICM Trm expressed more CD49a than healthy heart Trm (Fig 1C). NK-cells also demonstrated higher CD69 expression (trNK) in heart than in blood, with associated expression of CD103, CD49a, and CXCR6 (Fig 1D). Compared to healthy hearts, NICM trNK were predominantly CD56bright/CD16- (Fig 1E and 1F) and expressed less CD57 (Fig 1D), overall indicating a less mature state with lower cytotoxic potential. Confocal imaging of cardiac tissue revealed CD69-expressing tissue-resident lymphocytes within the cardiac interstitium. Conclusions The adult human heart contains diverse populations of lymphocytes which express canonical markers of tissue residency, similar to lymphocytes resident in other tissues. Compared to healthy hearts, NICM hearts have more CD49a+ Trm, perhaps related to greater fibrosis, and also harbor a distinct subset of immature tissue-resident NK cells which may shed light on pathophysiology. Future work is focused on better exploring the functional phenotypes of these resident cells and better localizing them within the myocardium.FA - Figure 1

Immune system dysfunction in personnel of chemical hazard facilities: purpose and effectiveness of immunotherapeutic drugs

Clinical signs of the presence of immune dysfunction/insufficiency, identified by questioning workers at the landfill for the storage and destruction of industrial toxic waste, were the basis for performing a screening study of immune status. This included a clinical blood test with determination of the leukocyte formula, assessment of the phenotypic status of lymphocytes for the main subpopulations, determination of the concentration in serum immunoglobulins of various classes, assessment of the migration activity of leukocytes, assessment of the microbicidal capacity of neutrophils and their ability to phagocytosis. When the examined employees were found to have more than 20% changes in the normative range of immune status parameters and the presence of combined disorders in different parts of immunoreactivity, in particular combined disorders in the cellular part of the immune system, it was the basis for conducting an in-depth stage of immunoepidemiological examination. This included determination of functional activity cellular elements of the adaptive component of immunity, assessment of the severity of autosensitization, assessment of the severity and specificity of atopic hypersensitization, assessment of cytokine status in normal conditions and in response to mitogen. When assessing the phenotypic status of immunoreactivity cells, it turned out that the absolute number of T lymphocytes (CD3+ phenotype), helper T lymphocytes (CD3+CD4+ phenotype) and killer T lymphocytes (CD3+CD8+ phenotype) was significantly reduced in the peripheral blood of test site employees (p ≤ 0.05, compared with similar indicators in the control group). On the contrary, the content of NK cells (CD3-CD56+ phenotype) tended to increase (both the absolute number and the proportion among other lymphocyte populations). Dysfunction of the cellular component of humoral immunoreactivity (a significant decrease in the absolute number of lymphocytes with the CD3-CD20+ phenotype [B lymphocytes] in the peripheral blood), as well as a significant increase in the concentration of serum IgA-class immunoglobulin and pronounced disimmunoglobulinemia in the serum of the examined individuals (compared to individuals in the control group ) indicated a predominantly inhalation method of exposure to immunotoxic industrial toxicants from the landfill on the immune system. Pathogenetically targeted immune-oriented therapy for the personnel of the test site was carried out with drugs that have thymomimetic activity (cytovir-3, thymogen) and are a means of replacement immunocorrection with a cytokine drug (genetically engineered recombinant yeast IL-2 [roncoleukin]). The established effectiveness of the immunotherapy, in particular the reduction in the incidence rate of various nosological forms of immune-related pathology among the site employees who received immunotherapy and the presence of an immunocorrective effect in the immunoactive drugs used for therapy, indicate the advisability of carrying out preventive medical measures in persons professionally exposed to xenobiotic influences as a component of improving medical provision.

Regulator of G-Protein Signaling 2 Knockout in CD4+ T Cells Promotes Anti-Inflammatory T Cells, Enhancing Ovulation, and Oocyte Yield.

