Demonstration of interleukin-2, interleukin-4 and interleukin-6 in sera from patients with localized scleroderma

Type-2 immunity associated with type-1 related skin inflammatory diseases: friend or foe?

Chronic inflammatory skin diseases are multifactorial diseases that combine genetic predisposition, environmental triggers, and metabolic disturbances associated with abnormal immune responses. From an immunological perspective, the better understanding of their physiopathology has demonstrated a large complex network of immune cell subsets and related cytokines that interact with both epidermal and dermal cells. For example, in type-1-associated diseases such as alopecia areata, vitiligo, and localized scleroderma, recent evidence suggests the presence of a type-2 inflammation that is well known in atopic dermatitis. Whether this type-2 immune response has a protective or detrimental impact on the development and chronicity of these diseases remains to be fully elucidated, highlighting the need to better understand its involvement for the management of patients. This mini-review explores recent insights regarding the potential role of type-2-related immunity in alopecia areata, vitiligo, and localized scleroderma.

Unravelling morphoea aetiopathogenesis by next-generation sequencing of paired skin biopsies

BACKGROUND

Morphoea can have a significant disease burden. Aetiopathogenesis remains poorly understood, with very limited existing genetic studies. Linear morphoea (LM) may follow Blascho's lines of epidermal development, providing potential pathogenic clues.

OBJECTIVE

The first objective of this study was to identify the presence of primary somatic epidermal mosaicism in LM. The second objective was tTo explore differential gene expression in morphoea epidermis and dermis to identify potential pathogenic molecular pathways and tissue layer cross-talk.

METHODOLOGY

Skin biopsies from paired affected and contralateral unaffected skin were taken from 16 patients with LM. Epidermis and dermis were isolated using a 2-step chemical-physical separation protocol. Whole Genome Sequencing (WGS; n = 4 epidermal) and RNA-seq (n = 5-epidermal, n = 5-dermal) with gene expression analysis via GSEA-MSigDBv6.3 and PANTHER-v14.1 pathway analyses, were performed. RTqPCR and immunohistochemistry were used to replicate key results.

RESULTS

Sixteen participants (93.8% female, mean age 27.7 yrs disease-onset) were included. Epidermal WGS identified no single affected gene or SNV. However, many potential disease-relevant pathogenic variants were present, including ADAMTSL1 and ADAMTS16. A highly proliferative, inflammatory and profibrotic epidermis was seen, with significantly-overexpressed TNFα-via-NFkB, TGFβ, IL6/JAKSTAT and IFN-signaling, apoptosis, p53 and KRAS-responses. Upregulated IFI27 and downregulated LAMA4 potentially represent initiating epidermal 'damage' signals and enhanced epidermal-dermal communication. Morphoea dermis exhibited significant profibrotic, B-cell and IFN-signatures, and upregulated morphogenic patterning pathways such as Wnt.

CONCLUSION

This study supports the absence of somatic epidermal mosaicism in LM, and identifies potential disease-driving epidermal mechanisms, epidermal-dermal interactions and disease-specific dermal differential-gene-expression in morphoea. We propose a potential molecular narrative for morphoea aetiopathogenesis which could help guide future targeted studies and therapies.

Morphea: The 2023 update

Morphea, also known as localized scleroderma, is a chronic inflammatory connective tissue disorder with variable clinical presentations, that affects both adults and children. It is characterized by inflammation and fibrosis of the skin and underlying soft tissue, in certain cases even of the surrounding structures such as fascia, muscle, bone and central nervous system. While the etiology is still unknown, many factors may contribute to disease development, including genetic predisposition, vascular dysregulation, T_H1/T_H2 imbalance with chemokines and cytokines associated with interferon-γ and profibrotic pathways as well as certain environmental factors. Since the disease may progress to permanent cosmetic and functional sequelae, it is crucial to properly assess the disease activity and to initiate promptly the adequate treatment, thus preventing subsequent damage. The mainstay of treatment is based on corticosteroids and methotrexate. These, however, are limited by their toxicity, especially if applied long-term. Furthermore, corticosteroids and methotrexate often do not sufficiently control the disease and/or the frequent relapses of morphea. This review presents the current understanding of morphea by discussing its epidemiology, diagnosis, management and prognosis. In addition, it will describe recent pathogenetic findings, thus proposing potential novel targets for therapeutic development in morphea.

Novel role of long non-coding RNAs in autoimmune cutaneous disease

Systemic autoimmune rheumatic diseases (SARDs) are a heterogeneous group of chronic multisystem inflammatory disorders that are thought to have a complex pathophysiology, which is not yet fully understood. Recently, the role of non-coding RNAs, including long non-coding RNA (lncRNA), has been of particular interest in the pathogenesis of SARDs. We aimed to summarize the potential roles of lncRNA in SARDs affecting the skin including, systemic sclerosis (SSc), dermatomyositis (DM) and cutaneous lupus erythematosus (CLE). We conducted a narrative review summarizing original articles published until July 19, 2021, regarding lncRNA associated with SSc, DM, and CLE. Several lncRNAs were hypothesized to play an important role in disease pathogenesis of SSc, DM and CLE. In SSc, Negative Regulator of IFN Response (NRIR) was thought to modulate Interferon (IFN) response in monocytes, anti-sense gene to X-inactivation specific transcript (TSIX) to regulate increased collagen stability, HOX transcript antisense RNA (HOTAIR) to increase numbers of myofibroblasts, OTUD6B-Anti-Sense RNA 1 to decrease fibroblast apoptosis, ncRNA00201 to regulate pathways in SSc pathogenesis and carcinogenesis, H19X potentiating TGF-β-driven extracellular matrix production, and finally PSMB8-AS1 potentiates IFN response. In DM, linc-DGCR6-1 expression was hypothesized to target the USP18 protein, a type 1 IFN-inducible protein that is considered a key regulator of IFN signaling. Additionally, AL136018.1 is suggested to regulate the expression Cathepsin G, which increases the permeability of vascular endothelial cells and the chemotaxis of inflammatory cells in peripheral blood and muscle tissue in DM. Lastly, lnc-MIPOL1-6 and lnc-DDX47-3 in discoid CLE were thought to be associated with the expression of chemokines, which are significant in Th1 mediated disease. In this review, we summarize the key lncRNAs that may drive pathogenesis of these connective tissue diseases and could potentially serve as therapeutic targets in the future.

