Ectopic lymphoid structures support ongoing production of class-switched autoantibodies in rheumatoid synovium

Correlation of Professional Antigen-Presenting Tbet+CD11c+ B Cells With Bone Destruction in Untreated Rheumatoid Arthritis

OBJECTIVE

Subsets of CD21-/low memory B cells (MBCs), including double-negative (DN, CD27-IgD-) and Tbet+CD11c+ cells, are expanded in chronic inflammatory diseases. In rheumatoid arthritis (RA), CD21-/low MBCs correlate with joint destruction. However, whether this is due to the Tbet+CD11c+ subset, its function and pathogenic contribution to RA are unknown. This study aims to investigate the association between CD21-/lowTbet+CD11c+ MBCs and joint destruction as well as other clinical parameters and to elucidate their functional properties in patients with untreated RA (uRA).

METHODS

Clinical observations were combined with flow cytometry (n = 36) and single-cell RNA sequencing (scRNA-seq) and V(D)J sequencing (n = 4) of peripheral blood (PB) MBCs from patients with uRA. The transcriptome of circulating Tbet+CD11c+ MBCs was compared with scRNA-seq data of synovial B cells. In vitro coculture of Tbet+CD11c+ B cells with T cells was used to assess costimulatory capacity.

RESULTS

CD21-/lowTbet+CD11c+ MBCs in PB correlated with bone destruction but no other clinical parameters analyzed. The Tbet+CD11c+ MBCs have undergone clonal expansion and express somatically mutated V genes. Gene expression analysis of these cells identified a unique signature of more than 150 up-regulated genes associated with antigen presentation functions, including B cell receptor activation and clathrin-mediated antigen internalization; regulation of actin filaments, endosomes, and lysosomes; antigen processing, loading, presentation, and costimulation; a transcriptome mirrored in their synovial tissue counterparts. In vitro, Tbet+CD11c+ B cells induced retinoic acid receptor-related orphan nuclear receptor γT expression in CD4+ T cells, thereby polarizing to Th17 cells, a T cell subset critical for osteoclastogenesis and associated with bone destruction.

CONCLUSION

This study suggests that Tbet+CD11c+ MBCs contribute to the pathogenesis of RA by promoting bone destruction through antigen presentation, T cell activation, and Th17 polarization.

Monoclonal antibodies targeting interleukins for systemic lupus erythematosus: updates in early clinical drug development

INTRODUCTION

The advent of biological therapies has already revolutionized treatment strategies and disease course of several rheumatologic conditions, and monoclonal antibodies (mAbs) targeting cytokines and interleukins represent a considerable portion of this family of drugs. In systemic lupus erythematosus (SLE) dysregulation of different cytokine and interleukin-related pathways have been linked to disease development and perpetration, offering palatable therapeutic targets addressable via such mAbs.

AREAS COVERED

In this review, we provide an overview of the different biological therapies under development targeting cytokines and interleukins, with a focus on mAbs, while providing the rationale behind their choice as therapeutic targets and analyzing the scientific evidence linking them to SLE pathogenesis.

EXPERT OPINION

An unprecedented number of clinical trials on biological drugs targeting different immunological pathways are ongoing in SLE. Their success might allow us to tackle present challenges of SLE management, including the overuse of glucocorticoids in daily clinical practice, as well as SLE heterogenicity in treatment response among different individuals, hopefully paving the way toward precision medicine.

Fibroblast-like synoviocytes preferentially induce terminal differentiation of IgD+ memory B cells instead of naïve B cells

Rheumatoid arthritis (RA) is a systemic autoimmune disease driven by highly active autoantibody-producing B cells. Activation of B cells is maintained within ectopic germinal centres found in affected joints. Fibroblast-like synoviocytes (FLS) present in inflamed joints support B-cell survival, activation, and differentiation. CD27+ memory B cells and naive B cells show very different responses to activation, particularly by CD40 ligand (CD40L). We show that FLS-dependent activation of human B cells is dependent on interleukin-6 (IL-6) and CD40L. FLS have been shown to activate both naive and memory B cells. Whether the activating potential of FLS is different for naive and memory B cells has not been investigated. Our results suggest that FLS-induced activation of B cells is dependent on IL-6 and CD40L. While FLS are able to induce plasma cell differentiation, isotype switching, and antibody production in memory B cells, the ability of FLS to activate naive B cells is significantly lower.

Unveiling Novel Drug Targets and Emerging Therapies for Rheumatoid Arthritis: A Comprehensive Review

Rheumatoid arthritis (RA) is a chronic debilitating autoimmune disease, that causes joint damage, deformities, and decreased functionality. In addition, RA can also impact organs like the skin, lungs, eyes, and blood vessels. This autoimmune condition arises when the immune system erroneously targets the joint synovial membrane, resulting in synovitis, pannus formation, and cartilage damage. RA treatment is often holistic, integrating medication, physical therapy, and lifestyle modifications. Its main objective is to achieve remission or low disease activity by utilizing a "treat-to-target" approach that optimizes drug usage and dose adjustments based on clinical response and disease activity markers. The primary RA treatment uses disease-modifying antirheumatic drugs (DMARDs) that help to interrupt the inflammatory process. When there is an inadequate response, a combination of biologicals and DMARDs is recommended. Biological therapies target inflammatory pathways and have shown promising results in managing RA symptoms. Close monitoring for adverse effects and disease progression is critical to ensure optimal treatment outcomes. A deeper understanding of the pathways and mechanisms will allow new treatment strategies that minimize adverse effects and maintain quality of life. This review discusses the potential targets that can be used for designing and implementing precision medicine in RA treatment, spotlighting the latest breakthroughs in biologics, JAK inhibitors, IL-6 receptor antagonists, TNF blockers, and disease-modifying noncoding RNAs.

Bispecific T cell engager therapy for refractory rheumatoid arthritis

Bispecific T cell engagers (BiTEs) kill B cells by engaging T cells. BiTEs are highly effective in acute lymphoblastic leukemia. Here we treated six patients with multidrug-resistant rheumatoid arthritis (RA) with the CD19xCD3 BiTE blinatumomab under compassionate use. Low doses of blinatumomab led to B cell depletion and concomitant decrease of T cells, documenting their engager function. Treatment was safe, with brief increase in body temperature and acute phase proteins during first infusion but no signs of clinically relevant cytokine-release syndrome. Blinatumomab led to a rapid decline in RA clinical disease activity in all patients, improved synovitis in ultrasound and FAPI-PET-CT and reduced autoantibodies. High-dimensional flow cytometry analysis of B cells documented an immune reset with depletion of activated memory B cells, which were replaced by nonclass-switched IgD-positive naïve B cells. Together, these data suggest the feasibility and potential for BiTEs to treat RA. This approach warrants further exploration on other B-cell-mediated autoimmune diseases.

Autoimmunity to stromal-derived autoantigens in rheumatoid ectopic germinal centers exacerbates arthritis and affects clinical response

Ectopic lymphoid structures (ELSs) in the rheumatoid synovial joints sustain autoreactivity against locally expressed autoantigens. We recently identified recombinant monoclonal antibodies (RA-rmAbs) derived from single, locally differentiated rheumatoid arthritis (RA) synovial B cells, which specifically recognize fibroblast-like synoviocytes (FLSs). Here, we aimed to identify the specificity of FLS-derived autoantigens fueling local autoimmunity and the functional role of anti-FLS antibodies in promoting chronic inflammation. A subset of anti-FLS RA-rmAbs reacting with a 60 kDa band from FLS extracts demonstrated specificity for HSP60 and partial cross-reactivity to other stromal autoantigens (i.e., calreticulin/vimentin) but not to citrullinated fibrinogen. Anti-FLS RA-rmAbs, but not anti-neutrophil extracellular traps rmAbs, exhibited pathogenic properties in a mouse model of collagen-induced arthritis. In patients, anti-HSP60 antibodies were preferentially detected in RA versus osteoarthritis (OA) synovial fluid. Synovial HSPD1 and CALR gene expression analyzed using bulk RNA-Seq and GeoMx-DSP closely correlated with the lympho-myeloid RA pathotype, and HSP60 protein expression was predominantly observed around ELS. Moreover, we observed a significant reduction in synovial HSP60 gene expression followed B cell depletion with rituximab that was strongly associated with the treatment response. Overall, we report that synovial stromal-derived autoantigens are targeted by pathogenic autoantibodies and are associated with specific RA pathotypes, with potential value for patient stratification and as predictors of the response to B cell-depleting therapies.

