Plasma cytokine profiles in systemic sclerosis: associations with autoantibody subsets and clinical manifestations

Anti-Th/To Antibodies in Scleroderma: Good Prognosis or Serious Concern?

Systemic sclerosis (SSc) represents a rare and intricate autoimmune connective tissue disease, the pathophysiology of which has not been fully understood. Its key features include progressive fibrosis of the skin and internal organs, vasculopathy and aberrant immune activation. While various anti-nuclear antibodies can serve as biomarkers for the classification and prognosis of SSc, their direct role in organ dysfunction remains unclear. Anti-Th/To antibodies are present in approximately 5% of SSc patients, and are particularly prevalent among those with the limited subtype of the disease. Although the presence of these autoantibodies is associated with a mild course of the disease, there is a strong connection between them and severe clinical manifestations of SSc, including interstitial lung disease, pulmonary arterial hypertension and gastrointestinal involvement. Also, the additional clinical correlations, particularly with malignancies, need further research. Moreover, the disease's course seems to be influenced by antibodies, specific serum cytokines and TLR signaling pathways. Understanding the relationships between presence of anti-Th/To, its molecular aspects and response to treatment options is crucial for the development of novel, personalized therapeutic techniques and should undergo profound analysis in future studies.

Th17/IL-17A axis is critical for pulmonary arterial hypertension (PAH) in systemic sclerosis (SSc): SSc patients with high levels of serum IL-17A exhibit reduced lung functions and increased prevalence of PAH

BACKGROUND

It is thought that systemic sclerosis (SSc) might be a T helper 17 (Th17) cell-driven autoimmune disease. Noticeably, pulmonary arterial hypertension (PAH) is a leading cause of death in patients with SSc. Here, we investigated the association between serum Th17-related cytokines and prevalence of PAH in SSc patients.

METHODS

This study included 72 SSc patients and 51 healthy controls (HC). We determined clinical manifestations, immunophenotypes including Th subsets in peripheral blood lymphocytes, and the serum levels of interleukin (IL)-17A, IL-17A/F, IL-17B. IL-17C, IL-17D. IL-1β, IL-6, IL-21, IL-22, and IL-23.

RESULTS

The frequency of Th17 cells was significantly increased in SSc patients compared to HC and was positively correlated with the modified Rodnan skin scores. Furthermore, the serum levels of IL-17A, IL-17D, IL-1β, and IL-6 were significantly increased in SSc patients compared to HC. SSc patients with detected IL-17A showed high levels of IL-17A/F, IL-1β, IL-6, and IL-22, and high frequency of Th17 cells. Interestingly, these patients exhibited the reduced lung functions and increased prevalence of PAH significantly compared to patients with undetected IL-17A. Similarly, SSc patients with detected IL-17A and high IL-6 (≥1.2 pg/mL) exhibited the decreased lung functions and increased prevalence of PAH compared to patients with undetected IL-17A and low IL-6.

CONCLUSION

We found that SSc patients with high levels of serum IL-17A or both IL-17A and IL-6 show reduced lung functions and high prevalence of PAH. Consequently, it is highly probable that Th17/IL-17A axis is critical for the prevalence of PAH in SSc patients.

Associations of the circulating levels of cytokines with risk of systemic sclerosis: a bidirectional Mendelian randomized study

Objective

Systemic sclerosis(SSc) remains unclear, studies suggest that inflammation may be linked to its pathogenesis. Hence, we conducted a bidirectional Mendelian randomization (MR) analysis to evaluate the association between cytokine and growth factor cycling levels and the risk of SSc onset.

Methods

In our study, the instrumental variables(IVs) for circulating cytokines were sourced from the genome-wide association study (GWAS) dataset of 8293 Finnish individuals. The SSc data comprised 302 cases and 213145 controls, and was included in the GWAS dataset. We employed four methods for the MR analysis: MR Egger, Inverse variance weighted (IVW), Weighted medium, and Weighted Mode, with IVW being the primary analytical method. Sensitivity analyses were performed using heterogeneity testing, horizontal pleiotropy testing, and the Leave One Out (LOO) method. We also conducted a reverse MR analysis to determine any reverse causal relationship between SSc and circulating cytokines.

Results

After Bonferroni correction, MR analysis revealed that the Interleukin-5 (IL-5) cycle level was associated with a reduced risk of SSc [odds ratio (OR)=0.48,95% confidence interval (CI): 0.27-0.84, P=0.01]. It also indicated that the Stem cell growth factor beta (SCGF-β) cycling level might elevate the risk of SSc (OR = 1.36, 95% CI: 1.01-1.83, P = 0.04). However, the reverse MR analysis did not establish a causal relationship between SSc and circulating cytokine levels. Additionally, sensitivity analysis outcomes affirm the reliability of our results.

Conclusion

Our MR study suggests potential causal relationships between IL-5, SCGF-β, and the risk of SSc. Further research is essential to determine how IL-5 and SCGF-β influence the development of SSc.

Exploring the polarization of M1 and M2 macrophages in the context of skin diseases

Macrophages are critical components of the immune system and play vital roles in pathogen defense, immune regulation, and tissue repair. These cells exhibit different polarization states depending on environmental signals, and the M1/M2 paradigm is a useful tool for comprehending these states. This review article comprehensively presents the underlying mechanisms of M1 and M2 macrophage polarization and examines their polarization in various skin diseases. Additionally, this paper discusses therapeutic strategies that target M1 and M2 macrophage polarization in skin diseases. A more profound understanding of macrophage polarization in skin diseases could provide valuable insights for the development of innovative therapeutic strategies.

Enhanced Innate and Acquired Immune Responses in Systemic Sclerosis Primary Peripheral Blood Mononuclear Cells (PBMCs)

Chronic immune activation in systemic sclerosis is supported by the production of a plethora of cytokines with proven regulatory activities of the immune responses. This study aimed to explore PBMCs' cytokine profiles in SSc patients versus controls, as well as to investigate the balance between pro- and anti-inflammatory cytokines in association with disease duration. PBMCs were isolated from 18 SSc patients and 17 controls and further subjected to in vitro stimulation with lipopolysaccharide and heat-killed Candida albicans. Cytokine production was measured after 24 h and 7 days, respectively, using ELISA kits for interleukin (IL)-1β, IL-1 receptor antagonist (IL-1Ra), IL-6, tumor necrosis factor (TNF), IL-10, IL-17, and interferon-gamma (IFN-gamma). IL-1 β, IL-6, and TNF levels were increased in SSc patients compared with healthy volunteers irrespective of the stimulus used. IL-1Ra and Il-17 concentrations were not statistically different between groups, even though a trend toward higher levels in patients compared with their matched controls was also observed. Most cytokines demonstrated a stable course with disease progression, except for IL-10 levels, which declined over time. In conclusion, the results of this pilot study reveal that in patients with SSc a persistently enhanced immune response is established and maintained regardless of stimulus or disease duration.

A comparative study of modulatory interaction between cytokines and apoptotic proteins among Scleroderma patients with and without pulmonary involvement

BACKGROUND

Interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH) are the most eminent forms of pulmonary involvement in Scleroderma. In this study we investigate the interaction between cytokines and apoptotic proteins in treatment naive Scleroderma (SSc) patients with and without pulmonary involvement.

