Th Cell Subsets Research Articles

186 TH9 cells depend on cystine uptake and PPAR-γ signaling to prevent unchecked lipid ROS and cell death

TH9 cells, also known as pathogenic TH2 cells, are a subset of proinflammatory effector TH cells characterized by high levels of IL-9 expression. They share many properties with conventional TH2 cells but are distinguished by their expression of the transcription factor PPAR-γ, on which they depend for full effector function. PPAR-γ is best known for its role in controlling lipid and glucose metabolism but is increasingly implicated in type 2 inflammation. However, the role of PPAR-γ in TH9 cells remains unclear. Transcriptional profiling of human TH9 cells in presence or absence of the PPAR-γ inhibitor, GW9662, showed strong upregulation of genes involved in cystine transport and redox control of lipid peroxidation. One of the top upregulated genes was SLC7A11, which encodes a cystine/glutamate transporter. Interestingly, we found that the chemical inhibition of SLC7A11 by erastin and cystine starvation in cystine free medium leads to an increase in lipid ROS levels and cell death in TH9 cells but not in conventional TH2 cells. Moreover, PPAR-γ inhibition promotes a further increase in lipid ROS and cell death upon erastin treatment only in TH9 cells, and this effect was not associated with augmented cellular ROS or mitochondrial ROS. Importantly, the anti-oxidant N-acetylcysteine completely rescued the effect of erastin, alone or in combination with GW9662. Erastin and/or GW9662 were also able to selectively deplete the CCR8+CRTh2+ effector memory T cells isolated from allergic contact dermatitis skin biopsies, which share phenotypic and functional features with TH9 cells. These preliminary data suggest that PPAR-y plays a role in protecting pathogenic TH2 cells from unchecked lipid ROS and consecutive cell death. Our findings open up new therapeutic avenues to selectively target pathogenic TH2 cells in the treatment of allergic diseases by leveraging their particular dependency on cystine to prevent cell death from unchecked lipid ROS.

Granulocytic myeloid-derived suppressor cells inhibit T follicular helper cells during experimental Schistosoma japonicum infection

BackgroundCD4+ T helper (Th) cells play critical roles in both host humoral and cellular immunity against parasitic infection and in the immunopathology of schistosomiasis. T follicular helper (Tfh) cells are a specialized subset of Th cells involved in immunity against infectious diseases. However, the role of Tfh cells in schistosome infection is not fully understood. In this study, the dynamics and roles of Tfh cell regulation were examined. We demonstrated that granulocytic myeloid-derived suppressor cells (G-MDSC) can suppress the proliferation of Tfh cells.MethodsThe levels of Tfh cells and two other Th cells (Th1, Th2) were quantitated at different Schistosoma japonicum infection times (0,3, 5, 8, 13 weeks) using flow cytometry. The proliferation of Tfh cells stimulated by soluble egg antigen (SEA) and soluble worm antigen (SWA) in vivo and in vitro were analyzed. Tfh cells were co-cultured with MDSC to detect the proliferation of Tfh cells labelled by 5(6)-carboxyfluorescein diacetate N-succinimidyl ester. We dynamically monitored the expression of programmed cell death protein 1 (PD-1) on the surface of Tfh cells and programmed cell death ligand 1 (PD-L1) on the surface of MDSC at different infection times (0, 3, 5, 8 weeks). Naïve CD4+ T cells (in Tfh cell differentiation) were co-cultured with G-MDSC or monocytic MDSC in the presence, or in the absence, of PD-L1 blocking antibody.ResultsThe proportion of Tfh cells among CD4+ T cells increased gradually with time of S. japonicum infection, reaching a peak at 8 weeks, after which it decreased gradually. Both SEA and SWA caused an increase in Tfh cells in vitro and in vivo. It was found that MDSC can suppress the proliferation of Tfh cells. The expression of PD-1 on Tfh cells and PD-L1 from MDSC cells increased with prolongation of the infection cycle. G-MDSC might regulate Tfh cells through the PD-1/PD-L1 pathway.ConclusionsThe reported study not only reveals the dynamics of Tfh cell regulation during S. japonicum infection, but also provides evidence that G-MDSC may regulate Tfh cells by PD-1/PD-L1. This study provides strong evidence for the important role of Tfh cells in the immune response to S. japonicum infection.Graphical abstract

Repositioning TH cell polarization from single cytokines to complex help.

