Spotlight on tocilizumab and its potential in the treatment of systemic sclerosis

The intervention of macrophages in progressive fibrosis characterizing systemic sclerosis: A systematic review

BACKGROUND AND AIM

Systemic sclerosis (SSc) is an immune mediated connective tissue disease characterized by microvascular dysfunction, aberrant immune response, and progressive fibrosis. Although the immuno-pathophysiological mechanisms underlying SSc are not fully clarified, they are often associated with a dysfunctional macrophage activation toward an alternative (M2) phenotype induced by cytokines [i.e., IL-4, IL-10, IL-13, and transforming growth factor (TGF-β)] involved in the fibrotic and anti-inflammatory process. A spectrum of macrophage activation state has been identified ranging from M1 to M2 phenotype, gene expression of phenotype markers, and functional aspects. This systematic review aims to analyze the importance of M2 macrophage polatization during the immune mediated process and the identification of specific pathways, cytokines, and chemokines involved in SSc pathogenesis. Moreover, this review provides an overview on the in vitro and in vivo studies aiming to test therapeutic strategies targeting M2 macrophages.

METHODS

A systematic literature review was performed according to the preferred Reported Items for Systematic Reviews and Meta-Analyses (PRISMA). The search encompassed the online medical databases PubMed and Embase up to the 30th of June 2024. Original research manuscripts (in vitro study, in vivo study), animal model and human cohort, were considered for the review. Exclusion criteria encompassed reviews, case reports, correspondences, and conference abstracts/posters. The eligible manuscripts main findings were critically analyzed, discussed, and summarized in the correspondent tables.

RESULTS

Out of the 77 screened abstracts, 49 papers were deemed eligible. Following a critical analysis, they were categorized according to the primary (29 original articles) and secondary (20 original articles) research objectives of this systematic review. The data from the present systematic review suggest the pivotal role of M2 macrophages differentiation and activation together with the dysregulation of the immune system in the SSc pathogenesis. Strong correlations have been found between M2 macrophage presence and clinical manifestations in both murine and human tissue samples. Interestingly, the presence of M2 cell surface markers on peripheral blood monocytes has been highlighted, suggesting a potential biomarker role for this finding. Therapeutic effects reducing M2 macrophage activities have been observed and/or tested for existing and for new drugs, demonstrating potential efficacy in modulating the pro-fibrotic immune response for treatment of SSc.

CONCLUSIONS

The increased M2 macrophage activation in course of SSc seems to offer new insights on the self-amplifying inflammatory and fibrotic response by the immune system on such disease. Therefore, the revaluation of immunomodulatory and ongoing antifibrotic therapies, as well as novel therapeutical approaches in SSc that contribute to limit the M2 macrophage activation are matter of intense investigations.

Effector and regulatory B-cell imbalance in systemic sclerosis: cooperation or competition?

B cells play a central role in the pathogenesis of systemic sclerosis (SSc). Most B-cell studies have focused on their pathological role as antibody producers. However, in addition to immunoglobulin secretion, these cells have a wide range of functions in the immune response, including antigen presentation to T cells and cytokine production. Importantly, not all B-cell subsets promote the immune response. Regulatory B cells (Bregs) attenuate inflammation and contribute to the maintenance of immune tolerance. However, effector B cells (Beffs) positively modulate the immune response through the production of various cytokines. In SSc, Bregs are insufficient and/or dysfunctional. B-cell-targeting biologics have been trialled with promising results in the treatment of SSc. These therapies can affect Bregs or Beffs, which can potentially limit their long-term efficacy. Future strategies might involve the modulation of effector B cells in combination with the stimulation of regulatory subsets. Additionally, the monitoring of individual B-cell subsets in patients may lead to the discovery of novel biomarkers that could help predict disease relapse or progression. The purpose of this review is to summarize the relevant literatures and explain how Bregs and Beffs jointly participate in the pathogenesis of SSc.

Prognostic and predictive markers of systemic sclerosis-associated interstitial lung disease in a clinical trial and long-term observational cohort

OBJECTIVES

To explore prognostic and predictive markers of SSc-associated interstitial lung disease (SSc-ILD) outcomes in a phase 3 trial (focuSSced) and prognostic markers in a real-world cohort (SMART).