METHODS

Newly diagnosed treatment naïve Scleroderma (SSc) patients (n = 100) and healthy controls (n = 100) were enrolled. Patients were classified as ILD-SSc, PAH-SSc and non-pulmonary SSc (np-SSc). Study variables like mRSS score, autoantibody profile, serum cytokines, serum TGF-β (1,2,3) and apoptotic proteins were assessed for these patients.

RESULTS

Scleroderma patients showed elevated levels of serum cytokines, but significantly lower IL-22 and TGF- β1 when compared to healthy controls (p < 0.05). Apoptotic proteins were significantly elevated among Scleroderma patients, but the patient groups also showed significant lower caspase 1/3/9 levels when compared to healthy controls (p < 0.05). ILD-SSc patients reported higher mRSS score (p = 0.0436) when compared with PAH-SSc and np-SSc. In ILD-SSc patients, finger tightening (p = 0.0481) and calcinosis/lesions (p = 0.0481) were significant clinical presentations whereas, digital ulcers were significantly prominent in np-SSc patients (p = 0.0132). Elevated TGF-β3 levels (p = 0.02) in SSC-ILD and reduced IL-4 levels (p = 0.02) in SSC-PAH were significant cytokines as compared to np-SSc. Significant correlations were obtained among serum cytokines and apoptotic proteins in Scleroderma patients with and without pulmonary involvement. (p < 0.05) CONCLUSION: Our study highlights the correlation between mRSS score, cytokines and apoptotic proteins in SSc patients with pulmonary involvement. A longitudinal follow up in these patients with assessment of these immunological parameters may be helpful in monitoring the disease.

Therapeutic Potential of a Senolytic Approach in a Murine Model of Chronic GVHD

Graft-versus-host disease (GVHD) is a life-threatening systemic complication of allogeneic hematopoietic stem cell transplantation (HSCT) characterized by dysregulation of T and B cell activation and function, scleroderma-like features, and multi-organ pathology. The treatment of cGVHD is limited to the management of symptoms and long-term use of immunosuppressive therapy, which underscores the need for developing novel treatment approaches. Notably, there is a striking similarity between cytokines/chemokines responsible for multi-organ damage in cGVHD and pro-inflammatory factors, immune modulators, and growth factors secreted by senescent cells upon the acquisition of senescence-associated secretory phenotype (SASP). In this pilot study, we questioned the involvement of senescent cell-derived factors in the pathogenesis of cGVHD triggered upon allogeneic transplantation in an irradiated host. Using a murine model that recapitulates sclerodermatous cGVHD, we investigated the therapeutic efficacy of a senolytic combination of dasatinib and quercetin (DQ) administered after 10 days of allogeneic transplantation and given every 7 days for 35 days. Treatment with DQ resulted in a significant improvement in several physical and tissue-specific features, such as alopecia and earlobe thickness, associated with cGVHD pathogenesis in allograft recipients. DQ also mitigated cGVHD-associated changes in the peripheral T cell pool and serum levels of SASP-like cytokines, such as IL-4, IL-6 and IL-8Rα. Our results support the involvement of senescent cells in the pathogenesis of cGVHD and provide a rationale for the use of DQ, a clinically approved senolytic approach, as a potential therapeutic strategy.

Management of Patients with Systemic Sclerosis-Associated Interstitial Lung Disease: A Focus on the Role of the Pharmacist

Interstitial lung disease (ILD) is a common manifestation of systemic sclerosis (SSc), which becomes fibrosing and progressive in some patients. Regular monitoring of patients with SSc-ILD is important to assess progression and inform treatment decisions. Therapy for SSc-ILD may include immunomodulatory and antifibrotic therapies. Therapeutic decisions should be made on a case-by-case basis, ideally following multidisciplinary discussion. Most patients with SSc-ILD have several organ manifestations of SSc or comorbidities and are taking a complex medication regimen. Patients with SSc are particularly susceptible to gastrointestinal side-effects of medications due to the gastrointestinal manifestations of the disease. Pharmacists play an important role in the management of patients with SSc-ILD by assisting patients with access to medications, optimizing medication regimens, and advising on alternative dosage forms. Pharmacists can also contribute to patient education to help patients better understand their treatment and how to prevent and manage potential side effects.

Cytokine profiling in pulmonary arterial hypertension: the role of redox homeostasis and sex

Pulmonary arterial hypertension (PAH) is a fatal disease with a well-established sexual dimorphism. Activated inflammatory response and altered redox homeostasis, both known to manifest in a sex-specific manner, are implicated in the pathogenic mechanisms involved in PAH development. This study aimed to evaluate the impact of sex and plasma redox status on circulating cytokine profiles. Plasma oxidation-reduction potential (ORP), as a substitute measure of redox status, was analyzed in male and female Group 1 PAH and healthy subjects. The profiles of 27 circulating cytokines were compared in 2 PAH groups exhibiting the highest and lowest quartile for plasma ORP, correlated with clinical parameters, and used to predict patient survival. The analysis of the PAH groups with the highest and lowest ORP revealed a correlation between elevated cytokine levels and increased oxidative stress in females. In contrast, in males, cytokine expressions were increased in the lower oxidative environment (except for IL-1b). Correlations of the increased cytokine expressions with PAH severity were highly sex-dependent and corresponded to the increase in PAH severity in males and less severe PAH in females. Machine learning algorithms trained on the combined cytokine and redox profiles allowed the prediction of PAH mortality with 80% accuracy. We conclude that the profile of circulating cytokines in PAH patients is redox- and sex-dependent, suggesting the vital need to stratify the patient cohort subjected to anti-inflammatory therapies. Combined cytokine and/or redox profiling showed promising value for predicting the patients' survival.

The Roles of Noncoding RNAs in Systemic Sclerosis

Noncoding RNAs (ncRNAs) constitute more than 90% of the RNAs in the human genome. In the past decades, studies have changed our perception of ncRNAs from “junk” transcriptional products to functional regulatory molecules that mediate critical processes, including chromosomal modifications, mRNA splicing and stability, and translation, as well as key signaling pathways. Emerging evidence suggests that ncRNAs are abnormally expressed in not only cancer but also autoimmune diseases, such as systemic sclerosis (SSc), and may serve as novel biomarkers and therapeutic targets for the diagnosis and treatment of SSc. However, the functions and underlying mechanisms of ncRNAs in SSc remain incompletely understood. In this review, we discuss the current findings on the biogenetic processes and functions of ncRNAs, including microRNAs and long noncoding RNAs, as well as explore emerging ncRNA-based diagnostics and therapies for SSc.

Determination of T Cell Responses in Thai Systemic Sclerosis Patients

Objectives

This study is aimed at determining the role of T cells by assessing the numbers of IFN-γ- and IL-2-secreting T cells following stimulation with peptides derived from DNA topoisomerase-I protein in Thai SSc patients.

Methods

Fifty Thai SSc patients and 50 healthy controls (HC) joined this study. IFN-γ and IL-2 levels upon stimulation of T cells with 6 peptides derived from DNA topoisomerase-I protein were determined. Anti-nuclear antibodies (ANA) and anti-Scl-70 antibodies were determined by using the ELISA method.