Clinical Phenotypes, Serological Biomarkers, and Synovial Features Defining Seropositive and Seronegative Rheumatoid Arthritis: A Literature Review

Rheumatoid arthritis (RA) is a chronic autoimmune disorder which can lead to long-term joint damage and significantly reduced quality of life if not promptly diagnosed and adequately treated. Despite significant advances in treatment, about 40% of patients with RA do not respond to individual pharmacological agents and up to 20% do not respond to any of the available medications. To address this large unmet clinical need, several recent studies have focussed on an in-depth histological and molecular characterisation of the synovial tissue to drive the application of precision medicine to RA. Currently, RA patients are clinically divided into "seropositive" or "seronegative" RA, depending on the presence of routinely checked antibodies. Recent work has suggested that over the last two decades, long-term outcomes have improved significantly in seropositive RA but not in seronegative RA. Here, we present up-to-date differences in epidemiology, clinical features, and serological biomarkers in seronegative versus seropositive RA and discuss how histological and molecular synovial signatures, revealed by recent large synovial biopsy-based clinical trials, may be exploited to refine the classification of RA patients, especially in the seronegative group.

Tertiary lymphoid structural heterogeneity determines tumour immunity and prospects for clinical application

Tertiary lymphoid structures (TLS) are clusters of immune cells that resemble and function similarly to secondary lymphoid organs (SLOs). While TLS is generally associated with an anti-tumour immune response in most cancer types, it has also been observed to act as a pro-tumour immune response. The heterogeneity of TLS function is largely determined by the composition of tumour-infiltrating lymphocytes (TILs) and the balance of cell subsets within the tumour-associated TLS (TA-TLS). TA-TLS of varying maturity, density, and location may have opposing effects on tumour immunity. Higher maturity and/or higher density TLS are often associated with favorable clinical outcomes and immunotherapeutic response, mainly due to crosstalk between different proportions of immune cell subpopulations in TA-TLS. Therefore, TLS can be used as a marker to predict the efficacy of immunotherapy in immune checkpoint blockade (ICB). Developing efficient imaging and induction methods to study TA-TLS is crucial for enhancing anti-tumour immunity. The integration of imaging techniques with biological materials, including nanoprobes and hydrogels, alongside artificial intelligence (AI), enables non-invasive in vivo visualization of TLS. In this review, we explore the dynamic interactions among T and B cell subpopulations of varying phenotypes that contribute to the structural and functional diversity of TLS, examining both existing and emerging techniques for TLS imaging and induction, focusing on cancer immunotherapies and biomaterials. We also highlight novel therapeutic approaches of TLS that are being explored with the aim of increasing ICB treatment efficacy and predicting prognosis.

Intra-abdominal transplantation of PLGA/PCL/M13 phage electrospun scaffold induces self-assembly of lymphoid tissue-like structure

Lymphoid organs are the main structural components of the immune system. In the current research, the mixture of poly lactic-co-glycolic acid (PLGA), polycaprolactone (PCL), and M13 phage or its RGD-modified form was used in the construction of a fibrillar scaffold using the electrospinning method. The constructs were transplanted intra-abdominally and examined for the formation of lymphoid-like tissues at different time intervals. The confocal and scanning electron microscopy demonstrate that M13 phage-containing scaffolds provide a suitable environment for lymph node-isolated fibroblasts. Morphological analysis demonstrate the formation of lymph node-like tissues in the M13 phage-containing scaffolds after transplantation. Histological analysis confirm both blood and lymph angiogenesis in the implanted construct and migration of inflammatory cells to the M13 phage-containing scaffolds. In addition, flow cytometry and immunohistochemistry analysis showed the homing and compartmentalization of dendritic cells (DCs), B and T lymphocytes within the PLGA/PCL/M13 phage-RGD based scaffolds and similar to what is seen in the mouse lymphoid tissues. It seems that the application of M13 phage could improve the generation of functional lymphoid tissues in the electrospun scaffolds and could be used for lymphoid tissue regeneration.

Histologically Proven Recurrent Synovitis after Nivolumab Treatment

A 58-year-old woman with rheumatoid arthritis was diagnosed with methotrexate-associated Hodgkin lymphoma. After receiving several chemotherapy regimens, she started nivolumab treatment. Two weeks later, she was hospitalized with worsening finger, wrist, and elbow joint pain. A synovial biopsy of the wrist joint showed villous synovial proliferation and linear infiltration of CD68-/CD3-positive T cells (with more CD8 than CD4 T cells) but no CD20-positive B cells or CD138-positive macrophages. These findings corresponded to synovitis associated with immune-related adverse events, which are induced mainly by T cells and are different from typical rheumatoid arthritis (RA), in which B cells play a central role.

Seven-chain adaptive immune receptor repertoire analysis in rheumatoid arthritis reveals novel features associated with disease and clinically relevant phenotypes

BACKGROUND

In rheumatoid arthritis (RA), the activation of T and B cell clones specific for self-antigens leads to the chronic inflammation of the synovium. Here, we perform an in-depth quantitative analysis of the seven chains that comprise the adaptive immune receptor repertoire (AIRR) in RA.

RESULTS

In comparison to controls, we show that RA patients have multiple and strong differences in the B cell receptor repertoire including reduced diversity as well as altered isotype, chain, and segment frequencies. We demonstrate that therapeutic tumor necrosis factor inhibition partially restores this alteration but find a profound difference in the underlying biochemical reactivities between responders and non-responders. Combining the AIRR with HLA typing, we identify the specific T cell receptor repertoire associated with disease risk variants. Integrating these features, we further develop a molecular classifier that shows the utility of the AIRR as a diagnostic tool.

CONCLUSIONS

Simultaneous sequencing of the seven chains of the human AIRR reveals novel features associated with the disease and clinically relevant phenotypes, including response to therapy. These findings show the unique potential of AIRR to address precision medicine in immune-related diseases.

Correlation of serum and local CXCL13 levels with disease severity in patients with non-traumatic osteonecrosis of femoral head

OBJECTIVE

The primary aim of the present study was to explore the potential correlation of serum / local CXCL13 expressions and disease severity in non-traumatic osteonecrosis of the femoral head (NT-ONFH).

METHODS

In total, NT-ONFH patients (n = 130) together with healthy controls (HCs, n = 130) were included in this investigation. Radiographic progression was evaluated based on the imaging criteria outlined in the ARCO classification system. To assess the diagnostic value of serum CXCL13 in relation to radiographic progression, Receiver operating characteristic (ROC) curve analysis was conducted. Serum CXCL13 levels were quantified utilizing ELISA in all participants. Furthermore, local protein/mRNA expressions of CXCL13 were examined employing immunohistochemistry, western blot, as well as RT-PCR techniques. Clinical severity was appraised using the visual analogue scale (VAS), Harris Hip Score (HHS), and Western Ontario as well as McMaster Universities Osteoarthritis Index (WOMAC).

RESULTS

The findings revealed a significant reduction in serum CXCL13 levels among NT-ONFH patients in contrast with HCs. Moreover, both mRNA and protein expressions of CXCL13 were markedly decreased in the necrotic area (NA) than the non-necrotic area (NNA) as well as the healthy femoral head tissues. Additionally, serum CXCL13 levels were substantially lower among patients classified as ARCO stage 4 than those at ARCO stage 3. The concentrations of CXCL13 in stage 3 patients were notably diminished relative to those at ARCO stage 2. Notably, serum CXCL13 levels demonstrated a negative association with ARCO grade. Furthermore, these levels were also inversely linked to VAS scores as well as WOMAC scores while displaying a positive association with HHS scores. The findings of ROC curve suggested that reduced serum CXCL13 levels could be an underlying indicator for ARCO stage.

CONCLUSIONS

The reduced levels of either serum CXCL13 or local CXCL13 were intricately linked to disease severity for patients with NT-ONFH.

