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

Unique and shared transcriptomic signatures underlying localized scleroderma pathogenesis identified using interpretable machine learning

Using transcriptomic profiling at single-cell resolution, we investigated cell-intrinsic and cell-extrinsic signatures associated with pathogenesis and inflammation-driven fibrosis in both adult and pediatric patients with localized scleroderma (LS). We performed single-cell RNA-Seq on adult and pediatric patients with LS and healthy controls. We then analyzed the single-cell RNA-Seq data using an interpretable factor analysis machine learning framework, significant latent factor interaction discovery and exploration (SLIDE), which moves beyond predictive biomarkers to infer latent factors underlying LS pathophysiology. SLIDE is a recently developed latent factor regression-based framework that comes with rigorous statistical guarantees regarding identifiability of the latent factors, corresponding inference, and FDR control. We found distinct differences in the characteristics and complexity in the molecular signatures between adult and pediatric LS. SLIDE identified cell type-specific determinants of LS associated with age and severity and revealed insights into signaling mechanisms shared between LS and systemic sclerosis (SSc), as well as differences in onset of the disease in the pediatric compared with adult population. Our analyses recapitulate known drivers of LS pathology and identify cellular signaling modules that stratify LS subtypes and define a shared signaling axis with SSc.

Disabling pansclerotic morphoea: a century of discovery

BACKGROUND

Disabling pansclerotic morphoea (DPM) is a rare systemic inflammatory disorder at the severe end of the localized scleroderma spectrum. It primarily affects children < 14 years old. DPM is characterized by rapid sclerosis with circumferential involvement that frequently extends to the fascia, muscle and bone. Disease progression often involves the development of sclerotic plaques, chronic skin ulcers and painful joint contractures, leading to patient immobility and a high mortality rate. Internal organ fibrosis is typically absent. The aggressive and systemic nature of DPM leads patients to seek multidisciplinary care. Current treatments are targeted toward immunomodulation and measures to preserve mobility while limiting infection, but they often have limited efficacy.

OBJECTIVES

To summarize all patients with DPM reported in the English-language literature, common clinical symptoms, laboratory investigations and treatments reported to date.

METHODS

A literature search was conducted on PubMed and Google Scholar. All English-language original articles, case reports, abstracts and letters to the editor were included. Each publication was reviewed for diagnosis, clinical presentation, available laboratory/histological studies, treatment and outcome.

RESULTS

We identified 52 reports comprising 86 patients published up to December 2023. Assessment of published cases suggested that the number of treatments does not influence disease outcome and that female patients are younger at the time of reported death.

CONCLUSIONS

Clinician familiarity and awareness of common DPM symptoms are important for an accurate and early diagnosis. Knowledge of treatments that have been reported to be effective in mitigating disease progression may be helpful in expanding the available treatment options.

What Is New in Morphea-Narrative Review on Molecular Aspects and New Targeted Therapies

Morphea, also known as localized scleroderma, is an autoimmune chronic connective tissue disease. It is characterized by excessive collagen deposition in the dermis and/or subcutaneous tissue. The etiopathogenesis of this disease is not fully understood, with endothelial cell damage, immunological disorders, extracellular matrix disorders and factors such as infection, trauma and other autoimmune diseases being considered. As medicine advances, there is increasing evidence that genetic factors play a significant role in disease risk and progression. In addition to environmental factors and genetic predisposition, epigenetic factors may be potential triggers for morphea. Epigenetics studies changes that affect gene expression without altering the DNA sequence, such as microRNAs, long non-coding RNAs or DNA methylation. Understanding the pathogenesis of this disease is key to identifying potential new treatments. There are anecdotal reports of good therapeutic effects following the use of biological drugs such as tocilizumab, a humanized IgG monoclonal antibody; abatacept, a recombinant soluble fusion protein; JAK inhibitors, such as tofacitinib and baricitinib; and a drug used successfully in cancer treatment, imatinib, a tyrosine kinase receptor inhibitor. In this article, we aim to review up-to-date knowledge on the pathogenesis of morphea, with particular emphasis on genetic and epigenetic factors. In addition, we present the new options of morphea treatment based on several case series treated with new drugs that are potential targets for the development of therapies for this disease.

Interferons dominate damage and activity in juvenile scleroderma

OBJECTIVES

Juvenile scleroderma is a heterogeneous group of diseases associated with sclerotic skin lesions, grouped as juvenile systemic sclerosis and juvenile localized scleroderma. This study aims to measure the cytokine and chemokine levels involved in interferon (IFN) signalling in patients with juvenile scleroderma and determine their correlation with disease severity.

METHODS

Twenty-nine juvenile localized scleroderma, five juvenile systemic sclerosis, and nine healthy controls were included in the study. Cytokines and chemokines involved in IFN gene signalling (IL-1, IL-6, IL-8, IP-10, MCP1, TNF-α, CXCL-11, IFN-α, IFN-β, IFN-γ) and IFN-stimulated genes (ISGs), including IFI27, IFI44, ISIG15, IFIT1, OAS1, RSAD2, were measured by ELISA and RT-PCR method, respectively.

