Activated inducible co-stimulator-positive programmed cell death 1-positive follicular helper T cells indicate disease activity and severity in ulcerative colitis patients

Exhausted Lag-3+ CD4+ T cells are increased in pediatric Inflammatory Bowel Disease

T cells are one of the main drivers of inflammatory bowel diseases (IBD). Infliximab (IFX) is used in the treatment of IBD as an anti-inflammatory drug to induce remission by neutralizing TNFα. We determined the individual chemokine/homing receptor and cytokine profile in pediatric IBD patients before and during IFX therapy to identify predictive biomarkers for therapy success. Peripheral blood CD4+ cells from pediatric patients with IBD were immunomagnetically isolated and either directly analyzed by FACS for cell distribution and chemokine/homing receptor expression or evaluated for cytokine production after in-vitro-stimulation. Twenty-one responders (RS) and 21 non-responders (NRS) were recruited. Before IFX therapy, flow cytometry revealed decreased percentages of naïve conventional T cells in pediatric IBD patients. The proportions of CD62-L+ T cells were decreased in both CD and UC therapy responders. The cytokine profile of T cells was highly altered in IBD patients compared to healthy controls (HC). During IFX therapy, the frequencies of conventional memory and regulatory memory T cells expanded in both cohorts. IFX response was marked by a decrease of α4β7+ and IFNγ+ memory T cells in both CD and UC. In contrast, frequencies of Lag-3+ T cells proved to be significantly increased in NRS. These observations were irrespective of the underlying disease. T cells of pediatric IBD patients display an activated and rather Th1/Th17-shifted phenotype. The increased expression of the checkpoint molecule Lag-3 on T cells of NRS resembles a more exhausted phenotype than in RS and HC which appeared to be a relevant predictive marker for therapy failure.

Reduced TRIM expression correlates with anomalous CD4 T cell activation in systemic lupus Erythematosus and its clinical diagnostic potential

OBJECTIVE

This study seeks to elucidate the expression, function, and clinical relevance of the T cell receptor interacting molecule (TRIM) within circulating CD4+T cell subsets in systemic lupus erythematosus (SLE) patients.

METHODS

We assessed TRIM expression across distinct subpopulations of human peripheral blood mononuclear cells (PBMCs) through the analysis of publicly available single-cell RNA sequencing data. In addition, TRIM expression was investigated within CD4+T cell subsets of peripheral blood and spleens in mice. PBMCs were isolated from both SLE patients, healthy controls (HCs) and rheumatoid arthritis (RA) patients with subsequent measurement and comparative analysis of TRIM expression and functional molecules using flow cytometry. To gauge the clinical relevance of TRIM in SLE, correlation and ROC curve analyses were performed.

RESULTS

In both healthy humans and mice, TRIM was higher expressed within CD4+T cell subsets, especially in naive CD4+T cells. TRIM+ Tregs exhibited lower Helios+ cells and CD45RA-FoxP3hi cells percentages compared to TRIM- Treg cells. TRIM+T cells demonstrated reduced granzyme B and perforin secretion and increased IFN-γ secretion in comparison to TRIM- T cells. Notably, the proportion of TRIM+CD4+T cells was diminished in SLE patients. The downregulation of TRIM+ in CD4+T cells positively correlated with diminished complement C3 and C1q levels and inversely correlated with CRP. The identification of TRIM-associated CD4 T cell subsets aids in distinguishing SLE patients from HCs and those with RA.

CONCLUSIONS

Reduced TRIM expression is linked to abnormal CD4+T cell activation in SLE. TRIM-associated CD4+T cells may be implicated in the pathogenesis of SLE and hold potential for clinical diagnostic purposes.