Translational and oncologic significance of tertiary lymphoid structures in pancreatic adenocarcinoma

Pancreatic adenocarcinoma (PDAC) is an aggressive tumor with poor survival and limited treatment options. PDAC resistance to immunotherapeutic strategies is multifactorial, but partially owed to an immunosuppressive tumor immune microenvironment (TiME). However, the PDAC TiME is heterogeneous and harbors favorable tumor-infiltrating lymphocyte (TIL) populations. Tertiary lymphoid structures (TLS) are organized aggregates of immune cells that develop within non-lymphoid tissue under chronic inflammation in multiple contexts, including cancers. Our current understanding of their role within the PDAC TiME remains limited; TLS are complex structures with multiple anatomic features such as location, density, and maturity that may impact clinical outcomes such as survival and therapy response in PDAC. Similarly, our understanding of methods to manipulate TLS is an actively developing field of research. TLS may function as anti-tumoral immune niches that can be leveraged as a therapeutic strategy to potentiate both existing chemotherapeutic regimens and potentiate future immune-based therapeutic strategies to improve patient outcomes. This review seeks to cover anatomy, relevant features, immune effects, translational significance, and future directions of understanding TLS within the context of PDAC.

Comparative analysis of late-stage rheumatoid arthritis and osteoarthritis reveals shared histopathological features

OBJECTIVES

Osteoarthritis (OA) is a debilitating and heterogeneous condition, characterized by various levels of articular cartilage degradation, osteophytes formation, and synovial inflammation. Multiple evidences suggest that synovitis may appear early in the disease development and correlates with disease severity and pain, therefore representing a relevant therapeutic target. In a typical synovitis-driven joint disease, namely rheumatoid arthritis (RA), several pathotypes have been described by our group and associated with clinical phenotypes, disease progression, and response to therapy. However, whether these pathotypes can be also observed in the OA synovium is currently unknown.

METHODS

Here, using histological approaches combined with semi-quantitative scoring and quantitative digital image analyses, we comparatively characterize the immune cell infiltration in a large cohort of OA and RA synovial tissue samples collected at the time of total joint replacement.

RESULTS

We demonstrate that OA synovium can be categorized also into three pathotypes and characterized by disease- and stage-specific features. Moreover, we revealed that pathotypes specifically reflect distinct levels of peripheral inflammation.

CONCLUSIONS

In this study, we provide a novel and relevant pathological classification of OA synovial inflammation. Further studies investigating synovial molecular pathology in OA may contribute to the development of disease-modifying therapies.

Presence of ectopic germinal center structures in autoimmune hepatitis

Autoimmune tissues may contain ectopic germinal centers (EGCs). However, these structures have never been described in the liver of patients suffering from autoimmune hepatitis (AIH). We retrospectively reviewed histological features of 120 definite AIH cases, and found 10 cases harboring markers of EGCs. In these cases, CD21+ follicular dendritic cells were intermixed with CD3+ T and CD20+ B lymphocytes. The latter expressed the GC-specific marker bcl6, and some were proliferative as assessed by Ki67 expression. Antibody-secreting cells (ASCs) defined by expression of the mum-1 transcription factor and presence of cytoplasmic IgMs were usually present in the periphery of these structures, but some were also present within the EGCs. Notably, some ASCs were IgG-switched. Common treatment applied to AIH patients achieved biochemical normalization as efficiently as in patients without EGCs. In the present study, we provide the proof for the occurrence of functional EGCs enabling differentiation of B cells into ASCs and occurrence of immunoglobulin switch in AIH livers.

Synovial tissue features associated with poor prognosis in inflammatory arthritis

BACKGROUND

Inflammatory arthritis encompasses a group of immune-mediated diseases characterized by chronic joint inflammation. Despite having pathogenic mechanisms in common, the prognosis of rheumatoid arthritis (RA), psoriatic arthritis (PsA), and undifferentiated arthritis (UA) could be different regarding progression to chronic, to erosive, or to self-limited disease. Our aim was to evaluate the potential association of synovial tissue (ST) inflammatory cell infiltrate, the presence of ectopic lymphoid neogenesis (LN +) structures, and poor prognosis factors (PPF) in patients with RA, PsA, and UA.

METHODS

We conducted a retrospective study including patients with active arthritis (RA, PsA, UA) who had ST obtained by rheumatological arthroscopy or ultrasound-guided biopsy. Clinical, demographic, and immunohistochemical data of the synovium was evaluated. Patients with biological therapy at the time of synovial biopsy were excluded. PPF in patients with RA and UA were defined by the presence of anti-cyclic citrullinated peptide antibodies and/or rheumatoid factor, development of bone erosions, or requirement of biological therapy during the follow-up. PPF in patients with PsA were defined as the presence of high levels of acute-phase reactants (ESR/CRP), dactylitis or nail involvement at the time of biopsy, development of bone erosion, or requirement of biological therapy during the follow-up.

RESULTS

A total of 88 patients were included: 26 RA, 33 PsA, and 29 UA. All patients were followed up for 5 years after the biopsy. Fourteen (53.84%) RA patients had PPF, and 17 (65.38%) had LN + . LN + was associated with PPF (p 0.038) and biologic therapy initiation (p 0.018). A total of 14 (43.75%) PsA patients had PPF. CD15 infiltrate (410.68 [SD 477.63] cells/mm2) was associated with PPF (p 0.008) in PsA patients. Sixteen (55.17%) patients with UA had PPF, and 13 (44.82%) had LN + . In this group, synovial CD68 + macrophages cells density was negatively correlated with DAS28-CRP (r =  - 0.346, p 0.042).

CONCLUSIONS

The presence of LN + and higher CD15 + polymorphonuclear cells infiltrate was associated with PPF in RA and PsA, respectively. No associations were found for UA. These findings suggest a great heterogeneity of the ST features and its pathogenic implications in the subtypes of inflammatory arthritis.

Distinct fibroblast functions associated with fibrotic and immune-mediated inflammatory diseases and their implications for therapeutic development

Fibroblasts are ubiquitous cells that can adopt many functional states. As tissue-resident sentinels, they respond to acute damage signals and shape the earliest events in fibrotic and immune-mediated inflammatory diseases. Upon sensing an insult, fibroblasts produce chemokines and growth factors to organize and support the response. Depending on the size and composition of the resulting infiltrate, these activated fibroblasts may also begin to contract or relax thus changing local stiffness within the tissue. These early events likely contribute to the divergent clinical manifestations of fibrotic and immune-mediated inflammatory diseases. Further, distinct changes to the cellular composition and signaling dialogue in these diseases drive progressive fibroblasts specialization. In fibrotic diseases, fibroblasts support the survival, activation and differentiation of myeloid cells, granulocytes and innate lymphocytes, and produce most of the pathogenic extracellular matrix proteins. Whereas, in immune-mediated inflammatory diseases, sequential accumulation of dendritic cells, T cells and B cells programs fibroblasts to support local, destructive adaptive immune responses. Fibroblast specialization has clear implications for the development of effective induction and maintenance therapies for patients with these clinically distinct diseases.

Tertiary lymphoid structures in autoimmune diseases

Tertiary lymphoid structures (TLSs) are organized lymphoid-like aggregations in non-lymphoid tissues. Tissues with chronic and persistent inflammation infiltration may drive and form ectopic germinal center-like structures, which are very common in autoimmune diseases, chronic infections, and tumor microenvironments. However, the mechanisms governing the formation of TLSs are still being explored. At present, it is not clear whether the formation of TLSs is associated with local uncontrolled immune inflammatory responses. While TLSs suggest a good prognosis in tumors, the opposite is true in autoimmune diseases. This review article will discuss the current views on initiating and maintaining TLSs and the potential therapeutic target in autoimmune diseases.

