Three Distinct Transcriptional Profiles of Monocytes Associate with Disease Activity in Scleroderma Patients

OBJECTIVE

Patients with diffuse cutaneous systemic sclerosis (dcSSc) display a complex clinical phenotype. Transcriptional profiling of whole blood or tissue from patients are affected by changes in cellular composition that drive gene expression and an inability to detect minority cell populations. We undertook this study to focus on the 2 main subtypes of circulating monocytes, classical monocytes (CMs) and nonclassical monocytes (NCMs) as a biomarker of SSc disease severity.

METHODS

SSc patients were recruited from the Prospective Registry for Early Systemic Sclerosis. Clinical data were collected, as well as peripheral blood for isolation of CMs and NCMs. Age-, sex-, and race-matched healthy volunteers were recruited as controls. Bulk macrophages were isolated from the skin in a separate cohort. All samples were assayed by RNA sequencing (RNA-seq).

RESULTS

We used an unbiased approach to cluster patients into 3 groups (groups A-C) based on the transcriptional signatures of CMs relative to controls. Each group maintained their characteristic transcriptional signature in NCMs. Genes up-regulated in group C demonstrated the highest expression compared to the other groups in SSc skin macrophages, relative to controls. Patients from groups B and C exhibited worse lung function than group A, although there was no difference in SSc skin disease at baseline, relative to controls. We validated our approach by applying our group classifications to published bulk monocyte RNA-seq data from SSc patients, and we found that patients without skin disease were most likely to be classified as group A.

CONCLUSION

We are the first to show that transcriptional signatures of CMs and NCMs can be used to unbiasedly stratify SSc patients and correlate with disease activity outcome measures.

Genome-Wide Reduction in Chromatin Accessibility and Unique Transcription Factor Footprints in Endothelial Cells and Fibroblasts in Scleroderma Skin

OBJECTIVE

Systemic sclerosis (SSc) is characterized by widespread fibrosis and vascular complications. This study was undertaken to examine the chromatin landscape and transcription factor footprints in SSc, using an assay for genome-wide chromatin accessibility.

METHODS

Dermal endothelial cells (ECs) and fibroblasts were isolated from healthy controls and patients with diffuse cutaneous SSc (dcSSc). Assay for transposase-accessible chromatin with sequencing (ATAC-seq) was performed to assess genome-wide chromatin accessibility at a read depth of ~150 million reads per sample. Transcription factor footprinting and motif binding analysis were performed, followed by functional experiments.

RESULTS

Chromatin accessibility was significantly reduced in dcSSc patients compared to healthy controls. Differentially accessible chromatin loci were enriched in pathways and gene ontologies involved in the nervous system, cell membrane projections and cilia motility, nuclear and steroid receptors, and nitric oxide. In addition, chromatin binding of transcription factors SNAI2, ETV2, and ELF1 was significantly increased in dcSSc ECs, while recruitment of RUNX1 and RUNX2 was enriched in dcSSc fibroblasts. We found significant down-regulation of the neuronal gene NRXN1 and up-regulation of SNAI2 and ETV2 in dcSSc ECs. In dcSSc fibroblasts, down-regulation of the neuronal gene ENTPD1 and up-regulation of RUNX2 were confirmed. Further functional analysis revealed that ETV2 and NRXN1 dysregulation affected angiogenesis in ECs, while ENTPD1 enhanced profibrotic properties in dcSSc fibroblasts.

CONCLUSION

Our data identify the chromatin blueprint of dcSSc, and suggest that neuronal-related characteristics of SSc ECs and fibroblasts could be a culprit for dysregulated angiogenesis and enhanced fibrosis. Targeting the key pathways and transcription factors identified might present novel therapeutic approaches in SSc.