METHODS

The focuSSced SSc-ILD subgroup included 68 of 106 placebo-treated and 68 of 104 tocilizumab-treated patients. The SMART cohort included 505 patients with SSc-ILD. Linear mixed-effect models were used to identify factors associated with change in forced vital capacity (FVC). Kaplan-Meier estimation and Cox regression were used for time-to-event analyses.

RESULTS

In placebo-treated focuSSced patients, sex was a significant prognostic factor for FVC decline; males had increased risk for absolute decline ≥10% in percent-predicted FVC (ppFVC) and 0.22% faster weekly FVC decline than females (P = 0.0001). FVC was 9.8% lower in patients with CRP >6 mg/ml vs those with CRP ≤6 mg/ml (P = 0.0059). Tocilizumab reduced the risk for ≥10% decline in ppFVC in patients who were male, had earlier disease (<2 years duration), had IL-6 levels <10 pg/ml, or had anti-topoisomerase antibodies (ATA). In the SMART cohort, prognostic factors for ppFVC <70% were male sex, ATA, and low baseline FVC. Males had 3.3% lower FVC 1 year after disease onset (P < 0.001) and 0.6% faster yearly decline (P = 0.03) than females.

CONCLUSION

Prognostic markers in SSc-ILD were similar between focuSSced and SMART. Male sex and inflammatory markers were associated with lower FVC but IL-6 ≥10 pg/ml was not predictive of response to tocilizumab.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02453256.

M2 macrophage polarization in systemic sclerosis fibrosis: pathogenic mechanisms and therapeutic effects

Systemic sclerosis (SSc, scleroderma), is an autoimmune rheumatic disease characterized by fibrosis of the skin and internal organs, and vasculopathy. Preventing fibrosis by targeting aberrant immune cells that drive extracellular matrix (ECM) over-deposition is a promising therapeutic strategy for SSc. Previous research suggests that M2 macrophages play an essential part in the fibrotic process of SSc. Targeted modulation of molecules that influence M2 macrophage polarization, or M2 macrophages, may hinder the progression of fibrosis. Here, in an effort to offer fresh perspectives on the management of scleroderma and fibrotic diseases, we review the molecular mechanisms underlying the regulation of M2 macrophage polarization in SSc-related organ fibrosis, potential inhibitors targeting M2 macrophages, and the mechanisms by which M2 macrophages participate in fibrosis.

The Role of T Cells in Systemic Sclerosis: An Update

Systemic sclerosis (SSc) is a chronic disease characterized by microvasculopathy, autoantibodies (autoAbs), and fibrosis. The pathogenesis of the disease is incompletely understood. Microvasculopathy and autoAbs appear very early in the disease process. AutoAbs, such as those directed against DNA topoisomerase I (Topo I), are disease specific and associated with disease manifestations, and indicate activation of the adaptive immune system. B cells are involved in fibrosis in SSc. T cells are also involved in disease pathogenesis. T cells show signs of antigen-induced activation; T cells of TH2 type are increased and produce profibrotic cytokines interleukin (IL)-4, IL-13, and IL-31; CD4+ cytotoxic T lymphocytes are increased in skin lesions, and cause fibrosis and endothelial cell apoptosis; circulating T follicular helper (TFH) cells are increased in SSc produce IL-21 and promote plasmablast antibody production. On the other hand, regulatory T cells are impaired in SSc. These findings provide strong circumstantial evidence for T cell implication in SSc pathogenesis and encourage new T cell-directed therapeutic strategies for the disease.

Problems to Consider Before Determining the Regimen of the Treatment for Juvenile Systemic Sclerosis Treatment: A Case Report Where Tocilizumab Monotherapy Succeeded Efficiently and Safely

Juvenile systemic sclerosis (SSc) is a rare condition that results in various disorders, including growth retardation and learning disabilities in addition to impaired quality of life due to fibrosis and microvascular disorders in multiple organs. Recently, efficacies of immunosuppressants such as cyclophosphamide and mycophenolate mofetil, as well as biological agents, have been reported in adult patients with SSc. However, there has been no consensus in the treatment of juvenile SSc due to its rarity and the fact that skin sclerosis may be self-limiting in some patients. Here, we present a case of 13-year-onset SSc with growth retardation and learning disabilities, in addition to skin sclerosis, interstitial lung disease, and possible myocardial fibrosis that was successfully treated with tocilizumab monotherapy without remarkable adverse reactions. As careful case-by-case management of patient's growth and education along with standard treatment is needed, the documentation of such case is important for the evaluation of the efficient and safe therapy for juvenile SSc.