Serum Levels of Selected IL-1 Family Cytokines in Patients with Morphea

Morphea/localized scleroderma (LoS) represents an inflammatory-sclerotic skin disease, the pathogenesis of which is not fully understood. Given the important role of IL-1 family cytokines in the development and therapy of inflammatory diseases, including systemic sclerosis, we analyzed the clinical significance of serum levels of selected IL-1 family cytokines (IL-1α, IL-1β, IL-18, IL-33, IL-37 and IL-38) in LoS patients (n = 30) using the standardized disease assessment tools and comparison to healthy controls (n = 28). We also compared the pre- and post-treatment concentrations, i.e., before and after systemic (glucocorticosteroids and/or methotrexate) and/or topical (topical glucocorticosteroids and/or calcineurin inhibitors). Our findings did not reveal significant differences in baseline IL-1α, IL-1β, IL-18, IL-33, IL-37 and IL-38 levels between LoS group and HCs; however, after treatment, there were marked changes in concentrations of IL-1α and IL-33 within LoS group as well as in comparison to HCs. We also found significant negative correlations between PGA-A and IL-1α concentration as well as between mLoSSI and IL-1α after treatment. Furthermore, we showed an inverse correlation of baseline IL-1β levels with mLoSSI scores of borderline significance. We believe that IL-1α and IL-33, as well as Il-1β, may be potential mediators and targets of interest in LoS.

Efficacy and Safety of Ablative Fractional Laser-Assisted Delivery of Methotrexate in Adults with Localized Scleroderma: A Randomized and Controlled Clinical Trial

Localized scleroderma (LS) is an autoimmune disease with sclerosis of the skin as the main manifestation. Currently, there is no specific treatment for LS. The effectiveness of ablative fractional laser (AFL) therapy for LS has been demonstrated in several studies. Combining ablative fractional Er:YAG laser therapy with topical methotrexate may yield therapeutic benefits for patients with LS. To compare the efficacy and safety of AFL-assisted delivery of methotrexate in adults with LS, we randomly divided patients into an AFL therapy group and an ablative fractional laser-assisted delivery of methotrexate (AFL+MTX) therapy group. Laser and assisted drug delivery treatment were given every four weeks for four months, and 22 patients completed the trial. Ultrasound measurements of dermal thickness and histological fibrosis degree and the Localized Scleroderma Cutaneous Assessment Tool (LoSCAT) score were used to assess therapeutic effects. Treatment results showed that both AFL and AFL-assisted methotrexate delivery were effective in treating LS, and the laser combined with methotrexate therapy was more effective in improving clinical appearance (p value = 0.042) and dermal thickness (p value = 0.016). No serious adverse reaction occurred in either group. In conclusion, AFL and assisted delivery of methotrexate are effective and safe treatments for LS.

Fractional Ablative Carbon Dioxide Lasers for the Treatment of Morphea: A Case Series and Literature Review

Morphea is an inflammatory, immune-mediated disease of unknown aetiology. It is characterised by excessive collagen deposition, which leads to the hardening of the dermis and subcutaneous tissues. The disease is associated with cosmetic and functional impairment, which can affect the patients’ quality of life. Fractional ablative lasers (FALs) are currently used for the treatment of many skin diseases that are connected to tissue fibrosis due to the low risk of side effects and their great effectiveness. This study aimed to improve the aesthetic defects that are caused by morphea lesions and assess the efficacy and safety of FAL use in this indication. We also reviewed the literature on the subject. We present four women with biopsy-proven morphea, manifesting as hyperpigmented plaques and patches. One of the patients additionally had morphea-related knee joint contracture. Four fractional CO2 laser sessions, separated by one-month intervals, were performed and produced significant improvements in dyspigmentation and induration. An improved elasticity and a decrease in dermal thickness were also obtained, as proven by measurements using DermaLab Combo. No severe adverse effects occurred. Based on these cases presented by the authors, fractional CO2 lasers appear to be an effective, well-tolerated, and safe therapeutic option for patients suffering from morphea.

Case Report: Bullous Pemphigoid Associated With Morphea and Lichen Sclerosus: Coincidental Diseases or Pathogenetic Association?

Bullous pemphigoid (BP) represents the most common autoimmune bullous disease and is characterized by IgG autoantibodies targeting collagen XVII (BP180). BP has reportedly been occurred in association with other inflammatory skin diseases. Here, we describe the unusual occurrence of BP in a female patient with a concomitant history of generalized morphea (localized scleroderma, LoS) and cutaneous and genital lichen sclerosus (LiS). The occurrence of BP was associated with elevated serum levels of anti-BP180 IgG autoantibodies, which decreased upon clinical remission. Autoimmune bullous diseases and sclerosing dermatitis are immunologically distinct entities, whose association has been rarely described. In this study, we provide a literature review on cases of BP developed in patients with either LoS or LiS. Further, we discussed immunological mechanisms which may have favored the emergence of BP in our patient.

Therapeutic and Reconstructive Management Options in Scleroderma (Morphea) en Coup de Sabre in Children and Adults. A Systematic Literature Review

Scleroderma (morphea) en coup de sabre is a localized subtype restricted to the frontoparietal region of the head. Current treatment paradigms rely on low levels of evidence, primarily case reports and case series-supported by expert opinions. The aim of this article was to systematically analyze current data related to the treatment of localized scleroderma en coup de sabre. The databases Scopus, PubMed, and EBSCO were searched for all reports discussing the treatment of localized scleroderma en coup de sabre. The keywords en coup de sabre, “facial linear scleroderma”, and “morphea linearis”, combined with “treatment” or “therapy” were used as search terms. A total of 34 articles analyzed treatment outcomes for patients with localized scleroderma en coup de sabre including 4 retrospective cohort studies, 2 prospective cohort studies, 4 case series, and 24 case reports, representing a total of 69 patients (38 children and 31 adults). Methotrexate was the most commonly investigated treatment (26 patients) with a highest response rate (26/26, 100%). Other treatments included systemic glucocorticosteroids (nine patients), followed by UVA1 (four patients), mycophenolate mofetil (two patients), hydroxychloroquine (five patients), abatacept (two patients), tocilizumab (three patients), cyclosporine (one patient), interferon gamma (one patient), PUVA therapy (two patients), NB-UVB therapy (one patient), and pulsed dye laser (one patient). Reconstructive and surgery treatment was successfully used for lesions with settled disease activity to improve the cosmetic aspect of the lesions. Conclusion: methotrexate is the most often-studied treatment and reported good clinical outcomes in children and adults with localized scleroderma en coup de sabre.