RESULTS

A significant increase in IFN-α, IFN-β, IFN-γ, TNF-α, IL-1, IL-6 IL-8, IP-10, and MCP1 levels was observed in patients with juvenile systemic sclerosis compared with the healthy control group. Furthermore, IFN-α and IP-10 were elevated in both juvenile localized scleroderma and juvenile systemic sclerosis compared to the healthy control group. IFN-γ and IFN-α positively correlated with LoSAI and LoSDI levels, respectively. According to PGA-A analysis, IFN-β, IFN-γ, TNF-α, IL-8, IP10, MCP1, and CXCL11 were significantly higher in active disease than in the inactive state in both groups.

CONCLUSION

The results suggest that IFN signalling may be impaired in patients with juvenile scleroderma. Significant changes were observed in cytokines and genes related to IFN signalling, which may have a crucial role in monitoring disease activity. In addition, we have gained important insights into the possibility of using IFN-α and IFN-γ as biomarkers for monitoring juvenile scleroderma activity and damage.

Characterization of Endothelial Cell Subclusters in Localized Scleroderma Skin with Single-Cell RNA Sequencing Identifies NOTCH Signaling Pathway

Localized scleroderma (LS) is an autoimmune disease characterized by inflammation and fibrosis, leading to severe cutaneous manifestations such as skin hardening, tightness, discoloration, and other textural changes that may result in disability. While LS shares similar histopathologic features and immune-fibroblast interactions with systemic sclerosis (SSc), its molecular mechanisms remain understudied. Endothelial cells (EC) are known to play a crucial role in SSc but have not been investigated in LS. Single-cell RNA sequencing (scRNA-seq) now allows for detailed examination of this cell type in the primary organ of interest for scleroderma, the skin. In this study, we analyzed skin-isolated cells from 27 LS patients (pediatric and adult) and 17 healthy controls using scRNA-seq. Given the known role of EC damage as an initial event in SSc and the histologic and clinical skin similarities to LS, we focused primarily on endothelial cells. Our analysis identified eight endothelial subclusters within the dataset, encompassing both disease and healthy samples. Interaction analysis revealed that signaling from diseased endothelial cells was predicted to promote fibrosis through SELE interaction with FGFBP1 and other target genes. We also observed high levels of JAG in arterial endothelial cells and NOTCH in capillary endothelial cells, indicating the activation of a signaling pathway potentially responsible for epidermal abnormalities and contributing to LS pathogenesis. In summary, our scRNA-seq analysis identified potential disease-propagating endothelial cell clusters with upregulated pathways in LS skin, highlighting their importance in disease progression.

Interferon-Gamma-Inducible Protein-10 (IP-10) and Tumor Necrosis Factor-α (TNF-α) as Serological Predictors of Active Disease Status in Localized Scleroderma

We investigated the ability of a panel of immune-related cytokines and chemokines to predict the disease activity state in localized scleroderma (LS) subjects followed longitudinally. A total of 194 sera samples were obtained from 45 LS subjects with diverse types of LS (40% linear, 20% mixed, 16% craniofacial, 13% generalized, and 11% circumscribed) in our cohort. Cytokines/chemokines that were significantly elevated at the baseline active disease visit compared to the inactive disease state at follow-up were Interferon-Gamma-Inducible Protein (IP)-10 (p < 0.021) and Tumor Necrosis Factor (TNF)-α (p < 0.033). Mixed effect logit modeling identified IP-10 (Odds Ratio (OR) [95% confidence interval] = 2.1 [1.4, 3.2], p < 0.001), TNF-α (OR = 1.8 [1.1, 3.0], p = 0.016), and Monocyte Chemoattractant Protein (MCP)-1 (OR = 2.0 [1.1, 3.9], p = 0.034) as significant predictors of active disease status. These findings support earlier correlations between IP-10 and TNF-α with disease activity parameters in a cross-sectional Luminex™ serological study and may enhance clinical decision-making when disease activity is challenging to assess by clinical examination alone.

Microfluidic finger-actuated mixer for ultrasensitive electrochemical measurements of protein biomarkers for point-of-care testing

Current diagnostic tests for high sensitivity detection of protein biomarkers involve long incubation times or require bulky/expensive instrumentation, hindering their use for point-of-care testing. Here, we report a microfluidic electrochemical immunosensor that employs a unique finger-actuated mixer for rapid, ultrasensitive measurements of protein biomarkers. Mixing was implemented during the incubation steps, which accelerated biomolecular transport and promoted immunocomplex formation, leading to enhanced analytical sensitivity and a shortened detection time. Electrochemical measurements were performed using a handheld diagnostic device consisting of a smartphone and miniature potentiostat. Proof of principle was demonstrated by using this platform for quantitative measurements of C-X-C motif chemokine ligand 9 (CXCL9), a serological biomarker for autoimmune and inflammatory diseases, which could be detected in human plasma at concentrations as low as 4.7 pg mL-1 in <25 min. The ability to rapidly detect protein biomarkers with high sensitivity in a point-of-care format makes this device a promising tool for diagnostic testing, particularly in resource-limited settings.

