Identification of Hub Genes and Prediction of Targeted Drugs for Rheumatoid Arthritis and Idiopathic Pulmonary Fibrosis

There is a potential link between rheumatoid arthritis (RA) and idiopathic pulmonary fibrosis (IPF). The aim of this study is to investigate the molecular processes that underlie the development of these two conditions by bioinformatics methods. The gene expression samples for RA (GSE77298) and IPF (GSE24206) were retrieved from the Gene Expression Omnibus (GEO) database. After identifying the overlapping differentially expressed genes (DEGs) for RA and IPF, we conducted functional annotation, protein-protein interaction (PPI) network analysis, and hub gene identification. Finally, we used the hub genes to predict potential medications for the treatment of both disorders. We identified 74 common DEGs for further analysis. Functional analysis demonstrated that cellular components, biological processes, and molecular functions all played a role in the emergence and progression of RA and IPF. Using the cytoHubba plugin, we identified 7 important hub genes, namely COL3A1, SDC1, CCL5, CXCL13, MMP1, THY1, and BDNF. As diagnostic indicators for RA, SDC1, CCL5, CXCL13, MMP1, and THY1 showed favorable values. For IPF, COL3A1, SDC1, CCL5, CXCL13, THY1, and BDNF were favorable diagnostic markers. Furthermore, we predicted 61 Chinese and 69 Western medications using the hub genes. Our research findings demonstrate a shared pathophysiology between RA and IPF, which may provide new insights for more mechanistic research and more effective treatments. These common pathways and hub genes identified in our study offer potential opportunities for developing more targeted therapies that can address both disorders.

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.

Cytokine responses of immunosuppressed and immunocompetent patients with Neoehrlichia mikurensis infection

Purpose

The tick-borne bacterium Neoehrlichia mikurensis causes the infectious disease neoehrlichiosis in humans. Vascular endothelium is one of the target cells of the infection. Neoehrlichiosis patients with compromised B cell immunity present with more severe inflammation than immunocompetent patients. The aim of this study was to compare the cytokine profiles of immunocompetent and immunosuppressed patients with neoehrlichiosis.

Methods

Blood samples from Swedish and Norwegian immunosuppressed (N = 30) and immunocompetent (N = 16) patients with neoehrlichiosis were analyzed for the levels of 30 cytokines, using a multiplex cytokine assay and ELISA. A gender-matched healthy control group (N = 14) was analyzed in parallel. Data were analyzed using the multivariate method OPLS-DA.

Results

The multiplex cytokine analyses generated more cytokine results than did the uniplex ELISA analyses. Multivariate analysis of the multiplex cytokine results established that increased levels of FGF2, GM-CSF, CXCL10, and IFN-γ were associated with immunosuppressed patients, whereas increased levels of IL-15 and VEGF were associated with immunocompetent neoehrlichiosis patients. When multivariate analysis findings were confirmed with uniplex ELISA, it was found that both groups of patients had similarly elevated levels of VEGF, FGF2 and IFN-γ. In contrast, the immunosuppressed patients had clearly elevated levels of CXCL10, CXCL13 and BAFF, whereas the immunocompetent patients had the same levels as healthy controls.

Conclusion

Pro-angiogenic and type 1 cytokines were produced as part of the host response of neoehrlichiosis independent of immune status, whereas immunosuppressed neoehrlichiosis patients produced cytokines required for B cell-mediated defense.

Role of the CXCL13/CXCR5 Axis in Autoimmune Diseases

CXCL13 is a B-cell chemokine produced mainly by mesenchymal lymphoid tissue organizer cells, follicular dendritic cells, and human T follicular helper cells. By binding to its receptor, CXCR5, CXCL13 plays an important role in lymphoid neogenesis, lymphoid organization, and immune responses. Recent studies have found that CXCL13 and its receptor CXCR5 are implicated in the pathogenesis of several autoimmune diseases, such as rheumatoid arthritis, multiple sclerosis, systemic lupus erythematosus, primary Sjögren’s syndrome, myasthenia gravis, and inflammatory bowel disease. In this review, we discuss the biological features of CXCL13 and CXCR5 and the recent findings on the pathogenic roles of the CXCL13/CXCR5 axis in autoimmune diseases. Furthermore, we discuss the potential role of CXCL13 as a disease biomarker and therapeutic target in autoimmune diseases.

Circulating C-X-C Motif Ligand 13 as a Biomarker for Early Predicting Efficacy of Subcutaneous Immunotherapy in Children With Chronic Allergic Rhinitis

BACKGROUND

C-X-C motif ligand 13 (CXCL13) and B cell-activating factor (BAFF) are proven to be involved in inflammatory diseases, but their role in allergic rhinitis (AR) remains unclear. The aim of this study was to investigate the role of serum CXCL13 and BAFF in AR and their clinical values as objective biomarkers to predict the efficacy of subcutaneous immunotherapy (SCIT).

METHODS

We prospectively recruited 90 children with AR treated with SCIT and collected their serum specimens before SCIT. One-year follow-up was conducted for all patients, and they were categorized into effective and ineffective groups based on efficacy. The serum concentrations of CXCL13 and BAFF were detected and compared between the two groups. A validation cohort of 52 responders and 26 non-responders were further assessed for both cytokines and serum CXCL13 and BAFF levels were assayed by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Eighty children completed the follow-up schedule, and 56 children were categorized into the effective group and 24 children into the ineffective group. The serum levels of CXCL13 in the effective group were clearly higher than those in the ineffective group (P < 0.05). Receiver operating characteristic (ROC) curves revealed the potential values of CXCL13 as a biomarker in predicting the response of SCIT. Further, in the validation cohort, ELISA results demonstrated that serum CXCL13 levels were increased in responders than non-responders (P < 0.05). ROC curves showed good accuracy of serum CXCL13 in predicting the efficacy of SCIT.

CONCLUSION

Our discovery-validation study demonstrated that circulating CXCL13 might serve as a novel biomarker to predict the outcome of SCIT in childhood AR. The findings indicated that CXCL13 was involved in the pathological mechanisms of AR and made help to the fundamental therapeutic mechanism of SCIT.

Molecular and Cellular Heterogeneity in Rheumatoid Arthritis: Mechanisms and Clinical Implications

Rheumatoid arthritis is an autoimmune disease that exhibits significant clinical heterogeneity. There are various treatments for rheumatoid arthritis, including disease-modifying anti-rheumatic drugs (DMARDs), glucocorticoids, non-steroidal anti-inflammatory drugs (NSAIDs), and inflammatory cytokine inhibitors (ICI), typically associated with differentiated clinical effects and characteristics. Personalized responsiveness is observed to the standard treatment due to the pathophysiological heterogeneity in rheumatoid arthritis, resulting in an overall poor prognosis. Understanding the role of individual variation in cellular and molecular mechanisms related to rheumatoid arthritis will considerably improve clinical care and patient outcomes. In this review, we discuss the source of pathophysiological heterogeneity derived from genetic, molecular, and cellular heterogeneity and their possible impact on precision medicine and personalized treatment of rheumatoid arthritis. We provide emphasized description of the heterogeneity derived from mast cells, monocyte cell, macrophage fibroblast-like synoviocytes and, interactions within immune cells and with inflammatory cytokines, as well as the potential as a new therapeutic target to develop a novel treatment approach. Finally, we summarize the latest clinical trials of treatment options for rheumatoid arthritis and provide a suggestive framework for implementing preclinical and clinical experimental results into clinical practice.

Will rheumatologists ever pick up the arthroscope again?

Conditions prompting physicians and surgeons first adapting endoscopes to peer into joints were mainly the sort of synovial conditions that would concern today's rheumatologists. Rheumatologists were among the pre-World War II pioneers developing and documenting arthroscopy. The post-War father of modern arthroscopy, Watanabe, found rheumatologists among his early students, who took back the technique to their home countries, teaching orthopedists and rheumatologists alike. Rheumatologists described and analyzed the intra-articular features of their common diseases in the '60s and '70s. A groundswell of interest from academic rheumatologists in adapting arthroscopy grew considerably in the '90s with development of "needle scopes" that could be used in an office setting. Rheumatologists helped conduct the very trials the findings of which reduced demand for their arthroscopic services by questioning the efficacy of arthroscopic debridement in osteoarthritis (OA) and also developing biological compounds that greatly reduced the call for any resective intervention in inflammatory arthropathies. The arthroscope has proven an excellent tool for viewing and sampling synovium and continues to serve this purpose at several international research centers. While cartilage is now imaged mainly by magnetic resonance imaging, some OA features - such as a high prevalence of visible calcinosis - beg further arthroscopy-directed investigation. A new generation of "needle scopes" with far superior optics awaits future investigators, should they develop interest.