To determine the downstream effects on ovarian function and immune cell differentiation in the ovary and uterus using a model in which RGS2 was knocked out specifically in CD4+ T cells. Laboratory based experiments with female mice. Female congenic (fully backcrossed) and non-congenic (mixed strain) mice with CD4 T cell-specific RGS2 knockout. Four-week-old female CD4 RGS2 knockout (CD4 RGS2 KO ) mice and their littermate controls (CD4 RGS2 CTL ) were subjected to superovulation using pregnant mare serum gonadotropins. Oocyte numbers, lymphocyte populations in the ovary and uterus, and serum estradiol and progesterone concentrations. In non-congenic (mixed strain) mice, CD4 RGS2 knockout (KO) promoted higher oocyte ovulation and increased uterine total leukocyte numbers. Similarly, congenic (fully backcrossed strain) mice showed higher oocyte numbers and increased uterine total leukocytes in the CD4 RGS2 KO mice compared to CD4 RGS2 CTL mice. Pro-inflammatory CD4+ T helper (T H ) 1 and T H 17 cell frequencies in the ovary and uterus were unchanged, while Treg and T H 2 cell frequencies were elevated, along with increased concentrations of estradiol and progesterone in the serum of CD4 RGS2 KO mice. Our study highlights the important role of RGS2 in CD4+ T cells within the context of reproduction. The dysregulation of immune responses due to RGS2 knockout in CD4+ T cells appears to enhance oocyte production. Further research is warranted to elucidate the precise mechanisms by which RGS2 influences reproductive outcomes, including its impact on fecundability, endometrial receptivity, and successful implantation.

Antigen specificity of clonally-enriched CD8+ T cells in multiple sclerosis.

CD8+ T cells are the dominant lymphocyte population in multiple sclerosis (MS) lesions where they are highly clonally expanded. The clonal identity, function, and antigen specificity of CD8+ T cells in MS are not well understood. Here we report a comprehensive single-cell RNA-seq and T cell receptor (TCR)-seq analysis of the cerebrospinal fluid (CSF) and blood from a cohort of treatment-naïve MS patients and control participants. A small subset of highly expanded and activated CD8+ T cells were enriched in the CSF in MS that displayed high activation, cytotoxicity and tissue-homing transcriptional profiles. Using a combination of unbiased and targeted antigen discovery approaches, MS-derived CD8+ T cell clonotypes recognizing Epstein-Barr virus (EBV) antigens and multiple novel mimotopes were identified. These findings shed vital insight into the role of CD8+ T cells in MS and pave the way towards disease biomarkers and therapeutic targets.

Composite Lymphoma Comprising of BCL2 Rearrangement Negative, CD23 Positive Follicle Center Cell Lymphoma and Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma: A Case Report

Abstract Introduction/Objective BCL2 rearrangement negative, CD23-positive follicle center cell lymphoma (BCL2 neg CD23 pos FCL) is a rare, recently described provisional entity in International Consensus Classification (2022). It has a predominantly diffuse growth pattern and often involves inguinal region. The molecular profile includes a high frequency of STAT6 and CREBBP co-mutation as well as 1q gain and a recurrent 1p36 loss/TNFRS14 abnormalities. We describe a composite tumor comprising of a rare entity BCL2 neg CD23 pos FCL and Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL). To the best of our knowledge this is the first reported case description of this co-occurrence. Methods/Case Report A 59 y/o woman presented with right cervical and axillary lymphadenopathy (upto 1.6 cm). Sections showed partial effacement of nodal architecture by interfollicular and diffuse proliferation of atypical lymphoid cells. The interfollicular areas were comprised of a monotonous population of small lymphocytes. Immunohistochemical stains performed showed that the interfollicular CD20+ PAX5+ atypical lymphoid cells coexpressed CD5, CD23, BCL2 and LEF1 and were negative for CD10, BCL6, CD3, and SOX11, with MIB1 of 5-10%. Based on these, a diagnosis of CLL/SLL was made. Admixed with the CLL/SLL, a second neoplastic B-cell component that distorted nodal architecture was also identified. It composed of a diffuse proliferation of intermediate sized lymphoid cells with a centrocytic/centroblastic morphology. This smaller population of small to intermediate sized B cells expressed CD10, BCL6, and CD23 with a MIB1 proliferation index of ~30%. This population was CD5 and BCL2 negative. CD21 showed residual follicular dendritic cell meshworks. SOX11 and BCL1 were negative. Therefore, a diagnosis of BCL2 neg CD23 pos FCL was made. Flow cytometry showed two distinct populations of monotypic B-cells, one CD5-positive and the other CD10-positive. FISH studies were negative for BCL2 and BCL6 rearrangements as well as del1p36. Cytogenetics was positive for trisomy 12, supporting CLL/SLL. Next Generation Sequencing showed Tier 1 / 2 mutations in STAT6, TNFRSF14, CREBBP, and FOXO1, supporting BCL2 neg CD23 pos FCL. Hence, this represents a unique case of composite CLL/SLL and BCL2 neg CD23 pos FCL. B cell gene rearrangement showed 2 distinct clones confirming 2 separate B cell lymphomas. Results (if a Case Study enter NA) NA Conclusion Here, we describe a composite CLL/SLL and BCL2 rearrangement negative, CD23 positive, FCL never previously described in literature.