Cellular and Molecular Diversity in Scleroderma

With the increasing armamentarium of high-throughput tools available at manageable cost, it is attractive and informative to determine the molecular underpinnings of patient heterogeneity in systemic sclerosis (SSc). Given the highly variable clinical outcomes of patients labelled with the same diagnosis, unravelling the cellular and molecular basis of disease heterogeneity will be crucial to predicting disease risk, stratifying management and ultimately informing a patient-centered precision medicine approach. Herein, we summarise the findings of the past several years in the fields of genomics, transcriptomics, and proteomics that contribute to unraveling the cellular and molecular heterogeneity of SSc. Expansion of these findings and their routine integration with quantitative analysis of histopathology and imaging studies into clinical care promise to inform a scientifically driven patient-centred personalized medicine approach to SSc in the near future.

Recognition and Management of Cutaneous Connective Tissue Diseases

Connective tissue diseases (CTDs) encompass a broad spectrum of clinical presentations that involve multidisciplinary management. Cutaneous findings are common in CTD and careful examination of these features aids in appropriate diagnosis and subsequent evaluation. Thorough work-up of CTD is crucial to properly identify disease subtypes and systemic involvement. Management plans can be developed based on diagnosis and systemic manifestations of disease. Disease management often requires treatment with pharmacotherapies with potential for toxicities, further underscoring the importance of diagnostic accuracy in this patient population. Evolving research strives to better elucidate the pathogenic mechanisms of CTDs allowing for more targeted treatment modalities.

Can Nuclear Imaging of Activated Macrophages with Folic Acid-Based Radiotracers Serve as a Prognostic Means to Identify COVID-19 Patients at Risk?

Herein, we discuss the potential role of folic acid-based radiopharmaceuticals for macrophage imaging to support clinical decision-making in patients with COVID-19. Activated macrophages play an important role during coronavirus infections. Exuberant host responses, i.e., a cytokine storm with increase of macrophage-related cytokines, such as TNFα, IL-1β, and IL-6 can lead to life-threatening complications, such as acute respiratory distress syndrome (ARDS), which develops in approximately 20% of the patients. Diverse immune modulating therapies are currently being tested in clinical trials. In a preclinical proof-of-concept study in experimental interstitial lung disease, we showed the potential of ¹⁸F-AzaFol, an ¹⁸F-labeled folic acid-based radiotracer, as a specific novel imaging tool for the visualization and monitoring of macrophage-driven lung diseases. ¹⁸F-AzaFol binds to the folate receptor-beta (FRβ) that is expressed on activated macrophages involved in inflammatory conditions. In a recent multicenter cancer trial, ¹⁸F-AzaFol was successfully and safely applied (NCT03242993). It is supposed that the visualization of activated macrophage-related disease processes by folate radiotracer-based nuclear imaging can support clinical decision-making by identifying COVID-19 patients at risk of a severe disease progression with a potentially lethal outcome.

Designing therapeutic strategies to combat severe acute respiratory syndrome coronavirus-2 disease: COVID-19

A highly contagious coronavirus disease COVID-19 caused by a recently identified severe acute respiratory syndrome CoV-2 (SARS-CoV-2) initially detected in Wuhan, China has spread worldwide and become a major health crisis in the absence of specific vaccine or antiviral drugs. SARS-CoV-2 infection has resulted in overwhelming number of reported deaths. Unfortunately it is still spreading uncontrollably despite implementing stringent protective measures. Rapid development of effective therapeutic strategies for treatment and prevention of infection is crucially required. Although genomic characterization has assisted in unfolding various aspects of SARS-CoV-2 but development of specific antiviral drugs and vaccine against COVID-19 is still a worldwide challenge. Understanding the disease pathological course underlying the clinical manifestations of COVID-19 is imperative to identify the vital targets for drug development. SARS-CoV-2 uses angiotensin converting enzyme 2 (ACE2) receptor to enter the host cell and primarily target type II alveolar cells. COVID-19 disease progression is associated with distressed immune functions and hyper active inflammatory system leading to development of cytokine storm which is a vital factor involved in disease advancement. The current review elucidates the disease pathology and summarizes the possible therapeutic options to battle against COVID-19 on the basis of current state of understanding about SARS-CoV-2 pathogenic pathways and knowledge gained from previous SARS and MERS-CoV epidemics. Therapeutic strategies to treat and prevent infection as well as to suppress the disease progression to reduce severity and mortality rate is discussed. Drug candidates currently under consideration and undergoing clinical trials for COVID-19 treatment are highlighted.