Microenvironmental network of clonal CXCL13+CD4+ T cells and Tregs in pemphigus chronic blisters

BACKGROUNDPemphigus, a rare autoimmune bullous disease mediated by antidesmoglein autoantibodies, can be controlled with systemic medication like rituximab and high-dose systemic corticosteroids combined with immunosuppressants. However, some patients continue to experience chronically recurrent blisters in a specific area and require long-term maintenance systemic therapy.METHODSSkin with chronic blisters was obtained from patients with pemphigus. Immunologic properties of the skin were analyzed by immunofluorescence staining, bulk and single-cell RNA and TCR sequencing, and a highly multiplex imaging technique known as CO-Detection by indEXing (CODEX). Functional analyses were performed by flow cytometry and bulk RNA-Seq using peripheral blood from healthy donors. Intralesional corticosteroid was injected into patient skin, and changes in chronically recurrent blisters were observed.RESULTSWe demonstrated the presence of skin tertiary lymphoid structures (TLSs) with desmoglein-specific B cells in chronic blisters from patients with pemphigus. In the skin TLSs, CD4+ T cells predominantly produced CXCL13. These clonally expanded CXCL13+CD4+ T cells exhibited features of activated Th1-like cells and downregulated genes associated with T cell receptor-mediated signaling. Tregs are in direct contact with CXCL13+CD4+ memory T cells and increased CXCL13 production of CD4+ T cells through IL-2 consumption and TGF-β stimulation. Finally, intralesional corticosteroid injection improved chronic blisters and reduced skin TLSs in patients with pemphigus.CONCLUSIONThrough this study we conclude that skin TLSs are associated with the persistence of chronically recurrent blisters in patients with pemphigus, and the microenvironmental network involving CXCL13+CD4+ T cells and Tregs within these structures plays an important role in CXCL13 production.TRIAL REGISTRATIONClinicalTrials.gov NCT04509570.FUNDINGThis work was supported by National Research Foundation of South Korea (NRF-2021R1C1C1007179) and Korea Drug Development Fund, which is funded by Ministry of Science and ICT; Ministry of Trade, Industry, and Energy; and Ministry of Health and Welfare (grant RS-2022-00165917).

Synovial biopsies for molecular definition of rheumatoid arthritis and treatment response phenotyping: where can we improve?

INTRODUCTION

The extensive knowledge gained in the cellular and molecular mechanisms underlying Rheumatoid Arthritis (RA) pathogenesis has led to therapeutic advances. However, up to 10-20% of patients fail to respond to multiple therapeutic agents being classified as multi-drugresistant. A key challenge moving forward will be the implementation of synovial biopsies in clinical practice to facilitate the shift from the current trial-and-error strategy toward new forms of clinical trials. Biomarker-driven trials have the potential to improve drug selection and patient stratification, reduce economic costs and unnecessary drug-related toxicity.

AREAS COVERED

This special report explores the clinical and research applications of synovial biopsy, the advancement in the molecular pathobiology of RA to better understand disease pathogenesis and treatment response, and the way forward for the paradigm shift needed.

EXPERT OPINION

In the current era of highly targeted biologic drugs which have dramatically transformed the outlook of RA patients, the use of synovial biopsy represents a valuable practical tool to dissect disease pathogenesis and, consequently, treatment response. In the near future, it is hoped that technological advances will allow for speeding up synovial molecular analysis and that the design of new biomarker-driven trials will enable the allocation of patients to more effective treatment.

Integrating the autoimmune connective tissue diseases for the medical student: A classification proposal based on pathogenesis and clinical phenotype

It is hard for medical students to recognize and understand the clinical presentation of systemic connective tissue diseases (SCTDs). In this study, we aimed to review the immune mechanisms of the main SCTDs and to propose a classification system focused on the student and based on each immune dysfunction's clinical phenotype. The search involved the MEDLINE database and included the terms "systemic lupus erythematosus," "antiphospholipid syndrome," "inflammatory myopathies," "rheumatoid arthritis," "Sjögren's syndrome" or "systemic sclerosis" and "pathogenesis," and "immunology" or "mechanism of disease." Systemic lupus erythematosus (SLE) is a prototypic immune-complex disease with a tendency toward vascular injury. Antiphospholipid syndrome (APS) is a diffuse immune-mediated thrombotic vasculopathy. In inflammatory myopathies (IMs), muscle inflammation leading to muscle weakness is the cardinal manifestation. Rheumatoid arthritis (RA) is a unique form of erosive and destructive polyarthritis. Sjögren's syndrome (SS) causes sicca symptoms due to infiltration of the exocrine glands. Disseminated fibrosis in systemic sclerosis (SSc) is caused by vascular injury with excessive fibroblast activation. After the review, we created a focus group involving all the authors to group the diseases according to their pathogenesis and clinical phenotype. Our group agreed that SCTDs can be divided in 3 groups based on the preferential clinical presentation and immune dysfunction: 1) vasculopathic features (SLE and APS), 2) tissue inflammation (IMs, RA, and SS), and 3) tissue fibrosis (SSc). In synthesis, we suggest that clustering SCTDs in groups based on clinical phenotype and presumptive immune dysfunction instead of ordering autoantibodies randomly can help students understand the diseases.

The roles of tertiary lymphoid structures in chronic diseases

Tertiary lymphoid structures (TLSs) are ectopic lymphoid tissues that drive antigen-specific immune responses at sites of chronic inflammation. Unlike secondary lymphoid organs such as lymph nodes, TLSs lack capsules and have their own unique characteristics and functions. The presumed influence of TLSs on the disease course has led to widespread interest in obtaining a better understanding of their biology and function. Studies using single-cell analyses have suggested heterogeneity in TLS composition and phenotype, and consequently, functional correlates with disease progression are sometimes conflicting. The presence of TLSs correlates with a favourable disease course in cancer and infection. Conversely, in autoimmune diseases and chronic age-related inflammatory diseases including chronic kidney disease, the presence of TLSs is associated with a more severe disease course. However, the detailed mechanisms that underlie these clinical associations are not fully understood. To what extent the mechanisms of TLS development and maturation are shared across organs and diseases is also still obscure. Improved understanding of TLS development and function at the cellular and molecular levels may enable the exploitation of these structures to improve therapies for chronic diseases, including chronic kidney disease.

The Search for the Pathogenic T Cells in the Joint of Rheumatoid Arthritis: Which T-Cell Subset Drives Autoimmune Inflammation?

Rheumatoid arthritis (RA) is a chronic inflammatory disorder affecting systemic synovial tissues, leading to the destruction of multiple joints. Its etiology is still unknown, but T-cell-mediated autoimmunity has been thought to play critical roles, which is supported by experimental as well as clinical observations. Therefore, efforts have been made to elucidate the functions and antigen specificity of pathogenic autoreactive T cells, which could be a therapeutic target for disease treatment. Historically, T-helper (Th)1 and Th17 cells are hypothesized to be pathogenic T cells in RA joints; however, lines of evidence do not fully support this hypothesis, showing polyfunctionality of the T cells. Recent progress in single-cell analysis technology has led to the discovery of a novel helper T-cell subset, peripheral helper T cells, and attracted attention to the previously unappreciated T-cell subsets, such as cytotoxic CD4 and CD8 T cells, in RA joints. It also enables a comprehensive view of T-cell clonality and function. Furthermore, the antigen specificity of the expanded T-cell clones can be determined. Despite such progress, which T-cell subset drives inflammation is yet known.

T peripheral helper cells in autoimmune diseases: What do we know?

The interactions between T cells and B cells are essential for antibody responses and the development of autoimmune diseases. Recently, a distinct subset of T cells capable of helping B cells was established in synovial fluid, and they were termed peripheral helper T (Tph) cells. PD-1hiCXCR5−CD4+ Tph cells express high levels of CXCL13, which drives the formation of lymphoid aggregates and tertiary lymphoid structures, ultimately facilitating the local production of pathogenic autoantibodies. Tph and T follicular helper cells share some key features but can be distinguished by their surface markers, transcriptional regulation, and migration capability. We summarize recent findings on Tph cells in this review and provide a perspective on their potential roles in a range of autoimmune diseases. More clinical and in-depth mechanistic investigations of Tph cells may help to improve the understanding of pathogenesis and further provide novel therapeutic targets in autoimmune diseases.