Association of the CXCL9-CXCR3 and CXCL13-CXCR5 axes with B-cell trafficking in giant cell arteritis and polymyalgia rheumatica

OBJECTIVE

B-cells are present in the inflamed arteries of giant cell arteritis (GCA) patients and a disturbed B-cell homeostasis is reported in peripheral blood of both GCA and the overlapping disease polymyalgia rheumatica (PMR). In this study, we aimed to investigate chemokine-chemokine receptor axes governing the migration of B-cells in GCA and PMR.

METHODS

We performed Luminex screening assay for serum levels of B-cell related chemokines in treatment-naïve GCA (n = 41), PMR (n = 31) and age- and sex matched healthy controls (HC, n = 34). Expression of chemokine receptors on circulating B-cell subsets were investigated by flow cytometry. Immunohistochemistry was performed on GCA temporal artery (n = 14) and aorta (n = 10) and on atherosclerosis aorta (n = 10) tissue.

RESULTS

The chemokines CXCL9 and CXCL13 were significantly increased in the circulation of treatment-naïve GCA and PMR patients. CXCL13 increased even further after three months of glucocorticoid treatment. At baseline CXCL13 correlated with disease activity markers. Peripheral CXCR3+ and CXCR5+ switched memory B-cells were significantly reduced in both patient groups and correlated inversely with their complementary chemokines CXCL9 and CXCL13. At the arterial lesions in GCA, CXCR3+ and CXCR5+ B-cells were observed in areas with high CXCL9 and CXCL13 expression.

CONCLUSION

Changes in systemic and local chemokine and chemokine receptor pathways related to B-cell migration were observed in GCA and PMR mainly in the CXCL9-CXCR3 and CXCL13-CXCR5 axes. These changes can contribute to homing and organization of B-cells in the vessel wall and provide further evidence for an active involvement of B-cells in GCA and PMR.

The growing role of precision medicine for the treatment of autoimmune diseases; results of a systematic review of literature and Experts' Consensus

Autoimmune diseases (AIDs) share similar serological, clinical, and radiological findings, but, behind these common features, there are different pathogenic mechanisms, immune cells dysfunctions, and targeted organs. In this context, multiple lines of evidence suggest the application of precision medicine principles to AIDs to reduce the treatment failure. Precision medicine refers to the tailoring of therapeutic strategies to the individual characteristics of each patient, thus it could be a new approach for management of AIDS which considers individual variability in genes, environmental exposure, and lifestyle. Precision medicine would also assist physicians in choosing the right treatment, the best timing of administration, consequently trying to maximize drug efficacy, and, possibly, reducing adverse events. In this work, the growing body of evidence is summarized regarding the predictive factors for drug response in patients with AIDs, applying the precision medicine principles to provide high-quality evidence for therapeutic opportunities in improving the management of these patients.

RETRACTED ARTICLE: Does serum B lymphocyte chemoattractant protein13 (CXCL13) level correlate with parameters of disease activity and severity in rheumatoid arthritis? Clinical and musculoskeletal ultrasonographic assessment

Background

Rheumatoid arthritis (RA) affects about 1–3% of the population making it one of the most popular autoimmune diseases. Chemokines through switching on their receptors exert a climacteric role in RA pathogenesis. The purpose of this cross-sectional study was to quantify the serum levels of serum B lymphocyte chemoattractant protein13 (CXCL13) chemokine in recent onset RA patients and to correlate its levels with clinical, laboratory, and musculoskeletal ultrasonographic parameters (MSUS) of disease activity and severity.

Results

The mean serum CXCL13 value showed a significant increase in the RA patients (388.86 ± 283.63 pg/ml) than in the controls (62.94 ± 31.62 pg/ml) (P < 0.001). Highly active RA patients had significantly the highest mean of CXCL13 (mean ± SD 819.13 ± 191.05) compared with the moderately active RA patients (mean ± SD 284.95 ± 137.93) (P < 0.001) and the RA patients with low disease activity (mean ± SD 129.5 ± 21.27) (P < 0.001) and its levels were positively related with clinical disease activity and musculoskeletal ultrasonographic severity parameters.

Conclusion

Serum CXCL13 is correlated with clinical disease activity and MSUS disease severity that encourages its use for monitoring the activity and severity of synovitis in recent onset RA patients. Future studies to detect the effect of disease activity control by medications on CXCL13 levels and the effect of the CXCL13 antagonist on controlling RA disease activity and severity are recommended.

A systematic review of CXCL13 as a biomarker of disease and treatment response in rheumatoid arthritis

BACKGROUND

The B cell chemoattractant CXCL13 is a promising biomarker in rheumatoid arthritis (RA), with a plausible role in supporting diagnosis, monitoring disease activity and as a prognostic value. It is a key chemokine driving the formation of lymphoid follicles within the inflamed synovium. The objective of this systematic review was to evaluate the role of CXCL13 as a viable biomarker in RA.

METHODS

We conducted a systematic literature review of all published cohort and randomised controlled trials evaluating the role of CXCL13 in RA. The primary outcomes were; i) CXCL13 levels in RA patients compared to healthy controls, ii) the correlation between CXCL13 and markers of disease activity, and iii) the association between CXCL13 and treatment response.

RESULTS

The search produced 278 articles, of which 31 met the inclusion criteria. Of the 12 studies evaluating CXCL13 expression in early or established RA, all reported higher levels than that seen in healthy controls. Twelve of sixteen studies reported a weakly positive correlation between CXCL13 and markers of disease activity including DAS28 and swollen joint count, with rho values between 0.20-0.67. In 2 studies, CXCL13 levels correlated with ultrasonographic evidence of synovitis. Eighteen studies assessed CXCL13 in response to therapeutic intervention. The majority signified a fall in levels in response to treatment including biologics and Janus kinase (JAK) inhibition. In some, this reduction was only seen in treatment responders. High CXCL13 levels predicted failure to achieve disease remission with csDMARDs. The evidence for treatment prediction with biologics was conflicting.

CONCLUSION

Despite evidence to suggest a role in diagnosing RA and in detecting synovitis, the heterogeneity of studies included in this review limit our ability to draw robust conclusions. At present there are inadequate results to justify the routine use of CXCL13 as a biomarker in RA routine clinical practice.

Levels of CXCL13 and sICAM-1 correlate with disease activity score in patients with rheumatoid arthritis treated with tocilizumab

Background

Tocilizumab (TCZ), a humanized monoclonal antibody against the interleukin-6 receptor, has been proven to be a safe and effective treatment for rheumatoid arthritis (RA). Because RA is a heterogenous disease and patient response to treatments can vary, identifying characteristics that predict which patients are more likely to respond to TCZ is important for optimal patient care. Serum levels of C-X-C motif chemokine ligand 13 (CXCL13) and soluble intercellular adhesion molecule-1 (sICAM-1) have been associated with response to TCZ in patients with RA.

Objectives

To evaluate the association of CXCL13 and sICAM-1 with disease activity and response to TCZ in patients with early RA and those with inadequate response to disease-modifying antirheumatic drugs (DMARD-IR).

Methods

Baseline and week 24 serum CXCL13 and sICAM-1 levels were measured using available patient samples from the FUNCTION (early RA) and LITHE (DMARD-IR) trials. Correlations between CXCL13 and sICAM-1 levels and Disease Activity Score in 28 joints calculated with erythrocyte sedimentation rate (DAS28-ESR) at baseline and between change in CXCL13 and sICAM-1 and change in DAS28-ESR at week 24 were estimated. CXCL13 and sICAM-1 changes from baseline to week 24 were compared between treatment arms. The effects of TCZ treatment and baseline DAS28-ESR, CXCL13 and sICAM-1 levels on DAS28-ESR remission and 50% improvement per the American College of Rheumatology (ACR50) response at week 24 were determined.

Results

Overall, 458 patients from FUNCTION and 287 patients from LITHE were included. Correlation of baseline serum CXCL13 and sICAM-1 levels with DAS28-ESR was weak to moderate. CXCL13 and sICAM-1 levels decreased significantly at week 24 in TCZ-treated patients in both the early-RA and DMARD-IR populations. CXCL13 and sICAM-1 changes correlated moderately to weakly with DAS28-ESR changes at week 24 in both populations. The treatment regimen, but not baseline CXCL13 and sICAM-1 levels, had a significant effect on the likelihood of DAS28-ESR remission and ACR50 response.

Conclusions

Although CXCL13 and sICAM-1 are modestly associated with RA disease activity, they do not predict response to TCZ in all RA populations.