When helper T (TH) cell polarization was initially described three decades ago, the TH cell universe grew dramatically. New subsets were described based on their expression of few specific cytokines. Beyond TH1 and TH2 cells, this led to the coining of various TH17 and regulatory (Treg) cell subsets as well as TH22, TH25, follicular helper (TFH), TH3, TH5 and TH9 cells. High-dimensional single-cell analysis revealed that a categorization of TH cells into a single-cytokine-based nomenclature fails to capture the complexity and diversity of TH cells. Similar to the simple nomenclature used to describe innate lymphoid cells (ILCs), we propose that TH cell polarization should be categorized in terms of the help they provide to phagocytes (type 1), to B cells, eosinophils and mast cells (type 2) and to non-immune tissue cells, including the stroma and epithelium (type 3). Studying TH cells based on their helper function and the cells they help, rather than phenotypic features such as individual analyzed cytokines or transcription factors, better captures TH cell plasticity and conversion as well as the breadth of immune responses in vivo.

Dexmedetomidine Directs T Helper Cells toward Th1 Cell Differentiation via the STAT1-T-Bet Pathway

Dexmedetomidine is an α2 adrenergic receptor agonist that has been reported to modulate the polarization of CD4+ T cells. However, the underlying mechanisms by which dexmedetomidine induces T-helper 1 (Th1) cell differentiation remain poorly understood. The aim of this study was to explore the potential mechanisms through which dexmedetomidine can induce Th1 cell differentiation. Purified CD4+ T cells were stimulated with anti-CD3/anti-CD28 and then treated with dexmedetomidine. Flow cytometry analysis was adopted to measure the concentration of Th1 cells. Enzyme-linked immunosorbent assay (ELISA) and real-time quantitative polymerase chain reaction (qPCR) were performed to detect protein levels and mRNA expression, respectively, of IFN-γ and IL-4. Western blotting was used to determine the phosphorylation of signal transducer and activator of transcription 1 (STAT1) and T-bet expression. The Th1 cell subset and IFN-γ levels were elevated in the dexmedetomidine-induced CD4+ T cells. Dexmedetomidine enhanced the phosphorylation of STAT1 and the expression of T-bet in the CD4+ T cells. Atipamezole (an α2 adrenergic antagonist) and fludarabine (a STAT1 inhibitor) reversed the dexmedetomidine-induced Th1 cell differentiation. These results suggested that dexmedetomidine induced Th1 cell differentiation via the STAT1-T-bet signaling pathway.

Role of Th22 Cells in Human Viral Diseases.

Naive CD4+ T cells can differentiate into different cell subsets after receiving antigen stimulation, which secrete corresponding characteristic cytokines and thereby exert biological effects in various diseases. Th22 cells, a novel subset of CD4+ T cells, are different from Th1, Th2, Th17, and Treg cell subsets, which have been discovered in recent years. They can express CCR4, CCR6, and CCR10 molecules and secrete IL-22, IL-13, and TNF-α. They are not able to secrete IL-17, IL-4, and interferon-γ (IFN-γ). IL-22 is considered as a major effector molecule of Th22 cells whose functions and mechanisms of regulating cell differentiation have been constantly improved. In this review, we provide an overview of the origin, differentiation of Th22 cells. Moreover, we also describe the interrelationships between Th22 cells and Th17, Th1, and Th2 cells. Additionally, the role of Th22 cells were discussed in human diseases with virus infection, which will provide novel insight for the prevention and treatment of viral infection in human.

Polyamine metabolism is a central determinant of helper T cell lineage fidelity

SummaryPolyamine synthesis represents one of the most profound metabolic changes during T cell activation, but the biological implications of this are scarcely known. Here, we show that polyamine metabolism is a fundamental process governing the ability of CD4+ helper T cells (TH) to polarize into different functional fates. Deficiency in ornithine decarboxylase, a crucial enzyme for polyamine synthesis, results in a severe failure of CD4+ T cells to adopt correct subset specification, underscored by ectopic expression of multiple cytokines and lineage-defining transcription factors across TH cell subsets. Polyamines control TH differentiation by providing substrates for deoxyhypusine synthase, which synthesizes the amino acid hypusine, and mice in which T cells are deficient for hypusine develop severe intestinal inflammatory disease. Polyamine-hypusine deficiency caused widespread epigenetic remodeling driven by alterations in histone acetylation and a re-wired tricarboxylic acid (TCA) cycle. Thus, polyamine metabolism is critical for maintaining the epigenome to focus TH cell subset fidelity.