The molecular subtypes of autoimmune diseases

Autoimmune diseases (ADs) are characterized by their complexity and a wide range of clinical differences. Despite patients presenting with similar symptoms and disease patterns, their reactions to treatments may vary. The current approach of personalized medicine, which relies on molecular data, is seen as an effective method to address the variability in these diseases. This review examined the pathologic classification of ADs, such as multiple sclerosis and lupus nephritis, over time. Acknowledging the limitations inherent in pathologic classification, the focus shifted to molecular classification to achieve a deeper insight into disease heterogeneity. The study outlined the established methods and findings from the molecular classification of ADs, categorizing systemic lupus erythematosus (SLE) into four subtypes, inflammatory bowel disease (IBD) into two, rheumatoid arthritis (RA) into three, and multiple sclerosis (MS) into a single subtype. It was observed that the high inflammation subtype of IBD, the RA inflammation subtype, and the MS "inflammation & EGF" subtype share similarities. These subtypes all display a consistent pattern of inflammation that is primarily driven by the activation of the JAK-STAT pathway, with the effective drugs being those that target this signaling pathway. Additionally, by identifying markers that are uniquely associated with the various subtypes within the same disease, the study was able to describe the differences between subtypes in detail. The findings are expected to contribute to the development of personalized treatment plans for patients and establish a strong basis for tailored approaches to treating autoimmune diseases.

Stem-like T cells are associated with the pathogenesis of ulcerative colitis in humans

To understand the role of T cells in the pathogenesis of ulcerative colitis (UC), we analyzed colonic T cells isolated from patients with UC and controls. Here we identified colonic CD4+ and CD8+ T lymphocyte subsets with gene expression profiles resembling stem-like progenitors, previously reported in several mouse models of autoimmune disease. Stem-like T cells were increased in inflamed areas compared to non-inflamed regions from the same patients. Furthermore, TCR sequence analysis indicated stem-like T cells were clonally related to proinflammatory T cells, suggesting their involvement in sustaining effectors that drive inflammation. Using an adoptive transfer colitis model in mice, we demonstrated that CD4+ T cells deficient in either BCL-6 or TCF1, transcription factors that promote T cell stemness, had decreased colon T cells and diminished pathogenicity. Our results establish a strong association between stem-like T cell populations and UC pathogenesis, highlighting the potential of targeting this population to improve clinical outcomes.

The differentiation courses of the Tfh cells: a new perspective on autoimmune disease pathogenesis and treatment

The follicular helper T cells are derived from CD4+T cells, promoting the formation of germinal centers and assisting B cells to produce antibodies. This review describes the differentiation process of Tfh cells from the perspectives of the initiation, maturation, migration, efficacy, and subset classification of Tfh cells, and correlates it with autoimmune disease, to provide information for researchers to fully understand Tfh cells and provide further research ideas to manage immune-related diseases.

A precise molecular subtyping of ulcerative colitis reveals the immune heterogeneity and predicts clinical drug responses

BACKGROUND AND AIMS

We sought to identify novel molecular subtypes of ulcerative colitis (UC) based on large-scale cohorts and establish a clinically applicable subtyping system for the precision treatment of the disease.

METHODS

Eight microarray profiles containing colon samples from 357 patients were utilized. Expression heterogeneity was screened out and stable subtypes were identified among UC patients. Immune infiltration pattern and biological agent response were compared among subtypes to assess the value in guiding treatment. The relationship between PRLR and TNFSF13B genes with the highest predictive value was further validated by functional experiments.

RESULTS

Three stable molecular subtypes were successfully identified. Immune cell infiltration analysis defined three subtypes as innate immune activated UC (IIA), whole immune activated UC (WIA), and immune homeostasis like UC (IHL). Notably, the response rate towards biological agents (infliximab/vedolizumab) in WIA patients was the lowest (less than 10%), while the response rate in IHL patients was the highest, ranging from 42 to 60%. Among the featured genes of subtypes, the ratio of PRLR to TNFSF13B could effectively screen for IHL UC subtype suitable for biological agent therapies (Area under curve: 0.961-0.986). Furthermore, we demonstrated that PRLR expressed in epithelial cells could inhibit the expression of TNFSF13B in monocyte-derived macrophages through the CXCL1-NF-κB pathway.

CONCLUSIONS

We identified three stable UC subtypes with a heterogeneous immune pattern and different response rates towards biological agents for the first time. We also established a precise molecular subtyping system and classifier to predict clinical drug response and provide individualized treatment strategies for UC patients.