Results

In SSc patients, we detected a significantly higher number of IFN-γ- and IL-2-secreting CD8⁺ T cells than IFN-γ- and IL-2-secreting CD4⁺ T cells after stimulation with pooled peptides derived from DNA topoisomerase-I protein. A similar percentage of CD4⁺IL-2⁺, CD4⁺IFN-γ⁺, and CD8⁺IL-2⁺ were detected following stimulation with DNA topoisomerase-I protein -in SSc patients with anti-Scl-70 antibody (SSc/anti-Scl-70⁺) and those without. In contrast, the amount of CD8⁺IFN-γ⁺ cells was significantly higher in SSc/anti-Scl-70⁺ than those without. Stimulation with individual peptides showed that CSLRVEHINLHPELD (sPep3; 15 amino acids; position 505-519 of DNA topoisomerase-I protein) was the optimal epitope that induced T cells secreting the highest levels of IFN-γ and IL-2. A higher percentage of IFN-γ⁺CD4⁺ T cells was detected in SSc/anti-Scl-70⁺ than those without the following stimulation with peptides 2 (amino acid position 475-486 [RAVALYFIDKLA] of protein DNA topoisomerase).

Conclusion

The results from this study emphasize the critical role of DNA topoisomerase-I peptides on the activation of T cells in SSc patients. The findings provide a better understanding of SSc's immunopathogenesis and may lead to the development of diagnostic tools and specific treatments for SSc in the future.

iNKT cells can effectively inhibit IL-6 production by B cells in systemic sclerosis

OBJECTIVE

Systemic sclerosis (SSc) is a connective tissue disease with poorly understood pathogenesis and limited treatment options. Patient mortality is rooted predominantly in the development of pulmonary and cardiac complications. The overactivated immune system is assumed to sustain the inflammatory signature of this autoimmune disease. Here, we investigate the potential of immunoregulatory invariant natural killer T (iNKT) cells to inhibit proinflammatory B cell responses in an in vitro model of inflammation.

METHODS

B cells from healthy volunteers (n = 17) and patients with SSc (n = 15) were used for functional testing upon lipopolysaccharide (LPS) stimulation in a co-culture system with third-party iNKT cells. Cytokine production was measured with antibody-based immunoassays (ELISA) and intracellular cytokine staining.

RESULTS

iNKT cells strongly inhibited the production of proinflammatory interleukin-6 by B cells upon stimulation with LPS in both healthy volunteers and patients with SSc. In a Transwell assay, cell contact between B cells and iNKT cells proved necessary for this inhibitory effect. Similarly, blocking of CD1d on the surface of B cells abolished the immunoregulatory effect of iNKT cells on B cells. B cell subsets with higher expression of CD1d, namely unswitched memory B cells, were more susceptible to iNKT cell inhibition.

CONCLUSION

Our in vitro data underline the potential of iNKT cells in the control of SSc and provide a rationale for the use of novel iNKT cell-based therapeutic strategies in the context of autoimmune diseases.

Utility of cytokines CXCL4, CXCL8 and GDF15 as biomarkers in systemic sclerosis

BACKGROUND AND OBJECTIVES

Systemic sclerosis (SSc) is an autoinmune disease that can affect several organs and its mortality is fundamentally related to its pulmonary involvement. There are some cytokines with high serum levels of patients with SSc. Our goal is to determine the role of CXCL4, CXCL8 and GDF15 in the physiopathology of SSc and whether they can be considered organic damage biomarkers.

PATIENTS AND METHODS

Observational case-control study of SSc patients (ACR/EULAR 2013 criteria). Demographic, clinical, analytical, activity, severity, health perception, and disability variables were collected. Moreover, Videocapillaroscopy, Echocardiography and Respiratory Function Test were made. Serum levels of CXCL4, CXCL8 and GDF15 were measured both in SSc patients and in healthy controls.

RESULTS

A total of 42 patients were included (95.4% women), with an average age of 59.2 years and a median of 4 years from diagnosis. We also included 42 healthy controls. We found significantly higher levels of GDF15 in SSc patients than in controls (p<0.001), but no higher CXCL4 or CXCL8 levels. GDF15 was associated with Diffuse SSc, pulmonary arterial hypertension, interstitial lung disease, less forced vital capacity, high titles of antiScl70, disease activity, and dilated loops in capillaroscopy. CXCL4 levels were associated to a higher Rodnan punctuation, while CXCL8 was associated to C4 fraction consumption and tortuosities in capillaroscopy.

CONCLUSIONS

GDF15 high levels were associated with diffuse SSc, lung impairment, disease activity and changes in capillaroscopy. Moreover, CXCL4 was only associated with skin impairment, while CXCL8 was not related to organic damage.

Molecular Basis of Accelerated Aging with Immune Dysfunction-Mediated Inflammation (Inflamm-Aging) in Patients with Systemic Sclerosis

Systemic sclerosis (SSc) is a chronic connective tissue disorder characterized by immune dysregulation, chronic inflammation, vascular endothelial cell dysfunction, and progressive tissue fibrosis of the skin and internal organs. Moreover, increased cancer incidence and accelerated aging are also found. The increased cancer incidence is believed to be a result of chromosome instability. Accelerated cellular senescence has been confirmed by the shortening of telomere length due to increased DNA breakage, abnormal DNA repair response, and telomerase deficiency mediated by enhanced oxidative/nitrative stresses. The immune dysfunctions of SSc patients are manifested by excessive production of proinflammatory cytokines IL-1, IL-6, IL-17, IFN-α, and TNF-α, which can elicit potent tissue inflammation followed by tissue fibrosis. Furthermore, a number of autoantibodies including anti-topoisomerase 1 (anti-TOPO-1), anti-centromere (ACA or anti-CENP-B), anti-RNA polymerase enzyme (anti-RNAP III), anti-ribonuclear proteins (anti-U1, U2, and U11/U12 RNP), anti-nucleolar antigens (anti-Th/T0, anti-NOR90, anti-Ku, anti-RuvBL1/2, and anti-PM/Scl), and anti-telomere-associated proteins were also found. Based on these data, inflamm-aging caused by immune dysfunction-mediated inflammation exists in patients with SSc. Hence, increased cellular senescence is elicited by the interactions among excessive oxidative stress, pro-inflammatory cytokines, and autoantibodies. In the present review, we will discuss in detail the molecular basis of chromosome instability, increased oxidative stress, and functional adaptation by deranged immunome, which are related to inflamm-aging in patients with SSc.

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.

Characterization of Long Non-Coding RNAs in Systemic Sclerosis Monocytes: A Potential Role for PSMB8-AS1 in Altered Cytokine Secretion

Systemic sclerosis (SSc) is a chronic autoimmune disease mainly affecting the connective tissue. In SSc patients, monocytes are increased in circulation, infiltrate affected tissues, and show a pro-inflammatory activation status, including the so-called interferon (IFN) signature. We previously demonstrated that the dysregulation of the IFN response in SSc monocytes is sustained by altered epigenetic factors as well as by upregulation of the long non-coding RNA (lncRNA) NRIR. Considering the enormously diverse molecular functions of lncRNAs in immune regulation, the present study investigated the genome-wide profile of lncRNAs in SSc monocytes, with the aim to further unravel their possible role in monocyte dysregulation and disease pathogenesis. Transcriptomic data from two independent cohorts of SSc patients identified 886 lncRNAs with an altered expression in SSc monocytes. Differentially expressed lncRNAs were correlated with neighboring protein coding genes implicated in the regulation of IFN responses and apoptotic signaling in SSc monocytes. In parallel, gene co-expression network analysis identified the lncRNA PSMB8-AS1 as a top-ranking hub gene in co-expression modules implicated in cell activation and response to viral and external stimuli. Functional characterization of PSMB8-AS1 in monocytes demonstrated that this lncRNA is involved in the secretion of IL-6 and TNFα, two pivotal pro-inflammatory cytokines altered in the circulation of SSc patients and associated with fibrosis and disease severity. Collectively, our data showed that lncRNAs are linked to monocyte dysregulation in SSc, and highlight their potential contribution to disease pathogenesis.