Transcriptomic Evaluation of Juvenile Localized Scleroderma Skin With Histologic and Clinical Correlation

OBJECTIVE

Juvenile localized scleroderma (LS) is an autoimmune disease of the skin whose pathogenesis is not well understood due to the rarity of the disease. This study was undertaken to determine the skin transcriptome in skin biopsy tissue from children with juvenile LS compared to pediatric healthy controls, with identification of significant molecular targets using RNA sequencing (RNA-Seq). In this study, differentially expressed genes (DEGs) were assessed for correlations with histopathologic and clinical features in children with juvenile LS, and were used to group the children into distinct genetic clusters based on immunophenotype.

METHODS

RNA-Seq was performed on sections of paraffin-embedded skin tissue obtained from 28 children with juvenile LS and 10 pediatric healthy controls. RNA-Seq was carried out using an Illumina HTS TruSeq RNA Access library prep kit, with data aligned using STAR and data analysis using a DESeq2 platform. A standardized histologic scoring system was used to score skin sections for the severity of inflammation and levels of collagen deposition. Histologic scoring was completed by 2 pathologists who were blinded with regard to the status of each sample. Spearman's rank correlation coefficients were used to assess significant correlations between DEG expression profiles and skin histologic findings in patients with juvenile LS.

RESULTS

We identified 589 significant DEGs in children with juvenile LS as compared to healthy controls. Hierarchical clustering was used to demonstrate 3 distinct juvenile LS immunophenotype clusters. The histologic scores of skin inflammation (based on numbers and categories of inflammatory cell infiltrates) were significantly correlated with the expression levels of HLA-DPB1, HLA-DQA2, HLA-DRA, and STAT1 genes (r_s > 0.5, P < 0.01). Collagen thickness correlated with the expression levels of collagen organization genes as well as with genes found to be correlated with the severity of inflammation, including genes for major histocompatibility complex (MHC) class I, MHC class II, and interferon-γ signaling.

CONCLUSION

Among children with juvenile LS, 3 distinct genetic signatures, or clusters, were identified. In one cluster, inflammation-related pathways were up-regulated, corresponding to the histologic skin inflammation score. In the second cluster, fibrosis-related pathways were up-regulated. In the third cluster, gene expression in the skin corresponded to the patterns seen in healthy controls. Up-regulation of HLA class II genes was observed within the first cluster (characterized by predominant inflammation), a feature that has also been observed in the peripheral blood of patients with morphea and in the skin of patients with systemic sclerosis.

Case Report: Pansclerotic Morphea-Clinical Features, Differential Diagnoses and Modern Treatment Concepts

Pansclerotic morphea (PSM) is a rare skin disease characterized by progressive stiffening of the skin with or without the typical superficial skin changes usually seen in morphea (localized scleroderma). Standard therapy, consisting of a combination of systemic glucocorticoids and methotrexate or mycophenolate mofetil, does rarely stop disease progression, which may lead to severe cutaneous sclerosis and secondary contractures. Little is known about the efficacy of newer biologicals such as abatacept, a fusion protein antibody against CTLA-4, or tocilizumab, a fully humanized IL-6R antibody, in the treatment of this pathology. We present the case of an 8 years old girl with an unusual, progressive stiffening of the skin, which was eventually diagnosed as pansclerotic morphea. A treatment with systemic glucocorticoids and methotrexate combined with tocilizumab led to a good clinical response within 2 months after initiation. In this paper, we discuss differential diagnoses to be considered and this new promising treatment option based on a case review of the literature.

Morphea: progress to date and the road ahead

Morphea is a rare autoimmune condition causing inflammation and sclerosis of the skin and underlying soft tissue. It is characterized by periods of activity (inflammation admixed with fibrosis), ultimately resulting in permanent damage (pigment change and tissue loss). Damage resulting from unchecked activity can lead to devastating, permanent cosmetic and functional sequelae including hair loss; cutaneous, soft tissue and bony atrophy; joint contractures; and growth restriction of the affected body site in children. This makes the early identification of activity and initiation of appropriate treatment crucial to limiting damage in morphea. To this end, recent investigative work has focused on validation of clinical, biomarker, imaging, and histologic outcomes aimed at accurately quantifying activity and damage. Despite promising results, further work is needed to better validate these measures before they can be used in the clinic and research settings. Although there has been recent approval of less toxic, targeted therapies for many inflammatory skin conditions, none have been systematically investigated in morphea. The mainstays of treatment for active morphea are corticosteroids and methotrexate. These are often limited by substantial toxicity. The paucity of new treatments for morphea is the result of a lack of studies examining its pathogenesis, with many reviews extrapolating from research in systemic sclerosis. Recent studies have demonstrated the role of dysregulated immune and fibrotic pathways in the pathogenesis of morphea, particularly interferon (IFN) gamma related pathways. Active morphea lesions have been found to display an inflammatory morphea signature with CXCR3 receptor ligands, as well as a distinct fibrotic signature reflecting fibroblast activation and collagen production. CXCL9 and 10 have been associated with increased measures of disease activity. While immune dysfunction is thought to play the primary role in morphea pathogenesis, there are other factors that may also contribute, including genetic predisposition, environmental factors, and vascular dysregulation. There remains an essential need for further research to elucidate the pathogenesis of morphea and the mode of action of dysregulated upstream and downstream immune and fibrotic pathways. These studies will allow for the discovery of novel biomarkers and targets for therapeutic development.