Analysis of PI3K Pathway Associated Molecules Reveals Dysregulated Innate and Adaptive Functions of B Cells in Early Diffuse Cutaneous Systemic Sclerosis

B cell activation is an early event in the development of systemic sclerosis (SSc). The classical activation of B cells downstream of the B-cell receptor (BCR) involves the phosphatidylinositol-3 kinase (PI3K) pathway that integrates the effects of multiple co-stimulatory receptors. Our analysis of PI3K pathway associated molecules in peripheral blood B cells of early diffuse cutaneous SSc (dcSSc) patients showed altered mRNA expression of Toll-like receptor (TLR) homolog CD180, TLR4, complement component 3, IL-4 receptor and secreted phosphoprotein 1 (SPP1). Parallel to this, we found elevated basal SPP1 secretion in dcSSc B cells, but, with BCR + IL-4 receptor co-stimulation, we could not induce further secretion. CD180 stimulation alone resulted in NF-κB activation in more B cells than CD180 + BCR co-stimulation both in dcSSc and healthy control (HC), but the co-engagement increased the phosphorylation of NF-κB only in dcSSc B cells. Additionally, in contrast with HC B cells, the lower basal production of IL-10 by dcSSc B cells could not be elevated with CD180 stimulation. Furthermore, activation via CD180 increased the percentage of CD86+ switched memory (CD27+IgD−) B cells in dcSSc compared to HC. Our results suggest that alternative B cell activation and CD180 dysfunction cause imbalance of regulatory mechanisms in dcSSc B cells.

Machine learning integration of scleroderma histology and gene expression identifies fibroblast polarisation as a hallmark of clinical severity and improvement

OBJECTIVE

We sought to determine histologic and gene expression features of clinical improvement in early diffuse cutaneous systemic sclerosis (dcSSc; scleroderma).

METHODS

Fifty-eight forearm biopsies were evaluated from 26 individuals with dcSSc in two clinical trials. Histologic/immunophenotypic assessments of global severity, alpha-smooth muscle actin (aSMA), CD34, collagen, inflammatory infiltrate, follicles and thickness were compared with gene expression and clinical data. Support vector machine learning was performed using scleroderma gene expression subset (normal-like, fibroproliferative, inflammatory) as classifiers and histology scores as inputs. Comparison of w-vector mean absolute weights was used to identify histologic features most predictive of gene expression subset. We then tested for differential gene expression according to histologic severity and compared those with clinical improvement (according to the Combined Response Index in Systemic Sclerosis).

RESULTS

aSMA was highest and CD34 lowest in samples with highest local Modified Rodnan Skin Score. CD34 and aSMA changed significantly from baseline to 52 weeks in clinical improvers. CD34 and aSMA were the strongest predictors of gene expression subset, with highest CD34 staining in the normal-like subset (p<0.001) and highest aSMA staining in the inflammatory subset (p=0.016). Analysis of gene expression according to CD34 and aSMA binarised scores identified a 47-gene fibroblast polarisation signature that decreases over time only in improvers (vs non-improvers). Pathway analysis of these genes identified gene expression signatures of inflammatory fibroblasts.

CONCLUSION

CD34 and aSMA stains describe distinct fibroblast polarisation states, are associated with gene expression subsets and clinical assessments, and may be useful biomarkers of clinical severity and improvement in dcSSc.

Abatacept in Early Diffuse Cutaneous Systemic Sclerosis: Results of a Phase II Investigator-Initiated, Multicenter, Double-Blind, Randomized, Placebo-Controlled Trial

OBJECTIVE

T cells play a key role in the pathogenesis of early systemic sclerosis. This study was undertaken to assess the safety and efficacy of abatacept in patients with diffuse cutaneous systemic sclerosis (dcSSc).

METHODS

In this 12-month, randomized, double-blind, placebo-controlled trial, participants were randomized 1:1 to receive either subcutaneous abatacept 125 mg or matching placebo, stratified by duration of dcSSc. Escape therapy was allowed at 6 months for worsening disease. The coprimary end points were change in the modified Rodnan skin thickness score (MRSS) compared to baseline and safety over 12 months. Differences in longitudinal outcomes were assessed according to treatment using linear mixed models, with outcomes censored after initiation of escape therapy. Skin tissue obtained from participants at baseline was classified into intrinsic gene expression subsets.