MSCs Derived from Human Amnion Possess a Higher Proliferation Activity and Clearer Stem Cell Properties Than from Bone Marrows and They Exhibit Similar Immunosuppressive Ability In Vitro

Objectives: Human bone marrow mesenchymal stem cells (hBMSCs) have been used for the prevention and treatment of acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cells transplantation (allo-HSCT). In this study, we compared the biological characteristics and immunosuppressive activity of human amniotic mesenchymal stem cells (hAMSCs) and hBMSCs to provide experimental evidence for the potential use of hAMSCs for treating aGVHD, thus solving the problem of insufficient hBMSCs sources. Methods: hAMSCs and hBMSCs were isolated by using enzymatic digestion and Ficoll-Hypaque density gradient centrifugation, respectively, were culture-expanded in vitro to obtain the 4th-generation cells. The biological characteristics of both stem cell types were compared by morphological analysis, analysis of cell growth, cell cycle profiling, immunophenotyping, and immunofluorescence assays. An in vitro co-culture of MSCs and peripheral blood mononuclear cells (PBMCs) stimulated with phytohemagglutinin (PHA-PBMSC) was performed. The proliferation and changes of T lymphocyte subsets were measured using the Cell Counting Kit-8(CCK-8) assay and flow cytomety, respectively. The production of Interferon-γ (IFN-γ), interleukin-2 (IL-2) and IL-10 in the co-culture supernatant was determined using enzyme-linked immunosorbent assay (ELISA). Results: Both hAMSCs and hBMSCs had fibroblast-like morphology. hAMSCs could be maintained for at least 15 culture passages, but hBMSCs started to show signs of aging and remarkably reduced proliferation at 6-7 passages. There was no significant difference in the proportion of cells in G2/M phase between hAMSCs and hBMSCs (P > 0.05). Immunophenotyping revealed positive expression of CD105, CD90, and CD73 and negative expression of CD34, CD45, CD11b, CD19, and HLA-DR on the surface of both hAMSCs and hBMSCs. hAMSCs were positive for Oct-3/4, but hBMSCs were not. Both hAMSCs and hBMSCs expressed vimentin. PHA-stimulated PBMCs proliferation was inhibited by hAMSCs and hBMSCs. There were not significant differences between the inhibitory effects of the two MSCs types on PBMCs proliferation (P > 0.05). Co-culture with either hAMSCs or hBMSCs significantly increased the proportions of Treg, Th2 and Tc2 and decreased Th1 and Tc1 cell subsets in the PBMCs as compared with the PBMCs cultured alone (P < 0.05), and the changes in the PBMCs were similar between the two co-culture systems (P>0.05). In both of the two co-culture systems, IFN-γ, IL-2 production by the lymphocytes was significantly lowered (P < 0.05) and IL-10 production was significantly increased (P < 0.05) as compared with their levels in the PBMCs cultured alone; no significant difference was found in IFN-γ, IL-2 or IL-10 levels between the two co-culture systems (P > 0.05).Conclusion: The results of this study demonstrated that MSCs derived from human amnion and bone marrows have similar immunomodulatory effects on the T lymphocytes, however, hAMSCs have higher proliferation activity and clearer stem cell properties than hBMSCs, suggesting the possibility of using hAMSCs in the treatment of aGVHD after allo-HSCT. DisclosuresNo relevant conflicts of interest to declare.

Differentiation and Regulation of TH Cells: A Balancing Act for Cancer Immunotherapy.