Animal models of pulmonary hypertension: Getting to the heart of the problem

Despite recent therapeutic advances, pulmonary hypertension (PH) remains a fatal disease due to the development of right ventricular (RV) failure. At present, no treatments targeted at the right ventricle are available, and RV function is not widely considered in the preclinical assessment of new therapeutics. Several small animal models are used in the study of PH, including the classic models of exposure to either hypoxia or monocrotaline, newer combinational and genetic models, and pulmonary artery banding, a surgical model of pure RV pressure overload. These models reproduce selected features of the structural remodelling and functional decline seen in patients and have provided valuable insight into the pathophysiology of RV failure. However, significant reversal of remodelling and improvement in RV function remains a therapeutic obstacle. Emerging animal models will provide a deeper understanding of the mechanisms governing the transition from adaptive remodelling to a failing right ventricle, aiding the hunt for druggable molecular targets.

Fibroblasts and their responses to chronic injury in pulmonary fibrosis

The field of pulmonary fibrosis is rapidly expanding as new insights highlight novel mechanisms that influence fibroblast biology and likely promote aberrant and chronic activation of the tissue repair response. Current paradigms suggest repeated epithelial microinjury as a driver for pathology; however, the rapid expansion of pulmonary fibrosis research calls for an overview on how fibroblasts respond to both neighbouring cells and the injury microenvironment. This review seeks to highlight recent discoveries and identify areas that require further research regarding fibroblasts, and their role in pulmonary fibrosis.

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.

Impact of Human Cytomegalovirus and Human Herpesvirus 6 Infection on the Expression of Factors Associated with Cell Fibrosis and Apoptosis: Clues for Implication in Systemic Sclerosis Development

Systemic sclerosis (SSc) is a severe autoimmune disorder characterized by vasculopathy and multi-organ fibrosis; its etiology and pathogenesis are still largely unknown. Herpesvirus infections, particularly by human cytomegalovirus (HCMV) and human herpesvirus 6 (HHV-6), have been suggested among triggers of the disease based on virological and immunological observations. However, the direct impact of HCMV and/or HHV-6 infection on cell fibrosis and apoptosis at the cell microenvironment level has not yet been clarified. Thus, this study aimed to investigate the effects of HCMV and HHV-6 infection on the induction of pro-fibrosis or pro-apoptosis conditions in primary human dermal fibroblasts, one of the relevant SSc target cells. The analysis, performed by microarray in in vitro HCMV- or HHV-6-infected vs. uninfected cells, using specific panels for the detection of the main cellular factors associated with fibrosis or apoptosis, showed that both viruses significantly modified the expression of at least 30 pro-fibrotic and 20 pro-apoptotic factors. Notably, several recognized pro-fibrotic factors were highly induced, and most of them were reported to be involved in vivo in the multifactorial and multistep pathogenic process of SSc, thus suggesting a potential role of both HCMV and HHV-6.

Neutrophil Extracellular Traps Generation Relates with Early Stage and Vascular Complications in Systemic Sclerosis

Systemic sclerosis (SSc) is a systemic disease characterized by a great clinical and immunological heterogeneity whose pathophysiology is still being unraveled. Recently, innate immunity has been proposed to participate to the pathogenesis of SSc. In this study, we investigated the release of neutrophil extracellular traps (NETs) according to patient phenotype. Polymorphonuclear neutrophils (PMN) from 34 SSc patients and 26 healthy controls were stimulated by serum from SSc or healthy subject. NETs were visualized using epifluorescence microscope after DNA, myeloperoxidase, and Histone H3 tagging. Area of NETs were quantified using an original macro running in ImageJ^® software. PMN from SSc patients were significantly more prone to releasing NETs than control PMN after autologous stimulation. PMN from patients with severe vascular complications (pulmonary arterial hypertension, digital ulcers) produced more NETs than PMN from other SSc patients and their aberrant NET production appeared to be sustained over time. In patients with pulmonary interstitial disease or extensive cutaneous fibrosis, NET production was high at an early stage of the disease before progressively decreasing. Both serum factors and PMN activation status were involved in the enhanced production of NETs in SSc. Consequently, neutrophils and especially NETosis represent new physiopathological and therapeutic fields in SSc.

The Role of Endogenous Eicosapentaenoic Acid and Docosahexaenoic Acid-Derived Resolvins in Systemic Sclerosis

Resolvins, the member of specialized pro-resolving mediators, are produced from omega-3 polyunsaturated fatty acids as a response to an acute inflammatory process in that termination and resolution of inflammation. In the acute inflammation, these lipid mediators limit polymorphonuclear cells infiltration, proinflammatory cytokine production; promote efferocytosis, and regulate several cell types being important roles in innate and adaptive immunity. Any dysregulation or defect of the resolution phase result in prolonged, persistent inflammation and eventually fibrosis. Resolvins are implicated in the development of various chronic autoimmune diseases. Systemic sclerosis (SSc) is a very complicated, chronic autoimmune disorder proceeding with vasculopathy, inflammation, and fibrosis. Dysregulation of innate and adaptive immunity is another important contributing factor in the pathogenesis of SSc. In this review, we will focus on the different roles of this new family of lipid mediators, characterized by the ability to prevent the spread of inflammation and its chronicity in various ways and how they can control the development of fibrotic diseases like SSc.

Inhibition of effector B cells by ibrutinib in systemic sclerosis

Objective

Systemic sclerosis (SSc) is a connective tissue disease with a significant morbidity and reduced survival of patients. Effective treatment and clinical control of the disease remain challenging. In particular, the development of pulmonary and cardiac fibrosis and pulmonary hypertension are severe complications responsible for excessive mortality. Currently available treatment strategies only alleviate symptoms and slow disease progression. Here, we investigated the therapeutic potential of ibrutinib, a Bruton’s tyrosine kinase (BTK) inhibitor used in B cell malignancies, to alter B cell pathology in SSc in an in vitro model of autoimmunity.

Methods

PBMCs and sorted B cells of 24 patients with SSc were used for functional testing after stimulation with hypomethylated DNA fragments (CpG) to induce an innate immune response. The effects of ibrutinib on cytokine production, autoantibody release, and activation of the transcription factor NFκB were evaluated.

Results

Ibrutinib was able to reduce the production of the profibrotic hallmark cytokines IL-6 and TNF-α mainly from the effector B cell population in patients with SSc. Importantly, small doses of ibrutinib (0.1 μM) preserved the production of immunoregulatory IL-10 while effectively inhibiting hyperactivated, profibrotic effector B cells. In a flow cytometry analysis of phosphorylated NFκB, an important transcription factor in the induction of innate immune responses in B cells, significantly less activation was observed with ibrutinib treatment.

Conclusion

Our data could pave the avenue for a clinical application of ibrutinib for patients with SSc as a novel treatment option for the underlying pathogenetic immune imbalance contributing to disease onset and progression.

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.

The profiles of miRNAs and lncRNAs in peripheral blood neutrophils exosomes of diffuse cutaneous systemic sclerosis

BACKGROUND

Diffuse cutaneous systemic sclerosis (dSSc) is a systemic autoimmune disease with skin fibrosis. Neutrophils display important roles in autoimmunity, inflammation, vasculopathy and fibrosis. Exosomes (EXOs) are cell-derived vesicles contained various noncoding RNAs, mRNA and proteins with biological roles.