Genetic Signatures From RNA Sequencing of Pediatric Localized Scleroderma Skin

The purpose of this study was to explore the skin transcriptional profile in pediatric localized scleroderma (LS) to provide a better understanding of the altered immune and fibrotic pathways promoting disease. LS is a progressive disease of the skin and underlying tissue that causes significant functional disability and disfigurement, especially in developing children. RNA sequencing (RNAseq) technology allows for improved understanding of relevant cellular expression through transcriptome analysis of phases during LS disease progression (more active/inflammatory vs. inactive/fibrotic) and also permits the use of RNA extracted from existing paraffin-embedded skin tissue, which is important in pediatrics. A strong correlation was observed between the comparison of genes expressed between fresh (RNAlater) and paraffinized skin in healthy and LS subjects, supporting the use of paraffinized tissue. LS gene signatures compared to healthy controls showed a distinct expression of an inflammatory response gene signature (IRGS) composed of IFNγ-, IFNα-, and TNFα-associated genes. GSEA^© enrichment analysis showed that the IRGS, including interferon-inducible chemokines such as CXCL9, CXCL10, CXCL11, and IFNγ itself, was more highly expressed in LS patients with more inflammatory lesions. The use of paraffinized skin for sequencing was proven to be an effective substitute for fresh skin by comparing gene expression profiles. The prevalence of the IFNγ signature in the lesion biopsies of active LS patients indicates that these genes reflect clinical activity parameters and may be the promoters of early, inflammatory disease.

Clinical characteristics and histopathologic changes of morphea: A single-center, retrospective study of 137 patients

BACKGROUND

The clinicopathologic correlations and prognostic risk factors for refractory disease in morphea (localized scleroderma) are poorly described.

OBJECTIVE

To investigate the association between clinical characteristics and histopathologic features of morphea and identify risk factors for refractory disease.

METHODS

We retrospectively reviewed the clinical and histopathologic features, treatment regimens, and clinical responses for 137 patients with biopsy-proven morphea from January 2008 to May 2019. Multivariate analysis was conducted to identify factors associated with poor treatment response.

RESULTS

We detected associations between the pattern and degree of sclerosis and the anatomic site of the lesion, as well as between severe inflammation and concomitant autoimmune disease. Additionally, both bottom-heavy sclerosis and increased inflammation were associated with functional limitations/clinical symptoms. Based on our multivariate analysis, we found that increased risk of poor treatment response was correlated with tissue eosinophils and basal pigmentation.

LIMITATIONS

This was a single-center retrospective study.

CONCLUSION

Skin biopsy samples could show specific features of morphea, including eosinophil infiltration and basal pigmentation, which may indicate the need for aggressive treatment and frequent monitoring.

Update on the Systemic Treatment of Pediatric Localized Scleroderma

Juvenile localized scleroderma (jLS) is an orphan disease that can lead to cosmetic disfiguration and orthopedic problems. Two recent publications review the current recommendations regarding diagnosis, assessment, follow up and treatment of pediatric localized scleroderma cases, both of which suggest the Localized Scleroderma Cutaneous Assessment Tool as an important instrument to assess activity and damage. This review focuses on the systemic treatment of jLS. Systemic treatment includes synthetic and biologic disease-modifying antirheumatic drugs. Systemic therapy is indicated if the lesion crosses any joint, or leads to potential cosmetic disfiguration or orthopedic problems. The only controlled trial of systemic treatment has shown the efficacy of methotrexate, which is the first choice of treatment. It appears superior to phototherapy according to a recently published meta-analysis. In case of methotrexate intolerance, mycophenolate mofetil is an option. In case of methotrexate nonresponse, addition of mycophenolate mofetil, tocilizumab or abatacept seems to be effective. Future treatment options derived and extrapolated from adult trials regarding treatment of skin involvement of systemic scleroderma or fibrosis are promising, as the final pathway in the skin seems to be similar in both diseases.

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.

Immunopathogenesis of Pediatric Localized Scleroderma

Localized scleroderma (LS) is a complex disease characterized by a mixture of inflammation and fibrosis of the skin that, especially in the pediatric population, also affects extracutaneous tissues ranging from muscle to the central nervous system. Although developmental origins have been hypothesized, evidence points to LS as a systemic autoimmune disorder, as there is a strong correlation to family history of autoimmune disease, the presence of shared HLA types with rheumatoid arthritis, high frequency of auto-antibodies, and elevated circulating chemokines and cytokines associated with T-helper cell, IFNγ, and other inflammatory pathways. This inflammatory phenotype of the peripheral blood is reflected in the skin via microarray, RNA Sequencing and tissue staining. Research is underway to identify the key players in the pathogenesis of LS, but close approximation of inflammatory lymphocytic and macrophage infiltrate with collagen and fibroblasts deposition supports the notion that LS is a disease of inflammatory driven fibrosis. The immune system is dynamic and undergoes changes during childhood, and we speculate on how the unique features of the immune system in childhood could potentially contribute to some of the differences in LS between children and adults. Interestingly, the immune phenotype in pediatric LS resembles to some extent the healthy adult cellular phenotype, possibly supporting accelerated maturation of the immune system in LS. We discuss future directions in better understanding the pathophysiology of and how to better treat pediatric LS.

European Dermatology Forum S1-guideline on the diagnosis and treatment of sclerosing diseases of the skin, Part 1: localized scleroderma, systemic sclerosis and overlap syndromes

The term 'sclerosing diseases of the skin' comprises specific dermatological entities, which have fibrotic changes of the skin in common. These diseases mostly manifest in different clinical subtypes according to cutaneous and extracutaneous involvement and can sometimes be difficult to distinguish from each other. The present guideline focuses on characteristic clinical and histopathological features, diagnostic scores and the serum autoantibodies most useful for differential diagnosis. In addition, current strategies in the first- and advanced-line therapy of sclerosing skin diseases are addressed in detail. Part 1 of this guideline provides clinicians with an overview of the diagnosis and treatment of localized scleroderma (morphea), and systemic sclerosis including overlap syndromes of systemic sclerosis with diseases of the rheumatological spectrum.

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.

