Serum chemokine and cytokine levels as indicators of disease activity in patients with systemic sclerosis

Understanding the pleiotropic effects of CXCL10/IP-10 in the immunopathogenesis of inflammatory rheumatic diseases: Implications for better understanding disease mechanisms

Chemokines play a critical role in immune responses, acting as chemotactic factors and effectors in different immune processes. CXCL10/IFN-gamma-inducible protein 10 (IP-10) is an inflammatory chemokine that regulates immune cell activation and recruitment by binding to its receptor CXCR3. Additionally, CXCL10 inhibits angiogenesis by interacting with endothelial cells (ECs). In the context of inflammatory rheumatic diseases, CXCL10 influences multiple pathways including chemotaxis, angiostasis, bone destruction, joint inflammation, and regulation of fibroblast-like synoviocyte properties. High levels of CXCL10 have been detected in the serum and tissues of individuals with autoimmune conditions like systemic sclerosis (SSc), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and among others (ankylosing spondylitis, Behçet's syndrome). The CXCL10 may inhibit fibroblast recruitment after tissue injury, delaying wound healing; inhibiting angiogenesis, and uncontrolled pulmonary fibrosis in SSc. In RA disease, the CXCL10-CXCR3 axis could increase the inflammatory cell infiltration, including T lymphocytes and macrophages, into inflamed joints, enhancing arthritis severity and bone and cartilage destruction. The interaction between CXCR3 and ligand-CXCL10 on directing the CD4+ T lymphocytes polarization and observed that CXCL10 skew T lymphocytes polarization into Th1/Th17 effector cells that could lead to an increase in the inflammatory responses in the SLE. This study aims to explore the role of CXCL10 in rheumatic diseases and its potential as both a therapeutic target and a biomarker for these conditions. Understanding the involvement of CXCL10 in the immunopathogenesis of inflammatory rheumatic diseases may provide valuable insights for the development of targeted therapies and diagnostic strategies.

Clinically Relevant Biomarkers in Connective Tissue Disease-Associated Interstitial Lung Disease

Interstitial lung disease (ILD) complicates connective tissue disease (CTD) with variable incidence and is a leading cause of death in these patients. To improve CTD-ILD outcomes, early recognition and management of ILD is critical. Blood-based and radiologic biomarkers that assist in the diagnosis CTD-ILD have long been studied. Recent studies, including -omic investigations, have also begun to identify biomarkers that may help prognosticate such patients. This review provides an overview of clinically relevant biomarkers in patients with CTD-ILD, highlighting recent advances to assist in the diagnosis and prognostication of CTD-ILD.

Association of serum Ly6/PLAUR domain-containing protein 1 levels with skin sclerosis in systemic sclerosis

Systemic sclerosis (SSc) is a connective tissue disease characterized by aberrant immune activation, vascular injury, and fibrosis of the skin and internal organs. Ly6/PLAUR domain-containing protein 1 (LYPD1) was reported to be secreted and to have various physiological functions such as anti-angiogenic effects. Here we investigated serum LYPD1 levels in SSc patients and the association of serum LYPD1 levels with clinical features of SSc. Serum samples were obtained from 75 SSc patients and 22 healthy individuals as controls. We measured serum LYPD1 levels using enzyme-linked immunosorbent assay kits. Then, the relationship between serum LYPD1 levels and clinical features of SSc was analyzed. Serum LYPD1 levels in diffuse cutaneous SSc (dcSSc) patients were significantly higher than those in the limited cutaneous SSc (lcSSc) patients (median [25-75th percentiles], 1693.43 [1086.61-1917.57] vs. 904.55 [714.356-1285.56] pg/mL), while there were no significant differences in the serum LYPD1 levels between lcSSc and healthy controls (904.55 [714.356-1285.56] vs. 750.71 pg/mL [544.00-912.14]). Further analysis revealed that serum LYPD1 levels in patients correlated with skin thickness scores and serum interleukin (IL)-6 levels, which were known to reflect the extent of skin thickening in SSc. Moreover, serum LYPD1 levels showed a decrease with improvement in skin thickness after treatment, along with a decrease in serum IL-6 levels. These results indicate that LYPD1 might be a potential marker for monitoring skin sclerosis and evaluating the efficacy of skin fibrosis treatment in SSc patients.

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.

Recent innovations in the screening and diagnosis of systemic sclerosis-associated interstitial lung disease

INTRODUCTION

Interstitial lung disease (ILD) is the leading cause of mortality in patients with systemic sclerosis (SSc). Risk of developing progressive ILD is highest among patients with diffuse cutaneous disease, positive anti-topoisomerase I antibody, and elevated acute phase reactants. With the FDA approval of two medications and a pipeline of novel therapeutics in trials, early recognition and intervention is critical. High-resolution computed tomography of the chest is the current gold standard test for diagnosis of ILD. Yet, it is not offered as a screening tool to all patients due to which ILD can be missed in up to a third of patients. There is a need to develop and validate more innovative screening modalities.

AREAS COVERED

In this review, we provide an overview of screening and diagnosis of SSc-ILD, highlighting the recent innovations particularly the role of soluble serologic, radiomic (quantitative lung imaging, lung ultrasound), and breathomic (exhaled breath analysis) biomarkers in the early detection of SSc-ILD.

EXPERT OPINION

There is remarkable progress in the development of new radiomics and serum biomarkers in diagnosing SSc-ILD. There is an urgent need for conceptualizing and testing composite ILD screening strategies that incorporate these biomarkers.

Clinically Relevant Biomarkers in Connective Tissue Disease-Associated Interstitial Lung Disease

Interstitial lung disease (ILD) complicates connective tissue disease (CTD) with variable incidence and is a leading cause of death in these patients. To improve CTD-ILD outcomes, early recognition and management of ILD is critical. Blood-based and radiologic biomarkers that assist in the diagnosis CTD-ILD have long been studied. Recent studies, including -omic investigations, have also begun to identify biomarkers that may help prognosticate such patients. This review provides an overview of clinically relevant biomarkers in patients with CTD-ILD, highlighting recent advances to assist in the diagnosis and prognostication of CTD-ILD.

DNA from macrophages induces fibrosis and vasculopathy through POLR3A/STING/type I interferon axis in systemic sclerosis

OBJECTIVE

To clarify the role of RNA polymerase III A (POLR3A)/type I IFN in the pathogenesis of SSc.

METHODS

Cytosolic DNA and stimulator of IFN genes (STING) pathway in skin or serum of SSc patients were detected by immunofluorescence, immunohistochemistry and western blotting. DNA from human macrophages was transfected to SSc fibroblasts or human umbilical vein endothelial cells (HUVECs) and then markers of POLR3A/STING pathway were detected by real-time qPCR, western blotting and confocal microscopy. After H151 treatment or knocking down POLR3A/STING, type I IFN response, monocytes adhesion and activation of fibroblasts and HUVECs were evaluated. Regulation of IFN regulatory factor 3 (IRF3) on monocyte chemoattractant protein-1 (MCP-1) was determined by chromatin immunoprecipitation. In bleomycin (BLM)-induced SSc mice, the effect of STING knockout or H151 on vasculopathy and fibrosis was assessed.