Adventitial adaptive immune cells are associated with ascending aortic dilatation in patients with a bicuspid aortic valve

Background

Bicuspid aortic valve (BAV) is associated with ascending aorta aneurysms and dissections. Presently, genetic factors and pathological flow patterns are considered responsible for aneurysm formation in BAV while the exact role of inflammatory processes remains unknown.

Methods

In order to objectify inflammation, we employ a highly sensitive, quantitative immunohistochemistry approach. Whole slides of dissected, dilated and non-dilated ascending aortas from BAV patients were quantitatively analyzed.

Results

Dilated aortas show a 4-fold increase of lymphocytes and a 25-fold increase in B lymphocytes in the adventitia compared to non-dilated aortas. Tertiary lymphoid structures with B cell follicles and helper T cell expansion were identified in dilated and dissected aortas. Dilated aortas were associated with an increase in M1-like macrophages in the aorta media, in contrast the number of M2-like macrophages did not change significantly.

Conclusion

This study finds unexpected large numbers of immune cells in dilating aortas of BAV patients. These findings raise the question whether immune cells in BAV aortopathy are innocent bystanders or contribute to the deterioration of the aortic wall.

Relations Between Adolescent Sensation Seeking and Risky Sexual Behaviors Across Sex, Race, and Age: A Meta-Analysis

Sensation seeking (SS)-the seeking of novel and intense sensations or experiences and the willingness to take risks for the sake of such experiences-has been shown to be related to various risky sexual behaviors (RSBs) in areas such as multiple sexual partners, condom use, and sexual initiation. The aims of the current meta-analysis were to examine (1) how SS relates to specific RSBs in adolescents and (2) how the overall relationship between SS and RSB differs across sex, race, and age. Overall, a total of 40 studies met the inclusion criteria for our meta-analysis examining the relationship between SS and RSB, contributing 102 effect sizes. RSB variables included unprotected sex; multiple sexual partners; hazardous sexual activity; sexual initiation; virginity status; and history of sexually transmitted disease (STD) diagnosis. Moderating effects of sex, race, and age were also examined. The overall mean effect size of the correlational relationship between adolescent SS and RSB was statistically significant, as were the mean effect sizes of the relationships between SS and RSB subgroups, except for history of STD diagnosis. Race and age did not significantly moderate the overall relationship between SS and RSB; however, results indicated that SS and RSB relations were stronger in females compared to males. Our findings suggest that adolescents with elevations in SS tendencies tend to engage in more RSBs compared to their peers with lower levels of SS, increasing their risk of unplanned pregnancy and STD acquisition.

Heterogeneity of antibody-secreting cells infiltrating autoimmune tissues

The humoral response is frequently dysfunctioning in autoimmunity with a frequent rise in total serum immunoglobulins, among which are found autoantibodies that may be pathogenic by themselves and/or propagate the inflammatory reaction. The infiltration of autoimmune tissues by antibody-secreting cells (ASCs) constitutes another dysfunction. The known high dependency of ASCs on the microenvironment to survive combined to the high diversity of infiltrated tissues implies that ASCs must adapt. Some tissues even within a single clinical autoimmune entity are devoid of infiltration. The latter means that either the tissue is not permissive or ASCs fail to adapt. The origin of infiltrated ASCs is also variable. Indeed, ASCs may be commonly generated in the secondary lymphoid organ draining the autoimmune tissue, and home at the inflammation site under the guidance of specific chemokines. Alternatively, ASCs may be generated locally, when ectopic germinal centers are formed in the autoimmune tissue. Alloimmune tissues with the example of kidney transplantation will also be discussed own to their high similarity with autoimmune tissues. It should also be noted that antibody production is not the only function of ASCs, since cells with regulatory functions have also been described. This article will review all the phenotypic variations indicative of tissue adaptation described so for at the level of ASC-infiltrating auto/alloimmune tissues. The aim is to potentially define tissue-specific molecular targets in ASCs to improve the specificity of future autoimmune treatments.

A Review of Compartmentalised Inflammation and Tertiary Lymphoid Structures in the Pathophysiology of Multiple Sclerosis

Multiple sclerosis (MS) is a chronic, immune-mediated, demyelinating disease of the central nervous system (CNS). The most common form of MS is a relapsing–remitting disease characterised by acute episodes of demyelination associated with the breakdown of the blood–brain barrier (BBB). In the relapsing–remitting phase there is often relative recovery (remission) from relapses characterised clinically by complete or partial resolution of neurological symptoms. In the later and progressive stages of the disease process, accrual of neurological disability occurs in a pathological process independent of acute episodes of demyelination and is accompanied by a trapped or compartmentalised inflammatory response, most notable in the connective tissue spaces of the vasculature and leptomeninges occurring behind an intact BBB. This review focuses on compartmentalised inflammation in MS and in particular, what we know about meningeal tertiary lymphoid structures (TLS; also called B cell follicles) which are organised clusters of immune cells, associated with more severe and progressive forms of MS. Meningeal inflammation and TLS could represent an important fluid or imaging marker of disease activity, whose therapeutic abrogation might be necessary to stop the most severe outcomes of disease.

The Brave New World of Early Treatment of Multiple Sclerosis: Using the Molecular Biomarkers CXCL13 and Neurofilament Light to Optimize Immunotherapy

Multiple sclerosis (MS) is a highly heterogeneous disease involving a combination of inflammation, demyelination, and CNS injury. It is the leading cause of non-traumatic neurological disability in younger people. There is no cure, but treatments in the form of immunomodulatory drugs (IMDs) are available. Experience over the last 30 years has shown that IMDs, also sometimes called disease-modifying therapies, are effective in downregulating neuroinflammatory activity. However, there are a number of negatives in IMD therapy, including potential for significant side-effects and adverse events, uncertainty about long-term benefits regarding disability outcomes, and very high and increasing financial costs. The two dozen currently available FDA-approved IMDs also are heterogeneous with respect to efficacy and safety, especially long-term safety, and determining an IMD treatment strategy is therefore challenging for the clinician. Decisions about optimal therapy have been particularly difficult in early MS, at the time of the initial clinical demyelinating event (ICDE), at a time when early, aggressive treatment would best be initiated on patients destined to have a highly inflammatory course. However, given the fact that the majority of ICDE patients have a more benign course, aggressive immunosuppression, with its attendant risks, should not be administered to this group, and should only be reserved for patients with a more neuroinflammatory course, a decision that can only be made in retrospect, months to years after the ICDE. This quandary of moderate vs. aggressive therapy facing clinicians would best be resolved by the use of biomarkers that are predictive of future neuroinflammation. Unfortunately, biomarkers, especially molecular biomarkers, have not thus far been particularly useful in assisting clinicians in predicting the likelihood of future neuroinflammation, and thus guiding therapy. However, the last decade has seen the emergence of two highly promising molecular biomarkers to guide therapy in early MS: the CXCL13 index and neurofilament light. This paper will review the immunological and neuroscientific underpinnings of these biomarkers and the data supporting their use in early MS and will propose how they will likely be used to maximize benefit and minimize risk of IMDs in MS patients.

From vaccines to nanovaccines: A promising strategy to revolutionize rheumatoid arthritis treatment

Rheumatoid arthritis (RA) is a joint-related autoimmune disease that is difficult to cure. Most therapeutics act to alleviate the symptoms but not correct the causes of RA. Novel strategies that specifically target the causes are highly needed for RA management. Currently, early interruption of RA is increasingly suggested but the corresponding therapeutics are not available. Vaccines that have shown great success to combat infection, cancer, degenerative diseases, autoimmune diseases, etc. are ideal candidates for a new generation of anti-RA therapeutics to correct the causes and prevent RA or interrupt RA in early phases. Anti-RA vaccines can be divided into two major categories. One is to induce neutralizing antibodies and the other is to induce antigen-specific immune tolerance. The vaccines are inherently linked to nanotechnology because they usually need a biomacromolecule or carrier to provoke sufficient immune responses. In the past decade, designed nanocarriers such as nanoparticles, liposomes, nanoemulsion, etc., have been applied to optimize the vaccines for autoimmune disease treatment. Nanotechnology endows vaccines with a higher biostability, tunable in vivo behavior, better targeting, co-delivery with stimulatory agents, regulatory effects on immune responses, etc. In this review, unmet medical needs for RA treatment and anti-RA vaccinology are first introduced. The development of anti-RA therapies from vaccines to nanovaccines are then reviewed and perspectives on how nanotechnology promotes vaccine development and advancement are finally provided. In addition, challenges for anti-RA vaccine development are summarized and advantages of nanovaccines are analyzed. In conclusion, nanovaccines will be a promising strategy to revolutionize the treatment of RA by correcting the causes in an early phase of RA.