Current status of potential therapeutic candidates for the COVID-19 crisis

As of April 15, 2020, the ongoing coronavirus disease 2019 (COVID-2019) pandemic has swept through 213 countries and infected more than 1,870,000 individuals, posing an unprecedented threat to international health and the economy. There is currently no specific treatment available for patients with COVID-19 infection. The lessons learned from past management of respiratory viral infections have provided insights into treating COVID-19. Numerous potential therapies, including supportive intervention, immunomodulatory agents, antiviral therapy, and convalescent plasma transfusion, have been tentatively applied in clinical settings. A number of these therapies have provided substantially curative benefits in treating patients with COVID-19 infection. Furthermore, intensive research and clinical trials are underway to assess the efficacy of existing drugs and identify potential therapeutic targets to develop new drugs for treating COVID-19. Herein, we summarize the current potential therapeutic approaches for diseases related to COVID-19 infection and introduce their mechanisms of action, safety, and effectiveness.

Characterizing Disease Manifestations and Treatment Patterns Among Adults with Systemic Sclerosis: A Retrospective Analysis of a US Healthcare Claims Population

INTRODUCTION

Real-world use of immunomodulating therapy (IMT) in patients with systemic sclerosis (SSc) was investigated for the first time in a descriptive, retrospective cohort analysis of claims made in a healthcare insurance database to characterize treatment patterns and their alignment with SSc disease manifestations.

METHODS

Treatment patterns and disease manifestations, symptoms, complications, and comorbidities were assessed in patients with SSc enrolled in a US healthcare claims database who received treatment between January 2006 and December 2013 and for whom data were available 6 months before and 12 months after SSc diagnosis.

RESULTS

Among 7812 eligible patients, 6852 received treatments of interest for SSc and 2404 (30.8%) received IMT during the first year after SSc diagnosis. In the first year after diagnosis, the most common claims were for antibiotics (61.7%), opioids (50.6%), glucocorticoids (46.5%), and proton pump inhibitors (35.4%); the most common organs involved with complications among patients with SSc were lung (30.5%), heart (17.4%), and gastrointestinal tract (22.4%); the most common signs or symptoms were musculoskeletal (16.1%) and fatigue (10.5%); 1035 patients (15.1%) had infections and 14 (0.2%) had malignancies. Among patients who received IMT, 43.8% received at least hydroxychloroquine and 21.1% received at least methotrexate; 460 patients switched to a second IMT, 23.0% to at least methotrexate and 22.8% to at least mycophenolate mofetil. The most common comorbidities reported with first IMT were in lung (11.8%), overlap syndrome (8.4%), heart (5.3%), and gastrointestinal (6.8%) categories.

CONCLUSION

One-third of patients with SSc in the healthcare claims population received IMTs during the first year after diagnosis. However, patients who received IMTs had disease manifestations similar to those of the overall SSc healthcare claims population.

Systemic sclerosis-associated interstitial lung disease

Systemic sclerosis is an autoimmune connective tissue disease, which is characterised by immune dysregulation and progressive fibrosis that typically affects the skin, with variable internal organ involvement. It is a rare condition that affects mostly young and middle-aged women, resulting in disproportionate morbidity and mortality. Currently, interstitial lung disease is the most common cause of death among patients with systemic sclerosis, with a prevalence of up to 30% and a 10-year mortality of up to 40%. Interstitial lung disease is more common among African Americans and in people with the diffuse cutaneous form of systemic sclerosis or anti-topoisomerase 1 antibodies. Systemic sclerosis-associated interstitial lung disease most commonly presents with dyspnoea, cough, and a non-specific interstitial pneumonia pattern on CT scan, with a minority of cases fulfilling the criteria for usual interstitial pneumonia. The standard therapy has traditionally been combinations of immunosuppressants, particularly mycophenolate mofetil or cyclophosphamide. These immunosuppressants can be supplemented by targeted biological and antifibrotic therapies, whereas autologous haematopoietic stem-cell transplantation and lung transplantation are reserved for refractory cases.