RESULTS

Among 88 participants, the adjusted mean change in the MRSS at 12 months was -6.24 units for those receiving abatacept and -4.49 units for those receiving placebo, with an adjusted mean treatment difference of -1.75 units (P = 0.28). Outcomes for 2 secondary measures (Health Assessment Questionnaire disability index and a composite measure) were clinically and statistically significantly better with abatacept. The proportion of subjects in whom escape therapy was needed was higher in the placebo group relative to the abatacept group (36% versus 16%). In the inflammatory and normal-like skin gene expression subsets, decline in the MRSS over 12 months was clinically and significantly greater in the abatacept group versus the placebo group (P < 0.001 and P = 0.03, respectively). In the abatacept group, adverse events occurred in 35 participants versus 40 participants in the placebo group, including 2 deaths and 1 death, respectively.

CONCLUSION

In this phase II trial, abatacept was well-tolerated, but change in the MRSS was not statistically significant. Secondary outcome measures, including gene expression subsets, showed evidence in support of abatacept. These data should be confirmed in a phase III trial.

Simultaneous inhibition of c-Abl and Src kinases abrogates the exaggerated expression of profibrotic genes in cultured systemic sclerosis dermal fibroblasts

OBJECTIVES

To examine the effects of simultaneous inhibition of c-Abl and Src kinases on the gene expression and in vitro production of profibrotic molecules by dermal fibroblasts from patients with diffuse systemic sclerosis (SSc) of recent onset.

METHODS

Dermal fibroblasts from normal individuals or from patients with diffuse cutaneous SSc fulfilling the American College of Rheumatology/EULAR SSc classification criteria were cultured in media containing increasing concentrations of the dual c-Abl and Src kinase inhibitor Bosutinib for 24 h. Total soluble collagen in cell culture supernatants was quantified. Western blots were performed for quantitative assessment of type I collagen, fibronectin, and α-smooth muscle actin (α-SMA) production. Quantitative PCR was performed to examine the effects of Bosutinib on the expression of profibrotic and TGF-β-responsive genes in cultured SSc dermal fibroblasts.

RESULTS

Simultaneous inhibition of c-Abl and Src kinases with Bosutinib reduced the expression of numerous fibrosis-associated genes including COL1A1, COL1A3, FN, and TGFβ and the production of the corresponding proteins by SSc dermal fibroblasts. Bosutinib also decreased the transition of normal dermal fibroblasts into activated myofibroblasts induced by TGF-β as evidenced by reduction of α-SMA in cell extracts from normal and SSc dermal fibroblasts.

CONCLUSIONS

Simultaneous inhibition of c-Abl and Src kinases with Bosutinib abrogates the exaggerated expression of genes encoding fibrillar collagens, fibronectin, and TGF-β-responsive genes and reduces type I collagen, fibronectin and α-SMA production by SSc dermal fibroblasts in vitro. Bosutinib also abrogates TGF- β-induced transition of normal fibroblasts to activated myofibroblasts. These results indicate that inhibition of c-Abl and Src kinases activity may be an effective disease modifying antifibrotic therapeutic intervention for SSc.

Randomised, double-blind, placebo-controlled trial of IL1-trap, rilonacept, in systemic sclerosis. A phase I/II biomarker trial

OBJECTIVES

This clinical trial was designed to study the safety and efficacy of blocking IL-1 in skin fibrosis of patients with diffuse cutaneous systemic sclerosis (dcSSc), and to test the hypothesis that inhibition of IL-1 by rilonacept will downregulate expression of the 2G SSc gene biomarker as a surrogate for the modified Rodnan skin score (MRSS).

METHODS

19 dcSSc patients were randomised 2:1 active treatment:placebo in this double blinded trial. Study patients received weekly treatments with either subcutaneous rilanocept 320 mg loading dose at day 0 and then 160 mg for each of the 5 subsequent weekly doses, or placebo. Skin biopsies were taken to test 2G SSc biomarker gene expression at day 0 before treatment and one week after the final study drug dose, comparing gene expression changes between rilonacept- and placebo-treated patients, as well as the change in gene expression at week 6 compared to baseline in rilonacept-treated patients. Safety assessments extended to 6 weeks after the final dose of study drug or placebo. Other secondary outcome measures included global and IL-1-regulated gene expression, serum biomarkers and the MRSS.