OBJECTIVE

To investigate the roles of miRNAs and lncRNAs from dSSc neutrophils EXOs.

METHODS

EXOs were isolated from cultured neutrophils supernatants and identified by transmission electron microscopy. Global expression of miRNAs and lncRNAs in neutrophils EXOs were sequenced by Illumina HiSeq 3000 and bioinformatic analyses were performed by R/Bioconductor. Genes were validated by real-time quantitative PCR.

RESULTS

In profiles of neutrophils EXOs, we identified 22 dysregulated miRNAs and 281 dysregulated lncRNAs. Predicted target genes of them were enriched in GO, KEGG and Reactome pathways, Wnt, AMPK, IL-23 and NOTCH signaling pathways were selected for further analysis. Widely interactions among them were also found. Human dermal microvascular endothelial cells and human primary skin fibroblasts were stimulated with dSSc neutrophils EXOs, these fibrosis related genes were detected and some changes were found, such as ENST00000533886.1-hsa-miR-1268a-CAMK2G in Wnt and IL-23 signaling pathways, ENST00000610091.1-hsa-miR-299-3p, 512-3p-CPT1A in IL-23 and AMPK signaling pathways, NR_001564.2, ENST00000520562.1, ENST00000596567.1-hsa-miR-299-3p, 512-3p -TFDP2 in IL-23, AMPK and NOTCH signaling pathways.

CONCLUSIONS

The profiles of miRNAs and lncRNAs of neutrophils EXOs provided novel clues for dSSc pathogenesis. We identified several gene pairs in the Wnt, AMPK, IL-23 and NOTCH signaling pathways, which could be potential biomarkers and therapeutic targets in dSSc.

miR-181b-5p inhibits endothelial-mesenchymal transition in monocrotaline-induced pulmonary arterial hypertension by targeting endocan and TGFBR1

Endothelial-mesenchymal transition (EndMT) is a frequent event in endothelial dysfunction, which is associated with pulmonary arterial hypertension (PAH). MiR-181 family members exert diverse effects in multiple biological processes. However, the relationships between miR-181b-5p (miR-181b) and EndMT in PAH are not well understood. In this study, Sprague-Dawley (SD) rats were injected with monocrotaline (MCT) to establish PAH model, and primary rat pulmonary arterial endothelial cells (rPAECs) were treated with TNF-α, TGFβ1 and IL-1β in combination to induce EndMT (I-EndMT). Then we explored miR-181b expression and examined its functional role in PAH. Our data showed that miR-181b was down-expressed in PAH, and its overexpression attenuated the hemodynamics, pulmonary vascular hypertrophy, right ventricular remodeling and EndMT process in MCT-induced PAH rats. In I-EndMT rPAECs, we observed that inducing miR-181b reversed the decrease of endothelial markers and increase of mesenchymal markers. However, knockdown of miR-181b induced similar effects to EndMT. In addition, endocan and TGFBR1 levels were also increased in EndMT, which were negatively regulated by miR-181b. Luciferase activity results indicated that endocan and TGFBR1 were direct target genes of miR-181b. In summary, our findings firstly demonstrate that the beneficial effect of miR-181b on PAH may be associated with endocan/TGFBR1-mediated EndMT, providing a new insight into the diagnosis and treatment of PAH.

TNFA -308G>A and -238G>A polymorphisms and risk to systemic sclerosis: impact on TNF-α serum levels, TNFA mRNA expression, and autoantibodies

Systemic sclerosis (SSc) is a rare autoimmune disease with high mortality, characterized by chronic inflammation and fibrosis, which are processes associated with higher serum tumor necrosis factor-α (sTNF-α) levels. TNFA -308G>A and -238G>A polymorphisms have been associated with higher sTNF-α levels. In this study, we genotyped the TNFA -308G>A and -238G>A polymorphisms in 53 SSc patients and 115 unrelated control subjects (CS) from southern Mexico. The TNFA mRNA expression and sTNF-α levels were also quantified by qPCR and enzyme-linked immunosorbent assays, respectively. TNFA -308GA genotype was associated with disease susceptibility according to a codominant genetic model (OR = 3.2, 95% CI 1.05-9.75, p = 0.03), and with higher anti-fibrillarin antibodies (p = 0.01), and higher skin thickening (p = 0.006). TNFA -238GA was not associated with SSc risk. TNFA mRNA expression and sTNF-α levels were similar between SSc patients and CS and were not statistically associated with the TNFA polymorphisms; however, a correlation (rho = 0.362, p = 0.009) between sTNF-α levels with anti-RNA polymerase III antibodies was observed in the SSc patients. In conclusion, the -308G>A polymorphism is a genetic marker of SSc susceptibility in population from southern Mexico, and it is associated with skin thickening and anti-fibrillarin antibodies. In addition, sTNF-α levels correlate positively with the anti-RNA pol III antibodies levels.

IL-17 and Th17 cells in systemic sclerosis: a comprehensive review

T cells (especially T helper cells) seem to be strongly associated with systemic sclerosis pathogenesis. Th17-IL-17 axis was proved to be involved in the pathogenesis of multiple autoimmune diseases. By performing a comprehensive research of the literature indexed in PubMed database, the current review summarizes current knowledge related to Th17 and IL-17 in systemic sclerosis. While there is promising data suggesting inhibition of Tregulatory and Th1 signals on one hand and promotion of Th17 and Th2 signals on the other, studies that include prospective and integrated analysis of Tregulatory, Th17, Th1, Th2 (cells and derived cytokines) on the same cohort of Ssc patients are warranted.

Immunopathogenesis of Juvenile Systemic Sclerosis

Juvenile-onset systemic sclerosis (jSSc) is a rare and severe autoimmune disease with associated life-threatening organ inflammation and evidence of fibrosis. The organ manifestations of jSSc resemble adult SSc, but with better outcomes and survival. The etiology of jSSc appears to reflect adult-onset SSc, with similar inflammatory mediators and autoantibodies, but with a significant population of children with uncharacterized anti-nuclear antibodies. The genetics of patients with jSSc differ from women with SSc, resembling instead the genes of adult males with SSc, with additional HLA genes uniquely associated with childhood-onset disease. Current treatments are aimed at inhibiting the inflammatory aspect of disease, but important mechanisms of fibrosis regulated by dermal white adipose tissue dendritic cells may provide an avenue for targeting and potentially reversing the fibrotic stage.

Cytokine secretion and the risk of depression development in patients with connective tissue diseases

Research in the past two decades has revolutionized our understanding of depressive illnesses. Proinflammatory cytokines have become a point of interest in the interconnecting areas of neuropsychiatric and autoimmune diseases. The cytokine hypothesis of depression suggests that pro-inflammatory cytokines play a primary role in the mediation of the pathophysiological characteristics of major depression, in which an inflammatory process may be induced by external and internal stressors, such as psychological and inflammatory diseases, respectively. The higher prevalence of depression, particularly in patients with chronic autoimmune connective tissue disorders (CTD), suggests that depression may present a dysfunctional adaptation of cytokine-induced sickness, which could manifest in times of an exacerbated activation of the innate immune system. Inflammation is thought to contribute to the development of clinical depression through its ability to induce sickness behaviors corresponding to the neurovegetative features of depression, through the dysregulation of the hypothalamic-pituitary-adrenal axis, alterations in neurotransmitter synthesis and reuptake, and through its involvement in the neuroprogression pathways. This review explores the complex interrelationships in which inflammatory responses alter neuroendocrine and neuropsychological regulation contributing to depressive symptoms in CTD. The prevalence and characteristics of depression, and its correlation to the levels of inflammatory cytokines and disease activity among different CTD will be reviewed.