Beta cell and immune cell interactions in autoimmune type 1 diabetes: How they meet and talk to each other

Background

Scope of review

Major conclusions

Role of tertiary lymphoid organs in the regulation of immune responses in the periphery

Tertiary lymphoid organs (TLOs) are collections of immune cells resembling secondary lymphoid organs (SLOs) that form in peripheral, non-lymphoid tissues in response to local chronic inflammation. While their formation mimics embryologic lymphoid organogenesis, TLOs form after birth at ectopic sites in response to local inflammation resulting in their ability to mount diverse immune responses. The structure of TLOs can vary from clusters of B and T lymphocytes to highly organized structures with B and T lymphocyte compartments, germinal centers, and lymphatic vessels (LVs) and high endothelial venules (HEVs), allowing them to generate robust immune responses at sites of tissue injury. Although our understanding of the formation and function of these structures has improved greatly over the last 30 years, their role as mediators of protective or pathologic immune responses in certain chronic inflammatory diseases remains enigmatic and may differ based on the local tissue microenvironment in which they form. In this review, we highlight the role of TLOs in the regulation of immune responses in chronic infection, chronic inflammatory and autoimmune diseases, cancer, and solid organ transplantation.

T Cell Help in the Autoreactive Germinal Center

The germinal center serves as a site of B cell selection and affinity maturation, critical processes for productive adaptive immunity. In autoimmune disease tolerance is broken in the germinal center reaction, leading to production of autoreactive B cells that may propagate disease. Follicular T cells are crucial regulators of this process, providing signals necessary for B cell survival in the germinal center. Here we review the emerging roles of follicular T cells in the autoreactive germinal center. Recent advances in immunological techniques have allowed study of the gene expression profiles and repertoire of follicular T cells at unprecedented resolution. These studies provide insight into the potential role follicular T cells play in preventing or facilitating germinal center loss of tolerance. Improved understanding of the mechanisms of T cell help in autoreactive germinal centers provides novel therapeutic targets for diseases of germinal center dysfunction.

Dynamic spectrum of ectopic lymphoid B cell activation and hypermutation in the RA synovium characterized by NR4A nuclear receptor expression

Ectopic lymphoid structures (ELS) can develop in rheumatoid arthritis (RA) synovial tissue, but the precise pathways of B cell activation and selection are not well understood. Here, we identify a synovial B cell population characterized by co-expression of a family of orphan nuclear receptors (NR4A1-3), which is highly enriched in RA synovial tissue. A transcriptomic profile of NR4A synovial B cells significantly overlaps with germinal center light zone B cells and an accrual of somatic hypermutation that correlates with loss of naive B cell state. NR4A B cells co-express lymphotoxins α and β and IL-6, supporting functions in ELS promotion. Expanded and shared clones between synovial NR4A B cells and plasma cells and the rapid upregulation with BCR stimulation point to in situ differentiation. Together, we identify a dynamic progression of B cell activation in RA synovial ELS, with NR4A transcription factors having an important role in local adaptive immune responses.

Inside the Joint of Inflammatory Arthritis Patients: Handling and Processing of Synovial Tissue Biopsies for High Throughput Analysis

Inflammatory arthritis is a chronic systemic autoimmune disease of unknown etiology, which affects the joints. If untreated, these diseases can have a detrimental effect on the patient's quality of life, leading to disabilities, and therefore, exhibit a significant socioeconomic impact and burden. While studies of immune cell populations in arthritis patient's peripheral blood have been informative regarding potential immune cell dysfunction and possible patient stratification, there are considerable limitations in identifying the early events that lead to synovial inflammation. The joint, as the site of inflammation and the local microenvironment, exhibit unique characteristics that contribute to disease pathogenesis. Understanding the contribution of immune and stromal cell interactions within the inflamed joint has been met with several technical challenges. Additionally, the limited availability of synovial tissue biopsies is a key incentive for the utilization of high-throughput techniques in order to maximize information gain. This review aims to provide an overview of key methods and novel techniques that are used in the handling, processing and analysis of synovial tissue biopsies and the potential synergy between these techniques. Herein, we describe the utilization of high dimensionality flow cytometric analysis, single cell RNA sequencing, ex vivo functional assays and non-intrusive metabolic characterization of synovial cells on a single cell level based on fluorescent lifetime imaging microscopy. Additionally, we recommend important points of consideration regarding the effect of different storage and handling techniques on downstream analysis of synovial tissue samples. The introduction of new powerful techniques in the study of synovial tissue inflammation, brings new challenges but importantly, significant opportunities. Implementation of novel approaches will accelerate our path toward understanding of the mechanisms involved in the pathogenesis of inflammatory arthritis and lead to the identification of new avenues of therapeutic intervention.

Characteristics and Prognostic Value of Tertiary Lymphoid Organs in Membranous Nephropathy: A Retrospective Study

Background

Tertiary lymphoid organs play an essential role in the inflammation of the kidney. The clinical association between TLOs and membranous nephropathy (MN) is not clear yet.

Methods

Consecutive patients with the histologically confirmed membranous nephropathy in Tongji Hospital from July 19, 2012, to September 26, 2019, were included in this study. TLOs in renal biopsy tissues were detected by periodic acid–Schiff-stained and immunohistochemistry. Logistic regression was performed to evaluate the correlations of TLOs and clinical features of patients with MN. Kaplan–Meier analysis was utilized to examine the relationship between TLOs and remission of proteinuria.

Results

A total of 442 patients with MN were included in this study, of which the average age was 46.4 years old, and 58.8% were male. Moreover, 33% of patients with MN had TLOs in this study. The median value of proteinuria among patients with MN with TLOs was 4.9 g/24 h, which was much greater than no-TLOs ones (3.2 g/24 h, p < 0.001). Moreover, the patients with TLOs had higher serum creatinine and lower serum albumin. The severity of clinical features among the patients with MN aggravated with the increase in the grade of TLOs. In addition, the patients who had TLOs were more likely to be positive of anti-phospholipase A2 receptor autoantibodies. Meanwhile, the patients without TLOs showed significantly higher complete remission and total remission of proteinuria.

Conclusion

In this study, we demonstrated that TLOs were common among patients with MN. Moreover, the patients with MN with TLOs showed a worse clinical manifestation and an outcome compared with the patients without TLOs.

Differences in local immune cell landscape between Q fever and atherosclerotic abdominal aortic aneurysms identified by multiplex immunohistochemistry

Background:

Chronic Q fever is a zoonosis caused by the bacterium Coxiella burnetii which can manifest as infection of an abdominal aortic aneurysm (AAA). Antibiotic therapy often fails, resulting in severe morbidity and high mortality. Whereas previous studies have focused on inflammatory processes in blood, the aim of this study was to investigate local inflammation in aortic tissue.

Methods:

Multiplex immunohistochemistry was used to investigate local inflammation in Q fever AAAs compared to atherosclerotic AAAs in aorta tissue specimen. Two six-plex panels were used to study both the innate and adaptive immune systems.

Results:

Q fever AAAs and atherosclerotic AAAs contained similar numbers of CD68⁺ macrophages and CD3⁺ T cells. However, in Q fever AAAs, the number of CD68⁺CD206⁺ M2 macrophages was increased, while expression of GM-CSF was decreased compared to atherosclerotic AAAs. Furthermore, Q fever AAAs showed an increase in both the number of CD8⁺ cytotoxic T cells and CD3⁺CD8^-FoxP3⁺ regulatory T cells. Finally, Q fever AAAs did not contain any well-defined granulomas.

Conclusions:

These findings demonstrate that despite the presence of pro-inflammatory effector cells, persistent local infection with C. burnetii is associated with an immune-suppressed microenvironment.