Current success of immunotherapy in cancer has drawn attention to the subsets of TH cells in the tumor which are critical for activation of anti-tumor response either directly by themselves or by stimulating cytotoxic T cell activity. However, presence of immunosuppressive pro-tumorigenic TH subsets in the tumor milieu further contributes to the complexity of regulation of TH cell-mediated immune response. In this review, we present an overview of the multifaceted positive and negative effects of TH cells, with an emphasis on regulation of different TH cell subtypes by various immune cells, and how a delicate balance of contradictory signals can influence overall success of cancer immunotherapy. We focus on the regulatory network that encompasses dendritic cell-induced activation of CD4+ TH1 cells and subsequent priming of CD8+ cytotoxic T cells, along with intersecting anti-inflammatory and pro-tumorigenic TH2 cell activity. We further discuss how other tumor infiltrating immune cells such as immunostimulatory TH9 and Tfh cells, immunosuppressive Treg cells, and the duality of TH17 function contribute to tip the balance of anti- vs pro-tumorigenic TH responses in the tumor. We highlight the developing knowledge of CD4+ TH1 immune response against neoantigens/oncodrivers, impact of current immunotherapy strategies on CD4+ TH1 immunity, and how opposing action of TH cell subtypes can be explored further to amplify immunotherapy success in patients. Understanding the nuances of CD4+ TH cells regulation and the molecular framework undergirding the balancing act between anti- vs pro-tumorigenic TH subtypes is critical for rational designing of immunotherapies that can bypass therapeutic escape to maximize the potential of immunotherapy.

Mechanisms That Underly T Cell Immunity in Graves' Orbitopathy.

Graves’ orbitopathy (GO), also known as thyroid-associated ophthalmopathy, is the most common ocular abnormality of Graves’ disease. It is a disfiguring, invalidating, and potentially blinding orbital disease mediated by an interlocking and complicated immune network. Self-reactive T cells directly against thyroid-stimulating hormone receptor-bearing orbital fibroblasts contribute to autoimmune inflammation and tissue remodeling in GO orbital connective tissues. To date, T helper (Th) 1 (cytotoxic leaning) and Th2 (antibody leaning) cell subsets and an emerging role of Th17 (fibrotic leaning) cells have been implicated in GO pathogenesis. The potential feedback loops between orbital native residential CD34- fibroblasts, CD34+ infiltrating fibrocytes, and effector T cells may affect the T cell subset bias and the skewed pattern of cytokine production in the orbit, thereby determining the outcomes of GO autoimmune reactions. Characterization of the T cell subsets that drive GO and the cytokines they express may significantly advance our understanding of orbital autoimmunity and the development of promising therapeutic strategies against pathological T cells.

Programmed Cell Death-1 Pathway Deficiency Enhances Autoimmunity Leading to Dacryoadenitis of Mice

Programmed cell death protein (PD)-1 is a coinhibitory molecule that suppresses immune response and maintains immune homeostasis. Moreover, the PD-1 pathway blocks cancers from being attacked by immune cells. Anti-PD-1 antibody therapy such as nivolumab improves survival in cancer patients. However, the occurrence of autoimmune inflammatory disorders in various organs has been increasingly reported as an adverse effect of nivolumab. Of the disorders associated with nivolumab, Sicca syndrome occurs in 3% to 11% of cases and has unknown pathologic mechanisms. Whether the absence of the PD-1 pathway causes functional and morphologic disorders in lacrimal glands was determined by analyzing PD-1 gene-knockout (Pdcd1-/-) mice. Histopathologic analysis showed that Pdcd1-/- mice developed dacryoadenitis beginning at 3 to 4 months of age, and deteriorated with age. Flow-cytometric analysis confirmed that cells infiltrating the affected lacrimal glands consisted mainly of CD3+ T cells and only a small proportion of CD19+ B cells. Among infiltrating T cells, theCD4+ Th-cell subset consisted of Th1 cells producing interferon-γ in an early stage of dacryoadenitis in Pdcd1-/- mice. Experiments of lymphocyte transfer from Pdcd1-/- into irradiated wild-type mice confirmed that CD4+ T cells from Pdcd1-/- mice induced dacryoadenitis. These results indicate that PD-1 plays an important role in the prevention of autoimmune inflammatory disorders in lacrimal glands caused by activated CD4+ Th1 cells.