Senomorphic activity of a combination of niacinamide and hyaluronic acid: correlation with clinical improvement of skin aging

Intrinsic and extrinsic factors, including lifestyle and sun exposure, can contribute to cell senescence, which impairs skin homeostasis, that may in turn lead to skin aging. Senescent cells have a specific secretome, called the senescence-associated secretory phenotype (SASP) that includes MMPs, CXCLs and S100A8/9. Reducing the SASP with senotherapeutics is a promising strategy to reduce skin aging. Here we evaluated the effect of a formula containing niacinamide and hyaluronic acid, which are known to limit senescence and skin aging. We conducted three different studies. (1) Ex vivo explants treated with the formula had more collagen and glycosaminoglycan. (2) In a clinical trial with forty-four women, two months of treatment improved fine lines, wrinkles, luminosity, smoothness, homogeneity, and plumpness. (3) In a third study on thirty women, we treated one arm for two months and took skin biopsies to study gene expression. 101 mRNAs and 13 miRNAs were differentially expressed. We observed a likely senomorphic effect, as there was a decrease in many SASP genes including MMP12 and CXCL9 and a significant downregulation of autocrine signaling genes: S100A8 and S100A9. These pharmaco-clinical results are the first to demonstrate the senomorphic properties of an effective anti-aging formula in skin.

Responsiveness to Change of the Morphea Activity Measure in Pediatric Patients

Importance

Detecting activity of morphea can be complex but is crucial for adequate treatment and outcome assessment. The Morphea Activity Measure (MAM) was recently validated, but its responsiveness to change in disease activity has not been studied.

Objective

To evaluate the internal and external responsiveness of MAM to changes in disease activity in pediatric patients.

Design, Setting, and Participants

This multicenter prospective, longitudinal prognostic study was performed from October 2021 to January 2023 at 4 pediatric referral centers in North America. Consecutive pediatric patients with morphea who were available for data collection at baseline and at a follow-up visit at least 3 months later were studied.

Exposure

Patient demographics, clinical characteristics, and measurements of disease activity collected at baseline and the subsequent visit.

Main Outcome and Measures

Responsiveness of MAM to disease activity according to the modified Localized Scleroderma Severity Index (mLoSSI), the Physician Global Assessment (PGA), and a patient and parent global assessment (PtGA) was analyzed using mean and percentage change, standardized effect size, and standardized response mean (SRM) from baseline to follow-up 3 or more months later. Differences between patients whose activity improved vs did not improve were evaluated using the Mann-Whitney U test. The correlation between percentage change in MAM score and mLoSSI, the PGA, and the PtGA was calculated using Spearman rank correlation.

Results

A total of 43 patients (mean [SD] age at onset, 7.11 [3.18] years; 26 [60.5%] female) were included. The mean change and percentage change in MAM score were significantly larger in those whose disease activity improved by the PGA (mean: -18.75 [95% CI, -31.92 to -5.57] vs 2.73 [95% CI, -1.97 to 7.45]; percentage: -108.08% [95% CI, -155.21% to -60.95%] vs -24.11% [95% CI, -81.22% to 32.99%]) and by mLoSSI (mean: -24.15 [95% CI, -41.89 to -6.41] vs -1.30 [95% CI, -8.50 to 5.70]; percentage: -172.06% [95% CI, -263.68% to -80.45%] vs -21.57% [95% CI, -48.13% to 4.97%]) than in those whose activity did not change. The SRM of MAM was significantly different between groups for both measures; the responsiveness was large in those whose activity decreased by the PGA (-0.75 [95% CI, -1.29 to -0.22]) and mLoSSI (-0.97 [95% CI, -1.69 to -0.25]) and none to small in those whose activity did not change by the PGA (0.11 [95% CI, -0.08 to 0.30]) or mLoSSI (-0.05 [95% CI, -0.34 to 0.23]). Percentage change in MAM score correlated strongly and significantly with change in mLoSSI (ρ = 0.69; P < .001) and PGA (ρ = 0.65; P < .001), but there was no correlation with change in the PtGA (ρ = 0.26; P = .09).

Conclusions and Relevance

In this prognostic study, MAM was found to be internally and externally responsive to changes in disease activity. Further evaluation in mixed cohorts of all ages and specialties is needed.

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.

Gene Expression Signatures in Inflammatory and Sclerotic Morphea Skin and Sera Distinguish Morphea from Systemic Sclerosis

Morphea is an inflammatory fibrotic disorder of the skin that has been likened to systemic sclerosis (SSc). We sought to examine the molecular landscape of morphea by examining lesional skin gene expression and blood biomarkers and comparing the gene expression profiles with those from site-matched nonlesional and SSc lesional skin. We found the morphea transcriptome is dominated by IFN-γ-mediated T helper 1 immune dysregulation, with a relative paucity of fibrosis pathways. Specifically, expression profiles of morphea skin clustered with the SSc inflammatory subset and were distinct from the those of SSc fibroproliferative subset. Unaffected morphea skin also differed from unaffected SSc skin because it did not exhibit pathological gene expression signatures. Examination of downstream IFN-γ-mediated chemokines, CXCL9 and CXCL10, revealed increased transcription in the skin but not in circulation. In contrast to transcriptional activity, CXCL9 was elevated in serum and was associated with active, widespread cutaneous involvement. Taken together, these results indicate that morphea is a skin-directed process characterized by T helper 1 immune-mediated dysregulation, which contrasts with fibrotic signatures and systemic transcriptional changes associated with SSc. The similarity between morphea and the inflammatory subset of SSc on transcriptional profiling indicates that therapies under development for this subset of SSc are also promising for treatment of morphea.