T-cell Clonality in Pleomorphic Dermal Sarcoma in Male Veterans: A Report of 2 Cases and a Review of the Literature.

The standard treatment of choice for pleomorphic dermal sarcoma (PDS), a relatively uncommon soft tissue sarcoma and 1 morphologically similar to atypical fibroxanthoma, is wide local excision with close clinical follow-up. Studies regarding management of advanced/metastatic PDS with immune checkpoint inhibitors are limited as most STSs have historically been viewed as being immunologically inert. Contradicting this belief, in this report, we describe 2 cases of PDS with a robust host response. Histopathology of both cases revealed a dermal neoplasm comprising mitotically active, pleomorphic, spindled-to-ovoid cells, which were immunohistochemically negative for keratinocytic, melanocytic, and smooth muscle markers. An unusual feature in both cases was the presence of a brisk host response. Additional workup of the infiltrating lymphocyte population revealed an abnormal CD4:CD8 ratio in both cases, with the proportion of CD8+ lymphocytes surpassing (case 1) and equaling (case 2) that of the CD4+ T-lymphocyte population. The increased proportion of CD8+ lymphocytes prompted the additional workup of TCR gene rearrangement, which revealed a clonal population of T lymphocytes in both cases. The robust and clonal T-lymphocyte host response in both of our cases suggests that PDS appears to fit the classic model of an inflammatory-type tumor and may be a candidate for checkpoint inhibition. Future work includes additional reports of cases of PDS with an infiltrating clonal T-lymphocyte population and detailing the function and specificity of the infiltrating T lymphocytes to ascertain whether they have the potential to recognize and lyse the tumors they colonize.

Protective Effects of a Dihydrodiazepine Against Endotoxin Shock Through Suppression of TLR4/NF-κB/IRF3 Signaling Pathways.

Sepsis and septic shock are life-threatening systemic inflammatory conditions and among the most frequent causes of morbidity and mortality globally. Preclinical evidence has identified a number of diazepine-based compounds with therapeutic potential in inflammatory diseases. However, the potential anti-inflammatory properties of diazepines in the overwhelming immune response during sepsis have been rarely examined. Thus, the current study aimed to identify a new diazepine compound with therapeutic potential in sepsis. Assessing the inflammatory response of macrophages to Lipopolysaccharides (LPS) in vitro identified 2-[7-(trifluoromethyl)-2,3-dihydro-1H-1,4-diazepin-5-yl]phenol (2-TDDP) as a potential anti-inflammatory agent. It reduced secretion of Interleukin-1β (IL-1β), IL-6, IL-12p70, IL-18, Tumor necrosis factor-α (TNF-α), Interferon-γ (IFN-γ), IFN-β, and increased the secretion of IL-10. In a mouse model of LPS-induced endotoxin shock, 2-TDDP reduced mortality and attenuated inflammation-induced tissue injury in the spleen, liver, kidney, and lung. This was accompanied by reduced serum levels of IL-1β, IL-6, IL-12p70, TNF-α, IFN-γ, IFN-β, and increased levels of IL-10. Importantly, 2-TDDP suppressed the Toll-like receptor 4 (TLR4)/Nuclear factor-κB (NF-κB) and TLR4/Interferon regulatory factor 3 (IRF3) signaling pathways through a reduction in the expression of TLR4, Myeloid differentiation primary response 88 (MyD88), P65, and TNF receptor-associated factor 3 (Traf3). Moreover, 2-TDDP suppressed the expression of CD86, Programmed death-ligand 1 (PD-L1) and C5a receptor (C5aR), but not Major histocompatibility complex II (MHCII). Analysis of splenic lymphocyte populations revealed a decrease in the number of CD4+, CD8+, and B cells. Collectively, these findings introduced the dihydrodiazepine 2-TDDP as a new anti-inflammatory agent with potent therapeutic potential in endotoxin shock, paving an avenue for future clinical application.