Exploring a novel triptolide derivative possess anti-colitis effect via regulating T cell differentiation

Inflammatory bowel disease (IBD) is generally characterized by chronic inflammatory disorders of the gastrointestinal tract that are known as ulcerative colitis (UC) or Crohn’s disease (CD). Although the underlying mechanism of action of IBD is unclear and because of the lack of satisfactory treatment, increasing evidence has indicated that pro-inflammatory cytokines that activate JAK-STAT signaling pathway regulate the differentiation of naïve T cells towards T helper (Th)1 and Th17 cell subsets and contribute to the development of IBD. ZT01 is a newly obtained triptolide derivative with strong anti-inflammatory effects and low toxicity. In this study, we evaluated the effects of ZT01 on DSS-induced colitis and investigated the underlying mechanism of action involved. Mice with DSS-induced acute or chronic colitis were used to assess the efficacy of ZT01 treatment, and T cells were cultured to analyze the differentiation of Th1 and Th17 cell by flow cytometry. In addition, intestinal epithelial barrier function, macrophage polarization, activation of the JAK-STAT signaling pathway, and the expression of cytokines and transcription factors were measured to assess the possible mechanisms of ZT01. We found that ZT01 had an obviously beneficial effect on DSS-induced colitis by improving the symptoms of bloody diarrhea, weight loss, and a shortened colon, thereby preserving the epithelial barrier function in the mouse colon. Furthermore, ZT01 significantly inhibited T cell differentiation into Th1 and/or Th17 cell subsets and macrophage polarization towards into an inflammatory phenotype via regulating the JAK-STAT signaling pathway. Thus, our findings suggested that ZT01 might be a potential pharmaceutical candidate that deserves to be further investigated as a treatment for IBD patients.

Expanded circulating peripheral helper T cells in primary biliary cholangitis: Tph cells in PBC

BackgroundPeripheral helper T (TPH) cells, a recently defined subset of Th cells, promote B cell differentiation and antibody production in inflamed tissues. This study investigated whether circulating TPH cells are associated with primary biliary cholangitis (PBC), a typical organ-specific autoimmune disease. MethodsTwenty PBC patients and 20 age- and sex-matched healthy controls (HCs) were recruited. The circulating TPH cell subsets were analyzed by flow cytometry, and the associations of TPH cells with disease activity and plasma cells were determined. Functional analysis was performed using a TPH and B cell coculture experiment. ResultsThe frequencies of circulating TPH cells, ICOS+ TPH cells, and CD28+ TPH cells were increased in patients with PBC. Furthermore, the ICOS+ TPH cell level was higher in PBC patients with or without cirrhosis than in HCs, and the level decreased after treatment. Moreover, ICOS+ TPH cell levels correlated positively with specific clinical parameters (including anti-mitochondrial antibodies against M2 antigen (AMA-M2), IgM) and plasma cell levels, suggesting that the TPH cell activation status is associated with the severity of PBC. Coculture results revealed an enhanced ability of TPH cells from PBC patients to induce B cell differentiation. ConclusionsElevated numbers of TPH cells may be involved in the pathogenesis of PBC, and the activation status of TPH cells is related to the severity of PBC. Additionally, TPH cells can be used as a useful biomarker for evaluating the progression of PBC and may serve as a therapeutic target for PBC patients in the future.

MicroRNAs as the Important Regulators of T Helper 17 Cells: A Narrative Review.

T helper (Th)-17 cells are a distinct and important subset of Th cells and their functions are due to the ability of production and secretion of key cytokines in the immune system such as interleukin (IL)-17, IL-22, IL-21, and tumor necrosis factor-α (TNF-α). According to these cytokines, these cells have vital roles in the pathogenesis of the disease such as rheumatoid arthritis (RA) and osteoarthritis (OA). Nowadays, microRNAs (miRNAs) are defined as essential regulators of cell function by targeting transcription factors and other elements that act in cells to control gene expression. The purpose of this study was to detect and investigate articles evaluating the function of miRNA in Th-17 cell performance. The language was restricted to English and the search was done in PubMed, Web of Science and Embase. In this review, we first explain the role of effective factors in the function of Th17 lymphocytes, and then, we summarize the performance of several miRNAs involved in the activation and appropriate functions of Th17 cells in the immune system.