IL-6 trans-signaling in a humanized mouse model of scleroderma

Fibrosis is regulated by interactions between immune and mesenchymal cells. However, the capacity of cell types to modulate human fibrosis pathology is poorly understood due to lack of a fully humanized model system. MISTRG6 mice were engineered by homologous mouse/human gene replacement to develop an immune system like humans when engrafted with human hematopoietic stem cells (HSCs). We utilized MISTRG6 mice to model scleroderma by transplantation of healthy or scleroderma skin from a patient with pansclerotic morphea to humanized mice engrafted with unmatched allogeneic HSC. We identified that scleroderma skin grafts contained both skin and bone marrow-derived human CD4 and CD8 T cells along with human endothelial cells and pericytes. Unlike healthy skin, fibroblasts in scleroderma skin were depleted and replaced by mouse fibroblasts. Furthermore, HSC engraftment alleviated multiple signatures of fibrosis, including expression of collagen and interferon genes, and proliferation and activation of human T cells. Fibrosis improvement correlated with reduced markers of T cell activation and expression of human IL-6 by mesenchymal cells. Mechanistic studies supported a model whereby IL-6 trans-signaling driven by CD4 T cell-derived soluble IL-6 receptor complexed with fibroblast-derived IL-6 promoted excess extracellular matrix gene expression. Thus, MISTRG6 mice transplanted with scleroderma skin demonstrated multiple fibrotic responses centered around human IL-6 signaling, which was improved by the presence of healthy bone marrow-derived immune cells. Our results highlight the importance of IL-6 trans-signaling in pathogenesis of scleroderma and the ability of healthy bone marrow-derived immune cells to mitigate disease.

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.

Pansclerotic morphea is characterized by IFN-γ responses priming dendritic cell fibroblast crosstalk to promote fibrosis

Pansclerotic morphea (PSM) is a rare, devastating disease characterized by extensive soft tissue fibrosis, secondary contractions, and significant morbidity. PSM pathogenesis is unknown, and aggressive immunosuppressive treatments rarely slow disease progression. We aimed to characterize molecular mechanisms driving PSM and to identify therapeutically targetable pathways by performing single-cell and spatial RNA-Seq on 7 healthy controls and on lesional and nonlesional skin biopsies of a patient with PSM 12 months apart. We then validated our findings using immunostaining and in vitro approaches. Fibrotic skin was characterized by prominent type II IFN response, accompanied by infiltrating myeloid cells, B cells, and T cells, which were the main IFN-γ source. We identified unique CXCL9+ fibroblasts enriched in PSM, characterized by increased chemokine expression, including CXCL9, CXCL10, and CCL2. CXCL9+ fibroblasts were related to profibrotic COL8A1+ myofibroblasts, which had enriched TGF-β response. In vitro, TGF-β and IFN-γ synergistically increased CXCL9 and CXCL10 expression, contributing to the perpetuation of IFN-γ responses. Furthermore, cell-to-cell interaction analyses revealed cDC2B DCs as a key communication hub between CXCL9+ fibroblasts and COL8A1+ myofibroblasts. These results define PSM as an inflammation-driven condition centered on type II IFN responses. This work identified key pathogenic circuits between T cells, cDC2Bs, and myofibroblasts, and it suggests that JAK1/2 inhibition is a potential therapeutic option in PSM.

CXCL9 Links Skin Inflammation and Fibrosis through CXCR3-Dependent Upregulation of Col1a1 in Fibroblasts

Morphea is characterized by initial inflammation followed by fibrosis of the skin and soft tissue. Despite its substantial morbidity, the pathogenesis of morphea is poorly studied. Previous work showed that CXCR3 ligands CXCL9 and CXCL10 are highly upregulated in the sera and lesional skin of patients with morphea. We found that an early inflammatory subcutaneous bleomycin mouse model of dermal fibrosis mirrors the clinical, histological, and immune dysregulation observed in human morphea. We used this model to examine the role of the CXCR3 chemokine axis in the pathogenesis of cutaneous fibrosis. Using the REX3 (Reporting the Expression of CXCR3 ligands) mice, we characterized which cells produce CXCR3 ligands over time. We found that fibroblasts contribute the bulk of CXCL9-RFP and CXCL10-BFP by percentage, whereas macrophages produce high amounts on a per-cell basis. To determine whether these chemokines are mechanistically involved in pathogenesis, we treated Cxcl9-, Cxcl10-, or Cxcr3-deficient mice with bleomycin and found that fibrosis is dependent on CXCL9 and CXCR3. Addition of recombinant CXCL9 but not CXCL10 to cultured mouse fibroblasts induced Col1a1 mRNA expression, indicating that the chemokine itself contributes to fibrosis. Taken together, our studies provide evidence that CXCL9 and its receptor CXCR3 are functionally required for inflammatory fibrosis.