Pink1/Parkin deficiency alters circulating lymphocyte populations and increases platelet-T cell aggregates in rats

Parkinson’s disease (PD) is the most common progressive neurodegenerative movement disorder and results from the selective loss of dopaminergic neurons in the substantia nigra pars compacta. Pink1 and Parkin are proteins that function together in mitochondrial quality control, and when they carry loss-of-function mutations lead to familial forms of PD. While much research has focused on central nervous system alterations in PD, peripheral contributions to PD pathogenesis are increasingly appreciated. We report Pink1/Parkin regulate glycolytic and mitochondrial oxidative metabolism in peripheral blood mononuclear cells (PBMCs) from rats. Pink1/Parkin deficiency induces changes in the circulating lymphocyte populations, namely increased CD4 + T cells and decreased CD8 + T cells and B cells. Loss of Pink1/Parkin leads to elevated platelet counts in the blood and increased platelet-T cell aggregation. Platelet-lymphocyte aggregates are associated with increased thrombosis risk suggesting targeting the Pink1/Parkin pathway in the periphery might have therapeutic potential.

Myeloid deficiency of heparan sulfate 6-O-endosulfatases impairs bone marrow hematopoiesis

The heparan sulfate (HS) 6-O-endosulfatases or the Sulfs (Sulf1 and Sulf2) are the only known enzymes that can modify HS sulfation status extracellularly and have been shown to regulate diverse biological processes. The role of the Sulfs in bone marrow (BM) hematopoiesis is not known. In this study, we generated a novel mouse line with myeloid-specific deletion of the Sulfs by crossing Sulf1/2 double floxed mice with the LysM-cre line. The LysM-Sulf knockout (KO) male mice exhibited age-dependent expansion of hematopoietic stem cells and the granulocyte-monocyte lineages in the BM, whereas common lymphoid progenitors and B lymphocyte populations were significantly reduced. Although megakaryocytic and erythroid progenitors were not reduced in the BM, the LysM-Sulf KO males suffered age-dependent reduction of red blood cells (RBCs) and platelets in the peripheral blood, suggesting that the production of RBCs and platelets was arrested at later stages. In addition, LysM-Sulf KO males displayed progressive splenomegaly with extramedullary hematopoiesis. Compared to males, LysM-Sulf KO females exhibited a much-reduced phenotype, and ovariectomy had little effect. Mechanistically, reduced TGF-β/Smad2 but enhanced p53/p21 signaling were observed in male but not female LysM-Sulf KO mice. Finally, HS disaccharide analysis via LC-MS/MS revealed increased HS 6-O-sulfation in the BM from both male and female LysM-Sulf KO mice, however, the distribution of 6-O-sulfated motifs were different between the sexes with compensatory increase in Sulf1 expression observed only in LysM-Sulf KO females. In conclusion, our study reveals that myeloid deficiency of the Sulfs leads to multilineage abnormalities in BM hematopoiesis in an age- and sex-dependent manner.

Helios-Illuminating the way for lymphocyte self-control.