Funding:

This work was supported by SCAN consortium: European Research Area - CardioVascualar Diseases (ERA-CVD) grant [JTC2017-044] and TTW-NWO open technology grant [STW-14716].

Activated Peripheral Blood B Cells in Rheumatoid Arthritis and Their Relationship to Anti-Tumor Necrosis Factor Treatment and Response: A Randomized Clinical Trial of the Effects of Anti-Tumor Necrosis Factor on B Cells

OBJECTIVE

B cells can become activated in germinal center (GC) reactions in secondary lymphoid tissue and in ectopic GCs in rheumatoid arthritis (RA) synovium that may be tumor necrosis factor (TNF) and lymphotoxin (LT) dependent. This study was undertaken to characterize the peripheral B cell compartment longitudinally during anti-TNF therapy in RA.

METHODS

Participants were randomized in a 2:1 ratio to receive standard dosing regimens of etanercept (n = 43) or adalimumab (n = 20) for 24 weeks. Eligible participants met the American College of Rheumatology 1987 criteria for RA, had clinically active disease (Disease Activity Score in 28 joints >4.4), and were receiving stable doses of methotrexate. The primary mechanistic end point was the change in switched memory B cell fraction from baseline to week 12 in each treatment group.

RESULTS

B cell subsets remained surprisingly stable over the course of the study regardless of treatment group, with no significant change in memory B cells. Blockade of TNF and LT with etanercept compared to blockade of TNF alone with adalimumab did not translate into significant differences in clinical response. The frequencies of multiple activated B cell populations, including CD21- double-negative memory and activated naive B cells, were higher in RA nonresponders at all time points, and CD95+ activated B cell frequencies were increased in patients receiving anti-TNF treatment in the nonresponder group. In contrast, frequencies of transitional B cells-a putative regulatory subset-were lower in the nonresponders.

CONCLUSION

Overall, our results support the notion that peripheral blood B cell subsets are remarkably stable in RA and not differentially impacted by dual blockade of TNF and LT with etanercept or single blockade of TNF with adalimumab. Activated B cells do associate with a less robust response.

Follicular dendritic cell differentiation is associated with distinct synovial pathotype signatures in rheumatoid arthritis

Follicular dendritic cells (FDCs) fundamentally contribute to the formation of synovial ectopic lymphoid-like structures in rheumatoid arthritis (RA) which is associated with poor clinical prognosis. Despite this critical role, regulation of FDC development in the RA synovium and its correlation with synovial pathotype differentiation remained largely unknown. Here, we demonstrate that CNA.42⁺ FDCs distinctively express the pericyte/fibroblast-associated markers PDGFR-β, NG2, and Thy-1 in the synovial perivascular space but not in established follicles. In addition, synovial RNA-Seq analysis revealed that expression of the perivascular FDC markers was strongly correlated with PDGF-BB and fibroid synovitis, whereas TNF-α/LT-β was significantly associated with lymphoid synovitis and expression of CR1, CR2, and FcγRIIB characteristic of mature FDCs in lymphoid follicles. Moreover, PDGF-BB induced CNA.42⁺ FDC differentiation and CXCL13 secretion from NG2⁺ synovial pericytes, and together with TNF-α/LT-β conversely regulated early and late FDC differentiation genes in unsorted RA synovial fibroblasts (RASF) and this was confirmed in flow sorted stromal cell subsets. Furthermore, RASF TNF-αR expression was upregulated by TNF-α/LT-β and PDGF-BB; and TNF-α/LT-β-activated RASF retained ICs and induced B cell activation in in vitro germinal center reactions typical of FDCs. Additionally, FDCs trapped peptidyl citrulline, and strongly correlated with IL-6 expression, and plasma cell, B cell, and T cell infiltration of the RA synovium. Moreover, synovial FDCs were significantly associated with RA disease activity and radiographic features of tissue damage. To the best of our knowledge, this is the first report describing the reciprocal interaction between PDGF-BB and TNF-α/LT-β in synovial FDC development and evolution of RA histological pathotypes. Selective targeting of this interplay could inhibit FDC differentiation and potentially ameliorate RA in clinically severe and drug-resistant patients.

Cellular and molecular diversity in Rheumatoid Arthritis

Rheumatoid Arthritis (RA) is a chronic systemic autoimmune disease. RA mainly affects synovial joints, with inflammation of the synovial membrane (synovitis), characterised by neo-angiogenesis, hyperplasia of lining layer, and immune cell infiltration that drive local inflammation and, if untreated, can lead to joint destruction and disability. In parallel to the well-known clinical heterogeneity, the underlying synovitis can also be significantly heterogeneous, both at cellular and molecular level, which can at least in part explain why despite the availability of highly effective treatment options, a large proportion of patients are resistant to some individual treatments. The assimilation of recent high-throughput data from analysis at the single-cell level with rigorous and high-quality clinical outcomes obtained from large randomised clinical trials support the definition of disease and treatment response endotypes. Looking ahead, the integration of histological and molecular signatures from the diseased tissue into clinical algorithms may help decision making in the management of patients with Rheumatoid Arthritis in clinical practice.

Ovarian metastases from colorectal cancer in young women: a systematic review of the literature

BACKGROUND AND PURPOSE

In female colorectal cancer patients, a mean proportion of synchronous and/or metachronous ovarian metastases of 3.4% was described. Previous literature showed that young or premenopausal women (≤ 55 years of age) may be more frequently affected. Once ovarian metastases are diagnosed, the prognosis of the patient is generally dismal, with 5-year survival varying from 12 to 27%. The present study is aimed at determining the proportion of young or premenopausal women diagnosed with colorectal cancer who presented with or developed ovarian metastases by reviewing the current literature on this topic.

METHODS

This review was performed by querying MEDLINE and EMBASE databases using a combination of terms: "colorectal neoplasms, colorectal cancer, ovarian neoplasms, Krukenberg tumor, young adult, young age, premenopause." Studies that indicated ovarian metastases, either synchronous or metachronous (or a combination of the two), in young women were retrieved and analyzed.

RESULTS

The review identified 14 studies encompassing 3379 young or premenopausal female colorectal cancer patients. In this selected group of patients, a mean proportion of ovarian metastases of 4.6% [95% CI: 4.0;5.4] was found.

CONCLUSIONS

This review showed that approximately one in twenty young female colorectal cancer patients will present with or develop ovarian metastases. Since outcome of this specific oncological pathology is often dismal, this finding is clinically relevant. It demonstrates the need to develop strategies to lower the incidence of ovarian metastases with adequate treatment and counseling of these patients.

Cancer and mortality in coal mine workers: a systematic review and meta-analysis

Coal mine workers are exposed to a number of workplace hazards which may increase the risk of cancer and mortality. We conducted a systematic review and meta-analysis to investigate cancer and mortality in coal mine workers We searched in Ovid Medline, PubMed, Embase and Web of Science databases using keywords and text words related to coal mines, cancer and mortality and identified 36 full-text articles using predefined inclusion criteria. Each study's quality was assessed using the Newcastle-Ottawa Scale. We performed random-effect meta-analyses including 21 of the identified articles evaluating cancer and/or mortality of coal mine workers. The meta-analysis showed an increased risk of all-cause mortality (SMR 1.14, 95% CI 1.00 to 1.30) and mortality from non-malignant respiratory disease (NMRD) (3.59, 95% CI 3.00 to 4.30) in cohorts with coal workers' pneumoconiosis (CWP). We found a somewhat increased risk of stomach cancer (1.11, 95% CI 0.97 to 1.35) and of mortality from NMRD (1.26, 95% CI 0.99 to 1.61) in the cohorts of coal miners with unknown CWP status. The meta-analysis also showed a decreased risk of prostate cancer and cardiovascular and cerebrovascular mortality among coal miners. This may be a result of the healthy worker effect and possible lower smoking rates, and perhaps also reflect the physically active nature of many jobs in coal mines. The meta-analysis for lung cancer did not show increased risk in coal miners with CWP (1.49, 95% CI 0.70 to 3.18) or for coal miners of unknown CWP status (1.03, 95% CI 0.91 to 1.18). Lower smoking rates in coal mine workers could explain why case-control studies where smoking was controlled for showed higher risks for lung cancer than were seen in cohort studies. Coal mine workers are at increased risk of mortality from NMRD but decreased risk of prostate cancer and cardiovascular and cerebrovascular mortality. Studies of coal mine workers need long-term follow-up to identify increased mortality and cancer incidence.