Immunophenotyping in pemphigus reveals a TH17/TFH17 cell–dominated immune response promoting desmoglein1/3-specific autoantibody production

TH2 cells were thought to be a pivotal factor for initiation of the autoimmune blistering disease pemphigus. However, the role of other T-cell subsets in pemphigus pathogenesis remained unclear. We aimed to characterize the exact phenotype of T cells responsible for the development of pemphigus. Whole transcriptome shotgun sequencing was performed to determine differential gene expression in pemphigus lesions and skin of healthy individuals. The cutaneous cytokine signature was further evaluated by real-time quantitative PCR. In peripheral blood, the distribution of TH cell and folliclular helper (TFH) cell subsets was analyzed by flow cytometry. Finally, the capacity of TH and TFH cell subsets to induce desmoglein (Dsg)-specific autoantibodies by memory B cells was evaluated in coculture experiments. Transcriptome analysis of skin samples identified an IL-17A-dominated immune signature in patients with pemphigus, and Kyoto Encyclopedia of Genes and Genomes pathway analysis confirmed the dominance of the IL-17A signaling pathway. Increased expression of IL17A and associated cytokines was also detected by real-time quantitative PCR comparing lesional with perilesional or healthy skin. Interestingly, utilization of flow cytometry showed that patients with active pemphigus had elevated levels of circulating IL-17+, TH17, TFH17, and TFH17.1 cells. Notably, levels of TH17 and TFH17 cells correlated with levels of Dsg-specific CD19+CD27+ memory B cells, and patients with acute pemphigus showed higher levels of Dsg3-autoreactive TFH17 cells. Coculture experiments revealed TFH17 cells as primarily responsible for inducing Dsg-specific autoantibody production by B cells. Our findings show that TFH17 cells are critically involved in the pathogenesis of pemphigus and offer novel targets for therapeutic intervention.

Group 2 Innate Lymphoid Cells: A Double-Edged Sword in Cancer?

Simple SummaryGroup 2 innate lymphoid cells (ILC2s), like other ILCs, are a new resident cell subset of innate immunity that provides the first line of defense against pathogens such as helminths and largely contributes to inflammation observed in allergic disorders and in some tumors. They are considered sentinel cells, which reside at the interface between host and external environment and are rapidly activated by signals deriving from tissue. Depending on the type of signals and their high plasticity, ILC2s exert both enhancing and regulatory activity on other tissue-resident cells, including tumor- and tumor-associated cells. The functional profile of ILC2s, their pro- or antitumor activity in preclinical studies and patients and the potential therapeutic approaches targeting ILC2s have been extensively reviewed.Group 2 Innate Lymphoid Cells (ILC2s) belong to the family of helper ILCs which provide host defense against infectious agents, participate in inflammatory responses and mediate lymphoid organogenesis and tissue repair, mainly at the skin and mucosal level. Based on their transcriptional, phenotypic and functional profile, ILC2s mirror the features of the adaptive CD4+ Th2 cell subset, both contributing to the so-called type 2 immune response. Similar to other ILCs, ILC2s are rapidly activated by signals deriving from tissue and/or other tissue-resident immune cells. The biologic activity of ILCs needs to be tightly regulated in order to prevent them from contributing to severe inflammation and damage in several organs. Indeed, ILC2s display both enhancing and regulatory roles in several pathophysiological conditions, including tumors. In this review, we summarize the actual knowledge about ILC2s ability to induce or impair a protective immune response, their pro- or antitumor activity in murine models, human (children and adults) pathologies and the potential strategies to improve cancer immunotherapy by exploiting the features of ILC2s.