Transcription factor Helios, encoded by the IKZF2 gene, has an important role in regulatory T cells by stabilizing their suppressive phenotype. While Helios is prominently expressed in regulatory T cells, its expression extends beyond to include effector T cells, follicular regulatory T cells, B cells, and innate-like lymphocyte populations. Recent characterizations of patients with inborn error of immunity due to damaging IKZF2 variants coupled with translational research on lymphocytes from healthy individuals, have increased our understanding on Helios' multifaceted role in controlling the human adaptive immune system. A less studied role for Helios beyond the stabilizing of regulatory T cells has emerged in directing effector T cell maturation. In the absence of functional Helios, effector T cells acquire more inflammatory phenotype and are prone to senescence. Loss of Helios expression disrupts the regulation of the germinal centre reaction, often resulting in either hypogammaglobulinemia or B cell autoimmunity. This review summarizes findings from studies in both mice and men offering a comprehensive understanding of the impact of the transcription factor Helios on the adaptive immune system.

Phenotypic heterogeneity of the B lymphocyte population in the context of post-traumatic stress disorder in veterans of modern wars

Post-traumatic stress disorder in combat veterans has certain characteristics common to combatants. B lymphocytes may aggravate neurocognitive impairment by demonstrating a significant proinflammatory tendency through the production of immunoglobulins and a number of proinflammatory factors. Objective: to study the phenotypic heterogeneity of B lymphocyte subpopulations in veterans with post-traumatic stress disorder. Studies were conducted in a cohort of veterans of the special military operation in Ukraine (SVO), including 26 combatants with clinically verified PTSD who made up the main (1) group, and 30 veterans were included in the comparison group (2). The diagnosis was verified on the basis of neuropsychological and pathopsychological examination. Determination of IL-10 levels (pg/mL) using a multiplex analysis on a Luminex Magpix 100 immunoanalyzer (USA) using the Bio-Plex multiplex analysis test system (MERZ, Germany) was performed. Gating of the B lymphocyte population was performed on a Navios flow cytofluorimeter (Beckman Coulter, USA) using a standardized technology for assessing the lymphocyte component of immunity. In the group of SVO veterans with PTSD, we showed an increase in blood cells with the CD45+CD3-CD19+CD5+ phenotype in comparison with the indicators of groups 2 and 3. B lymphocytes expressing the CD5+ marker are found in various human tissues and can also produce autoantibodies. Analysis of subpopulations of B lymphocytes with markers of memory cells showed a significant decrease in the blood of SVO veterans in the total number of memory B lymphocytes (CD45+CD3-CD19+CD27+), against the background of an increase in the concentration of cells positive for CD5 and CD27 with the phenotype CD45+CD3-CD19 +CD5+CD27+CD27+. B cells play a critical role in the mechanisms of intercellular interaction. The phenotypic diversity of B lymphocyte subpopulations that we have established in veterans with post-traumatic stress disorder is characterized by an increase in the circulation of B lymphocytes with CD5 and CD27 molecules, against the background of a general decrease in memory B cells. This indicates a possible autoimmune orientation of neuroinflammatory processes in the brain, associated both with a stress-induced increase in the permeability of the blood-brain barrier, and with the need to control excessive activation of immunocompetent cells.

Exploring CD26-/lo subpopulations of lymphocytes in asthma phenotype and severity: A novel CD4+ T cell subset expressing archetypical granulocyte proteins.

Asthma pathology may induce changes in naïve/memory lymphocyte proportions assessable through the evaluation of surface CD26 (dipeptidyl peptidase 4/DPP4) levels. Our aim was to investigate the association of asthma phenotype/severity with the relative frequency of CD26-/lo, CD26int and CD26hi subsets within different lymphocyte populations. The proportion of CD26-/lo, CD26int and CD26hi subsets within CD4+ effector T cells (Teff), total CD4- lymphocytes, γδ-T cells, NK cells and NKT cells was measured in peripheral blood samples from healthy (N = 30) and asthma (N = 119) donors with different phenotypes/severities by flow cytometry. We performed K-means clustering analysis and further characterised the CD4+CD26-/lo Teff cell subset by LC-MS/MS and immunofluorescence. Cluster analysis including clinical and flow cytometry data resulted in four groups, two of them with opposite inflammatory profiles (neutrophilic vs. eosinophilic). Neutrophilic asthma presented reduced CD4-CD26hi cells, which negatively correlated with systemic inflammation. Eosinophilic asthma displayed a general expansion of CD26-/lo subsets. Specifically, CD4+CD26-/lo Teff expansion was confirmed in asthma, especially in atopic patients. Proteomic characterisation of this subset with a TEM/TEMRA phenotype revealed upregulated levels of innate (e.g. MPO and RNASE2) and cytoskeleton/extracellular matrix (e.g. MMP9 and ACTN1) proteins. Immunofluorescence assays confirmed the presence of atypical proteins for CD4+ T cells, and an enrichment in 'flower-like' nuclei and MMP9/RNASE2 levels in CD4+CD26-/lo Teff compared to CD4+ T lymphocytes. There is an association between CD26 levels in different lymphocyte subsets and asthma phenotype/severity. CD4+CD26-/loTEMRA cells expressing innate proteins specific to eosinophils/neutrophils could be determinant in sustaining long-term inflammation in adult allergic asthma.