RESULTS

Cytosolic DNA, colocalization of STING with alpha-smooth muscle actin (α-SMA) or CD31 in the skin, and STING pathway in the serum of SSc patients were increased. Macrophage-derived DNA stimulated the translocation of POLR3A from nucleus to the perinuclear region near STING and activated POLR3A/STING/type I IFN response, monocytes adhesion and MCP-1 expression in fibroblasts/HUVECs and collagen overproduction of fibroblasts. The activated IRF3 bound to the promoter of MCP-1. STING deficiency or H151 administration ameliorated fibrosis and vasculopathy both in vitro and in BLM-induced SSc mice.

CONCLUSIONS

SSc presented increased DNA leakage and STING pathway activation. DNA from macrophages induced type I IFN signature of fibroblasts and ECs through POLR3A/STING pathway. Blocking POLR3A/STING axis provides a new therapeutic target for SSc.

Mesenchymal stem cells alleviate systemic sclerosis by inhibiting the recruitment of pathogenic macrophages

Systemic sclerosis (SSc) is a recalcitrant autoimmune disease for which there is no cure. Mesenchymal stem cell (MSC)-based treatment has emerged as a promising therapeutic option for several autoimmune diseases. Previously, we found that the immunoregulatory potential of MSCs can be greatly enhanced by IFN-γ and TNF-α. Here, we found that IFN-γ- and TNF-α-pretreated MSCs significantly alleviated skin fibrosis in a bleomycin (BLM)-induced SSc model. Macrophages were found to be the predominant profibrotic immune cell population in the pathogenesis of SSc. The accumulation of macrophages was significantly decreased by MSC treatment. Importantly, MSCs primarily reduced the population of maturing macrophages with high CCR2 expression by inhibiting the generation of CCL2 from fibroblasts and macrophages. This finding may help to improve MSC-based clinical treatments for SSc patients.

The Role of IL-6 in Fibrotic Diseases: Molecular and Cellular Mechanisms

Fibrosis is a detrimental outcome of most chronic inflammatory disorders and is defined by the buildup of excess extracellular matrix (ECM) components, which eventually leads to organ failure and death. Interleukin 6 (IL-6) is promptly produced by immune cells in response to tissue injuries and has a wide range of effects on cellular processes such as acute responses, hematopoiesis, and immune reactions. Furthermore, high levels of IL-6 have been found in a variety of chronic inflammatory disorders characterized by fibrosis, and this factor plays a significant role in fibrosis in various organs via Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) activation. Here, we review what is known about the role of IL-6 in fibrosis and why targeting IL-6 for fibrotic disease treatment makes sense.

PET/CT and inflammatory mediators in systemic sclerosis-associated interstitial lung disease

Objective:

To investigate the correlation of HRCT findings with pulmonary metabolic activity in the corresponding regions using ¹⁸F-FDG PET/CT and inflammatory markers in patients with systemic sclerosis (SSc)-associated interstitial lung disease (ILD).

Methods:

This was a cross-sectional study involving 23 adult patients with SSc-associated ILD without other connective tissue diseases. The study also involved ¹⁸F-FDG PET/CT, HRCT, determination of serum chemokine levels, clinical data, and pulmonary function testing.

Results:

In this cohort of patients with long-term disease (disease duration, 11.8 ± 8.7 years), a nonspecific interstitial pneumonia pattern was found in 19 (82.6%). Honeycombing areas had higher median standardized uptake values (1.95; p = 0.85). Serum levels of soluble tumor necrosis factor receptor 1, soluble tumor necrosis factor receptor 2, C-C motif chemokine ligand 2 (CCL2), and C-X-C motif chemokine ligand 10 were higher in SSc patients than in controls. Serum levels of CCL2-a marker of fibroblast activity-were correlated with pure ground-glass opacity (GGO) areas on HRCT scans (p = 0.007). ¹⁸F-FDG PET/CT showed significant metabolic activity for all HRCT patterns. The correlation between serum CCL2 levels and GGO on HRCT scans suggests a central role of fibroblasts in these areas, adding new information towards the understanding of the mechanisms surrounding cellular and molecular elements and their expression on HRCT scans in patients with SSc-associated ILD.

Conclusions:

¹⁸F-FDG PET/CT appears to be unable to differentiate the intensity of metabolic activity across HRCT patterns in chronic SSc patients. The association between CCL2 and GGO might be related to fibroblast activity in these areas; however, upregulated CCL2 expression in the lung tissue of SSc patients should be investigated in order to gain a better understanding of this association.

Targeting Systemic Sclerosis from Pathogenic Mechanisms to Clinical Manifestations: Why IL-6?

Systemic sclerosis (SS) is a chronic autoimmune disorder, which has both cutaneous and systemic clinical manifestations. The disease pathogenesis includes a triad of manifestations, such as vasculopathy, autoimmunity, and fibrosis. Interleukin-6 (IL-6) has a special role in SS development, both in vascular damage and in the development of fibrosis. In the early stages, IL-6 participates in vascular endothelial activation and apoptosis, leading to the release of damage-associated molecular patterns (DAMPs), which maintain inflammation and autoimmunity. Moreover, IL-6 plays an important role in the development of fibrotic changes by mediating the transformation of fibroblasts into myofibroblasts. All of these are associated with disabling clinical manifestations, such as skin thickening, pulmonary fibrosis, pulmonary arterial hypertension (PAH), heart failure, and dysphagia. Tocilizumab is a humanized monoclonal antibody that inhibits IL-6 by binding to the specific receptor, thus preventing its proinflammatory and fibrotic actions. Anti-IL-6 therapy with Tocilizumab is a new hope for SS patients, with data from clinical trials supporting the favorable effect, especially on skin and lung damage.

Bronchoalveolar lavage and lung biopsy in connective tissue diseases, to do or not to do?