Single-Cell Transcriptome Analysis Identifies Subclusters with Inflammatory Fibroblast Responses in Localized Scleroderma

Localized scleroderma (LS) is an autoimmune disease with both inflammatory and fibrotic components causing an abnormal deposition of collagen in the skin and underlying tissue, often leading to disfigurement and disability. Much of its pathophysiology is extrapolated from systemic sclerosis (SSc) since the histopathology findings in the skin are nearly identical. However, LS is critically understudied. Single-cell RNA sequencing (scRNA seq) technology provides a novel way to obtain detailed information at the individual cellular level, overcoming this barrier. Here, we analyzed the affected skin of 14 patients with LS (pediatric and adult) and 14 healthy controls. Fibroblast populations were the focus, since they are the main drivers of fibrosis in SSc. We identified 12 fibroblast subclusters in LS, which overall had an inflammatory gene expression (IFN and HLA-associated genes). A myofibroblast-like cluster (SFRP4/PRSS23) was more prevalent in LS subjects and shared many upregulated genes expressed in SSc-associated myofibroblasts, though it also had strong expression of CXCL9/10/11, known CXCR3 ligands. A CXCL2/IRF1 cluster identified was unique to LS, with a robust inflammatory gene signature, including IL-6, and according to cell communication analysis are influenced by macrophages. In summary, potential disease-propagating fibroblasts and associated gene signatures were identified in LS skin via scRNA seq.

Development and Validation of the Morphea Activity Measure in Patients With Pediatric Morphea

Importance

Morphea is an insidious inflammatory disorder of the skin and deeper tissues. Determining disease activity is challenging yet important to medical decision-making and patient outcomes.

Objective

To develop and validate a scoring tool, the Morphea Activity Measure (MAM), to evaluate morphea disease activity of any type or severity that is easy to use in clinical and research settings.

Design, Setting, and Participants

This pilot diagnostic study was conducted from September 9, 2019, to March 6, 2020, in 2 phases: development and validation. During the development phase, 14 morphea experts (dermatologists and pediatric dermatologists) used a Delphi consensus method to determine items that would be included in the MAM. The validation phase included 8 investigators who evaluated the tool in collaboration with 14 patients with pediatric morphea (recruited from a referral center [Medical College of Wisconsin]) during a 1-day in-person meeting on March 6, 2020.

Main Outcomes and Measures

During the development phase, online survey items were evaluated by experts in morphea using a Likert scale (score range, 0-10, with 0 indicating not important and 10 indicating very important); agreement was defined as a median score of 7.0 or higher, disagreement as a median score of 3.9 or lower, and no consensus as a median score of 4.0 to 6.9. During the validation phase, reliability (interrater and intrarater agreement using intraclass correlation coefficients), validity (using the content validity index and κ statistics as well as correlations with the modified Localized Scleroderma Severity Index and the Physician Global Assessment of Activity using Spearman ρ coefficients), and viability (using qualitative interviews of investigators who used the MAM tool) were evaluated. Descriptive statistics were used for quantitative variables. Data on race and ethnicity categories were collected but not analyzed because skin color was more relevant for the purposes of this study.

Results

Among 14 survey respondents during the development phase, 9 (64.3%) were pediatric dermatologists and 5 (35.7%) were dermatologists. After 2 rounds, a final tool was developed comprising 10 items that experts agreed were indicative of morphea activity (new lesion in the past 3 months, enlarging lesion in the past 3 months, linear lesion developing progressive atrophy in the past 3 months, erythema, violaceous rim or color, warmth to the touch, induration, white-yellow or waxy appearance, shiny white wrinkling, and body surface area). The validation phase was conducted with 14 patients (median age, 14.5 years [range, 8.0-18.0 years]; 8 [57.1%] female), 2 dermatologists, and 6 pediatric dermatologists. Interrater and intrarater agreement for MAM total scores was good, with intraclass correlation coefficients of 0.844 (95% CI, 0.681-0.942) for interrater agreement and 0.856 (95% CI, 0.791-0.901) for intrarater agreement. Correlations between the MAM and the modified Localized Scleroderma Severity Index (Spearman ρ = 0.747; P < .001) and the MAM and the Physician Global Assessment of Activity (Spearman ρ = 0.729; P < .001) were moderately strong. In qualitative interviews, evaluators agreed that the tool was easy to use, measured morphea disease activity at a single time point, and should be responsive to changes in morphea disease activity over multiple time points.

Conclusions and Relevance

In this study, the MAM was found to be a reliable, valid, and viable tool to measure pediatric morphea activity. Further testing to assess validity in adults and responsiveness to change is needed.

Bullous lichen sclerosus-generalized morphea overlap syndrome improved by tofacitinib

We here report a case of a middle-aged man with an unusual case of bullous lichen sclerosus complicated with generalized morphea. He showed initial recurrent flaccid bullae, followed by ivory-white sclerotic plaques and extensive skin sclerosis, with additional walking disorder caused by knee-joint contracture, and ulcers on the lower extremities and back. The patient had no visceral involvement. After oral hydroxychloroquine and oral corticosteroids failed, the patient was given tofacitinib, which resolved his ulcers after 4 weeks and ameliorated his knee-joint contracture and skin sclerosis within 4 months. Owing to the occurrence of diffuse large B-cell lymphoma, he stopped using tofacitinib, and the ulcer and walking disorder reappeared. This is rare case of bullous lichen sclerosus-generalized morphea overlap syndrome. The patient recovered well after treatment with tofacitinib. His symptoms recurred after discontinuation of tofacitinib.