Dexamethasone inhibits cytokine production in PBMC from systemic sclerosis patients

Glucocorticoids (GC) are widely used in the treatment of SSc, although there is not much evidence to prove the benefits offered by these drugs in this disease. In this study, we evaluated the effects of a GC on cytokine production in peripheral blood mononuclear cells (PBMC) of SSc patients. The effect of dexamethasone (DEX) was evaluated in PBMC of 21 SSc patients and 10 healthy volunteers after stimulation of cells with anti-CD3 and anti-CD28. Cytokines IL-2, IL-4, IL-6, IL-10, IL-17A, IL-17F, IFN-γ, TNF, and IL-1β were quantified in the culture supernatant by CBA or ELISA. Of the patients evaluated in this study, 8 (38%) were taking corticosteroids, and esophageal dysfunction was more frequent in these patients when compared to those who did not take corticosteroids. DEX (1.000 nM) treatment in PBMC of SSc patients stimulated with anti-CD3 and anti-CD28 promoted a significant reduction in IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-γ, TNF, IL-1β (p < 0.001 for all), and IL-17F (p = 0.023) cytokines levels. We did not observe differences in response to in vitro treatment with DEX between groups of patients taking or not taking corticosteroids. In PBMC from healthy volunteers, we observed that DEX treatment significantly reduced IL-4, IFN-γ (p = 0.003 for both), IL-6, IL-10, IL-17A, and TNF (p = 0.002 for all) cytokines. These results show that DEX treatment in PBMC of SSc patients reduced the production of important cytokines involved in the pathogenesis of the disease, suggesting a possible mechanism of action of the CG in the treatment of SSc.

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.

The immunopathogenesis of fibrosis in systemic sclerosis

Systemic sclerosis (SSc) is an idiopathic systemic autoimmune disease. It is characterized by a triad of hallmarks: immune dysfunction, fibrosis and vasculopathy. Immune dysfunction in SSc is characterized by the activation and recruitment of immune cells and the production of autoantibodies and cytokines. How immune abnormalities link the fibrosis and vasculopathy in SSc is poorly understood. A plethora of immune cell types are implicated in the immunopathogenesis of SSc, including T cells, B cells, dendritic cells, mast cells and macrophages. How these different cell types interact to contribute to SSc is complicated, and can involve cell-to-cell interactions and communication via cytokines, including transforming growth factor (TGF)-β, interleukin (IL)-6 and IL-4. We will attempt to review significant and recent research demonstrating the importance of immune cell regulation in the immunopathogenesis of SSc with a particular focus on fibrosis.

Autologous Hematopoietic Stem Cell Transplantation for Treatment of Systemic Sclerosis

Systemic Sclerosis (SSc) is a complex autoimmune disease, characterized by high mortality and morbidity. The heterogeneity in terms of extent, severity, and rate of progression of skin and internal organ involvement gives rise to many difficulties in finding the optimal therapeutic interventions for SSc and, to date, no disease-modifying agents are available. In this scenario, it is not surprising that SSc was one of the first autoimmune diseases challenged with high-dose immunosuppressive treatment followed by autologous hematopoietic stem cell transplantation (AHSCT). In the last decades, AHSCT has emerged as a treatment option for refractory SSc through a reduction of the aberrant immune cells, followed by re-constitution of a new, self-tolerant immune system. After several case series and pilot studies, more recently three randomized controlled trials have shown a benefit in skin involvement, organ functions and quality of life measures in AHSCT compared to monthly cyclophosphamide. In addition, although AHSCT presents a certain risk of mortality, it has been shown that the overall survival is better, compared to the cyclophosphamide group. Current evidence suggests that SSc patients who are most likely to benefit from AHSCT are early, active, with rapidly progressing diffuse skin disease, and mild involvement of internal organs. As the studies have progressed, it has become evident the need for a more rigorous patient selection, the optimization of transplant and post-transplant procedures, and the intervention of multidisciplinary teams of specialists to increase the safety and efficacy of AHSCT in SSc.

Combination of 5-aminolevulinic acid and iron prevents skin fibrosis in murine sclerodermatous graft-versus-host disease

Scleroderma or systemic sclerosis (SSc) is a clinically heterogeneous rheumatological autoimmune disease affecting the skin, internal organs and blood vessels. There is at present no effective treatment for this condition. Our study investigated the effects of 5-aminolevulinic acid (5-ALA), which is a precursor of haem synthesis, on graft-vs-host disease (GvHD)-induced SSc murine model. Lymphocytes were intravenously injected from donor mice (B10.D2) into recipient BALB/c mice (recombination-activating gene 2 (Rag-2)-null mice) deficient in mature T and B cells to induce sclerodermatous GvHD (scl-GvHD). To investigate the effect of 5-ALA on scl-GvHD, combination of 5-ALA and sodium ferrous citrate (SFC) was orally administered to the recipient mice for 9 weeks. 5-ALA/SFC treatment significantly reduced progressive inflammation and fibrosis in the skin and ears. Furthermore, 5-ALA/SFC suppressed mRNA expression of transforming growth factor-β, type I collagen and inflammatory cytokines. These results indicate that the 5-ALA/SFC combination treatment has a protective effect against tissue fibrosis and inflammation in a murine scl-GvHD-induced skin and ear inflammation and fibrosis. Furthermore, the efficacy of 5-ALA/SFC suggests important implications of HO-1 protective activity in autoimmune diseases, and therefore, 5-ALA/SFC may have promising clinical applications. These findings suggested that the 5-ALA/SFC treatment may be the potential strategies for SSc.

Interleukin-6 and Type-I Collagen Production by Systemic Sclerosis Fibroblasts Are Differentially Regulated by Interleukin-17A in the Presence of Transforming Growth Factor-Beta 1

Functional cytokine networks have been poorly characterized in systemic sclerosis (SSc). While interleukin-17A (IL-17A) is increased in SSc skin and other organs, its role is still debated, particularly considering fibrogenesis. We uncover here a dual function of IL-17A in the presence of transforming growth factor-β 1 (TGF-β), the master pro-fibrotic cytokine. In the one hand, we report an unexpected synergic activity resulting in enhanced production of IL-6 by dermal fibroblasts; in the other hand, a substantial inhibition of type I collagen (col-I) production. IL-17A or TGF-β enhanced the production of IL-6 by 8- to 16-folds when compared to control in healthy donors (HD) and SSc cultures. However, the joint presence of IL-17A and TGF-β resulted in robustly exuberant responses with levels of IL-6 up to 100-folds higher than those observed in untreated cells. Inhibition of NFκB signaling pathway preferentially inhibited the production of IL-6 driven by IL-17A in HD fibroblasts, while inhibition of PI3K preferentially inhibited the production of IL-6 driven by TGF-β. Interestingly, when p38 MAPK was inhibited, substantial reduction of IL-6 production was observed for both IL-17A and TGF-β. Consistently with the inhibition experiments, the combined stimulation of fibroblasts by IL-17A and TGF-β resulted in 1.8-fold increase in p38 MAPK phosphorylation (P = 0.025), when compared to levels of phosphorylated p38 MAPK induced by IL-17A alone. Furthermore, the enhanced phosphorylation of p38 MAPK in the joint presence of IL-17A and TGF-β was unique among the signaling molecules we examined. As expected, TGF-β induced SMAD2 phosphorylation and col-I production. However, in fibroblasts cultured in the joint presence of TGF-β and IL-17A, SMAD2 phosphorylation was decreased by 0.6-folds (P = 0.022) when compared to that induced by TGF-β alone. Remarkably, in this condition, the production of col-I and fibronectin was significantly decreased in both HD and SSc. Thus, IL-17A and TGF-β reciprocally influence each other effector functions in fibroblasts. Intracellular molecular switches may favor synergic or antagonistic activities, which are revealed by specific readouts. The implications of these data in the context of SSc are far reaching, particularly in terms of therapeutic approaches since IL-6, IL-17A, and TGF-β are all putative targets of treatment.