The role of immune factors in the development of preterm birth

Preterm birth (PB) carries a high risk of developing neuropsychological development disorders, cognitive and somatic problems in the child. The maternal immune system plays a critical role in maintaining a physiological pregnancy. However, specific mechanisms and disorders of pregnancy development have been little studied. There is a lack of research on the role of immune competent cell (ICC) activation in preterm labor leading to uterine contractility. Understanding the importance of immune system factors in the formation of preterm birth may allow the development of strategies to prolong pregnancy and, thus, lead to improved perinatal outcomes. The purpose of the work is to study the role of immune factors in the development of preterm birth. Seventy pregnant women in the third trimester with recurrent miscarriage (RPL) and 25 healthy pregnant women (control group) were examined. Observed pregnant women with RPL were divided into two groups: Group I – patients who gave birth prematurely (n = 30); and Group II – patients who gave birth at term (n = 40). The population and subpopulation composition of peripheral blood lymphocytes was studied by cytofluorimetry using monoclonal antibodies to: CD3, CD4, CD8, CD16, CD19 (JSC "Sorbent", Russia) (FITC), CD11b (Beckman Coulter, USA); CD14, CD25, CD69, CD71, CD28, CD107a, HLA-DR (Beckman Coulter, USA) (PE). To create a database and conduct statistical research, the capabilities of an Excel spreadsheet and application packages (Megastat and Statistica 6.0) were used. When determining statistical significance between the study groups, the Mann-Whitney test was used for independent groups and the Wilcoxon test for dependent groups. Modulation of the number and functional activity of ICC in patients with RPL had a significant correlation with pregnancy outcome. Inadequate activation of the immune system is a factor that can lead to miscarriage. Termination of pregnancy before term is associated with subpopulation shifts, increased activation potencies of immunocompetent cells compared to full-term birth, which is an important feature of the inflammatory response. The identified immune changes will allow the development of early prevention methods and new approaches to the treatment of this pregnancy complication.

Dynamic responses of human lung innate and adaptive immune cells highlight the roles of genes at asthma risk loci.

The lung is a unique immunological niche with diverse immune cell types. The effects of stimulation through innate and adaptive immune receptors on human lung immune cells has largely been extrapolated from studies of blood immune cells. While multiple immune cell types and many genes have been implicated as contributing to asthma, the dynamics of these in human lung immune cells following activation will yield insights into asthma pathogenesis and lung immunity more broadly. Human lung immune cells from 6 donors were isolated. Mixed leukocytes were treated separately with lipopolysaccharide (LPS), F(ab)2-anti-human-IgM/IgG + IL4 and anti-CD3/CD28 for 4 and 18 hours and underwent single cell RNA sequencing (scRNAseq). Lung immune cell types were annotated, and gene expression compared across conditions. Genes at prior asthma-associated genetic loci were characterized across cell types, treatments and timepoints. Expression of non-classical class II genes associated with asthma, HLA-DQA2 and HLA-DQB2, and their protein products was characterized with immunohistochemistry. We characterized gene expression in 116,697 lung immune cells. Cell-, treatment-, and timepoint-specific effects on gene expression were detected in all lung immune cell populations. Correlation of gene expression between lung and blood lymphocyte populations decreased following stimulation. Among the genes that were differentially expressed, 97 receptor:ligand pairs had changes with treatments. 96.0% of genes at asthma risk loci demonstrated differential expression in at least one cell type and at least one treatment. B cells were the cell type with the highest expression of HLA-DQA2 and HLA-DQB2 which increased with anti-IgM/IgG treatment and the HLA-DQB2 protein was identified in lung B cells from a donor with asthma. Human lung immune activation elicits a broad range of cellular responses that deviate from those of blood immune cells and are relevant to asthma. Lung B cells expressing HLA-DQA2 and HLA-DQB2 appear to be involved in a novel antigen presentation pathway that contributes to asthma risk.