Bronchoalveolar lavage and lung biopsy (LBx) are helpful in patients with connective tissue diseases (CTD) and interstitial lung diseases (ILD) regardless of cause, including infectious, noninfectious, immunologic, or malignant. The decision whether to perform only bronchoalveolar lavage (BAL), and eventually a subsequent LBx in case of a nondiagnostic lavage, or one single bronchoscopy combining both sampling methods depends on the clinical suspicion, on patient’s characteristics (e.g. increased biopsy risk) and preferences, and on the resources and biopsy techniques available locally (e.g. regular forceps versus cryobiopsy). In CTD-ILD, BAL has major clinical utility in excluding infections and in the diagnosis of specific patterns of acute lung damage (e.g. alveolar hemorrhage, diffuse alveolar damage, and organizing pneumonia). LBx is indicated to exclude neoplasm or diagnose lymphoproliferative lung disorders that in CTD patients are more common than in the general population. Defining BAL cellularity and characterizing the CTD-ILD histopathologic pattern by LBx can be helpful in the differential diagnosis of cases without established CTD [e.g. ILD preceding full-blown CTD, interstitial pneumonia with autoimmune features (IPAF)], but the prognostic and theragnostic role of those findings remains unclear. Few studies in the pretranscriptomics era have investigated the diagnostic and prognostic role of BAL and LBx in CTD-ILD, and it is reasonable to hypothesize that future studies conducted applying innovative techniques on BAL and LBx might open new and unexpected avenues in pathogenesis, diagnosis, and treatment approach to CTD-ILD. This is particularly desirable now that a new drug treatment era is emerging, in which we have more than one therapeutic choice (immunosuppressive agents, antifibrotic drugs, and biological agents). We hope that future research will pave the path toward precision medicine providing data for a more accurate ILD-CTD endotyping that will guide the physicians through targeted therapeutic choices, rather than to the approximative approach ‘one drug fits them all’.

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.

Body mass index and adipokines/cytokines dysregulation in systemic sclerosis

Body fat has regulatory functions through producing cytokines and adipokines whose role in the pathogenesis of systemic sclerosis (SSc) is currently emerging. Changes in body mass, either over‐ or underweight, entail a dysregulation of the cytokine/adipokine network that may impact upon SSc disease activity. We evaluated serum levels of adipokines and cytokines in SSc patients and correlated them to clinical features and body mass index (BMI) categories. The study included 89 SSc patients and 26 healthy donors (HD). Serum levels of adiponectin, leptin, resistin, visfatin, tumor necrosis factor (TNF)‐α, interferon (IFN)‐γ, interleukin (IL)‐2, IL‐10 and IL‐17A were measured by multiplex immunoassay and correlated to BMI and disease‐specific features. Student’s t‐test or analysis of variance (ANOVA) were used for comparisons between groups. Spearman’s or Pearson’s tests were used for correlation analysis. Serum levels of TNF‐α, IL‐2, leptin and resistin were significantly higher in SSc than in HD. Leptin levels were significantly higher in interstitial lung disease (ILD)‐ and pulmonary arterial hypertension (PAH)‐SSc subgroups. The highest levels of IL‐17A, IL‐2, IL‐10, leptin and visfatin were detected in SSc patients with obesity (p < 0.01). Conversely, underweight SSc patients showed the highest TNF‐α levels (p < 0.05). Adipokines, IL‐2, IL‐10 and IL‐17A were found to be increased in SSc patients with obesity, but whether or not they play a role in the pathogenesis of the disease remains to be investigated. Intriguingly, underweight patients had the highest TNF‐α levels, suggesting a potential role of TNF‐α in inducing the cachexia observed in long‐lasting disease.

An update on the pathogenic role of IL-6 in rheumatic diseases

Interleukin (IL)-6 is a pleiotropic cytokine that is involved in the pathogenesis of various rheumatic diseases. Direct inhibition of the IL-6 pathway by an anti-IL-6 receptor or inhibiting the ligand itself has proved to be efficacious in the treatment of these diseases. Juvenile idiopathic arthritis, adult-onset Still's disease, large vessel vasculitis including giant cell arteritis and Takayasu disease, systemic sclerosis, and polymyalgia rheumatica respond well to IL-6 inhibition as expected. However, no clinically meaningful effect has been observed with regard to IL-6 blockade in ankylosing spondylitis, psoriatic arthritis, and systemic lupus erythematosus. This review discusses the current state of IL-6 targeting approaches in various rheumatic diseases other than rheumatoid arthritis.

Sildenafil Counteracts the In Vitro Activation of CXCL-9, CXCL-10 and CXCL-11/CXCR3 Axis Induced by Reactive Oxygen Species in Scleroderma Fibroblasts

Oxidative stress plays a key role in systemic sclerosis (SSc) pathogenesis, and an altered redox homeostasis might be responsible for abnormal inflammatory status, fibrosis and tissue damage extension. In this study, we explored the effect of the phosphodiesterase type 5 inhibitor sildenafil in modulating the activation of the CXCL-9, -10, -11/CXCR3 axis, which is fundamental in the perpetuation of inflammation in different autoimmune diseases, in the cell culture of SSc human dermal fibroblasts exposed to a pro-oxidant environment. We observed that sildenafil significantly reduced gene expression and release of CXCL-9, -10 and -11, inhibited the CXCR3 action and suppressed the activation of STAT1-, JNK- and p38MAPK pathways. This in vitro study on dermal fibroblasts supports clinical studies to consider the efficacy of sildenafil in preventing tissue damage and fibrosis in SSc by targeting central biomarkers of disease progression, vascular injuries and fibrosis and reducing the pro-inflammatory activation induced by oxidative stress.

Biomarkers in Progressive Fibrosing Interstitial Lung Disease: Optimizing Diagnosis, Prognosis, and Treatment Response

Interstitial lung disease (ILD) comprises a heterogenous group of diffuse lung disorders that commonly result in irreversible pulmonary fibrosis. While idiopathic pulmonary fibrosis (IPF) is the prototypical progressive fibrosing ILD (PF-ILD), a high proportion of patients with other ILD subtypes develop a PF-ILD phenotype. Evidence exists for shared pathobiology leading to progressive fibrosis, suggesting that biomarkers of disease activity may prove informative across the wide spectrum of ILDs. Biomarker investigation to date has identified a number of molecular markers that predict relevant ILD endpoints, including disease presence, prognosis, and/or treatment response. In this review, we provide an overview of potentially informative biomarkers in patients with ILD, including those suggestive of a PF-ILD phenotype. We highlight the recent genomic, transcriptomic, and proteomic investigations that identified these biomarkers and discuss the body compartments in which they are found, including the peripheral blood, airway, and lung parenchyma. Finally, we identify critical gaps in knowledge within the field of ILD biomarker research and propose steps to advance the field toward biomarker implementation.

Cytokines Involved in the Pathogenesis of SSc and Problems in the Development of Anti-Cytokine Therapy

Systemic sclerosis (SSc) is a connective tissue disease of unknown etiology. SSc causes damage to the skin and various organs including the lungs, heart, and digestive tract, but the extent of the damage varies from patient to patient. The pathology of SSc includes ischemia, inflammation, and fibrosis, but the degree of progression varies from case to case. Many cytokines have been reported to be involved in the pathogenesis of SSc: interleukin-6 is associated with inflammation and transforming growth factor-β and interleukin-13 are associated with fibrosis. Therapeutic methods to control these cytokines have been proposed; however, which cytokines have a dominant role in SSc might differ depending on the extent of visceral lesions and the stage of disease progression. Therefore, it is necessary to consider the disease state of the patient to be targeted and the type of evaluation method when an anti-cytokine therapy is conducted. Here, we review the pathology of SSc and potential cytokine targets, especially interleukin-6, as well as the use of anti-cytokine therapy for SSc.