Development and function of tissue-resident memory B cells

Barrier tissues are the primary site of infection for pathogens likely to cause future pandemics. Tissue-resident lymphocytes can rapidly detect pathogens upon infection of barrier tissues and are critical in preventing viral spread. However, most vaccines fail to induce tissue-resident lymphocytes and are instead reliant on circulating antibodies to mediate protective immunity. Circulating antibody titers wane over time following vaccination leaving individuals susceptible to breakthrough infections by variant viral strains that evade antibody neutralization. Memory B cells were recently found to establish tissue residence following infection of barrier tissues. Here, we summarize emerging evidence for the importance of tissue-resident memory B cells in the establishment of protective immunity against viral and bacterial challenge. We also discuss the role of tissue-resident memory B cells in regulating the progression of non-infectious diseases. Finally, we examine new approaches to develop vaccines capable of eliciting barrier immunity.

Upcoming treatments for morphea

Morphea (localized scleroderma) is a rare autoimmune connective tissue disease with variable clinical presentations, with an annual incidence of 0.4-2.7 cases per 100,000. Morphea occurs most frequently in children aged 2-14 years, and the disease exhibits a female predominance. Insights into morphea pathogenesis are often extrapolated from studies of systemic sclerosis due to their similar skin histopathologic features; however, clinically they are two distinct diseases as evidenced by different demographics, clinical features, disease course and prognosis. An interplay between genetic factors, epigenetic modifications, immune and vascular dysfunction, along with environmental hits are considered as the main contributors to morphea pathogenesis. In this review, we describe potential new therapies for morphea based on both preclinical evidence and ongoing clinical trials. We focus on different classes of therapeutics, including antifibrotic, anti-inflammatory, cellular and gene therapy, and antisenolytic approaches, and how these target different aspects of disease pathogenesis.

Bioinformatics analysis of the role of CXC ligands in the microenvironment of head and neck tumor

Chemokines play a significant role in cancer. CXC-motif chemokine ligands (CXCLs) are associated with the tumorigenesis and progression of head and neck squamous cell carcinoma (HNSC); however, their specific functions in the tumor microenvironment remain unclear. Here, we analyzed the molecular networks and transcriptional data of HNSC patients from the Oncomine, GEPIA, String, cBioPortal, Metascape, TISCH, and TIMER databases. To verify immune functions of CXCLs, their expression was analyzed in different immune cell types. To our knowledge, this is the first report on the correlation between CXCL9-12 and 14 expression and advanced tumor stage. CXCL2, 3, 8, 10, 13, and 16 were remarkably related to tumor immunity. Kaplan-Meier and TIMER survival analyses revealed that high expression of CXCL1, 2, 4, and 6-8 is correlated with low survival in HNSC patients, whereas high expression of CXCL9, 10, 13, 14, and 17 predicts high survival. Only CXCL13 and 14 were associated with overall survival in human papilloma virus (HPV)-negative patients. Single-cell datasets confirmed that CXCLs are associated with HNSC-related immune cells. Thus, CXCL1-6, 8-10, 12-14, and 17 could be prognostic targets for HNSC, and CXCL13 and 14 could be novel biomarkers of HPV-negative HNSC.

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.

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.

Single-cell transcriptome conservation in a comparative analysis of fresh and cryopreserved human skin tissue: pilot in localized scleroderma

BACKGROUND

The purpose of this study was to assess variability in cell composition and cell-specific gene expression in the skin of patients with localized scleroderma (LS) utilizing CryoStor® CS10 in comparison to RPMI to produce adequate preservation of tissue samples and cell types of interest for use in large-scale multi-institutional collaborations studying localized scleroderma and other skin disorders.

METHODS

We performed single-cell RNA sequencing on paired skin biopsy specimens from 3 patients with LS. Each patient with one sample cryopreserved in CryoStor® CS10 and one fresh in RPMI media using 10× Genomics sequencing.

RESULTS

Levels of cell viability and yield were comparable between CryoStor® CS10 (frozen) and RPMI (fresh) preserved cells. Furthermore, gene expression between preservation methods was collectively significantly correlated and conserved across all 18 identified cell cluster populations.

CONCLUSION

Comparable cell population and transcript expression yields between CryoStor® CS10 and RPMI preserved cells support the utilization of cryopreserved skin tissue in single-cell analysis. This suggests that employing standardized cryopreservation protocols for the skin tissue will help facilitate multi-site collaborations looking to identify mechanisms of disease in disorders characterized by cutaneous pathology.

Potential therapeutic manipulations of the CXCR3 chemokine axis for the treatment of inflammatory fibrosing diseases

Chemokines play important roles in homeostasis and inflammatory processes. While their roles in leukocyte recruitment are well-appreciated, chemokines play additional roles in the body, including mediating or regulating angiogenesis, tumor metastasis and wound healing. In this opinion article, we focus on the role of CXCR3 and its ligands in fibrotic processes. We emphasize differences of the effects of each ligand, CXCL9, CXCL10 and CXCL11, on fibroblasts in different tissues of the body. We include discussions of differences in signaling pathways that may account for protective or pro-fibrotic effects of each ligand in different experimental models and ex vivo analysis of human tissues. Our goal is to highlight potential reasons why there are disparate findings in different models, and to suggest ways in which this chemokine axis could be manipulated for the treatment of fibrosis.