Chemokines: A Potential Therapeutic Target to Suppress Autoimmune Arthritis

BACKGROUND

Chemokines are a family of low molecular weight proteins that induce chemotaxis of inflammatory cells, which mainly depends on the recognition of a chemo-attractant gradient and interaction with the substratum. In Rheumatoid Arthritis (RA), abundant chemokines are expressed in synovial tissue, cause inflammatory cells migration into the inflamed joint that necessitates the formation of new blood vessels i.e. angiogenesis. Over the decades, studies showed that continuous inflammation may lead to the loss of tissue architecture and function, causing severe disability and cartilage destruction. In spite of the advancement of modern drug therapy, thousands of arthritic patients suffer mortality and morbidity globally. Thus, there is an urgent need for the development of novel therapeutic agents for the treatment of RA.

METHODS

This review is carried out throughout a non-systematic search of the accessible literature, will provide an overview of the current information of chemokine in RA and also exploring the future perspective of the vital role of targeting chemokine in RA treatment.

RESULTS

Since, chemokines are associated with inflammatory cells/leucocyte migration at the site of inflammation in chronic inflammatory diseases and hence, blockade or interference with chemokines activity showing a potential approach for the development of new anti-inflammatory agents. Currently, results obtained from both preclinical and clinical studies showed significant improvement in arthritis.

CONCLUSION

This review summarizes the role of chemokines and their receptors in the pathogenesis of RA and also indicates possible interactions of chemokines/receptors with various synthetic and natural compounds that may be used as a potential therapeutic target in the future for the treatment of RA.

Increased circulating CXCL13 levels in systemic lupus erythematosus and rheumatoid arthritis: a meta-analysis

OBJECTIVES

CXC ligand 13 (CXCL13) is known as B cell chemotactic factor (BLC), promoting the migration of B lymphocytes by communicating with its receptor CXCR5, which can be regarded as part of pathogenesis of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). This meta-analysis was to evaluate the circulating CXCL13 levels in SLE and RA.

METHODS

All articles were respectively gathered from PubMed, Web of Science, and China National Knowledge Infrastructure (CNKI) (by the end of 10 April 2019). According to random effects model, standardized mean difference (SMD) and 95% confidence interval (CI) of CXCL13 levels in SLE and RA were calculated by Stata 12.0 software.

RESULTS

Totally, 15 studies were selected (981 SLE patients and 380 healthy controls, 332 RA patients and 147 healthy controls). SLE and RA patients were significantly increased in circulating CXCL13 levels (SMD = 1.851, 95% CI 0.604-3.098; SMD = 1.801, 95% CI = 1.145-2.457). Subgroup analyses showed that SLE patients from the Chinese group and systemic lupus erythematosus disease activity index (SLEDAI) score ≥ 6 group had higher circulating CXCL13 levels (SMD = 2.182, 95% CI 0.135-4.229; SMD = 0.767, 95% CI 0.503-1.030). However, there were no significant changes in CXCL13 concentrations in SLE patients from the English and SLEDAI score < 6 group. Similarly, subgroup analyses presented that RA patients from different classifications showed higher circulating CXCL13 levels. There was no publication bias.

CONCLUSIONS

This meta-analysis demonstrated increased circulating CXCL13 concentrations in SLE and RA patients. Circulating CXCL13 levels may act as biomarkers and therapy targets in the diagnosis and treatment of SLE and RA.Key Point• First, CXC ligand 13 (CXCL13) is closely related to the pathogenesis of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), Second, this study may provide novel therapeutic targets for the treatment of SLE and RA patients. This meta-analysis provides a comprehensive analysis of circulating CXCL13 levels in patients with SLE and RA and also explores related influencing factors.

Effector Functions of CD4+ T Cells at the Site of Local Autoimmune Inflammation-Lessons From Rheumatoid Arthritis

Infiltration of memory CD4+ T cells in synovial joints of Rheumatoid Arthritis (RA) patients has been reported since decades. Moreover, several genome wide association studies (GWAS) pinpointing a key genetic association between the HLA-DR locus and RA have led to the generally agreed hypothesis that CD4+ T cells are directly implicated in the disease. Still, RA is a heterogeneous disease and much effort has been made to understand its different facets. T cell differentiation is driven by mechanisms including antigen stimulation, co-stimulatory signals and cytokine milieu, all of which are abundant in the rheumatic joint, implying that any T cells migrating into the joint may be further affected locally. In parallel to the characterization and classification of T-cell subsets, the contribution of different effector T cells to RA has been investigated in numerous studies though sometimes with contradictory results. In particular, the frequency of Th1 and Th17 cells has been assessed in the synovial joints with various results that could, at least partly, be explained by the stage of the disease. For regulatory T cells, it is largely accepted that they accumulate in RA synovial fluid and that the equilibrium between regulatory T cells and effector cells is a key factor in controlling inflammation processes involved in RA. Recent phenotypic studies describe the possible implication of a novel subset of peripheral T helper cells (Tph) important for T-B cell cross talk and plasma cell differentiation in the RA joint of ACPA+ (autoantibodies against citrullinated proteins) RA patients. Finally, cytotoxic CD4+ T cells, historically described as increased in the peripheral blood of RA patients have attracted new attention in the last years. In view of the recently identified peripheral T-cell subsets, we will integrate immunological data as well as information on genetic variants and therapeutic strategy outcomes into our current understanding of the width of effector T cells. We will also integrate tissue-resident memory T cell aspects, and discuss similarities and differences with inflammatory conditions in skin (psoriasis) and mucosal organs (Crohn's disease).

Plasma proteomics identifies a 'chemokine storm' in idiopathic multicentric Castleman disease

Human Herpesvirus-8 (HHV-8)-negative/idiopathic multicentric Castleman disease (iMCD) is a poorly understood disease involving polyclonal lymphoproliferation with dysmorphic germinal centers, constitutional symptoms, and multi-organ failure. Patients can experience thrombocytopenia, anasarca, reticulin fibrosis, renal dysfunction, organomegaly, and normal immunoglobulin levels, - iMCD-TAFRO. Others experience thrombocytosis, milder effusions, and hypergammaglobulinemia, -iMCD-Not Otherwise Specified (iMCD-NOS). Though the etiology is unknown in both subtypes, iMCD symptoms and disease progression are believed to be driven by a cytokine storm, often including interleukin-6 (IL-6). However, approximately two-thirds of patients do not respond to anti-IL-6 therapy; alternative drivers and signaling pathways are not known for anti-IL-6 nonresponders. To identify potential mediators of iMCD pathogenesis, we quantified 1129 proteins in 13 plasma samples from six iMCD patients during flare and remission. The acute phase reactant NPS-PLA2 was the only significantly increased protein (P = .017); chemokines and complement were significantly enriched pathways. Chemokines represented the greatest proportion of upregulated cytokines, suggesting that iMCD involves a chemokine storm. The chemokine CXCL13, which is essential in homing B cells to germinal centers, was the most upregulated cytokine across all patients (log2 fold-change = 3.22). Expression of CXCL13 was also significantly increased in iMCD lymph node germinal centers compared to controls in a stromal meshwork pattern. We observed distinct proteomic profiles between the two iMCD-TAFRO patients, who both failed anti-IL-6-therapy, and the four iMCD-NOS patients, in whom all three treated with anti-IL-6-therapy responded, suggesting that differing mechanisms may exist. This study reveals proteomic differences between flare and remission and the potential to molecularly define iMCD subgroups.

Role of chemokines in ectopic lymphoid structures formation in autoimmunity and cancer

Ectopic (or tertiary) lymphoid structures (ELS) are organized aggregates of lymphocytes resembling secondary lymphoid organs and developing in chronically inflamed nonlymphoid tissues during persistent infections, graft rejection, autoimmune conditions, and cancer. In this review, we will first depict the mechanisms regulating ELS generation, focusing on the role played by lymphoid chemokines. We will then characterize ELS forming in target organs during autoimmune conditions, here exemplified by rheumatoid arthritis, and cancer, highlighting the relevance of the tissue-specific factors. Finally, we will discuss the clinical significance of ELS and the therapeutic potential of their inhibition and/or enhancement depending on the disease considered.

B cells and their cytokine activities implications in human diseases

B cells are the only cell type that can give rise to antibody-producing cells, and the only cell type whose selective depletion can, today, lead to an improvement of a wide range of immune-mediated inflammatory diseases, including disorders not primarily driven by autoantibodies. Here, I discuss this paradoxical observation, and propose that the capacity of B cells to act as cytokine-producing cells explains how they can control monocyte activity and subsequently disease pathogenesis. Together with current data on the effect of anti-CD20 B cell-depleting reagents in the clinic, this novel knowledge on B cell heterogeneity opens the way for novel safer and more efficient strategies to target B cells. The forthcoming identification of disease-relevant B cell subsets is awaited to permit their monitoring and specific targeting in a personalized medicine approach.