In vitro pharmacological effects of peficitinib on lymphocyte activation: a potential treatment for systemic sclerosis with JAK inhibitors

Objectives

Peficitinib, a novel Janus kinase (JAK) inhibitor, demonstrated promising results in treating RA in phase 3 clinical trials. This in vitro study was undertaken to characterize the pharmacological properties of peficitinib and investigate the involvement of JAK and signal transducer and activator of transcription (STAT) pathways in the pathological processes of SSc, which is also an autoimmune disease.

Methods

Phosphorylation levels of STAT molecules were assessed in peripheral blood mononuclear cells collected from patients with RA or SSc and healthy subjects, and in skin specimens obtained from 19 patients with SSc. In vitro inhibition of STAT phosphorylation and cytokine/chemokine production by peficitinib, tofacitinib and baricitinib were also characterized.

Results

Higher spontaneous STAT1 or STAT3 phosphorylation was observed in peripheral T-cells and monocytes from patients with RA and SSc compared with healthy subjects. In skin sections from patients with SSc, phosphorylated STAT3–positive cells were found in almost all cases, irrespective of disease subtype or patient characteristics. Conversely, phosphorylated STAT1-positive cells were observed only in samples from untreated patients with diffuse disease of short duration. Peficitinib inhibited STAT phosphorylation induced by various cytokines, with comparable efficacy to tofacitinib and baricitinib. Peficitinib also suppressed cytokine and chemokine production by peripheral blood mononuclear cells and skin fibroblasts.

Conclusion

Our results suggest that JAK/STAT pathways are constitutively activated in SSc and RA, and that the JAK inhibitor may represent a novel therapeutic option for SSc.

Targeted delivery in scleroderma fibrosis

Systemic sclerosis (SSc) is considered one of the most challenging and difficult to treat among rheumatic disorders, due to its severity, multiorgan manifestation and different outcomes. It manifests fibrosis in different organs, mostly in skin and lungs. The skin fibrosis expression is considered the first sign of the disease and usually it is followed by internal organ fibrosis. An aberrant immune system activation seems to relate to the expression of the disease, but even environmental influences and dysregulation of many molecules signalling pathways are involved in the development of the disease. Current therapies are limited and characterized by multiple side effects: systemic route is the elective administration route, which decreases patient adherence to the therapy, as they are often already bothered by pain and disfigurement. Treatments available are organ-based, originally indicated for other conditions and there is no therapy available to reduce the fibroblast population size within existing fibrotic lesions. Disease-modifying therapies or immunomodulatory agents that are highly effective in other rheumatic diseases have shown disappointing results in SSc. There are thus no standardized and effective treatments for this disease, and there are even unanswered questions related to the insurgence of the pathology and all the mechanisms involved. An ideal approach could be considered "targeted therapy" that will be an increasingly attainable objective insofar as our understanding of the disease improves. The advantages in identifying the molecule and the signalling pathways involved in the pathology have helped to find some novel compounds for the therapy of scleroderma fibrosis or following innovative uses for already-approved drugs, corroborated by many clinical studies.

Mesenchymal stem cell as a novel approach to systemic sclerosis; current status and future perspectives

Systemic sclerosis is a rare chronic autoimmune disease with extensive microvascular injury, damage of endothelial cells, activation of immune responses, and progression of tissue fibrosis in the skin and various internal organs. According to epidemiological data, women's populations are more susceptible to systemic sclerosis than men. Until now, various therapeutic options are employed to manage the symptoms of the disease. Since stem cell-based treatments have developed as a novel approach to rescue from several autoimmune diseases, it seems that stem cells, especially mesenchymal stem cells as a powerful regenerative tool can also be advantageous for systemic sclerosis treatment via their remarkable properties including immunomodulatory and anti-fibrotic effects. Accordingly, we discuss the contemporary status and future perspectives of mesenchymal stem cell transplantation for systemic sclerosis.

Prediction of severity and subtype of fibrosing disease using model informed by inflammation and extracellular matrix gene index

Fibrosis is a chronic disease with heterogeneous clinical presentation, rate of progression, and occurrence of comorbidities. Systemic sclerosis (scleroderma, SSc) is a rare rheumatic autoimmune disease that encompasses several aspects of fibrosis, including highly variable fibrotic manifestation and rate of progression. The development of effective treatments is limited by these variabilities. The fibrotic response is characterized by both chronic inflammation and extracellular remodeling. Therefore, there is a need for improved understanding of which inflammation-related genes contribute to the ongoing turnover of extracellular matrix that accompanies disease. We have developed a multi-tiered method using Naïve Bayes modeling that is capable of predicting level of disease and clinical assessment of patients based on expression of a curated 60-gene panel that profiles inflammation and extracellular matrix production in the fibrotic disease state. Our novel modeling design, incorporating global and parametric-based methods, was highly accurate in distinguishing between severity groups, highlighting the importance of these genes in disease. We refined this gene set to a 12-gene index that can accurately identify SSc patient disease state subsets and informs knowledge of the central regulatory pathways in disease progression.

Potential Biomarkers in Systemic Sclerosis: A Literature Review and Update

Systemic sclerosis (SSc) is a chronic autoimmune disease characterized by dysregulation of the immune system, vascular damage, and fibrosis of the skin and internal organs. Patients with SSc show a heterogeneous phenotype and a range of clinical courses. Therefore, biomarkers that are helpful for precise diagnosis, prediction of clinical course, and evaluation of the therapeutic responsiveness of disease are required in clinical practice. SSc-specific autoantibodies are currently used for diagnosis and prediction of clinical features, as other biomarkers have not yet been fully vetted. Krebs von den Lungen-6 (KL-6), surfactant protein-D (SP-D), and CCL18 have been considered as serum biomarkers of SSc-related interstitial lung disease. Moreover, levels of circulating brain natriuretic peptide (BNP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) can provide diagnostic information and indicate the severity of pulmonary arterial hypertension. Assessment of several serum/plasma cytokines, chemokines, growth factors, adhesion molecules, and other molecules may also reflect the activity or progression of fibrosis and vascular involvement in affected organs. Recently, microRNAs have also been implicated as possible circulating indicators of SSc. In this review, we focus on several potential SSc biomarkers and discuss their clinical utility.

Biomarkers as an opportunity to stratify for outcome in systemic sclerosis

Systemic sclerosis (SSc) is a highly complex disease whose heterogeneity includes multiple aspects of the condition, such as clinical presentation, progression, extent and type of organ involvement, and clinical outcomes. Thus far, these features remain not easily predictable both at the patient group level and in a given patient with regard to age at onset and clinical course. The unpredictable clinical course represents an obstacle to focusing potentially effective treatment in patients that need it the most. At the time of organ involvement and clinical diagnosis, most of the clinical manifestations are irreversible; therefore, predicting outcomes becomes crucial. This can explain the multiple attempts to identify prognostic, predictive, and monitoring-both soluble and imaging-biomarkers over the past years. They range from the currently most used biomarkers, the autoantibodies associated with disease-specific clinical features and course, to the single recently proposed skin, lung, cardiac involvement biomarkers and to the composite scores capturing multiple aspects of the disease. This review will focus on soluble and imaging biomarkers that recently showed promising evidence for outcome stratification in patients with SSc.