TGF-β pathway activation by idiopathic pulmonary fibrosis (IPF) fibroblast derived soluble factors is mediated by IL-6 trans-signaling

Background

Idiopathic pulmonary fibrosis (IPF) is a chronic and ultimately fatal disease characterized by a progressive decline in lung function. Fibrotic diseases, such as IPF, are characterized by uncontrolled activation of fibroblasts. Since the microenvironment is known to affect cell behavior, activated fibroblasts can in turn activate healthy neighboring cells. Thus, we investigated IPF paracrine signaling in human lung fibroblasts (HLFs) derived from patients with IPF.

Methods

Primary human fibroblast cultures from IPF (IPF-HLF) and control donor (N-HLF) lung tissues were established and their supernatants were collected. These supernatants were then added to N-HLFs for further culture. Protein and RNA were extracted from IPF/ N-HLFs at baseline. Interleukin-6 (IL-6) and TGF-β-related signaling factors (e.g. STAT3, Smad3) were evaluated by western blot and qPCR. IL-6 levels were measured by ELISA. IL-6 signaling was blocked by Tocilizumab (TCZ) (10 ng/ml).

Results

IPF-HLFs were found to significantly overexpress IL-6 receptor (IL-6R), suppressor of cytokine signaling 3 (SOCS3), phospho-STAT3-Y705 and phospho-Smad3 in comparison to N-HLFs (p < 0.05). In addition, they were found to proliferate faster, secrete more IL-6 and express higher levels of the soluble IL-6R. IPF-HLF increased proliferation was inhibited by TCZ. Moreover, IPF-HLF derived supernatants induced both direct and indirect STAT3 activation that resulted in Smad3 phosphorylation and elevated Gremlin levels in N-HLFs. These effects were also successfully blocked by TCZ.

Conclusions

IPF-HLF paracrine signaling leads to IL-6R overexpression, which in turn, affects N-HLF survival. The IL-6/STAT3/Smad3 axis facilitates cellular responses that could potentially promote fibrotic disease. This interplay was successfully blocked by TCZ.

Ongoing clinical trials and treatment options for patients with systemic sclerosis-associated interstitial lung disease

SSc is a rare CTD that affects multiple organ systems, resulting in substantial morbidity and mortality. Evidence of interstitial lung disease (ILD) is seen in ∼80% of patients with SSc. Currently there is no approved disease-modifying treatment for ILD and few effective treatment options are available. CYC is included in treatment guidelines, but it has limited efficacy and is associated with toxicity. MMF is becoming the most commonly used medication in clinical practice in North America and the UK, but its use is not universal. Newer agents targeting the pathogenic mechanisms underlying SSc-ILD, including fibrotic and inflammatory pathways, lymphocytes, cell-cell and cell-extracellular membrane interactions, hold promise for better treatment outcomes, including improved lung function, patient-related outcomes and quality of life. Here we review ongoing trials of established and novel agents that are currently recruiting patients with SSc-ILD.

Pulmonary Manifestations of Systemic Sclerosis and Mixed Connective Tissue Disease

Systemic sclerosis (SSc) is a rare disease characterized by widespread collagen deposition resulting in fibrosis. Although skin involvement is the most common manifestation and also the one that determines the classification of disease, mortality in SSc is usually a result of respiratory compromise in the form of interstitial lung disease (ILD) or pulmonary hypertension (PH). Clinically significant ILD is seen in up to 40% of patients and PH in up to 20%. Treatment with either cyclophosphamide or mycophenolate has been shown to delay disease progression, whereas rituximab and lung transplantation are reserved for refractory cases.