Contribution of Interleukin-6 to the Pathogenesis of Systemic Sclerosis

Systemic sclerosis (SSc) is a connective tissue disease of unknown etiology, manifesting in patients as tissue fibrosis, endothelial dysfunction, and inflammation. The disease is characterized by autoantibodies, a hallmark of autoimmunity. Various cytokines and growth factors are elevated in the systemic circulation and fibrotic lesions of patients with SSc. In particular, several studies over the past 2 decades have shown that interleukin-6 (IL-6) appears to be involved in the pathogenesis of SSc. Based on the association between aberrant IL-6 production and tissue fibrosis in patients with SSc, the anti-IL-6 receptor antibody, tocilizumab, is being investigated in clinical trials. This article reviews the biological features of IL-6 and the IL-6 receptor; the role of IL-6 in the pathogenesis of SSc; and the potential for IL-6 inhibition to be used in the treatment of patients with SSc.

The molecular pathogenesis of morphoea: from genetics to future treatment targets

A number of immunoinflammatory and profibrotic mechanisms are recognized in the pathogenesis of broad sclerotic skin processes and, more specifically, morphoea. However, the precise aetiopathogenesis is complex and remains unclear. Morphoea is clinically heterogeneous, with variable anatomical patterning, depth of tissue involvement and sclerotic, inflammatory, atrophic and dyspigmented morphology. Underlying mechanisms determining these reproducible clinical subsets are poorly understood but of great clinical and therapeutic relevance. Regional susceptibility mechanisms (e.g. environmental triggers, mosaicism and positional identity) together with distinct pathogenic determinants (including innate, adaptive and imbalanced pro- and antifibrotic signalling pathways) are likely implicated. In the age of genetic profiling and personalized medicine, improved characterization of the environmental, systemic, local, genetic and immunopathological factors underpinning morphoea pathogenesis may open the door to novel targeted therapeutic approaches.

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.

Localized scleroderma: a review

Localized scleroderma (LoS) comprises a heterogeneous spectrum of fibrotic diseases that primarily affect the skin with inflammation and skin thickening. The extent of skin involvement and manifestation at extra-cutaneous structures characterizes the specific subset. Fat tissue, fascia, and sometimes muscle, and bones might be involved, and in rare cases the central nervous or ocular system.

A worldwide accepted classification system for LoS is still lacking. The latest guidelines have proposed a distinction of limited, generalized, linear, deep, and mixed types. The exact pathophysiology of LoS is not fully understood yet, but it is thought that an externally triggered release of pro-inflammatory cytokines leads to a dysregulation of the connective tissue metabolism.

LoS is diagnosed according to typical clinical features. Further diagnostic procedures are helpful to characterize the subtype and to define the extent of inflammation and fibrosis.

Due to the heterogeneity of LoS, therapeutic strategies should always be selected depending on the respective subtype. The stage of tissue inflammation and sclerosis has to be considered. Treatment options such as topical corticosteroids, calcipotriol, and calcineurin inhibitors as well as phototherapy are well established. In subsets with severe wide-spread skin manifestation and/or extra-cutaneous involvement, methotrexate monotherapy or a combination of methotrexate and systemic corticosteroids need to be considered. Physical treatment should always be added to the topical and systemic treatment to prevent significant disabilities due to LoS. This article provides an updated review on the epidemiology, pathophysiology, clinical classification and treatment options for patients suffering from LoS.

Evaluation of serum concentrations of the selected cytokines in patients with localized scleroderma

Introduction

Localized scleroderma is an autoimmune disease primarily affecting the skin. The cause of disease remains unexplained although environmental factors are implicated, which are likely to be responsible for activation of the endothelium and subsequent inflammation leading to excessive synthesis of collagen and extracellular matrix components.

Aim

To determine concentrations of interleukin (IL)-27, transforming growth factor (TGF)-β1, TGF-β2, IL-6, and sIL-6R in patients with localized scleroderma compared to controls and to assess the relations between their levels and laboratory markers.

Material and methods

The study encompassed 17 females with localized scleroderma (aged 25–67). The control group consisted of 30 age-matched healthy women. The blood was sampled from the basilic vein. Serum levels of cytokines were determined using ELISA.

Results

The TGF-β2 levels were found to be significantly lower in patients with localized scleroderma compared to controls. Concentrations of TGF-β1 were decreased in scleroderma patients when compared to controls but without statistical significance. There were no significant differences in serum IL-6, sIL-6R and IL-27 levels between patients and the control group; however, we found a significant positive correlation between the level of sIL-6 and ESR among subjects with localized scleroderma.

Conclusions

The findings of decreased serum levels of TGF-β1 and TGF-β2 in patients with localized scleroderma demonstrate a possible association of these cytokines with pathogenesis of the disease. The results suggest also that sIL-6R is likely to be involved in inflammation in patients with localized scleroderma.

Systemic sclerosis and localized scleroderma--current concepts and novel targets for therapy

Systemic sclerosis (SSc) is a chronic autoimmune disease with a high morbidity and mortality. Skin and organ fibrosis are key manifestations of SSc, for which no generally accepted therapy is available. Thus, there is a high unmet need for novel anti-fibrotic therapeutic strategies in SSc. At the same time, important progress has been made in the identification and characterization of potential molecular targets in fibrotic diseases over the recent years. In this review, we have selected four targeted therapies, which are tested in clinical trials in SSc, for in depths discussion of their preclinical characterization. Soluble guanylate cyclase (sGC) stimulators such as riociguat might target both vascular remodeling and tissue fibrosis. Blockade of interleukin-6 might be particularly promising for early inflammatory stages of SSc. Inhibition of serotonin receptor 2b signaling links platelet activation to tissue fibrosis. Targeting simultaneously multiple key molecules with the multityrosine kinase-inhibitor nintedanib might be a promising approach in complex fibrotic diseases such as SSc, in which many partially independent pathways are activated. Herein, we also give a state of the art overview of the current classification, clinical presentation, diagnostic approach, and treatment options of localized scleroderma. Finally, we discuss whether the novel targeted therapies currently tested in SSc could be used for localized scleroderma.