Possible role of adipocytokines in systemic sclerosis–associated small pericardial effusion

Introduction:

Pericardial effusion is a common manifestation of systemic sclerosis, but its pathogenesis has been poorly investigated. Adipokines and interleukins may play a role in the pathophysiology of pericardial effusion. This study aimed at evaluating serum levels of adipokines and interleukins in systemic sclerosis patients with and without pericardial effusion.

Methods:

A total of 87 systemic sclerosis patients (age 52.6 ± 14 years; disease duration 8.2 ± 6.7 years) were recruited in this study. Demographics, body mass index, and clinical characteristics were recorded in each patient. Pericardial effusion was considered pathologic when ≥50 mL was detected by echocardiography. Serum levels of adiponectin, leptin, resistin, visfatin, tumor necrosis factor-α, interferon-γ, interlueukin-2, interlueukin-10, and interlueukin-17 were measured using Multiplex Immunoassay (Bioplex 200 System).

Results:

In all, 11 (13%) systemic sclerosis patients had pericardial effusion. Systemic sclerosis patients with and without pericardial effusion did not differ in age, sex, and body mass index. Systemic sclerosis patients with pericardial effusion had significantly higher levels of visfatin (median/interquartile range: 1546 pg/mL (interquartile range: 8590) vs 388 pg/mL (interquartile range: 103), p = 0.03) and interlueukin-17 (1.33 pg/mL (interquartile range: 3.5) vs 0.05 pg/mL (interquartile range: 0.56), p = 0.04), but lower levels of adiponectin (2,845,000 pg/mL (interquartile range: 4,132,900) vs 5,272,100 pg/mL (interquartile range 8,243,600), p = 0.02) than patients without pericardial effusion. Interstitial lung disease, pulmonary arterial hypertension, and “limited” or “diffuse” cutaneous subset did not correlate to adipokines or interleukin levels.

Conclusion:

Visfatin and adiponectin may play an important role in the pathogenesis of systemic sclerosis–related pericardial effusion. Further longitudinal studies are needed to unravel a possible role of these molecules as biomarkers of pericardial effusion in systemic sclerosis patients.

Add-on tocilizumab versus conventional treatment for systemic sclerosis, and cytokine analysis to identify an endotype to tocilizumab therapy

OBJECTIVES

To evaluate the anti-interleukin (IL)-6 receptor antibody tocilizumab (TCZ) as a treatment of systemic sclerosis (SSc), a randomised parallel group study was conducted, and compared their results and baseline cytokine/chemokine profiles.

METHODS

Patients were assigned to a TCZ add-on group (TCZ group, n = 7) and a conventional therapy group (Conv group, n = 6). TCZ (8 mg/kg/month) for 6 months, and the modified Rodnan total skin score (mRSS) were used to compare the efficacy. The association of medical history, baseline pulmonary function tests, blood cell counts, serum C-reactive protein (CRP) and 26 cytokines/chemokines and decrease in mRSS were analysed.

RESULTS

The mean change in mRSS was larger in the TCZ group (6.3) than in the Conv group (3.4), but the difference was not statistically significant because of high variance in the TCZ group. Patients with shorter disease histories and higher CRP had larger decreases in mRSS, and the decrease in mRSS was negatively correlated with IL-13 and C-C motif chemokine ligand (CCL)5.

CONCLUSION

Although significant between-group differences were not observed, some patients had a decrease in mRSS. Short disease duration, high CRP, low IL-13 and low CCL5 may represent an SSc endotype responsive to TCZ therapy.

Is there a role for IL-17 in the pathogenesis of systemic sclerosis?

In systemic sclerosis (SSc) immuno-inflammatory events are central to disease development. Amongst other mediators of inflammation, interleukin 17 (IL-17) and Th17 cells have been reported to be increased in the peripheral blood and target organs including involved skin in SSc. They participate and amplify inflammatory responses by inducing the production of cytokines such as IL-6, chemokines such as CCL2 and CXCL8 (IL-8), matrix metalloproteinases-1, -2, -9 and the expression of adhesion molecules in stromal cells including fibroblasts and endothelial cells. In this respect, IL-17 and Th17 cells behave paradigmatically as documented in other autoimmune pathological conditions or infectious diseases. In experimental animal models of skin and lung fibrosis, IL-17 indirectly enhances the fibrotic process by favoring further inflammation by recruiting inflammatory cells, by activating and/or stimulating the production of TGF-β and other pro-fibrotic mediators, by inhibiting autophagy. Whether the findings generated in animal models of fibrosis can be translated to human SSc is unproven. Furthermore, it is controversial whether IL-17 directly promotes the transdifferentiation of human fibroblasts into myofibroblasts and enhances collagen production, with most of the available evidence against this possibility. The reductionist approach in which fibroblast in monolayers are cultured in plastic dishes under the influence of IL-17 limits the relevance of these findings. Further in vitro/ex vivo models with human tissues are being developed to investigate the real effect of IL-17 on extracellular matrix deposition, since agents blocking IL-17 are available for the clinic and it will be important to know whether their use in SSc would be beneficial or detrimental.

IL-17 and related cytokines involved in systemic sclerosis: Perspectives

Systemic sclerosis (SSc) is a multisystemic, complex, and rare disease of connective tissue, with high morbidity and mortality, and without specific treatment. The disease is characterized by three main principles: vascular disease, autoantibody production and inflammation, and fibrosis. Since it is well defined that SSc is characterized by elevated production of TGF-β, IL-6, and IL-1, all of them cytokines related to Th17 differentiation, the hypothesis is that this disease may be strongly related to a polarization of the immune response towards the Th17 pathway. Considering the importance of a better understanding of the pathophysiology of Th17 pathway in SSc, this article aims to propose an update for a better understanding of current knowledge on main cytokines secreted by the Th17 cells (IL-17 A, IL-21, and IL-22) and the future prospects in the current disease.

Biomarkers in connective tissue diseases

Autoimmune connective tissue diseases are clinically variable, making biomarkers desirable for assessing future disease risk, supporting early and accurate diagnosis, monitoring disease activity and progression, selecting therapeutics, and assessing treatment response. Because of their correlations with specific clinical characteristics and often with disease progression, autoantibodies and other soluble mediators are considered potential biomarkers. Additional biomarkers might reflect downstream pathologic processes or appear because of ongoing inflammation and damage. Because of overlap between diseases, some biomarkers have limited specificity for a single autoimmune connective tissue disease. This review describes select current biomarkers that aid in the diagnosis and treatment of several major systemic autoimmune connective tissue disorders: systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, and anti-neutrophil cytoplasmic antibody-associated vasculitides. Newly proposed biomarkers that target various stages in disease onset or progression are also discussed. Newer approaches to overcome the diversity observed in patients with these diseases and to facilitate personalized disease monitoring and treatment are also addressed.