T cell specific Cxcr5 deficiency prevents rheumatoid arthritis

The chemokine receptor CXCR5 is primarily expressed on B cells and Tfh cells and facilitates their migration towards B cell follicles. In the present study we investigated the role of the CXCL13/CXCR5 axis in the pathogenesis of rheumatoid arthritis (RA) and specifically addressed the impact of CXCR5-mediated T and B cell migration in this disease. Employing collagen-induced arthritis (CIA) we identify CXCR5 as an absolutely essential factor for the induction of inflammatory autoimmune arthritis. Cxcr5-deficient mice and mice selectively lacking Cxcr5 on T cells were completely resistant to CIA, showed impaired germinal center responses and failed to mount an IgG1 antibody response to collagen II. Selective ablation of CXCR5 expression in B cells also led to suppression of CIA owing to diminished GC responses in secondary lymphoid organs (SLO) and impaired anti-collagen II antibody production. Chimeric mice harboring Cxcr5-proficient and Cxcr5-deficient immune cells revealed SLO and not the synovial tissue as the compartment where CXCR5-mediated cell migration induces autoimmune inflammation in arthritis. Thus our data demonstrate that CXCR5-mediated co-localization of Tfh cells and B cells in SLOs is absolutely essential for the induction of RA and identify CXCR5 and Tfh cells as promising therapeutic targets for the treatment of RA.

Pathogenetic insights from the treatment of rheumatoid arthritis

Rheumatoid arthritis is a chronic autoimmune disease that causes progressive articular damage, functional loss, and comorbidity. The development of effective biologics and small-molecule kinase inhibitors in the past two decades has substantially improved clinical outcomes. Just as understanding of pathogenesis has led in large part to the development of drugs, so have mode-of-action studies of these specific immune-targeted agents revealed which immune pathways drive articular inflammation and related comorbidities. Cytokine inhibitors have definitively proven a critical role for tumour necrosis factor α and interleukin 6 in disease pathogenesis and possibly also for granulocyte-macrophage colony-stimulating factor. More recently, clinical trials with Janus kinase (JAK) inhibitors have shown that cytokine receptors that signal through the JAK/STAT signalling pathway are important for disease, informing the pathogenetic function of additional cytokines (such as the interferons). Finally, successful use of costimulatory blockade and B-cell depletion in the clinic has revealed that the adaptive immune response and the downstream events initiated by these cells participate directly in synovial inflammation. Taken together, it becomes apparent that understanding the effects of specific immune interventions can elucidate definitive molecular or cellular nodes that are essential to maintain complex inflammatory networks that subserve diseases like rheumatoid arthritis.

Ectopic lymphoid neogenesis in rheumatic autoimmune diseases

Ectopic lymphoid neogenesis often occurs in the target tissues of patients with chronic rheumatic autoimmune diseases such as rheumatoid arthritis, Sjögren syndrome and other connective tissue disorders, including systemic lupus erythematosus and myositis. However, the mechanisms of ectopic lymphoid-like structure (ELS) formation and function are not entirely understood. For example, it is unclear whether ELSs indicate distinct disease phenotypes or whether they are evolutionary manifestations of chronic inflammation. Also unclear is why ELSs form in some patients but not in others. Nonetheless, ELSs frequently display functional features of ectopic germinal centres and can actively contribute to the maintenance of autoimmunity through the production of disease-specific autoantibodies; furthermore, they seem to influence disease severity and response to both synthetic and biologic DMARDs. In this Review, we discuss current knowledge and gaps in understanding of ELS formation and function including their prevalence in the above rheumatic autoimmune diseases; the mechanisms underlying their formation, maintenance and function, including positive and negative regulatory pathways; their functional relevance in the perpetuation of autoimmunity; their relationship with disease phenotypes, clinical outcomes and response to treatment; and the potential for specific targeting of ELSs through novel therapeutic modalities.

Use of polyclonal/monoclonal antibody therapies in transplantation

INTRODUCTION

For over thirty years, antibody (mAb)-based therapies have been a standard component of transplant immunosuppression, and yet much remains to be learned in order for us to truly harness their therapeutic capabilities. Current mAbs used in transplant directly target and destroy graft-destructive immune cells, interrupt cytokine and costimulation-dependent T and B cell activation, and prevent down-stream complement activation. Areas covered: This review summarizes our current approaches to using antibody-based therapies to prevent and treat allograft rejection. It also provides examples of promising novel mAb therapies, and discusses the potential for future mAb development in transplantation. Expert opinion: The broad capability of antibodies, in parallel with our growing ability to synthetically modulate them, offers exciting opportunities to develop better biologic therapeutics. In order to do so, we must further our understanding about the basic biology underlying allograft rejection, and gain better appreciation of how characteristics of therapeutic antibodies affect their efficacy.

Upregulation of (C-X-C motif) Ligand 13 (CXCL13) Attenuates Morphine Analgesia in Rats with Cancer-Induced Bone Pain

Background

The aim of this study was to investigate the role of chemokine (C-X-C motif) ligand 13 (CXCL13) in morphine tolerance in rats with cancer-induced bone pain (CIBP).

Material/Methods

We established a rat CIBP model and a rat CIBP-morphine tolerance (BM) model. BM rats were intrathecally administered rmCXCL13, neutralizing anti-CXCL13, and normal saline, while the control group rats underwent a sham operation and were injected with normal saline. The morphine analgesia was assessed by measuring mechanical withdrawal threshold (MWT) and mechanical withdrawal duration (MWD) at various time points. The co-expressions of CXCL13 and NeuN were measured by immunofluorescence double-staining. CXCL13 protein and mRNA expressions were detected by Western blot and quantitative real-time polymerase chain reaction (RT-qPCR), respectively.

Results

Compared to the sham-operation (S) group, the BM group showed obviously decreased MWT and increased MWD on Day 9 after CIBP, but obviously increased MWT and decreased MWD on Day 3 after morphine administration; subsequently, the MWT was decreased and MWD was increased (all P<0.05). In comparison with the S+saline group, increased MWT and decreased MWD were observed in BM rats on Day 3 after anti-CXCL13 administration, and obviously decreased MWT and increased MWD were found in BM rats on Day 3 after rmCXCL13 administration (all P<0.05).

Conclusions

Up-regulated CXCL13 has a negative role in morphine analgesia in relief of CIBP, which may provide a new target for the management of CIBP.

Inflammation Causes Resistance to Anti-CD20-Mediated B Cell Depletion

B cells play a central role in antibody-mediated rejection and certain autoimmune diseases. However, B cell-targeted therapy such as anti-CD20 B cell-depleting antibody (aCD20) has yielded mixed results in improving outcomes. In this study, we investigated whether an accelerated B cell reconstitution leading to aCD20 depletion resistance could account for these discrepancies. Using a transplantation model, we found that antigen-independent inflammation, likely through toll-like receptor (TLR) signaling, was sufficient to mitigate B cell depletion. Secondary lymphoid organs had a quicker recovery of B cells when compared to peripheral blood. Inflammation altered the pharmacokinetics (PK) and pharmacodynamics (PD) of aCD20 therapy by shortening drug half-life and accelerating the reconstitution of the peripheral B cell pool by bone marrow-derived B cell precursors. IVIG (intravenous immunoglobulin) coadministration also shortened aCD20 drug half-life and led to accelerated B cell recovery. Repeated aCD20 dosing restored B cell depletion and delayed allograft rejection, especially B cell-dependent, antibody-independent allograft rejection. These data demonstrate the importance of further clinical studies of the PK/PD of monoclonal antibody treatment in inflammatory conditions. The data also highlight the disconnect between B cell depletion on peripheral blood compared to secondary lymphoid organs, the deleterious effect of IVIG when given with aCD20 and the relevance of redosing of aCD20 for effective B cell depletion in alloimmunity.

CXCL13 and CCL11 Serum Levels and Lymphoma and Disease Activity in Primary Sjögren's Syndrome

OBJECTIVE

Non-Hodgkin's lymphoma (NHL) is a severe complication of primary Sjögren's syndrome (SS). Ectopic germinal centers (GCs) in the salivary glands are predictors of the occurrence of NHL. Given the association between CCL11 and CXCL13 and ectopic GCs, we assessed the link between these chemokines and NHL, as well as the association between these chemokines and disease activity, in patients with primary SS.

METHODS

Serum levels of CCL11 and CXCL13 were evaluated by multiplex assay in 385 patients included in the Assessment of Systemic Signs and Evolution of Sjögren's Syndrome (ASSESS) cohort. The association between chemokine levels, B cell biomarkers, and patient subsets was assessed using Spearman's test for continuous data and the nonparametric Mann-Whitney U test for categorical data. Multivariate analyses were performed to identify parameters associated with lymphoma and disease activity.