Biomarkers in systemic sclerosis-associated interstitial lung disease: review of the literature

SSc is a rare disease of unknown origin associated with multiple organ involvement. One of the major complications that drives the mortality of SSc patients is interstitial lung disease. The course of SSc-interstitial lung disease progression has a wide spectrum. Since the treatment is based on aggressive immunosuppression it should not be given to stable or non-progressing disease. The correct identification of disease with high risk of progression remains a challenge for early therapeutic intervention, and biomarkers remain urgently needed. In fact, eight categories of biomarkers have been identified and classified according to the different biological pathways involved. The purpose of this article is to describe the main biomarkers thought to be of interest with clinical value in the diagnosis and prognosis of SSc-interstitial lung disease.

Circulating biomarkers of systemic sclerosis - interstitial lung disease

Interstitial lung disease is a frequent organ manifestation in systemic sclerosis and is associated with high mortality. It is crucial to diagnose interstitial lung disease in systemic sclerosis and to assess severity and identify patients prone to progression at an early stage to ultimately decrease organ damage and improve outcome. Circulating anti-topoisomerase-I autoantibodies have long been associated with the presence and development of systemic sclerosis - interstitial lung disease, evidence on their potential to further predict the clinical course of systemic sclerosis is however conflicting. C-reactive protein is a marker of infection and systemic inflammation with widespread clinical application and is elevated in systemic sclerosis with a tendency towards higher abundancy in patients with early disease. The role of other circulating biomarkers is promising but hampered by the lack of standardized criteria and guidelines for sample/data collection, analyses, reporting and validation and has not reached prime time for clinical application. However, epithelial markers including Krebs von den Lungen-6 and surfactant protein D and several cytokines and chemokines including CCL2 and CCL18 for severity assessment of systemic sclerosis - interstitial lung disease patients at the time of interstitial lung disease diagnosis and to predict interstitial lung disease progression have been reported and seem to be promising candidate biomarkers in the future.

Adipose-derived stromal/stem cells successfully attenuate the fibrosis of scleroderma mouse models

AIM

Systemic sclerosis (SSc) is an autoimmune disease characterized by skin and lung fibrosis. Although SSc has a high mortality risk, an effective treatment for the disease has not been established yet. Mesenchymal stromal/stem cells (MSCs) are multipotential nonhematopoietic progenitor cells that have the ability to regulate immune responses. Adipose-derived stromal/stem cells (ASCs), one of the types of MSCs, have the advantage of accessibility and potent immunomodulatory effects when compared with other MSCs, such as bone marrow-derived MSCs. This study aimed to investigate the antifibrotic effect of ASCs in scleroderma mouse models, including bleomycin-induced scleroderma and sclerodermatous chronic graft-versus-host disease (Scl-cGVHD) models.

METHOD

ASCs were intravenously administered to a bleomycin-induced scleroderma or Scl-cGVHD model on day 0. We compared the skin and lung fibrosis of scleroderma model mice between the ASC-treated group and control group.

RESULTS

Administration of ASCs attenuated the skin and lung fibrosis of bleomycin-induced scleroderma and Scl-cGVHD model mice compared to that in the control mice. Immunohistochemical staining showed that ASCs suppressed the infiltration of CD4⁺ , CD8⁺ T cells and macrophages into the dermis of bleomycin model mice compared to that in control mice. In addition, ASCs attenuated the messenger RNA expression of collagen and fibrogenic cytokines, such as interleukin (IL)-6 and IL-13, in the skin of bleomycin model mice. ASCs also reduced the frequency of fibrogenic cytokine-producing CD4⁺ T cells and effector B cells in the spleen of bleomycin model mice.

CONCLUSION

ASCs could prove to be a potential therapeutic agent for use in patients with SSc.

[Altered serum cytokine expression profile in systemic sclerosis and its regulatory mechanisms]

OBJECTIVE

To analyze the expression profile of serum cytokines in patients with systemic sclerosis (SSc) and explore its possible regulatory mechanisms.

METHODS

Serum and DNA of peripheral blood mononuclear cells were collected from 30 SSc patients and 80 normal controls (NCs). According to the presence or absence of interstitial lung disease (ILD) in SSc, the patients were divided into SSc with ILD group and SSc without ILD group. According to the degree of skin involvement, the patients were divided into diffuse systemic scleroderma (dcSSc) group and limited systemic scleroderma (lcSSc) group. According to the presence of anti-topoisomerase-1 antibody (anti-Scl-70 antibody) in the serum of patients with SSc, they were divided into SSc Scl-70 (+) group and SSc Scl-70 (-) group. 27 cytokines in serum were detected by Luminex MAGPIX detection system and Bio-Plex Pro Human Cytokine 27-plex Assay kit: interleukin-1β (IL-1β), interleukin-1 receptor antagonist (IL-1ra), IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12P70, IL-13, IL-15, IL-17, basic fiber growth factor (BASIC FGF), eotaxin, granulocyte colony stimulating factor (G-CSF), granulocyte-macrophage colony stimulating factor (GM-CSF), interferon-γ (IFN-γ), interferon-gamma induced protein 10(IP-10), monocyte chemotactic protein 1(MCP-1), macrophage inflammatory protein-1α (MIP-1α), macrophage inflammatory protein 1β(MIP-1β), platelet-derived growth factor BB (PDGF-BB), regulated on activation in normal T-cell expressed and secreted (RANTES), tumor necrosis factor-α (TNF-α), and vascular endothelial growth factor(VEGF). Methylation sites were detected by Illumina 450K methylation chip.

RESULTS

Compared with NCs group, the expression of 12 cytokines (BASIC FGF, eotaxin, G-CSF, GM-CSF, IFN-γ, IL-1β, IL-1ra, IL-6, IP-10, MCP-1, TNF-α and RANTES) in the SSc group significantly increased (P<0.05), IL-5 was decreased expression in the SSc group (P<0.05), there was no significant difference in the expressions of the other 14 cytokines. Compared with lcSSc group, 9 cytokines (eotaxin, IL-5, MCP-1, IL-2, RANTES, IL17A, IL-8, MIP-1β and PDGF-BB) increased in dcSSc group, but there was no significant difference. Compared with SSc without ILD group, IL-15 increased in SSC with ILD group [18.2 (172.97) ng/L vs. 2.03(0.05) ng/L, P<0.05]. Compared with SSc Scl-70 (-) group, the expression of IP-10 decreased in SSc Scl-70 (+) group [1 030 (2 196.6) ng/L vs. 1 878 (2 964) ng/L, P<0.05]. The correlation analysis of serum cytokines with erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) showed that IL-6 was positively correlated with ESR (r =0.04, P= 0.017), MCP-1 (r=0.49, P=0.043) and MIP-1β (r=0.41, P=0.007) positively correlated with CRP. By analyzing the changes of methylation sites of cytokines, it was found that cg17744604 in IL-10 TSS1500 region, cg06111286 in IL-12P70 TSS200 region, cg07935264 in IL-1β TSS200 region, cg01467417 in IL-1ra TSS1500 region, cg03989987 in IL-1ra 5'UTR region and cg21099624 in VEGF TSS200 region were all hypomethylated.