RESULTS

Rilonacept compared to placebo-treated patients did not show any treatment-related effect on the 2G SSc biomarker. Rilonacept treatment also failed to alter IL-6 expression in skin, serum IL-6, C-reactive protein, or CCL18, a marker of IL-6 activity in SSc.

CONCLUSIONS

In this small trial we did not observe any effect of blocking IL-1 on clinical skin disease or biomarkers of IL-1 activity.

Belimumab for the Treatment of Early Diffuse Systemic Sclerosis: Results of a Randomized, Double-Blind, Placebo-Controlled, Pilot Trial

OBJECTIVE

To assess the safety and efficacy of treatment with belimumab in patients with early diffuse cutaneous systemic sclerosis (dcSSc) treated with background mycophenolate mofetil (MMF).

METHODS

In this 52-week, investigator-initiated, single-center, double-blind, placebo-controlled, pilot study, 20 patients with dcSSc recently started on MMF were randomized 1:1 to additionally receive belimumab at 10 mg/kg intravenously or placebo. We assessed safety, efficacy, and differential gene expression.

RESULTS

In the belimumab group, the median modified Rodnan skin thickness score (MRSS) decreased from 27 (interquartile range [IQR] 26.5, 31) to 18 (IQR 11, 23) (P = 0.039). In the placebo group, the median MRSS decreased from 28 (IQR 22, 28) to 21 (IQR 14, 25) (P = 0.023). The median change in MRSS was -10 (IQR -13, -9) in the belimumab group and -3.0 (IQR -15, -1) in the placebo group (P = 0.411). There were no significant differences between the groups in the number of adverse events (AEs). A significant decrease in expression of B cell signaling and profibrotic genes and pathways was observed in patients with improved MRSS in the belimumab group but not in the placebo group.

CONCLUSION

Patients in both treatment groups experienced significant improvements in MRSS. The median difference was greater in the belimumab group but did not achieve statistical significance in this small pilot study. AEs were similar between the groups. Changes in gene expression were consistent with mechanism of action and showed that clinical response to treatment with belimumab is associated with a significant decrease in profibrotic genes and pathways. Additional studies are needed to determine the role of belimumab in the treatment of dcSSc.

Brief Report: Association of Elevated Adipsin Levels With Pulmonary Arterial Hypertension in Systemic Sclerosis

OBJECTIVE

Adipose tissues secrete adipokines, peptides with potent effects modulating fibrosis, inflammation, and vascular homeostasis. Dysregulated adipose tissue biology and adipokine balance have recently been implicated in systemic sclerosis (SSc). This study was undertaken to determine whether altered circulating adipokine levels correlate with SSc disease subsets or clinical manifestations.

METHODS

Multiplex assays were used to measure circulating adipokine levels in 198 patients with SSc and 33 healthy controls. Data were evaluated for correlations between serum adipokine levels and demographic and clinical features, including pulmonary arterial hypertension (PAH). To assess the relevance of adipsin, an adipokine involved in complement pathway activation, in SSc, we analyzed publicly available genetic and transcriptomic data.

RESULTS

Levels of adiponectin and adipsin differed significantly between controls and patients. Adipsin was significantly elevated in patients with limited cutaneous SSc (odds ratio [OR] 28.3 [95% confidence interval (95% CI) 7.0-113.8]; P < 0.0001), and its levels were associated with serum autoantibody status, pulmonary function and cardiovascular parameters, and PAH (OR 3.3 [95% CI 1.3-8.7]; P = 0.02). Elevated adipsin was more strongly associated with PAH than B-type natriuretic peptide was. Moreover, in SSc patients, adipsin gene single-nucleotide polymorphisms were associated with PAH. Transcriptome data set analysis demonstrated elevated adipsin expression in patients with SSc-related PAH.

CONCLUSION

We identify adipsin as a novel adipose tissue-derived marker of SSc-related PAH. Circulating adipsin levels might serve as predictive biomarkers in SSc. Mechanistically, adipsin might represent a pathogenic link between adipocyte dysfunction and complement pathway activation and play an important role in the pathogenesis of SSc-related PAH.