Paediatric morphoea: a holistic review. Part 2: diagnosis, measures of disease activity, management and natural history

Paediatric morphoea is a debilitating fibrosing disorder of uncertain aetiology, affecting the skin and subcutaneous tissues. Defining optimum management strategies in paediatric morphoea remains an ongoing challenge, owing to the varied presentations and a relative paucity of paediatric-specific studies. We performed a literature search on PubMed, MEDLINE and Google Scholar, using keywords such as 'pediatric morphea', 'juvenile localised scleroderma' and 'juvenile systemic sclerosis'. Relevant studies, including randomized trials, reviews of standard current guidelines and original research articles, were selected and results analysed before summarizing them. In Part 1 of this review, we described the epidemiology, aetiopathogenesis and clinical classification; in this part, we discuss the diagnosis, markers of disease activity, management and natural history in paediatric morphoea.

Linear Scleroderma of the Head - Updates in management of Parry Romberg Syndrome and En coup de sabre: A rapid scoping review across subspecialties

To provide an update on the current management, including evaluation and treatment, and the available diagnostic tools for linear scleroderma of the head, i.e., Parry-Romberg Syndrome and en coup de sabre (PRS/ECDS). A rapid scoping review of the literature was conducted to include manuscripts published in English between 2010 and 2019. Literature searches were performed in PubMed and EMBASE databases. The were analyzed for descriptive statistic reporting. This study reviewed 215 manuscripts reporting these 1430 patients. Surgical reports comprised the majority of the reviewed literature. Most PRS/ECDS did not appear to receive comprehensive multisubspecialty evaluation for extracutaneous manifestations; 21% of cases noted neurological screening, 4% noted dental screening, and 3% noted ophthalmologic screening. Methotrexate and glucocorticoids remain the most frequent choice for immunosuppressive treatment, though fewer than 7% of patients reported receiving systemic medical therapies. Surgical procedures for cosmetic or functional improvement were common (59%) among the reported patients. Autologous fat grafting was the most frequently utilized cosmetic treatment (50% of procedures) followed by free flap transfers (24% of procedures). There is ongoing need for standardized evaluation, monitoring, and treatment to prevent morbidity in PRS/ECDS, especially in children. When these patients are managed by rheumatologists, methotrexate, and steroids remain the first-line treatment, but a review of the published literature reflects that this may be a minority. Most PRS/ECDS patients are not evaluated in a multidisciplinary fashion. We propose comprehensive evaluations across subspecialties at the baseline and follow-up levels to monitor disease activity and record extracutaneous manifestations, treatment algorithms, and surgical intervention considerations.

Overview of Juvenile localized scleroderma and its management

BACKGROUND

Juvenile localized scleroderma (JLS) is a rare pediatric disease characterized by inflammation and skin thickening. JLS is associated with deep tissue and extracutaneous involvement that often results in functional impairment and growth disturbances. This article provides an overview of the disease with a focus on active features and treatment.

DATA SOURCES

We searched databases including PubMed, Elsevier and MedLine and Wanfang, reviewing publications from 2013 to 2019. Selected earlier publications were also reviewed.

RESULTS

Linear scleroderma is the most common JLS subtype. Several lines of evidence suggest that JLS is an autoimmune disease. Extracutaneous involvement is common and can present before the onset of skin disease. Multiple skin features are associated with disease activity, and activity can also manifest as arthritis, myositis, uveitis, seizures, and growth impairment. Systemic immunosuppressive treatment, commonly methotrexate with or without glucocorticoids, greatly improves outcome and is recommended for treating JLS patients with active disease and moderate or higher severity. Long term monitoring is needed because of the disease's chronicity and the high frequency of relapses off of treatment.

CONCLUSIONS

JLS is associated with a risk for disabling and disfiguring morbidity for the growing child. Identifying active disease is important for guiding treatment, but often difficult because of the paucity of markers and lack of a universal skin activity feature. More studies of JLS pathophysiology are needed to allow the identification of biomarkers and therapeutic targets. Comparative effectiveness treatment studies are also needed to work towards optimizing care and outcome.

CXCL9 chemokine level is associated with spontaneous clearance and sustained virological response in Egyptian Chronic Hepatitis C patients receiving direct acting antivirals

BACKGROUND

Chronic Hepatitis C virus (HCV) infection is associated with progressive liver inflammation which in turn leads to cirrhosis and finally causes hepatocellular carcinoma (HCC). By different escape mechanisms, the virus succeeds to evade the innate and acquired immune responses to establish chronic infection.

AIM

This study aimed to evaluate the level of chemokine CXCL9 and its correlation with some biochemical parameters in different subjects of HCV patients.

MATERIALS AND METHODS

A total of 83 persons participated in this study including healthy subjects without both HCV antibodies and HCV RNA (22.9%), HCV treated responders accomplished SVR post treatment, with HCV antibodies and absence of HCV RNA (24.1%), spontaneous or natural clearance patients, with positive HCV antibodies and negative HCV RNA without treatment (26.5%) and chronic HCV-patients, with both positive HCV antibodies and HCV RNA with no treatment (26.5%). HCV RNA was quantitated by real time PCR and serum CXCL9 level was measured by ELISA commercial kit pre-coated with human MIG/CXCL9 antibody. Assessment of biochemical and hematological parameters was carried out.

RESULTS

Data showed that, the level of CXCL9 was significantly increased in chronic individuals (627.1 pg/ml) (P< 0.001) than spontaneous clearance (107.76 pg/ml) and responder subjects (117.28 pg/ml) (P⩽ 0.05). No correlation has been found between CXCL9 level and viral load. Furthermore, CXCL9 levels correlated variably with some biochemical and hematological parameters according to each subject.