CONCLUSION

There were different cytokines expression profiles in the serum of SSc patients, and the altered cytokines were correlected with the degree of skin damage and pulmonary fibrosis. Many cytokines were regulated by methylation.

Cytokine Profiling in Patients With Exudative Age-Related Macular Degeneration and Polypoidal Choroidal Vasculopathy

Purpose

The purpose of this study was to investigate the cytokine profiles in plasma and aqueous humor of patients with choroidal neovascularization (CNV) due to exudative AMD and polypoidal choroidal vasculopathy (PCV).

Methods

In this cross-sectional study, 16 patients clinically diagnosed with AMD, 18 patients with PCV, and 50 age- and sex-matched cataract patients without AMD/PCV (controls) were enrolled. Study subjects were treatment naïve, and 200 μL undiluted aqueous humor and 5 mL peripheral venous blood were collected from the study subjects. Clinical samples were analyzed for 41 different cytokines by Luminex bead-based multiplex assay. Cytokines concentrations with detection rates of 50% or more were included for the analysis, and the differences in plasma and aqueous humor cytokines levels between each group were analyzed.

Results

The age of the patients with AMD and PCV was 70.62 ± 10.15 (mean ± SD) and 71.48 ± 9.08 years, respectively, and that in the control group was 62.8 ± 10.67 years. Aqueous humor cytokines growth-regulated oncogene (GRO), macrophage-derived chemokine (MDC), and macrophage inflammatory protein (MIP)-1α were significantly higher in AMD patients than controls (all P < 0.04), and GRO, MDC, MIP-1α, IL-8, IFN-γ-inducible protein 10, and monocyte chemotactic protein levels were significantly higher in PCV patients than controls (all P < 0.03). Soluble CD40 ligand and platelet-derived growth factor-AA levels were higher in plasma of healthy controls compared with AMD subjects. No significant differences in cytokine levels were observed between AMD and PCV patients for both plasma and aqueous humor.

Conclusions

In AMD and PCV patients, our data suggest that the pathologic changes are primarily driven by dysregulation of local immune factors in the eye, whereas the plasma cytokine levels are not elevated.

The benefits and prospects of interleukin-6 inhibitor on systemic sclerosis

Systemic sclerosis (SSc) is a connective tissue disease, the pathogenesis of which is thought to involve interleukin-6 (IL-6), an inflammatory cytokine. This is based on findings of its concentration in patient serum, the results of an IL-6 suppression experiment in an animal model, and the results of a pilot study using IL-6 receptor antibody. However, it appears that a number of factors are involved in the pathology of SSc depending on the state of disease progression. In addition, the degree of involvement of IL-6 differs depending on the difference of organs within particular severe symptoms. Based on the findings from measurements of patient serum, the influence of IL-6 on the pathogenesis of SSc is greater in patients at a relatively early phase of the disease and in patients with lung lesions. Interleukin-13 (IL-13) is one of pro-fibrotic factors, and it is afraid that SSc patients with higher IL-13 have already lost the influence of IL-6. Therefore, although a clinical trial using the anti-IL-6 receptor antibody tocilizumab is underway, it is important to recognize the state of SSc patients prior to selecting treatment.

Increased frequencies of circulating CXCL10-, CXCL8- and CCL4-producing monocytes and Siglec-3-expressing myeloid dendritic cells in systemic sclerosis patients

Objective

To investigate the ex vivo pro-inflammatory properties of classical and non-classical monocytes as well as myeloid dendritic cells (mDCs) in systemic sclerosis (SSc) patients.

Methods

Spontaneous production of CXCL10, CCL4, CXCL8 and IL-6 was intracellularly evaluated in classical, non-classical monocytes and Siglec-3-expressing mDCs from peripheral blood of SSc patients and healthy controls (HC) through flow cytometry. In addition, production of these cytokines was determined upon toll-like receptor (TLR) 4 plus Interferon-γ (IFN-γ) stimulation.

Results

The frequency of non-classical monocytes spontaneously producing CXCL10 was increased in both limited (lcSSc) and diffuse cutaneous (dcSSC) subsets of SSc patients and CCL4 was augmented in dcSSc patients. The proportion of CCL4-producing mDCs was also elevated in dcSSc patients and the percentage of mDCS producing CXCL10 only in lcSSc patients. Upon stimulation, the frequency of non-classical monocytes expressing CXCL8 was increased in both patient groups and mDCs expressing CXCL8 only in lcSSc. Moreover, these parameters in unsupervised clustering analysis identify a subset of patients which are characterized by lung fibrosis and reduced pulmonary function.

Conclusions

These data point towards a role of activated non-classical monocytes and mDCs producing enhanced levels of proinflammatory cytokines in SSc, potentially contributing to lung fibrosis.

Electronic supplementary material

The online version of this article (10.1007/s00011-017-1106-7) contains supplementary material, which is available to authorized users.

Toll Like Receptors in systemic sclerosis: An emerging target

Pattern Recognition Receptors are critical receptors that elicit an immune response upon their activation that culminates in activation of NF-KB and cytokine secretion. Key among these receptors are the Toll-Like Receptors (TLRs). These evolutionary conserved receptors form a key part in the defence against various pathogens and comprise a key part of the innate immune system. Systemic sclerosis is an autoimmune disease in which a breach of tolerance has occurred and leads to fulminant autoimmunity, dysregulated cytokines, pro-fibrotic mediators and activation of fibroblasts leading to fibrosis via collagen deposition. It has become apparent in recent years that the innate immune system and specifically TLRs are important in disease pathogenesis; responding to internal ligands to initiate an innate immune response ultimately leading to release of a variety of factors that initiate and perpetuate fibrosis. This review will examine the recent evidence of TLR signalling in systemic sclerosis and the internal danger associated molecules that may mediate the fibrotic cascade. Evaluation of their contribution to disease in systemic sclerosis and possible therapeutic targeting will be discussed.

An Autotaxin/Lysophosphatidic Acid/Interleukin-6 Amplification Loop Drives Scleroderma Fibrosis

OBJECTIVE

We previously implicated the lipid mediator lysophosphatidic acid (LPA) as having a role in dermal fibrosis in systemic sclerosis (SSc). The aim of this study was to identify the role of the LPA-producing enzyme autotaxin (ATX), and to connect the ATX/LPA and interleukin-6 (IL-6) pathways in SSc.