Identification of diagnostic biomarks and immune cell infiltration in ulcerative colitis

We aimed to explore diagnostic biomarks and immune cell infiltration characteristics in ulcerative colitis (UC). We used the dataset GSE38713 as the training set and dataset GSE94648 as the test set. A total of 402 differentially expressed genes (DEGs) were obtained from GSE38713. Annotating, visualizing, and integrating discovery of these differential genes was performed using Gene Ontology (GO), Kyoto Gene and Genome Encyclopedia Pathway (KEGG), and Gene Set Enrichment Analysis (GSEA). Protein-protein interaction networks were constructed from the STRING database, and protein functional modules were identified using the CytoHubba plugin of Cytoscape. Random forest and LASSO regression were used to screen for UC-related diagnostic markers, and ROC curves were generated to validate their diagnostic value. The composition of 22 immune cells was analyzed, and the immune cell infiltration in UC was analyzed using CIBERSORT. Results: Seven diagnostic markers associated with UC were identified: TLCD3A, KLF9, EFNA1, NAAA,WDR4, CKAP4, and CHRNA1. Immune cell infiltration assessment revealed that macrophages M1, activated dendritic cells, and neutrophil cells infiltrated relatively more compared to normal control samples. Our results suggest a new functional feature of UC and suggest potential biomarkers for UC through comprehensive analysis of integrated gene expression data.

Human intestinal B cells in inflammatory diseases

The intestinal lumen contains an abundance of bacteria, viruses and fungi alongside ingested material that shape the chronically active intestinal immune system from early life to maintain the integrity of the gut epithelial barrier. In health, the response is intricately balanced to provide active protection against pathogen invasion whilst tolerating food and avoiding inflammation. B cells are central to achieving this protection. Their activation and maturation generates the body's largest plasma cell population that secretes IgA, and the niches they provide support systemic immune cell specialization. For example, the gut supports the development and maturation of a splenic B cell subset - the marginal zone B cells. In addition, cells such as the T follicular helper cells, which are enriched in many autoinflammatory diseases, are intrinsically associated with the germinal centre microenvironment that is more abundant in the gut than in any other tissue in health. In this Review, we discuss intestinal B cells and their role when a loss of homeostasis results in intestinal and systemic inflammatory diseases.

Fibrosis: Types, Effects, Markers, Mechanisms for Disease Progression, and Its Relation with Oxidative Stress, Immunity, and Inflammation

Most chronic inflammatory illnesses include fibrosis as a pathogenic characteristic. Extracellular matrix (ECM) components build up in excess to cause fibrosis or scarring. The fibrotic process finally results in organ malfunction and death if it is severely progressive. Fibrosis affects nearly all tissues of the body. The fibrosis process is associated with chronic inflammation, metabolic homeostasis, and transforming growth factor-β1 (TGF-β1) signaling, where the balance between the oxidant and antioxidant systems appears to be a key modulator in managing these processes. Virtually every organ system, including the lungs, heart, kidney, and liver, can be affected by fibrosis, which is characterized as an excessive accumulation of connective tissue components. Organ malfunction is frequently caused by fibrotic tissue remodeling, which is also frequently linked to high morbidity and mortality. Up to 45% of all fatalities in the industrialized world are caused by fibrosis, which can damage any organ. Long believed to be persistently progressing and irreversible, fibrosis has now been revealed to be a very dynamic process by preclinical models and clinical studies in a variety of organ systems. The pathways from tissue damage to inflammation, fibrosis, and/or malfunction are the main topics of this review. Furthermore, the fibrosis of different organs with their effects was discussed. Finally, we highlight many of the principal mechanisms of fibrosis. These pathways could be considered as promising targets for the development of potential therapies for a variety of important human diseases.