Investigating age-related dynamics and transcriptional signatures of CD8+HLA-DR+ regulatory T lymphocytes: perspectives in understanding immune system aging

The ability of the CD8+HLA-DR+ regulatory T lymphocytes population to regulate the immune response was first described several years ago. It is known that the suppressive effects of these cells depend on intercellular interactions and are mediated by the expression of checkpoint inhibitor molecules such as CTLA-4, TIM-3, PD-1 and LAG-3. The CD8+HLA-DR+ regulatory T cells also share some properties with conventional CD4+ regulatory T lymphocytes. Nevertheless, the characteristics and function of this subpopulation remain poorly understood. Furthermore, studying the properties of CD8+HLA-DR+ regulatory T cells becomes relevant in the light of general age-associated changes in the human immune system and the increased sensitivity of CD8+T lymphocytes to these changes. Therefore, the aim of this study was to investigate the age dynamics and search for transcriptional signatures of the CD8+HLA-DR+ regulatory T cells. For this purpose, flow cytometric analysis of peripheral blood mononuclear cells from 18 donors aged 21 to 85 years was performed. Bioinformatic analysis of single-cell RNA sequencing data was carried out to search for signatures. It was found that CD8+HLA-DR+ regulatory T cells accumulate with age. The transcriptional signatures of this population consist of genes involved in antigen presentation and cytotoxicity, along with a decrease in the expression of genes encoding proteins of activating protein 1 complex. These data suggest mechanisms of suppressor function of CD8+HLA-DR+ regulatory T lymphocytes associated with the ability of these cells to present antigens and perform cytotoxic activity against effector T lymphocytes. The accumulation of the studied cells may imply a potential influence of CD8+HLA-DR+ regulatory T lymphocytes on the efficiency of adaptive immune response in the aging. Further studies of this population may provide insights into its role in age-related changes in the immune system and develop strategies to improve the immune response in the elderly.

Interleukin-21 and Interleukin-23 levels in familial Mediterranean Fever before and after treatment: the role of cytokines in disease pathogenesis.

In a previous study, it has been shown that the population of Th17 lymphocytes was increased in patients with FMF. IL-21 and IL-23 play significant roles in the production and differentiation of Th17 cells. In this study, we aimed to evaluate serum levels of IL-21 and IL-23 in FMF patients both at diagnosis and after treatment, and to compare these levels with those of healthy controls. Twenty-seven newly diagnosed patients with FMF in attack-free periods and twenty-seven healthy volunteers enrolled in the study. The groups were comparable with respect to age and gender. IL-21 and IL-23 levels in serum samples from patients at the time of diagnosis, in remission after treatment, and from the control groups were analysed using the ELISA method. There was no significant difference between the cytokine levels of the patient group at the time of diagnosis and the cytokine levels of the control group (for IL-21, p: 0.28 and for IL-23, p: 0.56). Similarly, there was no significant difference between the patients' cytokine levels at the time of diagnosis and after treatment (for IL-21, p: 0.99 and for IL-23, p: 0.08). Interleukin levels at the time of diagnosis did not differ among patient groups based on the presence of clinical findings or the M694V genotype. Our results suggest that IL-21 and IL-23 do not play a role in the pathogenesis of the disease. However, while interpreting these findings, it should be considered that patients with active episodes were excluded and cytokine levels were not measured in tissue samples.