Peripheral blood cytokine and chemokine profiles in juvenile localized scleroderma: T-helper cell-associated cytokine profiles

OBJECTIVE

To evaluate peripheral blood T-helper (TH) cell-associated cytokine and chemokine profiles in localized scleroderma (LS), and correlate them with clinical disease features, including disease activity parameters.

METHODS

A 29-plex Luminex platform was used to analyze the humoral profile of plasma samples from 69 pediatric LS patients and 71 healthy pediatric controls. Cytokine/chemokine levels were compared between these two groups and within LS patients, focusing on validated clinical outcome measures of disease activity and damage in LS.

RESULTS

Plasma levels of IP-10, MCP-1, IL-17a, IL-12p70, GM-CSF, PDGF-bb, IFN-α2, and IFN-γ were significantly higher in LS subjects compared to healthy controls. Analysis within the LS group demonstrated IP-10, TNF-α, and GM-CSF correlated with clinical measures of disease activity. Several cytokines/chemokines correlated with anti-histone antibody, while only a few correlated with positive ANA and single-stranded DNA antibody.

CONCLUSION

This is the first time that multiple cytokines and chemokines have been examined simultaneously in LS. In general, a TH1 (IFN-γ) and TH17 (IL-17a) predominance was demonstrated in LS compared to healthy controls. There is also an IFN-γ signature with elevated IP-10, MCP-1, and IFN-γ, which has been previously demonstrated in systemic sclerosis, suggesting a shared pathophysiology. Within the LS patients, those with active disease demonstrated IP-10, TNF-α, and GM-CSF, which may potentially serve as biomarkers of disease activity in the clinical setting.

Major histocompatibility complex class I and class II alleles may confer susceptibility to or protection against morphea: findings from the Morphea in Adults and Children cohort

OBJECTIVE

To determine the HLA class I and class II alleles of the human major histocompatibility complex showing an association with morphea (localized scleroderma) in the Morphea in Adults and Children (MAC) cohort, using a nested case-control association study.

METHODS

Patients with morphea were identified from the MAC cohort, and matched controls were obtained from the National Institutes of Health/National Institute of Arthritis and Musculoskeletal and Skin Diseases Scleroderma Family Registry and DNA Repository and from the Division of Rheumatology at the University of Texas Health Science Center at Houston. HLA class II genotyping and single-strand conformational polymorphism typing were performed to identify HLA-A, B, and C alleles. Associations between HLA class I and class II alleles and morphea, as well as its subphenotypes, were determined.

RESULTS

Two hundred eleven patients with morphea and 726 matched controls were available for HLA class I typing, and 158 patients with morphea and 1,008 matched controls were available for HLA class II typing. The strongest associations were found with DRB1*04:04 (odds ratio [OR] 2.3, 95% confidence interval [95% CI] 1.4-4.0, P = 0.002), and HLA-B*37 conferred the highest OR among the class I alleles (OR 3.2, 95% CI 1.5-6.5, P = 0.001). Comparison of the risk allele profile in this cohort with the risk alleles previously identified in patients with systemic sclerosis, determined using the same methods and same control population, revealed one allele in common, DRB*04:04.

CONCLUSION

These results demonstrate that specific HLA class I and class II alleles are associated with morphea and are also likely to be associated with generalized and linear subtypes of morphea. The morphea-associated alleles are different from those found in scleroderma, suggesting that morphea is immunogenetically distinct. Risk alleles in morphea are also associated with conditions such as rheumatoid arthritis (RA) and other autoimmune conditions. Population-based studies have indicated that patients with RA have an increased risk of morphea, and therefore a common susceptibility allele may be implicated.

Interleukin-6 (IL-6) trans signaling drives a STAT3-dependent pathway that leads to hyperactive transforming growth factor-β (TGF-β) signaling promoting SMAD3 activation and fibrosis via Gremlin protein

Fibrosis is a common and intractable condition associated with various pathologies. It is characterized by accumulation of an excessive amount of extracellular matrix molecules that primarily include collagen type I. IL-6 is a profibrotic cytokine that is elevated in the prototypic fibrotic autoimmune condition systemic sclerosis and is known to induce collagen I expression, but the mechanism(s) behind this induction are currently unknown. Using healthy dermal fibroblasts in vitro, we analyzed the signaling pathways that underscore the IL-6-mediated induction of collagen. We show that IL-6 trans signaling is important and that the effect is dependent on STAT3; however, the effect is indirect and mediated through enhanced TGF-β signaling and the classic downstream cellular mediator Smad3. This is due to induction of the bone morphogenetic protein (BMP) antagonist Gremlin-1, and we show that Gremlin-1 is profibrotic and is mediated through canonical TGF-β signaling.

Updates on morphea: role of vascular injury and advances in treatment

Morphea and systemic sclerosis are fibrosing disorders of the skin that share common inflammatory and immunologic pathways that are responsible for the vascular changes, increased collagen production, and extracellular matrix proliferation seen in both conditions. Recent advances in molecular biology techniques have furthered our knowledge of the potential underlying pathogenic mechanisms and offer new and provocative areas of research for novel diagnostic and therapeutic interventions. This review focuses on the role of vascular injury in the development of morphea, the use of ultrasonography as a diagnostic modality, and well-established and newly proposed treatments.

Epithelial-mesenchymal transition of the eccrine glands is involved in skin fibrosis in morphea

Morphea is a type of localized scleroderma. It is a skin disease involving the development of fibrosis in the dermis and subcutaneous fat tissue beneath without a visceral lesion, and the cause is still unclear. An involvement of epithelial-mesenchymal transition (EMT) has been reported as a cause of tissue fibrosis, but this was mostly observed in pulmonary and hepatic fibrosis, and the involvement of EMT in a skin disease, morphea, has not been studied . Thus, we analyzed the involvement of EMT in skin fibrosis in morphea patients using pathological techniques. Skin lesions of six morphea patients were analyzed (five female and one male patient). As a control, non-light-exposed skin lesions of 11 healthy females were analyzed. Concretely, tissue samples were prepared from these subjects and subjected to immunostaining of transforming growth factor (TGF)-β1, α-smooth muscle actin (α-SMA) and fibronectin, which have been reported to be associated with fibrosis, and Snail1 and E-cadherin, which are considered to be involved in EMT, and expressions of these were analyzed. In morphea patients, dermal expression of TGF-β1, α-SMA and fibronectin, which are involved in fibrosis, was enhanced, and, at the same time, enhanced expression of Snail1 and reduced expression of E-cadherin, which are involved in EMT, were observed in the dermal eccrine glands. These findings suggested the progression of EMT in the dermal eccrine glands in morphea.