Autoantibodies are present in the bronchoalveolar lavage but not circulation in patients with fibrotic interstitial lung disease

Background

Fibrotic interstitial lung disease (fILD) has previously been associated with the presence of autoantibody. While studies have focused on systemic autoimmunity, the role of local autoantibodies in the airways remains unknown. We therefore extensively characterised the airway and peripheral autoantibody profiles in patients with fILD, and assessed association with disease severity and outcome.

Methods

Bronchoalveolar lavage (BAL) fluid was collected from a cohort of fILD patients and total BAL antibody concentrations were quantified. An autoantigen microarray was used to measure IgG and IgA autoantibodies against 122 autoantigens in BAL from 40 idiopathic pulmonary fibrosis (IPF), 20 chronic hypersensitivity pneumonitis (CHP), 20 connective tissue disease-associated ILD (CTD-ILD) patients and 20 controls.

Results

A subset of patients with fILD but not healthy controls had a local autoimmune signature in their BAL that was not present systemically, regardless of disease. The proportion of patients with IPF with a local autoantibody signature was comparable to that of CTD-ILD, which has a known autoimmune pathology, identifying a potentially novel subset of patients. The presence of an airway autoimmune signature was not associated with reduced survival probability or changes in lung function in the cohort as a whole. Patients with IPF had increased BAL total IgA and IgG₁ while subjects with CHP had increased BAL IgA, IgG₁ and IgG₄. In patients with CHP, increased BAL total IgA was associated with reduced survival probability.

Conclusion

Airway autoantibodies that are not present systemically identify a group of patients with fILD and the mechanisms by which these autoantibodies contribute to disease requires further investigation.

Autoantibodies are present in the bronchoalveolar lavage but not circulation in patients with fibrotic interstitial lung diseasehttps://bit.ly/3CNvKjj

Interleukin-2 and regulatory T cells in rheumatic diseases

Failure of regulatory T (T_reg) cells to properly control immune responses leads invariably to autoimmunity and organ damage. Decreased numbers or impaired function of T_reg cells, especially in the context of inflammation, has been documented in many human autoimmune diseases. Restoration of T_reg cell fitness and/or expansion of their numbers using low-dose natural IL-2, the main cytokine driving T_reg cell survival and function, has demonstrated clinical efficacy in early clinical trials. Genetically modified IL-2 with an extended half-life and increased selectivity for T_reg cells is now in clinical development. Administration of IL-2 combined with therapies targeting other pathways involved in the expression of autoimmune diseases should further enhance its therapeutic potential. Ongoing clinical efforts that capitalize on the early clinical success of IL-2 treatment should bring the use of this cytokine to the forefront of biological treatments for autoimmune diseases.

The Landscape of Immune Cells Indicates Prognosis and Applicability of Checkpoint Therapy in Hepatocellular Carcinoma

Background

Tumor-infiltrating immune cells are important components of tumor microenvironment (TME), and their composition reflects the confrontation between host immune system and tumor cells. However, the relationship between the composition of infiltrating immune cells, prognosis, and the applicability of anti-PD-1/PD-L1 therapy in hepatocellular carcinoma (HCC) needs systematic examination.

Methods

Cell-Type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT) was applied to evaluate the infiltration of immune cells based on The Cancer Genome Atlas (TCGA) liver hepatocellular carcinoma (LIHC) cohort. Diagnostic and prognostic models were constructed based on immune cells, and the models were validated by two external cohorts. The relationship between immune cells and PD-L1 was evaluated by Spearman correlation, and the finding was validated in our in-house HCC sample.

Result

Patients in TCGA LIHC cohort were classified into six subtypes with different prognosis based on the proportion of tumor-infiltrating immune cells simulated via CIBERSORT. Among 22 types of immune cells, intratumoral PD-L1 mRNA level exhibited linear relationship with the fraction of five types of immune cells (M1 macrophages, plasma cells, CD8⁺ T cells, resting mast cells, and regulatory T cells), and M1 macrophages showed the strongest relevance (R = 0.26, p < 0.001). Immunohistochemistry of our in-house HCC specimens verified this conclusion. Moreover, intratumoral mRNA levels of M1 macrophage-associated cytokines were positively correlated with PD-L1 level.

Conclusions

Our study demonstrated that the prognosis of HCC patients was associated with the pattern of infiltrating immune cells in TME, and macrophage-associated cytokines might be a potential non-invasive marker for predicting the PD-L1 level for HCC patients.

B Cells in Rheumatoid Arthritis：Pathogenic Mechanisms and Treatment Prospects

Rheumatoid arthritis (RA) is a common, chronic, systemic autoimmune disease, and its clinical features are the proliferation of joint synovial tissue, the formation of pannus and the destruction of cartilage. The global incidence of RA is about 1%, and it is more common in women. The basic feature of RA is the body’s immune system disorders, in which autoreactive CD4⁺T cells, pathogenic B cells, M1 macrophages, inflammatory cytokines, chemokines and autoantibodies abnormally increase in the body of RA patients B cell depletion therapy has well proved the important role of B cells in the pathogenesis of RA, and the treatment of RA with B cells as a target has also been paid more and more attention. Although the inflammatory indicators in RA patients receiving B-cell depletion therapy have been significantly improved, the risk of infection and cancer has also increased, which suggests that we need to deplete pathogenic B cells instead of all B cells. However, at present we cannot distinguish between pathogenic B cells and protective B cells in RA patients. In this review, we explore fresh perspectives upon the roles of B cells in the occurrence, development and treatment of RA.

The Germinal Center Milieu in Rheumatoid Arthritis: The Immunological Drummer or Dancer?

Rheumatoid Arthritis (RA) is a chronic autoimmune disease characterized by joint inflammation, affecting approximately 1% of the general population. To alleviate symptoms and ameliorate joint damage, chronic use of immunosuppressives is needed. However, these treatments are only partially effective and may lead to unwanted side effects. Therefore, a more profound understanding of the pathophysiology might lead to more effective therapies, or better still, a cure. The presence of autoantibodies in RA indicates that B cells might have a pivotal role in the disease. This concept is further supported by the fact that a diverse antibody response to various arthritis-related epitopes is associated with arthritis development. In this context, attention has focused in recent years on the role of Germinal Centers (GCs) in RA. Since GCs act as the main anatomic location of somatic hypermutations, and, thus, contributing to the diversity and specificity of (auto) antibodies, it has been speculated that defects in germinal center reactions might be crucial in the initiation and maintenance of auto-immune events. In this paper, we discuss current evidence that various processes within GCs can result in the aberrant production of B cells that possess autoreactive properties and might result in the production of RA related autoantibodies. Secondly, we discuss various (pre-)clinical studies that have targeted various GC processes as novel therapies for RA treatment.

CXCL13/CXCR5 axis facilitates endothelial progenitor cell homing and angiogenesis during rheumatoid arthritis progression

Angiogenesis is a critical process in the formation of new capillaries and a key participant in rheumatoid arthritis (RA) pathogenesis. The chemokine (C-X-C motif) ligand 13 (CXCL13) plays important roles in several cellular functions such as infiltration, migration, and motility. We report significantly higher levels of CXCL13 expression in collagen-induced arthritis (CIA) mice compared with controls and also in synovial fluid from RA patients compared with human osteoarthritis (OA) samples. RA synovial fluid increased endothelial progenitor cell (EPC) homing and angiogenesis, which was blocked by the CXCL13 antibody. By interacting with the CXCR5 receptor, CXCL13 facilitated vascular endothelial growth factor (VEGF) expression and angiogenesis in EPC through the PLC, MEK, and AP-1 signaling pathways. Importantly, infection with CXCL13 short hairpin RNA (shRNA) mitigated EPC homing and angiogenesis, articular swelling, and cartilage erosion in ankle joints of mice with CIA. CXCL13 is therefore a novel therapeutic target for RA.