Inflammatory Cytokine-Neutralizing Antibody Treatment Prevented Increases in Follicular Helper T Cells and Follicular Regulatory T Cells in a Mouse Model of Arthritis

Background

Follicular T helper (TFH) and follicular regulatory T (TFR) cells play important roles in humoral immunity. Nevertheless, their significance in rheumatoid arthritis (RA) pathogenesis has not been fully elucidated. As an important treatment strategy, the effect of inflammatory factor-neutralizing antibodies on TFH and TFR in RA remains unclear.

Methods

We used the collagen-induced arthritis (CIA) mouse model to illustrate the quantity and functional changes in TFH and TFR cells. The changes of plasmablast, TFH and TFR cells in the spleen and peripheral blood of CIA mice were analyzed by flow cytometry. The levels of TFH and TFR and their functional subsets in the spleen after anti-inflammatory antibody treatment were analyzed and compared. The functional changes of TFH and TFR in CIA mice before and after treatment were detected by in vitro culture experiments.

Results

Plasmablast levels were increased in CIA spleen and peripheral blood and both TFH and TFR cell levels were upregulated. TFH and TFR cells were decreased significantly after the anti-inflammatory antibody treatment. TIGIT⁺ and TIGIT⁺CD226⁻ TFH cells in CIA mouse spleen were elevated and PD-1 and ICOS expression on spleen TFH and TFR cells was increased. Both the ability of TFH cells to secrete IL-21 and aid B cells and the ability of TFR cells to secrete IL-10 and inhibit TFH cells were enhanced in the CIA mice. After antibody treatment, the cell subsets and functions were recovered.

Conclusion

Germinal center TFH and TFR cells were increased and their functions were enhanced. With inflammatory factor-neutralizing antibody treatment, TFH and TFR subsets and their functions returned to normal. These findings provide important information on the dynamics of humoral immune-related cell subsets in RA and the effects of treatment on them.

Curcumin Inhibits T Follicular Helper Cell Differentiation in Mice with Dextran Sulfate Sodium (DSS)-Induced Colitis

Follicular helper T cells (Tfh) regulate the differentiation of germinal center B cells and maintain humoral immunity. Notably, imbalances in Tfh differentiation often lead to the development of autoimmune diseases, including inflammatory bowel disease (IBD). Curcumin, a natural product derived from Curcuma longa, is effective in relieving IBD in humans and animals, and its mechanisms of immune regulation need further elaboration. In this study, dextran sodium sulfate induced ulcerative colitis in BALB/c mice, and curcumin was administered simultaneously for 7 days. Curcumin effectively upregulated the change rate of mouse weight, colonic length, down-regulated colonic weight, index of colonic weight, colonic damage score and the levels of pro-inflammatory cytokines IL-6, IL-12, IL-23 and TGF-[Formula: see text]1 in colonic tissues of colitis mice. Importantly, curcumin regulated the differentiation balance of Tfh and their subpopulation in colitis mice; the percentages of Tfh (CD4[Formula: see text]CXCR5[Formula: see text]BCL-6[Formula: see text], CD4[Formula: see text]CXCR5[Formula: see text]PD-1[Formula: see text], CD4[Formula: see text]CXCR5[Formula: see text]PD-L1[Formula: see text], CD4[Formula: see text]CXCR5[Formula: see text]ICOS[Formula: see text], Tfh17 and Tem-Tfh were downregulated significantly, while CD4[Formula: see text]CXCR5[Formula: see text]Blimp-1[Formula: see text], Tfh1, Tfh10, Tfh21, Tfr, Tcm-Tfh and Tem-GC Tfh were upregulated. In addition, curcumin inhibited the expression of Tfh-related transcription factors BCL-6, p-STAT3, Foxp1, Roquin-1, Roquin-2 and SAP, and significantly upregulated the protein levels of Blimp-1 and STAT3 in colon tissue. In conclusion, curcumin may be effective in alleviating dextran sulfate sodium-induced colitis by regulating Tfh differentiation.