METHODS

We evaluated the effect of a novel ATX inhibitor, PAT-048, on fibrosis and IL-6 expression in the mouse model of bleomycin-induced dermal fibrosis. We used dermal fibroblasts from SSc patients and control subjects to evaluate LPA-induced expression of IL-6, and IL-6-induced expression of ATX. We next evaluated whether LPA-induced ATX expression is dependent on IL-6, and whether baseline IL-6 expression in fibroblasts from SSc patients is dependent on ATX. Finally, we compared ATX and IL-6 expression in the skin of patients with SSc and healthy control subjects.

RESULTS

PAT-048 markedly attenuated bleomycin-induced dermal fibrosis when treatment was initiated before or after the development of fibrosis. LPA stimulated expression of IL-6 in human dermal fibroblasts, and IL-6 stimulated fibroblast expression of ATX, connecting the ATX/LPA and IL-6 pathways in an amplification loop. IL-6 knockdown abrogated LPA-induced ATX expression in fibroblasts, and ATX inhibition attenuated IL-6 expression in fibroblasts and the skin of bleomycin-challenged mice. Expression of both ATX and IL-6 was increased in SSc skin, and LPA-induced IL-6 levels and IL-6-induced ATX levels were increased in fibroblasts from SSc patients compared with controls.

CONCLUSION

ATX is required for the development and maintenance of dermal fibrosis in a mouse model of bleomycin-induced SSc and enables 2 major mediators of SSc fibrogenesis, LPA and IL-6, to amplify the production of each other. Our results suggest that concurrent inhibition of these 2 pathways may be an effective therapeutic strategy for dermal fibrosis in SSc.

Transcriptional and Cytokine Profiles Identify CXCL9 as a Biomarker of Disease Activity in Morphea

IFN-related pathways have not been studied in morphea, and biomarkers are needed. We sought to characterize morphea serum cytokine imbalance and IFN-related gene expression in blood and skin to address this gap by performing a case-control study of 87 participants with morphea and 26 healthy control subjects. We used multiplexed immunoassays to determine serum cytokine concentrations, performed transcriptional profiling of whole blood and lesional morphea skin, and used double-staining immunohistochemistry to determine the cutaneous cellular source of CXCL9. We found that CXCL9 was present at increased concentrations in morphea serum (P < 0.0001), as were other T helper type 1 cytokines. CXCL9 serum concentration correlated with the modified Localized Scleroderma Skin Severity Index (r = 0.44, P = 0.0001), a validated measure of disease activity. CXCL9 gene expression was also increased in inflammatory lesional morphea skin (fold change = 30.6, P = 0.006), and preliminary transcriptional profiling showed little evidence for IFN signature in whole blood. Double-staining immunohistochemistry showed CXCL9 co-localized with CD68⁺ dermal macrophages. In summary, inflammatory morphea is characterized by T helper type 1 cytokine imbalance in serum, particularly CXCL9, which is associated with disease activity. CXCL9 expression in lesional macrophages implicates the skin as the source of circulating cytokines. CXCL9 is a promising biomarker of disease activity in morphea.

Blockade of p38 Mitogen-Activated Protein Kinase Inhibits Murine Sclerodermatous Chronic Graft-versus-Host Disease

Bone marrow transplantation (BMT) of B10.D2 mice into sublethally irradiated BALB/c mice across minor histocompatibility loci is a well-established animal model for human sclerodermatous chronic graft-versus-host disease (Scl-cGVHD) and systemic sclerosis (SSc). The p38 mitogen-activated protein kinase (MAPK) pathway is a key regulator of inflammation and cytokine production. Furthermore, the activation of p38 MAPK plays an important role in collagen production in SSc. We investigated the effects of p38 MAPK inhibitor, VX-702, on Scl-cGVHD mice. VX-702 was orally administered to Scl-cGVHD mice from day 7 to 35 after BMT. We compared skin fibrosis of Scl-cGVHD mice between the VX-702-treated group and control group. Allogeneic BMT increased the phosphorylation of p38 MAPK in the skin. The administration of VX-702 attenuated the skin fibrosis of Scl-cGVHD compared to the control mice. Immunohistochemical staining showed that VX-702 suppressed the infiltration of CD4⁺ T cells, CD8⁺ T cells, and CD11b⁺ cells into the dermis of Scl-cGVHD mice compared to the control mice. VX-702 attenuated the mRNA expression of extracellular matrix and fibrogenic cytokines, such as IL-6 and IL-13, in the skin of Scl-cGVHD mice. In addition, VX-702 directly inhibited collagen production from fibroblasts in vitro. VX-702 was shown to be a promising candidate for use in treating patients with Scl-cGVHD and SSc.

Biomarkers in systemic sclerosis: Their potential to predict clinical courses

The concept of a biomarker was defined as "a characteristic marker that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention" by the National Institutes of Health Biomarkers Definitions Working group in 2001. Clinical features, disease progress, therapeutic response and prognosis are heterogeneous among patients with systemic sclerosis (SSc). Therefore, biomarkers that can predict these matters are required for the progress of clinical practice. At present, SSc-specific autoantibodies are the most useful biomarkers for diagnosis and predicting clinical features. Otherwise, biomarkers specific only for SSc have not been identified yet. The glycoprotein krebs von den Lungen-6, surfactant protein-D and CCL18 are promising serum biomarkers of SSc-related interstitial lung diseases. Serum/plasma levels of brain natriuretic peptide and serum N-terminal pro-brain natriuretic peptide have been used as biomarkers for SSc-related pulmonary arterial hypertension. Other potential serum/plasma biomarkers for fibrosis and vascular involvement of SSc are connective tissue growth factor, interleukin-6, CCL2, CXCL4, intercellular adhesion molecule (ICAM)-1, P-selectin, vascular endothelial growth factor, von Willebrand factor, endostatin, endoglin and endothelin-1. In our multicenter prospective studies of Japanese early SSc, serum ICAM-1 levels were predictive for subsequent respiratory dysfunction and serum levels of CXCL8 and P-selectin were predictive for subsequent physical disability. Further large, multicenter, prospective, longitudinal studies will be needed to identify and validate critical biomarkers of SSc.