Outcomes of patients with systemic sclerosis treated with tocilizumab: Case series and review of the literature

The treatment of systemic sclerosis (SSc) presents a clinical challenge because of the progressive nature of the disease, relatively poor prognosis, and lack of a proven treatment. In the last 10 years, several studies demonstrated the importance of interleukin 6 (IL6) as a pivotal cytokine in the development of fibrosis and angiopathy, especially in SSc. Tocilizumab, an IL6 receptor antibody, has shown promising results for patients with SSc. A total of 16 patients with SSc were treated with tocilizumab; 14 were female and 2 were male, with a median age of 45.5 years and median disease duration of 31.5 months. Ten patients had anti-SCl-70, none had anticentromere, and two had antipolymerase. Tocilizumab treatment was provided as long as the patient's condition improved. Total treatment duration was 30.33 patient-years. Median treatment duration was 18.5 months, and 3 patients were treated for a period of 4 years and longer. Ten patients were treated with tocilizumab to the date of data collection. All were feeling good and maintained the achieved improvement throughout the treatment period. Improvement was recorded in 12 patients (75%). Mean reduction in modified Rodnan skin score was 11 points (p < 0.001), musculoskeletal and joint involvement improved in 75% and 80% of patients, respectively, and improvement in lung function was recorded in 46%. Patients with early SSc responded better to tocilizumab (p = 0.01). This is the largest reported case series of tocilizumab treatment in patients with SSc. The treatment was without significant side-effects and was beneficial for most patients, especially in early disease. The present study reinforces previous findings regarding the efficacy of tocilizumab in treating SSc.

Use of tocilizumab in systemic sclerosis: A brief literature review

The available treatments for systemic sclerosis (SS) have limited effectiveness. Treatment with tocilizumab (TCZ), a biological drug that inhibits interleukin 6 (IL-6), has recently been proposed. In this study, we conducted a literature review to assess the safety and efficacy of TCZ in SS. We found 52 articles, 10 of which we selected after evaluating the articles. In a randomised clinical trial, TCZ showed a nonsignificant improvement in the degree of skin induration, while another observational study showed neutral results. In this same clinical trial, the functional respiratory parameters showed a certain degree of stabilization. The safety profile of TCZ is acceptable; however, the current evidence regarding treatment of SS with TCZ is highly limited, although the drug could have a beneficial effect in skin disorder. New clinical trials are needed to determine the usefulness of TCZ in SS.

Immunotherapy of systemic sclerosis

Systemic sclerosis (SSc) is a chronic systemic disease characterized by microvasculopathy, immune activation, and extensive collagen deposition. Microvasculopathy and immune activation occur very early in the disease process. Evidence from animal models and in vitro studies indicate that T-cells and B-cells activate fibroblasts to produce collagen. Traditional immunosuppressants, cyclophosphamide(CyP), methotrexate(MTX), and more recently mycophenolate mofetil(MMF), may prove more effective if used very early in the disease course. These drugs showed some benefit in skin (MTX, CyP, MMF) and lung function (CyP, MMF). Biologicals, such as intravenous immunoglobulin (IVIg), belimumab(Beli), tocilizumab(TCZ), abatacept(Aba), rituximab(RTX) and fresolimumab(Fresu) appear promising as they exhibited some benefit in skin (IVIg, Beli, TCZ, Aba, RTX, Fresu), hand function (IVIg), and joints (IVIg, TCZ, Aba). Autologous stem cell transplantation showed the best therapeutic efficacy on skin and internal organs, and looks very promising, as modification of transplantation immunosuppression is decreasing the early high mortality.

Intestinal Involvement in Systemic Sclerosis: A Clinical Review

Systemic sclerosis (SSc) is a chronic systemic disease characterized by microvasculopathy, autoantibodies, and extensive fibrosis. Intestinal involvement is frequent in SSc and represents a significant cause of morbidity. The pathogenesis of intestinal involvement includes vascular damage, nerve dysfunction, smooth muscle atrophy, and fibrosis, causing hypomotility, which leads to small intestinal bacterial overgrowth (SIBO), malabsorption, malnutrition, diarrhea, pseudo-obstruction, constipation, pneumatosis intestinalis, and fecal incontinence. Manifestations are often troublesome and reduce quality of life and life expectancy. Assessment of intestinal involvement includes screening for small intestine hypomotility, malnutrition, SIBO, and anorectal dysfunction. Current management of intestinal manifestations is largely inadequate. Patients with diarrhea are managed with low-fat diet, medium-chain triglycerides, avoidance of lactulose and fructose, and control of bacterial overgrowth with antibiotics for SIBO. In diarrhea/malabsorption, bile acid sequestrant and pancreatic enzyme supplementation may help, and nutritional support is needed. General measures are applied for constipation, and intestine rest plus antibiotics for pseudo-obstruction. Fecal incontinence is managed with measures for associated SIBO, or constipation, and with behavioral therapies. Pneumatosis intestinalis is usually an incidental finding that does not require any specific treatment. Immunomoduation should be considered early in intestinal involvement. Multidisciplinary approach of intestinal manifestations in SSc by gastroenterologists and rheumatologists is required for optimum management.