RESULTS

Seventeen patients had a history of lymphoma, and 5 of them had developed NHL during followup. The median serum levels of CCL11 and CXCL13 in the total cohort were 106.48 pg/ml (interquartile range 69.33-149.85) and 108.31 pg/ml (interquartile range 58.88-200.13), respectively. Patients with lymphoma had higher levels of CXCL13 than did patients without lymphoma (P = 0.006) and a trend toward a higher level of CCL11 (P = 0.056). Low C4 and high BAFF levels were associated with NHL on multivariate analysis (P = 0.01 and P = 0.0002, respectively). CCL11 and CXCL13 levels correlated positively with the rheumatoid factor titer, the κ-to-λ free light chain ratio, and the β2 -microglubulin level. CXCL13 was the only parameter associated with disease activity on multivariate analysis.

CONCLUSION

These findings demonstrate a link between CXCL13 and CCL11 and disease activity and lymphoma. This highlights the continuum between chronic B cell activation, disease activity, and lymphomagenesis in patients with primary SS.

Rituximab Downregulates Gene Expression Associated with Cell Proliferation, Survival, and Proteolysis in the Peripheral Blood from Rheumatoid Arthritis Patients: A Link between High Baseline Autophagy-Related ULK1 Expression and Improved Pain Control

Objective. To clarify molecular mechanisms for the response to rituximab in a longitudinal study. Methods. Peripheral blood from 16 RA patients treated with rituximab for a single treatment course and 26 healthy controls, blood and knee articular cartilages from 18 patients with long-standing RA, and cartilages from 14 healthy subjects were examined. Clinical response was assessed using ESR, ACPA, CRP, RF, DAS28 levels, CD19+ B-cell counts, bone erosion, and joint space narrowing scores. Protein expression in PBMCs was quantified using ELISA. Gene expression was performed with quantitative real-time PCR. Results. A decrease (p < 0.05) in DAS28, ESR, and CRP values after rituximab treatment was associated with the downregulation of MTOR, p21, caspase 3, ULK1, TNFα, IL-1β, and cathepsin K gene expression in the peripheral blood to levels found in healthy subjects. MMP-9 expression remained significantly higher compared to controls although decreased (p < 0.05) versus baseline. A negative correlation between baseline ULK1 gene expression and the number of tender joints at the end of follow-up was observed. Conclusions. The response to rituximab was associated with decreased MTOR, p21, caspase 3, ULK1, TNFα, IL-1β, and cathepsin K gene expression compared to healthy subjects. Residual increased expression in MMP-9, IFNα, and COX2 might account for remaining inflammation and pain. High baseline ULK1 gene expression indicates a good response in respect to pain.

Regulatory Effect of Iguratimod on the Balance of Th Subsets and Inhibition of Inflammatory Cytokines in Patients with Rheumatoid Arthritis

OBJECTIVE

To expand upon the role of iguratimod (T-614) in the treatment of rheumatoid arthritis (RA), we investigated whether the Th1, Th17, follicular helper T cells (Tfh), and regulatory T cells (Treg) imbalance could be reversed by iguratimod and the clinical implications of this reversal.

METHODS

In this trial, 74 patients were randomized into iguratimod-treated (group A) and control (broup B) group for a 24-week treatment period. In the subsequent 28 weeks, both groups were given iguratimod. Frequencies of Th1, Th17, Tfh, and Treg were quantified using flow cytometry, and serum cytokines were detected by enzyme-linked immunosorbent assay. mRNA expression of cytokines and transcriptional factor were quantified by RT-PCR. The composite Disease Activity Score, erythrocyte sedimentation rate, and C-reactive protein were assessed at each visit.

RESULT

The clinical scores demonstrated effective suppression of disease after treatment with iguratimod. In addition, iguratimod downregulated Th1, Th17-type response and upregulated Treg. Furthermore, the levels of Th1, Th17, and Tfh associated inflammatory cytokines and transcription factors were reduced after treatment with iguratimod, while the levels of Treg associated cytokines and transcription factors were increased.

Association of CXCL10 and CXCL13 levels with disease activity and cutaneous manifestation in active adult-onset Still's disease

INTRODUCTION

C-X-C motif chemokine 10 (CXCL10) is produced in response to interferon-γ, and tumor necrosis factor-α (TNF-α) triggers the accumulation of activated lymphocytes. CXCL13 is constitutively expressed in secondary lymphoid tissues, and the expression is upregulated by TNF-α, via T cell stimulation. It appears that CXCL10 and CXCL13 could play a potential role in the pathogenesis of adult-onset Still's disease (AOSD), therefore, we investigated the associations between CXCL10 and CXCL13 levels and clinical manifestations in patients with active AOSD.

METHODS

Blood samples were collected from 39 active AOSD patients, 32 rheumatoid arthritis (RA) patients and 40 healthy controls (HC). Of the AOSD patients, follow-up samples were collected from 15 9.6 ± 9.2 months later. Serum levels of CXCL10 and CXCL13 were determined using enzyme-linked immunosorbent assay. CXCL10, CXCL13, and C-X-C chemokine receptor type 3 (CXCR3) expression levels in biopsy specimens obtained from 26 AOSD patients with skin rashes were investigated via immunohistochemistry.

RESULTS

The CXCL10 levels in AOSD patients (1,031.3 ± 2,019.6 pg/mL) were higher than in RA (146.3 ± 91.4 pg/mL, p = 0.008) and HC (104.4 ± 47.9 pg/mL, p = 0.006). Also, the CXCL13 levels of AOSD patients (158.8 ± 151.2 pg/mL) were higher than those of RA (54.4 ± 61.1 pg/mL, p < 0.001) and HC (23.5 ± 18.1 pg/mL, p < 0.001). Serum CXCL10 levels correlated with ferritin and systemic scores. Serum CXCL13 levels correlated with those of hemoglobin, C-reactive protein, ferritin, and albumin, and systemic scores. In follow-up AOSD patients, the levels of CXCL10 and CXCL13 fell significantly (153.7 ± 130.1 pg/mL, p = 0.002, and 89.1 ± 117.4 pg/mL, p = 0.001, respectively). On immunohistochemistry, the percentages of inflammatory cells expressing CXCL10 ranged from 1 to 85%, CXCL13 from 1 to 72%, and CXCR3 from 2 to 65%. The percentage of CXCL10-positive inflammatory cells was higher in skin biopsy samples exhibiting mucin deposition than in those that did not (p = 0.01). CXCL13 levels were correlated with those of CD4 and CD68.

CONCLUSIONS

Serum CXCL10 and CXCL13 levels may serve as clinical markers for assessment of disease activity in AOSD. CXCL10/CXCR3 and CXCL13 may contribute to the inflammatory response, especially skin manifestations thereof, in AOSD.

Current and future trends in biomarker discovery and development of companion diagnostics for arthritis

Musculoskeletal diseases such as rheumatoid arthritis are complex multifactorial disorders that are chronic in nature and debilitating for patients. A number of drug families are available to clinicians to manage these disorders but few tests exist to target these to the most responsive patients. As a consequence, drug failure and switching to drugs with alternate modes of action is common. In parallel, a limited number of laboratory tests are available which measure biological indicators or 'biomarkers' of disease activity, autoimmune status, or joint damage. There is a growing awareness that assimilating the fields of drug selection and diagnostic tests into 'companion diagnostics' could greatly advance disease management and improve outcomes for patients. This review aims to highlight: the current applications of biomarkers in rheumatology with particular focus on companion diagnostics; developments in the fields of proteomics, genomics, microbiomics, imaging and bioinformatics and how integration of these technologies into clinical practice could support therapeutic decisions.

CXCL13 predicts disease activity in early rheumatoid arthritis and could be an indicator of the therapeutic 'window of opportunity'

Introduction

A key phenomenon in rheumatoid arthritis is the formation of lymphoid follicles in the inflamed synovial membrane. C-X-C motif chemokine 13 (CXCL13) is central in this process as it attracts C-X-C chemokine receptor type 5 (CXCR5)-expressing B cells and T follicular helper cells to the follicle. We here examine the role of CXCL13 and its association with disease in patients with treatment-naïve early rheumatoid arthritis.

Methods

Plasma samples from patients in the OPERA trial were examined for CXCL13 at treatment initiation and after 6 months of treatment with either methotrexate plus placebo (DMARD) (n = 37) or methotrexate plus adalimumab (DMARD + ADA) (n = 39). Treatment outcome was evaluated after 1 and 2 years. CXCL13 plasma levels in healthy volunteers (n = 38) were also examined.