Dendritic cells maintain dermal adipose-derived stromal cells in skin fibrosis

Scleroderma is a group of skin-fibrosing diseases for which there are no effective treatments. A feature of the skin fibrosis typical of scleroderma is atrophy of the dermal white adipose tissue (DWAT). Adipose tissue contains adipose-derived mesenchymal stromal cells (ADSCs) that have regenerative and reparative functions; however, whether DWAT atrophy in fibrosis is accompanied by ADSC loss is poorly understood, as are the mechanisms that might maintain ADSC survival in fibrotic skin. Here, we have shown that DWAT ADSC numbers were reduced, likely because of cell death, in 2 murine models of scleroderma skin fibrosis. The remaining ADSCs showed a partial dependence on dendritic cells (DCs) for survival. Lymphotoxin β (LTβ) expression in DCs maintained ADSC survival in fibrotic skin by activating an LTβ receptor/β1 integrin (LTβR/β1 integrin) pathway on ADSCs. Stimulation of LTβR augmented the engraftment of therapeutically injected ADSCs, which was associated with reductions in skin fibrosis and improved skin function. These findings provide insight into the effects of skin fibrosis on DWAT ADSCs, identify a DC-ADSC survival axis in fibrotic skin, and suggest an approach for improving mesenchymal stromal cell therapy in scleroderma and other diseases.

Dermal delivery of HSP47 siRNA with NOX4-modulating mesoporous silica-based nanoparticles for treating fibrosis

Fibrotic diseases such as scleroderma have been linked to increased oxidative stress and upregulation of pro-fibrotic genes. Recent work suggests a role of NADPH oxidase 4 (NOX4) and heat shock protein 47 (HSP47) in inducing excessive collagen synthesis, leading to fibrotic diseases. Herein, we elucidate the relationship between NOX4 and HSP47 in fibrogenesis and propose to modulate them altogether as a new strategy to treat fibrosis. We developed a nanoparticle platform consisting of polyethylenimine (PEI) and polyethylene glycol (PEG) coating on a 50-nm mesoporous silica nanoparticle (MSNP) core. The nanoparticles effectively delivered small interfering RNA (siRNA) targeting HSP47 (siHSP47) in an in vitro model of fibrosis based on TGF-β stimulated fibroblasts. The MSNP core also imparted an antioxidant property by scavenging reactive oxygen species (ROS) and subsequently reducing NOX4 levels in the in vitro fibrogenesis model. The nanoparticle was far superior to n-acetyl cysteine (NAC) at modulating pro-fibrotic markers. In vivo evaluation was performed in a bleomycin-induced scleroderma mouse model, which shares many similarities to human scleroderma disease. Intradermal administration of siHSP47-nanoparticles effectively reduced HSP47 protein expression in skin to normal level. In addition, the antioxidant MSNP also played a prominent role in reducing the pro-fibrotic markers, NOX4, alpha smooth muscle actin (α-SMA), and collagen type I (COL I), as well as skin thickness of the mice.

Serum levels, tissue expression and cellular secretion of macrophage migration inhibitory factor in limited and diffuse systemic sclerosis

OBJECTIVES

To investigate serum levels, tissue/cellular expression of macrophage migration inhibitory factor (MIF) in patients with limited (lSSc) and diffuse (dSSc) systemic sclerosis.

METHODS

10 lSSc-patients, 10 dSSc-patients and 10 controls were enrolled. MIF serum levels were assayed by ELISA. MIF and its receptors CD74/CD44 were evaluated by immunohistochemistry on skin biopsies from patients with dSSc, lSSc (affected and not-affected skin) and controls. MIF levels were assessed (ELISA) in supernatants of healthy dermal microvascular endothelial cells (MVECs) and in control (CTR), non-affected SSc (NA) and affected (SSc) fibroblasts treated for 48 h with 10% control serum and 10% SSc-serum. MIF supernatant (ELISA) and mRNA (quantitative real-time PCR) levels were determined in SSc dermal fibroblasts and in control dermal fibroblasts untreated or stimulated at 6 h-24 h-48 h with bleomycin (50 mU/ml).