Angiostatic and Angiogenic Chemokines in Systemic Sclerosis: An Overview

In systemic sclerosis (SSc), the dysregulation of several molecular pathways seem to have a role in the disease pathogenesis. Either angiogenesis and vasculogenesis are disturbed and impaired, and an imbalance between angiogenic and angiostatic factors may be involved in the genesis and maintenance of vasculopathy. Aberrant immune system activation and function involves both B and T cells, as well as many different chemokines and cytokines. Particularly, chemokines are central to the initiation and maintenance of inflammatory responses as well as angiogenesis and fibrosis. Increased expression of several chemokines as CXCL4 (platelet factor 4), CXCL8 (IL8), CXCL5 (ENA-78), CCL5 (RANTS), CXCL9 (MIG), CCL24, CXCL10 IP-10), CXCL12, CXCL16 (SRPSDX), CCL2 (MCP-1), CCL19 (MIP-3β/ELC), CCL24 (Eotaxin 2), suggests a complex mechanism by which many immune cell types, including T cells, macrophages and neutrophils are recruited to the skin in SSc patients. Many of these chemokines have redundant roles, possibly to ensure recruitment of specific cell types. Several studies have shown a synergistic effect of combinations of these chemokines in cell recruitment, emphasizing the importance of understanding global chemokine expressions. urthermore, chemokines can be detected in peripheral blood compared with cytokines or growth factors. The utility of cytokines as biomarkers has been investigated but longitudinal studies are necessary to clarify their clinical utility for the evaluation of disease activity, therapeutic effects on skin sclerosis or interstitial lung disease and risk stratification of SSc patients. An effective therapeutic agent, able to interfere with complex chemokine networks, is warranted to attenuate perivascular inflammation, dysregulated angiogenesis and the evolution of skin and internal organ fibrosis, is the most ambitious goal for the scientific research of the future.

Membrane array and multiplex bead analysis of tear cytokines in systemic sclerosis

Although serious ocular manifestations of systemic sclerosis (SSc) have been described, tear analysis of patients with SSc has not been performed in previous studies. Our aim was to measure a wide panel of cytokines and chemokines in tears of patients with SSc and to assess the most significant molecules with a more sensitive and specific method. Unstimulated tear samples were collected from nine patients with SSc and 12 age- and gender-matched healthy controls. The relative levels of 102 different cytokines were determined by a cytokine array, and then absolute levels of four key cytokines were determined by a magnetic bead assay. Array results revealed shifted cytokine profile characterized by predominance of inflammatory mediators. Of the 102 analyzed molecules, nine were significantly increased in tears of patients with SSc. Based on the multiplex bead results, C-reactive protein, interferon-γ-inducible protein-10, and monocyte chemoattractant protein-1 levels were significantly higher in tears of patients with SSc. Our current data depict a group of inflammatory mediators, which play a significant role in ocular pathology of SSc; furthermore, they might function as excellent candidates for future therapeutic targets in SSc patients with ocular manifestations.

Survival of adults with systemic sclerosis following lung transplantation: a nationwide cohort study

OBJECTIVE

Many transplant programs are hesitant to offer lung transplantation to patients with systemic sclerosis (SSc) due to concerns about extrapulmonary involvement that might affect survival. The aim of this study was to determine whether adults with SSc have higher 1-year mortality rates after lung transplantation compared to those with interstitial lung disease (ILD) or pulmonary arterial hypertension (PAH) not due to SSc.

METHODS

Using data provided by the United Network for Organ Sharing, we performed a retrospective cohort study of 229 adults with SSc, 201 with PAH, and 3,333 with ILD who underwent lung transplantation in the US between May 4, 2005 and September 14, 2012. We examined associations between diagnosis and 1-year survival after lung transplantation using stratified Cox models adjusted for recipient, donor, and procedure factors.

RESULTS

Adults with SSc undergoing lung transplantation in the US had a multivariable-adjusted 48% relative increase in the 1-year mortality rate compared to those with non-SSc-related ILD (hazard ratio 1.48 [95% confidence interval 1.01-2.17]). However, we did not detect a difference in the risk of death at 1 year between those with SSc and those with non-SSc-related PAH (hazard ratio 0.85 [95% confidence interval 0.50-1.44]).

CONCLUSION

A diagnosis of SSc may confer an increased risk of death 1 year following lung transplantation compared to a diagnosis of ILD, but this risk is similar to that of PAH, a widely accepted indication for lung transplantation. Future work should identify modifiable risk factors that can improve transplant outcomes in this population.

Profile of intraocular immune mediators in patients with age-related macular degeneration and the effect of intravitreal bevacizumab injection

PURPOSE

To measure intraocular cytokine levels in patients with exudative age-related macular degeneration and analyze changes in the cytokine profile 2 days after intravitreal bevacizumab injection.

METHODS

This prospective case-control study enrolled 37 patients (37 eyes) with age-related macular degeneration including polypoidal choroidal vasculopathy. Twenty-eight age-matched patients (28 eyes) who underwent cataract surgery were used as controls. Undiluted aqueous humor samples were collected after intravitreal bevacizumab injection. Two days after intravitreal bevacizumab injection, cataract surgery was performed and undiluted aqueous humor samples were collected at the beginning of surgery (10 eyes). Twenty-three cytokines were measured using flow cytometry. P values were corrected in multiple comparisons using the conservative Bonferroni-Holm method. The level of significance was set at 0.0022 (0.05/23).

RESULTS

At baseline, aqueous humor levels of vascular endothelial growth factor, angiogenin, interferon gamma-inducible protein (IP)-10, macrophage inflammatory protein (MIP)-1β, monokine induced by interferon γ (Mig), and monocyte chemotactic protein (MCP)-1 were significantly higher in the age-related macular degeneration group than in the control group (P < 0.0022). The result of exploratory multivariate analysis showed that elevated angiogenin level was an important factor that discriminates the two groups (P = 0.0004). Two days after intravitreal bevacizumab injection, vascular endothelial growth factor levels tended to be reduced (P = 0.049), whereas interleukin (IL)-6 and IL-8 levels increased significantly (P < 0.0022).

CONCLUSION

Vascular endothelial growth factor and also angiogenin, IP-10, MCP-1, MIP-1β, and Mig may be related to the pathogenesis of age-related macular degeneration. Intravitreal bevacizumab injection increases inflammatory cytokine levels, suggesting the induction of an inflammatory process.

Interferon-gamma inducible protein-10 as a potential biomarker in localized scleroderma

Introduction

The purpose of this study was to evaluate the presence and levels of interferon-gamma inducible protein-10 (IP-10) in the plasma and skin of pediatric localized scleroderma (LS) patients compared to those of healthy pediatric controls and to determine if IP-10 levels correlate to clinical disease activity measures.

Methods

The presence of IP-10 in the plasma was analyzed using a Luminex panel in 69 pediatric patients with LS and compared to 71 healthy pediatric controls. Of these patients, five had available skin biopsy specimens with concurrent clinical and serological data during the active disease phase, which were used to analyze the presence and location of IP-10 in the skin by immunohistochemistry (IHC).

Results

IP-10 levels were significantly elevated in the plasma of LS patients compared to that of healthy controls and correlated to clinical disease activity measures in LS. Immunohistochemistry staining of IP-10 was present in the dermal infiltrate of LS patients and was similar to that found in psoriasis skin specimens, the positive disease control.

Conclusions

Elevation of IP-10 levels in the plasma compared to those of healthy controls and the presence of IP-10 staining in the affected skin of LS patients indicates that IP-10 is a potential biomarker in LS. Furthermore, significant elevation of IP-10 in LS patients with active versus inactive disease and correlations between IP-10 levels and standardized disease outcome measures of activity in LS strongly suggest that IP-10 may be a biomarker for disease activity in LS.