A comprehensive and longitudinal evaluation of the different populations of lymphoid and myeloid cells in the peripheral blood of patients treated with chemoradiotherapy for head and neck cancer

BackgroundImmunotherapy provided significant survival benefits for recurrent and metastatic patients with head and neck cancer. These improvements could not be reproduced in patients treated with curative-intent chemoradiotherapy (CRT) and the optimal radio-immunotherapy (RIT) concepts have yet to be designed. Exploration and analysis of the pre-therapeutic immune status of these patients and the changes occurring during the treatment course could be crucial in rationally designing future combined treatments.MethodsBlood samples were collected from a cohort of 25 head and neck cancer patients treated with curative-intended (C)-RT prior to therapy, after the first week of treatment, and three months after treatment completion. Peripheral blood mononuclear cells (PBMCs) or all nucleated blood cells were isolated and analyzed via flow cytometry.ResultsAt baseline, patients showed reduced monocyte and lymphocyte counts compared to healthy individuals. Although overall CD8+ T-cell frequencies were reduced, the proportion of memory subsets were increased in patients. Radiotherapy (RT) treatment led to a further increase in CD8+ effector memory T-cells. Among myeloid populations, tumor-promoting subsets became less abundant after RT, in favor of pro-inflammatory cells.ConclusionThe present study prospectively demonstrated a complex interplay and distinct longitudinal changes in the composition of lymphocytic and myeloid populations during curative (C)-RT of head and neck cancer. Further validation of this method in a larger cohort could allow for better treatment guidance and tailored incorporation of immunotherapies (IT) in the future.

540. INFILTRATION OF RESECTED OESOPHAGEAL ADENOCARCINOMA WITH ANTIGEN-EXPERIENCED PD-1 AND CD39 POSITIVE CD8+ TISSUE RESIDENT MEMORY CELLS CORRELATE WITH IMPROVED SURVIVAL

Abstract Background The development of novel treatments for oesophageal adenocarcinoma (OAC) represents an area of significant unmet need. Despite the application of immune checkpoint blockade alongside chemotherapy as standard of care for some patients with metastatic OAC, responses to immunotherapies are modest and 5-year survival is 17%. The reasons for this remains unclear and while tumour infiltration with CD8+ T lymphocytes (TILs) at the time of resection is associated with improved outcomes, this heterogeneous population remains incompletely characterised in OAC. Tissue resident memory cells (TRM) are increasingly understood as key mediators of immunotherapy response but their role in OAC is poorly understood. Methods Tumour samples were accessed by punch biopsy from the central portion of cancers resected from 44 patients undergoing curative surgery for OAC. Samples were assessed by multi-parametric flow cytometry for the presence of antigen-experienced TILs and markers of activation and exhaustion. Populations of antigen-experienced PD-1 and CD39 positive CD8+ OAC TILs were sorted, and bulk RNA sequencing (RNAseq) undertaken using a modified SmartSeq2 protocol allowing differential gene expression analysis and gene set enrichment analysis. Flow cytometric assessment of functionality was completed. Results Resected OAC are often highly infiltrated with antigen experienced CD8+ TILs expressing high levels of PD-1 and CD39 and an abundance of this population correlates with improved survival (%PD-1/CD39+ >Median, OS HR 0.12). RNAseq of sorted TILs identified this PD-1+ and CD39+ lymphocyte population as enriched for precursor exhausted-like CD8+ TRM (NES 2.01 p=0.00). This is correlated by their CD103+ and TIM3- predominance on flow cytometry in keeping with TRMsassociated with immunotherapy response in other cancers. This population demonstrated a maintained proliferative potential, an ability to degranulate and produce the key effector molecules IFN-γ, TNF-α and Granzyme B. Conclusions An abundance of a PD-1 and CD39 positive CD8+ TIL population, consistent with a precursor exhausted-like TRM population with maintained proliferative and functional capacity, is observed to correlate with improved outcomes following curative surgery for OAC. This TRM population is consistent with analogous populations observed to be responsible for immunotherapy response in other cancers and their identification may predict benefit from such approaches in OAC and allow better patient selection for treatment with immune checkpoint inhibitors.