Coming of Age for Autotaxin and Lysophosphatidate Signaling: Clinical Applications for Preventing, Detecting and Targeting Tumor-Promoting Inflammation

A quarter-century after the discovery of autotaxin in cell culture, the autotaxin-lysophosphatidate (LPA)-lipid phosphate phosphatase axis is now a promising clinical target for treating chronic inflammatory conditions, mitigating fibrosis progression, and improving the efficacy of existing cancer chemotherapies and radiotherapy. Nearly half of the literature on this axis has been published during the last five years. In cancer biology, LPA signaling is increasingly being recognized as a central mediator of the progression of chronic inflammation in the establishment of a tumor microenvironment which promotes cancer growth, immune evasion, metastasis, and treatment resistance. In this review, we will summarize recent advances made in understanding LPA signaling with respect to chronic inflammation and cancer. We will also provide perspectives on the applications of inhibitors of LPA signaling in preventing cancer initiation, as adjuncts extending the efficacy of current cancer treatments by blocking inflammation caused by either the cancer or the cancer therapy itself, and by disruption of the tumor microenvironment. Overall, LPA, a simple molecule that mediates a plethora of biological effects, can be targeted at its levels of production by autotaxin, LPA receptors or through LPA degradation by lipid phosphate phosphatases. Drugs for these applications will soon be entering clinical practice.

Altered B lymphocyte homeostasis and functions in systemic sclerosis

Beyond the production of autoantibodies, B-cells are thought to play a role in systemic sclerosis (SSc) by secreting proinflammatory/profibrotic cytokines. B-cells are a heterogeneous population with different subsets distinguished by their phenotypes and cytokine production. Data about B-cell subsets, cytokine production and intracellular pathways leading to this production are scarce in SSc. The aim of our study was to describe B-cell homeostasis, activation, proliferation, cytokine production in B-cells and serum and B-cell intracellular signaling pathways in SSc. We hypothezided that B-cell homeostasis and cytokine production were altered in SSc and could be explained by serum cytokine as well as by intracellular signaling pathway abnormalities. Forty SSc patients and 20 healthy controls (HC) were prospectively included. B-cell subsets were determined by flow cytometry using CD19, CD21, CD24, CD38, CD27, IgM and IgD. CD25, CD80, CD95, HLA-DR were used to assess B-cell activation. Intracellular production of IL-10 and IL-6 were assessed by flow cytometry after TLR9 and CD40 stimulation. IL-6, IL-10, Ki67, Bcl2 mRNA were quantified in B-cells. Cytokine production was also assessed in sera and supernatants of B-cell culture, using a multiplex approach. Signaling pathways were studied through phosphorylation of mTOR, ERK, STAT3, STAT5 using a flow cytometry approach. We found that SSc patients exhibited an altered peripheral blood B-cell subset distribution, with decreased memory B-cells but increased proportion of naive and CD21^LoCD38^Lo B-cell subsets. We observed an increased expression of activation markers (CD80, CD95, HLA-DR) on some B-cell subsets, mainly the memory B-cells. Secretion of IL-6, BAFF and CXCL13 were increased in SSc sera. There was no correlation between the peripheral blood B-cell subsets and the serum concentrations of these cytokines. After stimulation, we observed a lower proportion of IL-10 and IL-6 producing B-cells in SSc. Finally, we observed a significant decrease of mTOR phosphorylation in SSc patient B-cells. In conclusion, we observed an altered B-cell homeostasis in SSc patients compared to HC. Memory B-cells were both decreased and activated in patients. IL-10 producing B-cells were decreased in SSc. This decrease was associated with an alteration of mTOR phosphorylation in B-cells. Conversely, there was no correlation between serum cytokine profile and B-cell homeostasis alterations.