Comprehensive Flow Cytometry Profiling of the Immune System in COVID-19 Convalescent Individuals

SARS-CoV-2 has infected more than 200 million people worldwide, with more than 4 million associated deaths. Although more than 80% of infected people develop asymptomatic or mild COVID-19, SARS-CoV-2 can induce a profound dysregulation of the immune system. Therefore, it is important to investigate whether clinically recovered individuals present immune sequelae. The potential presence of a long-term dysregulation of the immune system could constitute a risk factor for re-infection and the development of other pathologies. Here, we performed a deep analysis of the immune system in 35 COVID-19 recovered individuals previously infected with SARS-CoV-2 compared to 16 healthy donors, by flow cytometry. Samples from COVID-19 individuals were analysed from 12 days to 305 days post-infection. We observed that, 10 months post-infection, recovered COVID-19 patients presented alterations in the values of some T-cell, B-cell, and innate cell subsets compared to healthy controls. Moreover, we found in recovered COVID-19 individuals increased levels of circulating follicular helper type 1 (cTfh1), plasmablast/plasma cells, and follicular dendritic cells (foDC), which could indicate that the Tfh-B-foDC axis might be functional to produce specific immunoglobulins 10 months post-infection. The presence of this axis and the immune system alterations could constitute prognosis markers and could play an important role in potential re-infection or the presence of long-term symptoms in some individuals.

The Role of T Follicular Helper Cells and Interleukin-21 in the Pathogenesis of Inflammatory Bowel Disease

T follicular helper (Tfh) cells represent a novel subset of CD4⁺ T cells which can provide critical help for germinal center (GC) formation and antibody production. The Tfh cells are characterized by the expression of CXC chemokine receptor 5 (CXCR5), programmed death 1 (PD-1), inducible costimulatory molecule (ICOS), B cell lymphoma 6 (BCL-6), and the secretion of interleukin-21 (IL-21). Given the important role of Tfh cells in B cell activation and high-affinity antibody production, Tfh cells are involved in the pathogenesis of many human diseases. Inflammatory bowel disease (IBD) is a group of chronic inflammatory diseases characterized by symptoms such as diarrhea, abdominal pain, and weight loss. Ulcerative colitis (UC) and Crohn's disease (CD) are the most studied types of IBD. Dysregulated mucosal immune response plays an important role in the pathogenesis of IBD. In recent years, many studies have identified the critical role of Tfh cells and IL-21 in the pathogenic process IBD. In this paper, we will discuss the role of Tfh cells and IL-21 in IBD pathogenesis.

Altered follicular regulatory T (Tfr)- and helper T (Tfh)-cell subsets are associated with autoantibody levels in microscopic polyangiitis patients

Antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) is an autoimmune disease characterized by B cells-derived ANCAs, and ANCA was proved to be a key factor in its pathogenesis. Follicular regulatory T (Tfr) and follicular helper T (Tfh) cells were T-cell subsets that play important roles in B-cell maturation and antibody production. However, their significances in microscopic polyangiitis (MPA) patients, one type of AAV, has not been thoroughly studied. In this study, comprehensive pattern analyses of circulating Tfr and Tfh were performed in MPA patients and healthy controls (HCs), and we found Tfr levels and Tfr/Tfh ratios were significantly decreased in MPA patients. Compared with HCs, Helios+, CD45RA-FoxP3hi, and Ki-67+ Tfr were lower in MPA patients, while CD226+ Tfr cells were higher. These phenotypes suggest that function and proliferation ability of Tfr cells were relatively impaired. Tfh subsets, including ICOS+PD-1+ and Ki-67+ Tfh, were significantly increased, suggesting that the function of Tfh was enhanced in MPA although the total Tfh levels did not change significantly. Circulating memory B cells and plasmablasts were significantly elevated and negatively correlated with Tfr levels and Tfr/Tfh ratios in MPA patients. In addition, Tfr levels and Tfr/Tfh ratios were negatively while Tfh was positively correlated with serum myeloperoxidase (MPO)-ANCA levels. Furthermore, Tfr and Tfr/Tfh ratio were also reversely associated with SCr, BUN, IL-4, and IL-21 levels. Our results suggest that the imbalance of Tfr and Tfh functional subsets is related to increased level of autoantibodies in MPA patients, and we propose a new mechanism for the pathogenesis of MPA.