Results

Baseline CXCL13 plasma levels were increased in early rheumatoid arthritis patients in comparison with healthy volunteers. Also, plasma CXCL13 correlated positively with disease activity parameters; swollen joint count 28 (rho = 0.34) and 40 (rho = 0.39), visual analog score (rho = 0.38) and simplified disease activity index (rho = 0.25) (all P <0.05). CXCL13 levels decreased a significantly twofold more in the DMARD + ADA group than in the DMARD group. Baseline CXCL13 plasma levels in the DMARD group correlated inversely with disease activity parameters; disease activity score in 28 joints, four variables, C-reactive protein based (DAS28CRP) (rho = 0.58, P <0.05) at 12 months. High baseline CXCL13 was associated with remission (DAS28CRP less than 2.6) after 2 years.

Conclusions

In treatment-naïve early rheumatoid arthritis patients, plasma CXCL13 levels were associated with joint inflammation. Furthermore, patients with high baseline plasma CXCL13 levels had an improved chance of remission after 2 years. We propose that high CXCL13 concentrations indicate recent onset of inflammation that may respond better to early aggressive treatment. Thus, high levels of CXCL13 could reflect the ‘the window of opportunity’ for optimal treatment effect.

Trial registration

Clinicaltrial.gov NCT00660647. Registered 10 April 2008

Heterogeneous gene expression signatures correspond to distinct lung pathologies and biomarkers of disease severity in idiopathic pulmonary fibrosis

BACKGROUND

There is microscopic spatial and temporal heterogeneity of pathological changes in idiopathic pulmonary fibrosis (IPF) lung tissue, which may relate to heterogeneity in pathophysiological mediators of disease and clinical progression. We assessed relationships between gene expression patterns, pathological features, and systemic biomarkers to identify biomarkers that reflect the aggregate disease burden in patients with IPF.

METHODS

Gene expression microarrays (N=40 IPF; 8 controls) and immunohistochemical analyses (N=22 IPF; 8 controls) of lung biopsies. Clinical characterisation and blood biomarker levels of MMP3 and CXCL13 in a separate cohort of patients with IPF (N=80).

RESULTS

2940 genes were significantly differentially expressed between IPF and control samples (|fold change| >1.5, p<0.05). Two clusters of co-regulated genes related to bronchiolar epithelium or lymphoid aggregates exhibited substantial heterogeneity within the IPF population. Gene expression in bronchiolar and lymphoid clusters corresponded to the extent of bronchiolisation and lymphoid aggregates determined by immunohistochemistry in adjacent tissue sections. Elevated serum levels of MMP3, encoded in the bronchiolar cluster, and CXCL13, encoded in the lymphoid cluster, corresponded to disease severity and shortened survival time (p<10(-7) for MMP3 and p<10(-5) for CXCL13; Cox proportional hazards model).

CONCLUSIONS

Microscopic pathological heterogeneity in IPF lung tissue corresponds to specific gene expression patterns related to bronchiolisation and lymphoid aggregates. MMP3 and CXCL13 are systemic biomarkers that reflect the aggregate burden of these pathological features across total lung tissue. These biomarkers may have clinical utility as prognostic and/or surrogate biomarkers of disease activity in interventional studies in IPF.

Synovial phenotypes in rheumatoid arthritis correlate with response to biologic therapeutics

INTRODUCTION

Rheumatoid arthritis (RA) is a complex and clinically heterogeneous autoimmune disease. Currently, the relationship between pathogenic molecular drivers of disease in RA and therapeutic response is poorly understood.

METHODS

We analyzed synovial tissue samples from two RA cohorts of 49 and 20 patients using a combination of global gene expression, histologic and cellular analyses, and analysis of gene expression data from two further publicly available RA cohorts. To identify candidate serum biomarkers that correspond to differential synovial biology and clinical response to targeted therapies, we performed pre-treatment biomarker analysis compared with therapeutic outcome at week 24 in serum samples from 198 patients from the ADACTA (ADalimumab ACTemrA) phase 4 trial of tocilizumab (anti-IL-6R) monotherapy versus adalimumab (anti-TNFα) monotherapy.

RESULTS

We documented evidence for four major phenotypes of RA synovium - lymphoid, myeloid, low inflammatory, and fibroid - each with distinct underlying gene expression signatures. We observed that baseline synovial myeloid, but not lymphoid, gene signature expression was higher in patients with good compared with poor European league against rheumatism (EULAR) clinical response to anti-TNFα therapy at week 16 (P =0.011). We observed that high baseline serum soluble intercellular adhesion molecule 1 (sICAM1), associated with the myeloid phenotype, and high serum C-X-C motif chemokine 13 (CXCL13), associated with the lymphoid phenotype, had differential relationships with clinical response to anti-TNFα compared with anti-IL6R treatment. sICAM1-high/CXCL13-low patients showed the highest week 24 American College of Rheumatology (ACR) 50 response rate to anti-TNFα treatment as compared with sICAM1-low/CXCL13-high patients (42% versus 13%, respectively, P =0.05) while anti-IL-6R patients showed the opposite relationship with these biomarker subgroups (ACR50 20% versus 69%, P =0.004).

CONCLUSIONS

These data demonstrate that underlying molecular and cellular heterogeneity in RA impacts clinical outcome to therapies targeting different biological pathways, with patients with the myeloid phenotype exhibiting the most robust response to anti-TNFα. These data suggest a path to identify and validate serum biomarkers that predict response to targeted therapies in rheumatoid arthritis and possibly other autoimmune diseases.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01119859

B cells in rheumatoid arthritis: from pathogenic players to disease biomarkers

The therapeutic benefit of depleting B cells in rheumatoid arthritis (RA) has refocused attention on B cells with increasing awareness on their role in autoimmunity and their function beyond autoantibody production. The rapid increase in our comprehension of B-cell pathobiology is progressively opening novel perspectives in the area of B cell-targeted therapies with the expectation to define more specific approaches able to preserve the homeostasis of the humoral response while disrupting the pathogenic components. In parallel, B-cell activity in RA is starting to be explored in its clinical value, in search of novel biomarkers embedded in the pathogenic process that could help classifying the disease and predicting its heterogeneous outcome beyond inflammation dynamics. In this review, we summarize current knowledge on the multiple roles that B cells play in several aspects of RA. We also analyze their distribution and potential function in different anatomic compartments with specific reference to the main sites in which the disease may be sustained and exert its detrimental effects: the systemic circulation, synovium, bone marrow, and draining lymph nodes. We also highlight novel data encouraging further research in the field of biomarkers related to B cells and their regulatory factors.

Serum C-X-C motif chemokine 13 is elevated in early and established rheumatoid arthritis and correlates with rheumatoid factor levels

Introduction

We hypothesized that serum levels of C-X-C motif chemokine 13 (CXCL13), a B-cell chemokine, would delineate a subset of rheumatoid arthritis (RA) patients characterized by increased humoral immunity.

Methods

Serum from patients with established RA (the Dartmouth RA Cohort) was analyzed for CXCL13, rheumatoid factor (RF) levels, anticitrullinated peptide/protein antibody (ACPA) and total immunoglobulin G (IgG); other parameters were obtained by chart review. A confirmatory analysis was performed using samples from the Sherbrooke Early Undifferentiated PolyArthritis (EUPA) Cohort. The Wilcoxon rank-sum test, a t-test and Spearman’s correlation analysis were utilized to determine relationships between variables.

Results

In both the Dartmouth and Sherbrooke cohorts, CXCL13 levels were selectively increased in seropositive relative to seronegative RA patients (P = 0.0002 and P < 0.0001 for the respective cohorts), with a strong correlation to both immunoglobulin M (IgM) and IgA RF levels (P < 0.0001). There was a weaker relationship to ACPA titers (P = 0.03 and P = 0.006, respectively) and total IgG (P = 0.02 and P = 0.14, respectively). No relationship was seen with regard to age, sex, shared epitope status or inclusion high-sensitivity C-reactive protein (hsCRP) in either cohort or regarding the presence of baseline erosions in the Sherbrooke Cohort, whereas a modest relationship with Disease Activity Score in 28 joints CRP (DAS28-CRP) was seen in the Dartmouth cohort but not the Sherbrooke cohort.

Conclusion

Using both established and early RA cohorts, marked elevations of serum CXCL13 levels resided nearly completely within the seropositive population. CXCL13 levels exhibited a strong relationship with RF, whereas the association with clinical parameters (age, sex, DAS28-CRP and erosions) or other serologic markers (ACPA and IgG) was either much weaker or absent. Elevated serum CXCL13 levels may identify a subset of seropositive RA patients whose disease is shaped by or responsive to RF production.

High expression levels of the B cell chemoattractant CXCL13 in rheumatoid synovium are a marker of severe disease

OBJECTIVE

The B cell chemoattractant chemokine ligand 13 (CXCL13) is emerging as a new biochemical marker in RA. This study was undertaken to dissect the relationship between CXCL13 expression levels in the synovium and clinico-pathological variables relevant to RA pathogenesis and outcome.