CONCLUSION

Serum Chemokine CXCL9 level is associated with spontaneous clearance of HCV and response to HCV treatment, which may be identified as a predictive marker among HCV patients.

Identification of Key Biomarkers and Potential Molecular Mechanisms in Oral Squamous Cell Carcinoma by Bioinformatics Analysis

The aim of this study was to explore the key genes, microRNA (miRNA), and the pathogenesis of oral squamous cell carcinoma (OSCC) at the molecular level through the analysis of bioinformatics, which could provide a theoretical basis for the screening of drug targets. Data of OSCC were obtained from Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) were identified via GEO2R analysis. Next, protein-protein interaction (PPI) network of DEGs was constructed through Search Tool for the Retrieval of Interacting Gene and visualized via Cytoscape, whereas the hub genes were screened out with Cytoscape. Gene ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were performed by Database for Annotation, Visualization and Integrated Discovery. The miRNA, which might regulate hub genes, were screened out with TargetScan and GO and KEGG analysis of miRNA was performed by DNA Intelligent Analysis-miRPath. Survival analyses of DEGs were conducted via the Kaplan-Meier plotter. Finally, the relationships between gene products and tumors were analyzed by Comparative Toxicogenomics Database. A total of 121 differential genes were identified. One hundred thirty-five GO terms and 56 pathways were obtained, which were mainly related to PI3K-Akt signals pathway, FoxO signaling pathway, Wnt signaling pathway, cell cycle, p53 signaling pathway, cellular senescence, and other pathways; 10 genes were identified as hub genes through modules analyses in the PPI network. Finally, a survival analysis of 10 hub genes was conducted, which showed that the low expression of matrix metalloproteinase (MMP)1, MMP3, and C-X-C motif chemokine ligand (CXCL)1 and the high expression of CXCL9 and CXCL10 resulted in a significantly poor 5-year overall survival rate in patients with OSCC. In this study, the DEGs of OSCC was analyzed, which assists us in a systematic understanding of the pathogenicity underlying occurrence and development of OSCC. The MMP1, MMP3, CXCL1, CXCL9, and CXCL10 genes might be used as potential targets to improve diagnosis and as immunotherapy biomarkers for OSCC.

Diagnosis and management of linear scleroderma in children

PURPOSE OF REVIEW

Linear scleroderma is the most common subtype of localized scleroderma (LoS) in children. It can be associated with extracutaneous manifestations and long-term sequelae. Thus, appropriate diagnosis and management are key to improve the prognosis. In this review, we summarize the most relevant recent publications for the diagnosis, evaluation of disease activity and adequate management of patients with linear scleroderma.

RECENT FINDINGS

There are specific clinical features that indicate activity in LoS; dermoscopy and Wood's lamp may be useful. Summarizing, scoring methods seem to provide the most adequate assessment of LoS; but several biomarkers that correlate with activity have been studied: E-selectin and IL-2 receptor, CD34+ dermal dendritic cells and Th/Th1 immunophenotype with decreased T helper (Th2), T regulatory (Tregs), B and natural killer (NK) cells. Recent studies propose hydroxychloroquine monotherapy and tocilizumab as potential therapeutic options.

SUMMARY

Clinical evaluation, both physical exam and history, is the most important aspect in diagnosing and assessing activity of linear scleroderma. Clinical scoring methods may be most useful for evaluation of activity; eventually, other biomarkers could be relevant in clinical practice. For most patients with linear scleroderma, the first choice of treatment is methotrexate, but physical therapy, plastic surgery and/or orthopedic management are key to improve residual limitations and quality of life. VIDEO ABSTRACT: http://links.lww.com/MOP/A35.

Autoantibodies in Morphea: An Update

Skin autoimmune conditions belong to a larger group of connective tissue diseases and primarily affect the skin, but might also involve underlying tissues, such as fat tissue, muscle, and bone. Autoimmune antibodies (autoantibodies) play a role in autoimmune skin diseases, such as localized scleroderma also termed morphea, and systemic scleroderma, also called systemic sclerosis (SSc). The detailed studies on the biological role of autoantibodies in autoimmune skin diseases are limited. This results in a few available tools for effective diagnosis and management of autoimmune skin diseases. This review aims to provide an update on the detection and most recent research on autoantibodies in morphea. Several recent studies have indicated the association of autoantibody profiles with disease subtypes, damage extent, and relapse potential, opening up exciting new possibilities for personalized disease management. We discuss the role of existing autoantibody tests in morphea management and the most recent studies on morphea pathogenesis. We also provide an update on novel autoantibody biomarkers for the diagnosis and study of morphea.

T-cell positioning by chemokines in autoimmune skin diseases

Autoimmune skin diseases are complex processes in which autoreactive cells must navigate through the skin tissue to find their targets. Regulatory T cells in the skin help to mitigate autoimmune inflammation and may in fact be responsible for the patchy nature of these conditions. In this review, we will discuss chemokines that are important for global recruitment of T cell populations to the skin during disease, as well as signals that fine-tune their localization and function. We will describe prototypical disease responses and chemokine families that mediate these responses. Lastly, we will include an overview of chemokine-targeting drugs that have been tested as new treatment strategies for autoimmune skin diseases.

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.