Estimation of lymphocyte subsets and cytokine levels in workers occupationally exposed to cadmium

IntroductionOccupational exposure to Cadmium (Cd) may have serious health effect on workers. However, little is known about its effect on immune system. Moreover, previous studies have been inconclusive in stating the effect of Cd on immune system. The aim of our study was to estimate immune parameters in workers occupationally exposed to Cd. Material and methods110 individuals occupationally exposed to Cd and 97 apparently healthy non-exposed individuals were recruited for this study. Blood Cadmium levels were determined by AAS. Lymphocyte subset were analyzed using flow cytometry and the cytokine levels were determined by ELISA. ResultsExposed group have significantly higher levels of B-Cd. % of CD8 cells were higher in exposed while % of CD4 cells showed a decreasing trend in the exposed group. Among the CD3CD4 T cell subsets Th1 (%) and Tregs (%) cells were lower while Th17 (%) were higher in exposed group. Increased levels of IL-4 (Th2), IL-6 (Th2) and TNF- α (Th1) and decreased levels of IL-2 (Th1) and IL-10 (Tregs) were observed in Cd exposed workers which is indicative of a predominant pro-inflammatory response in Cd exposed workers. IL-17 (Th17) levels did not show any significant difference between the two groups. Increased Th17/Tregs ratio in the exposed group is also suggestive of an increased pro-inflammatory immune response in exposed group. ConclusionTo conclude, even low level of exposure to Cd in occupational settings is associated with alterations in Th17 cells, which may further predispose an individual to other systemic abnormalities.

Preserved Th2 lymphocytes improve prognosis of diabetic patients undergoing TAVR

Abstract Introduction Previous studies have shown that presence of diabetes (DM) worsens outcome of patients after transfemoral aortic valve (TAVR). DM has been associated with pathological T-lymphocyte (T-cell) polarization, marked by decreased anti-inflammatory Th2 cells and increased pro-inflammatory Th1 cells. However, the risk-modulatory impact of T-cell polarization in diabetic patients with severe aortic stenosis has not been shown thus far. In this study we assessed the role of T-cell subsets in diabetic patients undergoing TAVR. Methods and results A total of 129 patients (76% male, median age [IQR]: 83 years [79–86]) admitted for TAVR at the University Clinic Frankfurt were enrolled. The patients were evaluated using classical risk scores and the Th1/Th2 T-cell polarization was assessed using flow cytometry. The endpoint of the study was all-cause death. Kaplan-Meier survival, ROC curve analysis and Mann-Whitney-U-Test were used in statistical analysis. The differences were considered significant by error probability p&amp;lt;0.05. Twenty-six patients died within follow up of 274 (188–367) days. The conventional risk parameters were distributed as follows: STS score: 3.45 (2.47–4.97), LVEF: 60% (45–65), CRP: 0.33 mg/dl (0.15–0.79), hsTropT: 24.5 pg/ml (16.5–40.0), IL6: 6.7 pg/ml (4.1–12.2), Hb: 12.3 g/dl (11.00–13,75), Creatinine: 1.15 mg/dl (0.93–1.54), Th1 cells = 79.88 cells/μl (55.69–122.16), Th2 cells: 25.31 cells/μl (19.69–38.33), NT-proBNP: 2033 pg/ml (1076–5531). All these parameters were associated with mortality. Hence, only Hb (AUC=0.761), NT-proBNP (AUC=0.726), Th2 cells (AUC=0.712) and STS score (AUC=0.737) provided AUC&amp;gt;0.7. Diabetes was revealed to be significantly associated with mortality in patients with and without DM (15/48 (31%) vs. 11/81 (14%), respectively, P=0.019). There were no significant differences in the counts of Th-cell subsets between diabetic and non-diabetic patients (Th1 (90.95 (62.41–154.22) vs 76.36 (53.16–100.49), P=0.072); Th2 (29.18 (20.13–43.77) vs 24.74 (20.27- 35.11), p=0.245), for DM and non-DM respectively). However, the survival rate in patients with DM and Th2 cell counts higher than or equal to the calculated optimal cut-off of 24.3 cells/μl was comparable with patients without DM (25/28 (89%) vs. 36/38 (95%), p=0.453). In contrast, diabetic patients with reduced Th2 cells (&amp;lt;24.3 cells/μl) were much more likely to die (10/15 (67%) vs. 8/34 (24%), p=0.003, patients with DM and without, respectively). Conclusion Our results show for the first time a risk-modulatory impact of T-cell immunity in diabetic patients with severe degenerative aortic stenosis. Reduced Th2 cells are strongly associated with mortality in patients considered for TAVR and significantly deteriorate prognosis in patients with concomitant diabetes. Funding Acknowledgement Type of funding source: None

T helper cells in synovial fluid of patients with rheumatoid arthritis primarily have a Th1 and a CXCR3+Th2 phenotype