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.

Corticosteroid inhibits chemokines production in systemic sclerosis patients

In this study, we evaluated glucocorticoids (GC) effects on cytokine/chemokine levels in serum samples and peripheral blood mononuclear cell (PBMC) production from systemic sclerosis (SSc) patients. We evaluated cytokine and chemokine levels in serum samples from SSc patients taking or not taking systemic glucocorticoids. PBMCs response to methylprednisolone (MP) was examined from 15 SSc patients and 8 healthy control subjects following PBMC stimulation with anti-CD3/CD28. Cytokine (IFN-γ, TNF, IL-2, IL-4, IL-6, IL-10, and IL-17A) and chemokine (CXCL8/IL-8, CCL5/RANTES, CXCL9/MIG, CCL2/MCP-1, and CXCL10/IP-10) levels were quantified in serum and in PBMC culture supernatants by CBA or ELISA. Compared with patients not taking corticosteroids, we did not observe any significant differences in cytokines/chemokines serum levels in patients using systemic corticosteroids. After stimulation with anti-CD3/CD28, PBMCs treated with MP (100μM), showed a significant reduction of CCL2/MCP-1 (p=0.001), CCL5/RANTES (p=0.04), and CXCL8/IL-8 (p=0.003) levels in SSc patients. In PBMC from healthy controls, we observed decreased IFN-γ, TNF, IL-2, and IL-10 levels after MP treatment, compared with stimulated condition (p<0.01 for all). However in SSc patients, we did not find any significant reduction in these cytokine levels after MP treatment. In conclusion, CCL2/MCP-1, CCL5/RANTES, and CXCL8/IL-8 are chemokines that are potentially modulated by corticosteroids in vitro in SSc patients, but no effect was observed on IL-2, IL-4, IL-6, IL-10, IL-17A, TFN, and IFN-γ secretion. These results suggest a potential effect of GCs on SSc treatment and may reflect the benefit of their use in some patients.

Interleukin-6 and Related Proteins as Biomarkers in Systemic Sclerosis

The search for biomarkers in systemic sclerosis (SSc) is driven by a goal to stratify patients, identify potential subgroups for treatment, and help assess response to therapy. Emerging evidence indicates that interleukin-6 (IL-6) and some family members are key biomarkers involved in SSc pathogenesis and therefore suitable targets for therapy. Recent studies evaluating IL-6 and its canonical Janus kinase/signal transducers and activators of transcription downstream pathways in modulating fibrotic response and immune cell function suggest a pivotal role for IL-6 in SSc pathogenesis. Although the significance and effect of local tissue expression of IL-6 and its family members are less well established, high levels of circulating IL-6 may identify subgroups of patients with early-stage disease, particularly those at risk for progressive lung fibrosis. In addition, higher disease activity may portend poor prognostic outcome in terms of survival and skin disease. Longitudinal assessment of serum levels of IL-6 and its signaling associates may prove valuable in monitoring response to treatment. As an IL-6–dependent surrogate marker, C-reactive protein may assist cohort enrichment if targeted treatment for IL-6 demonstrates efficacy, especially in subgroups with high IL-6 levels. Although IL-6 appears to be a key factor in the hierarchy of the complex network of disease-associated molecules, the systemic or autocrine/paracrine manner in which IL-6 asserts its profibrotic effects—particularly its interaction with other key pathogenic factors in SSc—is unknown. Ongoing clinical trials will help to delineate the mechanisms of IL-6 in SSc pathogenesis and inform on the role of these biomarkers.

CCL2 in the Circulation Predicts Long-Term Progression of Interstitial Lung Disease in Patients With Early Systemic Sclerosis: Data From Two Independent Cohorts

OBJECTIVE

There are few clinical predictors of the progression of systemic sclerosis (SSc)-related interstitial lung disease (ILD). The purpose of this study was to examine the predictive significance of key cytokines for long-term progression of ILD and survival in 2 independent cohorts of patients with early SSc.

METHODS

Plasma levels of 11 Th1/Th2 cytokines (interleukin-1β [IL-1β], IL-5, IL-6, IL-8, IL-10, IL-12, IL-13, tumor necrosis factor, CCL2, interferon-inducible T cell α chemoattractant, and interferon-γ-inducible 10-kd protein) were measured in 266 patients with early SSc in the Genetics versus Environment in Scleroderma Outcome Study (GENISOS) discovery cohort. Levels of CCL2, IL-10, and IL-6 were measured in 171 patients with early SSc in the Canadian Scleroderma Research Group (CSRG) replication cohort. The primary outcome measure was a decline in the forced vital capacity percent predicted (FVC%) value over time. A joint analysis of longitudinal FVC% values and survival was performed.

RESULTS

After adjustment for age, sex, and ethnicity, CCL2 and IL-10 were found to be significant predictors of ILD progression in the discovery cohort. Higher CCL2 levels predicted a faster decline in FVC% values (b = -0.57, P = 0.032), while higher IL-10 levels predicted a slower decline (b = 0.26, P = 0.01). A higher CCL2 value was also predictive of poorer survival (hazard ratio 1.76, P = 0.030). In the CSRG replication cohort, higher CCL2 levels predicted a faster decline in FVC% values (b = -0.58, P = 0.038), but neither IL-10 nor IL-6 had predictive significance. A higher CCL2 level also predicted poorer survival (hazard ratio 3.89, P = 0.037).

CONCLUSION

Higher CCL2 levels in the circulation were predictive of ILD progression and poorer survival in patients with early SSc, findings that support the notion that CCL2 has a role as a biomarker and potential therapeutic target.

Effect of the anticoagulant, storage time and temperature of blood samples on the concentrations of 27 multiplex assayed cytokines - Consequences for defining reference values in healthy humans

Cytokines are potentially useful biomarkers of sepsis and other inflammatory conditions. Many cytokines can be released by leukocytes and platelets after sampling. The sampling and processing techniques are consequently critically important to measure the in vivo levels. We therefore examined the effects of four different anticoagulants, EDTA, citrate, lepirudin, heparin compared to serum, on the levels of 27 different cytokines. The effects of storage temperature, freezing and thawing on the plasma cytokines were examined. Cytokines were analysed using a multiplex immunoassay. The cytokine levels in serum were significantly higher compared with plasma, consistent with release of cytokines in vitro during coagulation. In general, the lowest values for all cytokines were found in EDTA samples, stored on crushed ice, centrifuged within 4h and thereafter stored at -80°C. MCP-1 and MIP-1β levels were highest in heparin plasma and storage of blood for up to 4h at room temperature significantly increased the interleukin (IL)-2, IL-6, IL-8, IFN-γ and GM-CSF levels in EDTA plasma, indicating post-sampling release. In contrast, the IP-10 levels were unaffected by sample storage at both temperatures. Our results indicate that the cytokines were more stable in plasma than in whole blood after sampling. Thus, cytokines should be analysed in EDTA plasma samples stored on ice and centrifuged within 4h. Based on these data, the reference ranges of 27 cytokines in EDTA plasma in 162 healthy human donors were calculated.