Localized scleroderma

Localized scleroderma (also called morphea) is a term encompassing a spectrum of sclerotic autoimmune diseases that primarily affect the skin, but also might involve underlying structures such as the fat, fascia, muscle, and bones. Its exact pathogenesis is still unknown, but several trigger factors in genetically predisposed individuals might initially lead to an immunologically triggered release of pro-inflammatory cytokines, resulting in a profound dysregulation of the connective tissue metabolism and ultimately to induction of fibrosis. To date, there are no specific serological markers available for localized scleroderma. Within the last years, several validated clinical scores have been introduced as potential outcome measures for the disease. Given the rarity of localized scleroderma, only few evidence-based therapeutical treatment options exist. So far, the most robust data is available for ultraviolet A1 phototherapy in disease that is restricted to the skin, and methotrexate alone or in combination with systemic corticosteroids in more severe disease that additionally affects extracutaneous structures. This practical review summarizes relevant information on the epidemiology, pathogenesis, clinical subtypes and classifications, differential diagnoses, clinical scores and outcome measures, and current treatment strategies of localized scleroderma.

Pediatric scleroderma: systemic or localized forms

Pediatric scleroderma includes 2 major groups of clinical entities, systemic sclerosis (SSc) and localized scleroderma (LS). Although both share a common pathophysiology, their clinical manifestations differ. LS is typically confined to the skin and underlying subcutis, with up to a quarter of patients showing extracutaneous disease manifestations such as arthritis and uveitis. Vascular, cutaneous, gastrointestinal, pulmonary, and musculoskeletal involvement are most commonly seen in children with SSc. Treatment of both forms targets the active inflammatory stage and halts disease progression; however, progress needs to be made toward the development of more effective antifibrotic therapy to help reverse disease damage.

Methotrexate and corticosteroids in the treatment of localized scleroderma: a standardized prospective longitudinal single-center study

OBJECTIVE

To evaluate the effectiveness of a uniform single-center treatment protocol composed of high-dose methotrexate (MTX) and oral corticosteroids in a pediatric localized scleroderma (LS) cohort.

METHODS

Thirty-six patients with LS were recruited. Patients with active disease, defined as erythematous lesions and/or new lesions, or expansion of existing lesions, were started on oral prednisone 2 mg/kg/day (maximum 60 mg/day) and subcutaneous (SC) MTX at 1 mg/kg/week (maximum 25 mg/week). Prednisone was tapered and kept at 0.25 mg/kg/day for 12 months. MTX SC was continued for 24 months, and then switched to oral administration to complete 36 months of therapy. Modified LS Skin Severity Index (mLoSSI) and the physician global assessment of disease activity (PGA-A) were used as outcome measures.

RESULTS

Twenty-five patients with LS were female with a median age at onset of 7.86 years [interquartile range (IQR) 4.63-11.91]. Median disease duration from onset until start of this treatment regimen was 19.2 months (IQR 8.96-35.35). Median duration of followup was 36.40 months (IQR 29.39-45.36). All patients demonstrated significant improvement in mLoSSI at median 1.77 months (IQR 0.76-2.37, 95% CI 1.54, 2.01). PGA-A followed the same trend. No significant adverse reactions or flares were observed during therapy.

CONCLUSION

This single-center LS treatment protocol was effective and well tolerated. Clinical outcome in LS is affected by dose and route of administration of immunosuppressive regimens. Daily tapering dose of corticosteroids and parenteral MTX were effective in controlling LS activity without significant adverse reaction. This regimen should be considered as one of the therapies for LS clinical trials.

Morphea associated with the use of adalimumab: a case report and review of the literature

Therapy with TNF blockers may induce cutaneous adverse events, but the development of morphea, a localized scleroderma lesion, is extremely infrequent. We describe a 37-year-old man with ankylosing spondylitis treated with adalimumab who developed morphea lesions in the lower limbs after 12 months of treatment. Adalimumab was discontinued, which resulted in progressive improvement in the skin lesions, with only mild hyperpigmentation remaining. We also review reports of morphea and other adverse cutaneous events related to anti-TNF treatment.

Methotrexate treatment in juvenile localized scleroderma: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

Juvenile localized scleroderma is a chronic progressive fibrotic disorder of the skin that causes permanent disability and aesthetic damage. This study was undertaken to assess the safety and efficacy of methotrexate (MTX) in the treatment of juvenile localized scleroderma.

METHODS

In this double-blind study, patients with active juvenile localized scleroderma were randomized (2:1) to receive oral MTX (15 mg/m², maximum 20 mg) or placebo once weekly, for 12 months or until treatment failure. Both groups received oral prednisone (1 mg/kg/day, maximum 50 mg) for the first 3 months. A target lesion was evaluated clinically, with infrared thermography and using a computerized scoring system with skin score rate (SSR) evaluation. Response to treatment was defined as the absence of new lesions, SSR ≤ 1, and a decrease in lesion temperature of at least 10% compared to baseline. Treatment failure was defined as the occurrence of new lesions, SSR > 1, or increased lesion temperature. All analyses were done on the intent-to-treat population.

RESULTS

Of the 85 patients screened, 70 (ages 6-17 years) were randomized (46 to the MTX group, 24 to the placebo group). The mean disease duration was 2.3 years. After an initial response in all patients, disease relapsed in 15 MTX-treated patients (32.6%) and 17 placebo-treated patients (70.8%) (P < 0.005). New lesions appeared in 3 MTX-treated patients (6.5%) versus 4 placebo-treated patients (16.7%). The mean SSR decreased from 1 to 0.79 in the MTX group and increased from 1 to 1.1 in the placebo group, and the mean target lesion temperature decreased by 44.4% in the MTX group versus 12.1% in the placebo group. Twenty-six patients in the MTX group (56.5%) and 11 patients in the placebo group (45.8%) developed mild side effects related to treatment. None of the side effects were severe enough to necessitate treatment discontinuation.