METHODS

Synovial tissues from 71 RA patients were evaluated by immunohistochemistry. Thirty paired samples were used for comparative gene expression analysis by quantitative real-time PCR. CXCL13 levels were analysed in relation to cellular, molecular and clinical features of inflammation, lymphocyte activation and joint damage.

RESULTS

In patients with early disease (<12 months duration), CXCL13 expression correlated significantly with synovial markers of local disease activity and systemic inflammation. Such correlation was less evident in established RA. Notably, the association with lymphocyte infiltration and with expression of B/T cell-related activation and proliferation genes, such as activation-induced cytidine deaminase, IFN-γ and IL-2, remained highly significant independent of disease duration and local disease activity. Patients featuring the highest levels of CXCL13 were more frequently ACPA positive and IgG ACPA titres were increased in the high CXCL13 expression group. Furthermore, the frequency of erosive disease on radiographs was significantly higher in the upper tertile of CXCL13 expression (P = 0.01 with adjustment for disease duration and ACPA). Accordingly, synovial CXCL13 and the local receptor activator of nuclear factor κB ligand (RANKL)/osteoprotegerin (OPG) ratio significantly co-varied (ρ = 0.52, P < 0.01), independent of the level of local inflammation.

CONCLUSION

Synovial CXCL13 appears to be a marker of a more severe pattern of RA disease, characterized by increased lymphocyte activation and bone remodelling beyond the level of conventional markers of inflammation.

Regulation of B lymphocytes and plasma cells by innate immune mechanisms and stromal cells in rheumatoid arthritis

B cells mediate multiple functions that influence immune and inflammatory responses in rheumatoid arthritis. Production of a diverse array of autoantibodies can happen at different stages of the disease, and are important markers of disease outcome. In turn, the magnitude and quality of acquired humoral immune responses is strongly dependent on signals delivered by innate immune cells. Additionally, the milieu of cells and chemokines that constitute a niche for plasma cells rely strongly on signals provided by stromal cells at different anatomical locations and times. The chronic inflammatory state therefore importantly impacts the developing humoral immune response and its intensity and specificity. We focus this review on B cell biology and the role of the innate immune system in the development of autoimmunity in patients with rheumatoid arthritis.

Rituximab for the treatment of rheumatoid arthritis: an update

Rituximab is a chimeric monoclonal antibody that targets the CD20 molecule expressed on the surface of B cells. It was first used in the treatment of non-Hodgkin's lymphoma and later approved for the treatment of rheumatoid arthritis (RA) that does not respond adequately to disease-modifying antirheumatic drugs, including the anti-tumor-necrosis-factor (TNF) biologics. Sustained efficacy in RA can be achieved by repeated courses of rituximab. However, the optimal dose and retreatment schedule of rituximab in RA remains to be established. Seropositivity, complete B cell depletion shortly after treatment, and previous failure to no more than one anti-TNF agent are three factors associated with greater clinical benefits to rituximab. Infusion reaction to the first dose of rituximab occurs in approximately 25% of RA patients, and the incidence reduces with subsequent exposure. Immunogenicity to the chimeric compound occurs in 11% of RA patients, but this does not correlate with its efficacy in B cell depletion. Extended observation of randomized controlled trials in RA does not reveal a significant increase in the incidence of serious infections related to rituximab compared to placebo groups, and the infection rate remains static over time. Repeated treatment with rituximab is associated with hypogammaglobulinemia, which may increase the risk of serious, but rarely opportunistic, infections. Reactivation of occult hepatitis B infection has been reported in RA patients receiving rituximab, but no increase in the incidence of tuberculosis was observed. Screening for baseline serum immunoglobulin G level and hepatitis B status (including occult infection) is important, especially in Asian countries where hepatitis B infection is prevalent. The rare but fatal progressive multifocal leukoencephalopathy linked to the use of rituximab has to be noted. Postmarketing surveillance and registry data, particularly in Asia, are necessary to establish the long-term efficacy and safety of rituximab in the treatment of RA.

CCL19, a B cell chemokine, is related to the decrease of blood memory B cells and predicts the clinical response to rituximab in patients with rheumatoid arthritis

OBJECTIVE

Migration of B cells from peripheral blood to the synovium in patients with rheumatoid arthritis (RA) may predict clinical response to rituximab (RTX). We undertook this study to investigate whether serum levels of chemokines involved in B cell trafficking are correlated with blood levels of memory B cells or serum levels of B cell activation biomarkers before B cell depletion and whether chemokine levels predict RTX responsiveness.

METHODS

Blood B cell subsets were analyzed by flow cytometry (CD27, IgD), and serum B cell activation biomarkers (rheumatoid factor, anti-cyclic citrullinated peptide, free light chains, IgG, IgA, IgM, and BAFF) were measured in 208 RA patients and 70 control subjects. Serum CCL19, CXCL12, and CXCL13 chemokine levels in patients and controls were determined by enzyme-linked immunosorbent assay. The first course of RTX was administered to RA patients, and the response was evaluated at week 24 according to European League Against Rheumatism (EULAR) criteria. Results were expressed as the odds ratio (OR) and 95% confidence interval (95% CI).

RESULTS

Levels of all chemokines were increased in RA patients compared with controls, and levels were inversely correlated with CD27+ memory B cell frequency. CCL19 and CXCL13 levels correlated with levels of 6 serum B cell biomarkers and 4 serum B cell biomarkers, respectively. By univariate analysis, the CCL19 level was positively associated with EULAR response (OR 1.43 [95% CI 1.08-1.90], P = 0.01). By multivariate analysis, the CCL19 level was predictive of a response to RTX (OR 1.48 [95% CI 1.06-2.06], P = 0.02), but this did not persist after adjustment for autoantibody status.

CONCLUSION

CXCL13 and CCL19 reflect blood B cell disturbances and their levels correlate with those of other serum B cell biomarkers. CXCL13 and CCL19 are, therefore, surrogate measures for serum B cell biomarkers in RA. Serum CCL19 measurement is a new hallmark of the B cell-mediated RA subtype and may predict clinical response to RTX.

Efficacy and safety of rituximab treatment in early primary Sjögren's syndrome: a prospective, multi-center, follow-up study

Introduction

Primary Sjögren’s syndrome (pSS) is an autoimmune disorder affecting exocrine glands; however, a subgroup of pSS patients experience systemic extra-glandular involvement leading to a worsening of disease prognosis. Current therapeutic options are mainly empiric and often translated by other autoimmune diseases. In the last few years growing evidence suggests that B-cell depletion by rituximab (RTX) is effective also in pSS. Patients with early active disease appear to be those who could benefit the most from RTX. The aim of this study was to investigate the efficacy and safety of RTX in comparison to disease modifying anti-rheumatic drugs (DMARDs) in early active pSS patients.

Methods

Forty-one patients with early pSS and active disease (EULAR Sjogren’s syndrome disease activity index, ESSDAI ≥ 6) were enrolled in the study. Patients were treated with either RTX or DMARDs in two different Rheumatology centers and followed up for 120 weeks. Clinical assessment was performed by ESSDAI every 12 weeks up to week 120 and by self-reported global disease activity pain, sicca symptoms and fatigue on visual analogic scales, unstimulated saliva flow and Schirmer’s I test at week 12, 24, 48, 72, 96, and 120. Laboratory assessment was performed every 12 weeks to week 120. Two labial minor salivary gland (MSG) biopsies were obtained from all patients at the time of inclusion in the study and at week 120.

Results

Our study demonstrated that RTX treatment results in a faster and more pronounced decrease of ESSDAI and other clinical parameters compared to DMARDs treatment. No adverse events were reported in the two groups. We also observed that RTX is able to reduce glandular infiltrate, interfere with B/T compartmentalization and consequently with the formation of ectopic lymphoid structures and germinal center-like structures in pSS-MSGs.

Conclusions

To our knowledge, this is the first study performed in a large cohort of early active pSS patients for a period of 120 weeks. We showed that RTX is a safe and effective agent to be employed in pSS patients with systemic, extra-glandular involvement. Furthermore, our data on pSS-MSGs provide additional biological basis to employ RTX in this disease.

Effects of CXCL13 inhibition on lymphoid follicles in models of autoimmune disease

The chemokine CXCL13 has a key role in secondary lymphoid tissue orchestration and lymphoid neogenesis. Transgenic mice deficient in CXCL13 or its receptor CXCR5 have severely impaired lymph node development, lack peritoneal B-lymphocytes and are deficient in circulating antibodies to common bacterial antigens. However, total circulating numbers of B-lymphocytes are slightly elevated and humoral responses to T-dependent or blood-borne antigens are relatively normal. Lymphoid neogenesis is an aberrant process that occurs in chronically inflamed tissue and provides a microenvironment supportive of pathogenic B-cell survival and activation. Here, we describe the impact of therapeutic dosing of a CXCL13 antibody in a mouse model of arthritis, and detail the contribution CXCL13 makes to lymphoid follicle microenvironment, without affecting humoral immune responses.