BackgroundThe majority of CD4+ T helper (Th) cells found in the synovial fluid (SF) of patients with rheumatoid arthritis (RA) express CXCR3, a receptor associated with Th1 cells. In blood, subsets of Th2 and Th17 cells also express CXCR3, but it is unknown if these cells are present in RA SF or how cytokines from these subsets affect cytokine/chemokine secretion by fibroblast-like synoviocytes (FLS) from patients with RA.MethodsWe examined the proportions of Th1, Th2, CXCR3+Th2, Th17, CXCR3+Th17, Th1Th17, peripheral T helper (TPh) and T follicular helper (TFh) cells in paired SF and blood, as well as the phenotype of TPh and TFh cells in RA SF (n = 8), by the use of flow cytometry. We also examined the cytokine/chemokine profile in paired SF and plasma (n = 8) and in culture supernatants of FLS from patients with chronic RA (n = 7) stimulated with Th-associated cytokines, by the use of cytometric bead arrays and ELISA. Cytokine receptor expression in FLS (n = 3) were assessed by the use of RNA sequencing and qPCR.ResultsThe proportions of Th1 and CXCR3+Th2 cells were higher in SF than in blood (P < 0.05). TPh and PD-1highTFh in RA SF were primarily of a Th1 and a CXCR3+Th2 phenotype. Moreover, the levels of CXCL9, CXCL10, CCL20, CCL2, CXCL8, IL-6 and IL-10 were higher in SF than in plasma (P < 0.05). Lastly, IL-4, IL-13 and IL-17A induced RA FLS to secrete proinflammatory IL-6, CCL2, CXCL1 and CXCL8, while IFNγ mainly induced CXCL10.ConclusionThese findings indicate that not only Th1 but also CXCR3+Th2 cells may have a pathogenic role in RA synovial inflammation.

Imbalance of Regulatory and Cytotoxic SARS-CoV-2-Reactive CD4+ T Cells in COVID-19

The contribution of CD4+ T cells to protective or pathogenic immune responses to SARS-CoV-2 infection remains unknown. Here, we present single-cell transcriptomic analysis of >100,000 viral antigen-reactive CD4+ T cells from 40 COVID-19 patients. In hospitalized patients compared to non-hospitalized patients, we found increased proportions of cytotoxic follicular helper cells and cytotoxic T helper (TH) cells (CD4-CTLs) responding to SARS-CoV-2 and reduced proportion of SARS-CoV-2-reactive regulatory T cells (TREG). Importantly, in hospitalized COVID-19 patients, a strong cytotoxic TFH response was observed early in the illness, which correlated negatively with antibody levels to SARS-CoV-2 spike protein. Polyfunctional TH1 and TH17 cell subsets were underrepresented in the repertoire of SARS-CoV-2-reactive CD4+ T cells compared to influenza-reactive CD4+ T cells. Together, our analyses provide insights into the gene expression patterns of SARS-CoV-2-reactive CD4+ T cells in distinct disease severities.

Granzyme A-producing T helper cells are critical for acute graft-versus-host disease.

Acute graft-versus-host disease (aGVHD) can occur after hematopoietic cell transplant in patients undergoing treatment for hematological malignancies or inborn errors. Although CD4+ T helper (Th) cells play a major role in aGVHD, the mechanisms by which they contribute, particularly within the intestines, have remained elusive. We have identified a potentially novel subset of Th cells that accumulated in the intestines and produced the serine protease granzyme A (GrA). GrA+ Th cells were distinct from other Th lineages and exhibited a noncytolytic phenotype. In vitro, GrA+ Th cells differentiated in the presence of IL-4, IL-6, and IL-21 and were transcriptionally unique from cells cultured with either IL-4 or the IL-6/IL-21 combination alone. In vivo, both STAT3 and STAT6 were required for GrA+ Th cell differentiation and played roles in maintenance of the lineage identity. Importantly, GrA+ Th cells promoted aGVHD-associated morbidity and mortality and contributed to crypt destruction within intestines but were not required for the beneficial graft-versus-leukemia effect. Our data indicate that GrA+ Th cells represent a distinct Th subset and are critical mediators of aGVHD.