CONCLUSION

Our findings indicate that MTX is efficacious in the treatment of juvenile localized scleroderma and is well tolerated.

Animal models of scleroderma: fresh insights

PURPOSE OF REVIEW

Recent years have seen the advent and progress in our understanding of fibrosis and vasculopathy in systemic sclerosis, scleroderma (SSc) largely mediated through the development and study of novel animal models. The most well studied animal models of SSc involve the bleomycin model of induced fibrosis and the Tsk/+ model. However, even though these models provide useful insights into the pathogenesis of fibrosis and vasculopathy, they do not mimic the disease accurately.

RECENT FINDINGS

Several mouse models have been developed that have specifically focused on the vasculopathy of SSc and have yielded relevant insights into this disorder further highlighting the novel mechanisms that may be responsible for this pathological feature. Furthermore, the contribution of the innate immune system mediated by the inflammasome in the induction of fibrosis has also demonstrated significant insights, possibly implicating an etiological mechanism of SSc. And recent transgenic or knockout animal models have emphasized the relevance of macrophage chemoattractant protein-1 (MCP-1), alpha-melanocyte stimulating hormone (α-MSH), and peroxisome proliferator-activated receptor-gamma (PPARγ) in fibrosis.

SUMMARY

Recent advances in animal models of SSc have elucidated the involvement of relevant proteins that appear to mediate vasculopathy and also implicated the involvement of the innate immune system in fibrosis. These models have identified novel therapeutic targets that may lead to more effective treatments for this incurable disease.

Cytokine profiles in localized scleroderma and relationship to clinical features

Localized scleroderma (LS) is a disfiguring autoimmune disease of the skin and underlying tissue that mainly affects the pediatric population. Inflammation of the tissue leads to fibrosis and atrophy, causing physical and psychological disability that can continue throughout childhood into adulthood. Available therapies for LS have had variable effects and are associated with morbidity themselves. A better understanding of the pathophysiology of LS, especially during the active inflammatory phase, would lead to more directed and efficacious therapies. As in systemic sclerosis (SSc), the other form of scleroderma, T-helper (Th) cells and their associated cytokines have been suggested to contribute significantly to the pathophysiology of LS supported by the presence of cytokines from these lineages in the sera and tissue of LS patients. It is postulated that the imbalance between Th1/Th2/Th17 cell subsets drives inflammation in the early stages of disease (Th1 and Th17 predominant) and fibrosis in the later stages of scleroderma (Th2 predominant). We review the available experimental data regarding cytokines in LS and compare them to available clinical disease severity and activity features. This provides the platform to launch further investigations into the role of select cytokines in the pathogenesis of LS and to provide directed therapeutic options in the future.

[AWMF Guideline no. 013/066. Diagnosis and therapy of circumscribed scleroderma]

Localized scleroderma is a rare autoimmune disease with primary affection of the skin, and occasional involvement of the fat tissue, muscle, fascia, and bone. Depending on the clinical subtype, the spectrum of skin lesions ranges from singular plaque lesions to severe generalized or linear subtypes which may lead to movement restrictions and permanent disability. This German S1-guideline proposes a classification of localized scleroderma that, considering the extent and depth of fibrosis, distinguishes limited, generalized, linear, and deep forms of localized scleroderma, together with its associated subtypes. The guideline includes a description of the pathogenesis, of differential diagnoses, and particular aspects of juvenile localized scleroderma, as well as recommendations for histopathologic, serologic, and biometric diagnostic procedures. Based on studies of topical and systemic treatments as well as phototherapy for localized scleroderma published in international literature, a treatment algorithm was developed which takes account of the different subtypes and the extent of disease.

Alternatively activated macrophages (M2 macrophages) in the skin of patient with localized scleroderma

Localized scleroderma is a connective tissue disorder that is limited to the skin and subcutaneous tissue. Macrophages have been reported to be particularly activated in patients with skin disease including systemic sclerosis and are potentially important sources for fibrosis-inducing cytokines, such as transforming growth factor beta. To clarify the features of immunohistochemical characterization of the immune cell infiltrates in localized scleroderma focusing on macrophages, skin biopsy specimens were analysed by immunohistochemistry. The number of cells stained with monoclonal antibodies, CD68, CD163 and CD204, was calculated. An evident macrophage infiltrate and increased number of alternatively activated macrophages (M2 macrophages) in their fibrotic areas were observed along with their severity of inflammation. This study revealed that alternatively activated macrophages (M2 macrophages) may be a potential source of fibrosis-inducing cytokines in localized scleroderma, and may play a crucial role in the pathogenesis of localized scleroderma.

Resistin-like molecule-beta in scleroderma-associated pulmonary hypertension

Scleroderma is a systemic, mixed connective tissue disease that can impact the lungs through pulmonary fibrosis, vascular remodeling, and the development of pulmonary hypertension and right heart failure. Currently, little is known about the molecular mechanisms that drive this condition, but we have recently identified a novel gene product that is up-regulated in a murine model of hypoxia-induced pulmonary hypertension. This molecule, known as hypoxia-induced mitogenic factor (HIMF), is a member of the newly described resistin gene family. We have demonstrated that HIMF has mitogenic, angiogenic, vasoconstrictive, inflammatory, and chemokine-like properties, all of which are associated with vascular remodeling in the lung. Here, we demonstrate that the human homolog of HIMF, resistin-like molecule (RELM)-beta, is expressed in the lung tissue of patients with scleroderma-associated pulmonary hypertension and is up-regulated compared with normal control subjects. Immunofluorescence colocalization revealed that RELM-beta is expressed in the endothelium and vascular smooth muscle of remodeled vessels, as well as in plexiform lesions, macrophages, T cells, and myofibroblast-like cells. We also show that addition of recombinant RELM-beta induces proliferation and activation of ERK1/2 in primary cultured human pulmonary endothelial and smooth muscle cells. These results suggest that RELM-beta may be involved in the development of scleroderma-associated pulmonary hypertension.