Mechanistic biomarkers for clinical decision making in rheumatic diseases

The use of biomarkers is becoming increasingly intrinsic to the practice of medicine and holds great promise for transforming the practice of rheumatology. Biomarkers have the potential to aid clinical diagnosis when symptoms are present or to provide a means of detecting early signs of disease when they are not. Some biomarkers can serve as early surrogates of eventual clinical outcomes or guide therapeutic decision making by enabling identification of individuals likely to respond to a specific therapy. Using biomarkers might reduce the costs of drug development by enabling individuals most likely to respond to be enrolled in clinical trials, thereby minimizing the number of participants required. In this Review, we discuss the current use and the potential of biomarkers in rheumatology and in select fields at the forefront of biomarker research. We emphasize the value of different types of biomarkers, addressing the concept of 'actionable' biomarkers, which can be used to guide clinical decision making, and 'mechanistic' biomarkers, a subtype of actionable biomarker that is embedded in disease pathogenesis and, therefore, represents a potentially superior biomarker. We provide examples of actionable and mechanistic biomarkers currently available, and discuss how development of such biomarkers could revolutionize clinical practice and drug development.

Assessment of synovitis to predict bone erosions in rheumatoid arthritis

Although rheumatoid arthritis (RA) is traditionally considered as the prototype of destructive arthritis, the course of the disease varies considerably, with some patients experiencing more rapid progression of joint damage and disability than others. Given the increasing availability of treatment targets and options, timely recognition of individual's outcomes could allow therapeutic allocation according to personalized benefit-risk profiles. Research efforts are thus increasingly focused at discovering predictive markers that could identify patients with aggressive, rapidly progressive disease and poor prognosis. As joint destruction in RA is the result of the cumulative burden of inflammation, variables reflecting the severity of synovitis and its persistence over time might refine our ability to build early prognostic algorithms. The goal of this article is to review the clinical implications of the assessment of synovitis in relation to radiographic outcomes. Traditional and novel assessment tools will be discussed, including clinical measures, imaging techniques and tissue biomarkers. Achievements in the field of synovial tissue analysis and peripheral blood biomarkers of synovitis represent only the first steps of ongoing progress, which still need to be integrated into the phenotypic heterogeneity of RA.

Serum levels of CXCL13 are associated with ultrasonographic synovitis and predict power Doppler persistence in early rheumatoid arthritis treated with non-biological disease-modifying anti-rheumatic drugs

Introduction

Biological markers specifically reflecting pathological processes may add value in the assessment of inter-individual variations in the course of rheumatoid arthritis (RA). The current study was undertaken to investigate whether baseline serum levels of the chemokine CXCL13 might predict clinical and ultrasonographic (US) outcomes in patients with recent-onset RA.

Methods

The study included 161 early RA patients (disease duration < 12 months) treated according to a disease activity score (DAS) driven step-up protocol aiming at DAS < 2.4. Clinical disease activity measures were collected at baseline, 2, 4, 6, 9 and 12 months, and US examination of the hands was performed at baseline, 6 and 12 months. Grey-Scale (GS) and Power Doppler (PD) synovitis were scored (0 to 3), with overall scores as the sum of each joint score. CXCL13 levels were measured at baseline by enzyme-linked immunosorbent assay and evaluated in relation to the achievement of low disease activity (LDA, DAS < 2.4) and US residual inflammation (PD ≤ 1) at 12 months.

Results

Baseline levels of CXCL13 were significantly higher in RA compared to healthy controls (n = 19) (P = 0.03) and correlated with measures of synovitis, such as the swollen joint count (R 0.28, P < 0.001), the US-GS (R 0.27, P = 0.003) and US-PD (R 0.26, P = 0.005) score. Although CXCL13 did not predict the likelihood of achieving clinical LDA at 12 months within a structured treat-to-target protocol, elevated levels of CXCL13 were associated with more frequent increases of methotrexate dosage (P < 0.001). Using adjusted analyses, the highest levels of CXCL13 (> 100 pg/ml) were the only independent predictor of residual imaging inflammation (P = 0.005), irrespective of initial US-PD scores, disease activity status, acute phase reactants and autoantibodies. Among the patients in clinical LDA at 12 months, US-PD scores ≤ 1 were less frequently achieved in the high baseline CXCL13 (> 100 pg/ml) group, with an adjusted OR = 0.06 (95% CI 0.01 to 0.55, P = 0.01).

Conclusions

CXCL13 emerges as a new biological marker in early RA, accurate in assessing the severity of synovitis and the persistence of US-PD activity over time in response to conventional treatments.

Safety, pharmacokinetics, and biologic activity of pateclizumab, a novel monoclonal antibody targeting lymphotoxin α: results of a phase I randomized, placebo-controlled trial

INTRODUCTION

Pateclizumab (MLTA3698A) is a humanized mAb against lymphotoxin α (LTα), a transiently expressed cytokine on activated B and T cells (Th1, Th17), which are implicated in rheumatoid arthritis (RA) pathogenesis. This study was conducted to assess the safety, tolerability, < NOTE: For clarity and per AMA/S-W Style, please restore the use of Oxford/serial commas (ie: David likes vanilla, strawberry, and chocolate ice cream) throughout. and biologic activity of single and multiple doses of intravenous (IV) or subcutaneous (SC) pateclizumab in RA patients.

METHODS

The single ascending dose (SAD) phase in patients with stable RA consisted of six cohorts (4:1 active:placebo at 0.3 mg/kg IV, 1.0 mg/kg IV, 1.0 mg/kg SC, 3.0 mg/kg IV, 3.0 mg/kg SC, and 5.0 mg/kg IV; n = 5/cohort). In the multiple ascending dose (MAD) phase, patients with prespecified RA disease activity received three doses of pateclizumab or placebo (4:1) every 2 weeks (1.0 mg/kg SC, n = 10; 3.0 mg/kg SC, n = 20; or 5.0 mg/kg IV, n = 5). Safety and tolerability were assessed throughout, and clinical activity was determined after three doses (Week 6).

RESULTS

We observed no serious adverse events (AEs) or dose-limiting toxicities, and the majority of AEs were mild to moderate. The pharmacokinetic profiles were linear, and clearance was independent of dose. Reductions in levels of serum CXCL13 were observed, supporting the biologic activity of pateclizumab on the LTα pathway. Patients receiving pateclizumab in the 3.0 mg/kg MAD group (3.0 mg/kg SC) demonstrated ACR20, ACR50, and ACR70 response rates at week 6 of 75%, 56% and 25%, respectively, compared with 57%, 29%, and 0% in the placebo group. The median Disease Activity Score in 28 joints, C-reactive protein, reduction was 28% for pateclizumab, versus 8.4% for placebo.

CONCLUSIONS

Pateclizumabwas generally well-tolerated in RA patients. Preliminary evidence of clinical activity was observed in active RA patients at the dose level targeted for clinical effect.

Synovial tissue heterogeneity and peripheral blood biomarkers

Rheumatoid arthritis is characterized by multiple pathobiological processes and heterogeneous clinical phenotypes. Not surprisingly, the inflamed synovium harbors an equally complex pathology. This includes variability in infiltrating and resident cell populations, spatial arrangements, and cell-cell interactions, as well as gene expression profiles. Remarkable progress in our understanding of the many facets of tissue heterogeneity has been facilitated by the increasing availability of patients' material and the development of advanced research technologies. The next challenge is to capitalize on the large amount of data generated to elucidate the specific pathogenic pathways disparately activated in different patients and/or different phases of the disease. When tissue pathology can be reliably explored through noninvasive circulating biomarkers, then the circle will be closed. We attempt to highlight key advances in the understanding of synovial tissue heterogeneity in rheumatoid arthritis and summarize novel perspectives in synovial biomarker discovery in relation to peripheral blood.

Targeting chemokine receptors in chronic inflammatory diseases: an extensive review

The traffic of the different types of immune cells is an important aspect in the immune response. Chemokines are soluble peptides that are able to attract cells by interaction with chemokine receptors on their target cells. Several different chemokines and receptors exist enabling the specific trafficking of different immune cells. In chronic inflammatory disorders there is abundance of immune cells present at the inflammatory site. This review focuses on the role of chemokine receptors in chronic inflammatory disorders of the lungs, intestine, joints, skin and nervous system and the potential of targeting these receptors as therapeutic intervention in these disorders.