RESULTS

Serum MIF was significantly higher in dSSc (18.7±4.1 ng/ml, p<0.001) and in lSSc (10.4±4.4 ng/ml, p<0.001) patients respect to controls (2.6±1.4 ng/ml). Enhanced MIF immunoreactivity was found in keratinocytes, fibroblasts, endothelium, sebaceous/sweat glands from lSSc/dSSc affected skin. Faint MIF immunoreactivity was found in control skin and not-affected skin of lSSc patients. No differences were found in CD74/CD44 receptors' analysis among control and dSSc/lSSc affected and non-affected skin. MVECs and fibroblasts (CTR, NA and SSc) produced significantly more MIF, when stimulated with SSc serum respect to control-serum (p<0.001). Finally, MIF mRNA levels significantly increased at 6h (p<0.001) and decreased at 48 h (p<0.001) in control fibroblasts treated with bleomycin compared to control untreated. Simultaneously, MIF supernatant protein levels increased after 48 h (p<0.01) in bleomycin-treated fibroblasts respect to untreated ones.

CONCLUSIONS

These results suggest that MIF could be implicated in the pathogenesis of SSc, probably acting as protective factor against the SSc stressful conditions.

Increased messenger RNA levels of the mesenchymal cadherin-11 in the peripheral blood of systemic sclerosis patients correlate with diffuse skin involvement

OBJECTIVES

Cadherin-11 is a cell-cell adhesion molecule also involved in cellular migration and invasion. Experimental studies implicated this molecule in inflammatory arthritis and fibrosing conditions. Moreover, cadherin-11 protein is hyper-expressed on fibroblasts and macrophages in the skin of systemic sclerosis (SSc) patients, whereas the respective mRNA levels correlate with skin thickness. Herein, we searched for possible cadherin-11 expression also in cells that circulate in SSc peripheral blood.

METHODS

Cadherin-11 mRNA was quantified by real-time reverse transcription-polymerase chain reaction in 3 ml blood samples obtained from 71 SSc patients (aged 53±2 years, 65 women) and 35 control non-SSc patients with Raynaud's phenomenon.

RESULTS

Cadherin-11 mRNA transcripts were detected in blood samples from 39% of patients with diffuse SSc, versus 16% of those with limited SSc, versus 6% and 16% of patients with idiopathic or associated with other connective tissue diseases Raynaud's phenomenon, respectively (p=0.049). Cadherin-11 mRNA levels in SSc patients were increased by 3.74-fold comparing to controls (p=0.036). By multivariate logistic regression analysis we found that diffuse skin involvement correlated, independently of age, gender, disease duration, lung involvement, digital ulcers, inflammatory indices or anti-Scl-70 autoantibody presence, with cadherin-11 mRNA positivity (p=0.028), but also with increased cadherin-11 mRNA levels (≥3-fold of non-SSc levels, p=0.011).

CONCLUSIONS

Cadherin-11 may be hyper-expressed in the peripheral blood of diffuse SSc patients. Studies on the origin and possible pathogenic function of these circulating cells may shed light into the complex disease pathogenesis and further support the notion that cadherin-11 is a potential therapeutic target in SSc.

Expression analysis of multiple microRNAs in each patient with scleroderma

In this study, we compared expression pattern of multiple microRNAs in individual patient with scleroderma with that in normal subject. Serum levels of six microRNAs (miR-7 g, miR-21, miR-29b, miR-125, miR-145 and miR-206) were evaluated using real-time PCR in 15 patients with scleroderma and 15 normal subjects. While levels of the six microRNAs were similar between the two groups, we found significant difference in the ranks between miRNAs in patients with scleroderma. Additionally, levels of let-7 g and miR-125b showed strong and significant correlation in normal subjects, but not in patients with scleroderma. Thus, miRNA expression pattern may be different in patients with scleroderma. We also found the combination of serum levels of miR-206 and miR-21 was more useful in distinguishing patients with scleroderma from normal subjects than either miR-206 or miR-21 alone. Our study is the first to demonstrate different expression profiles of multiple microRNAs in each patient with scleroderma and examine its clinical significance.

MicroRNA-21 in scleroderma fibrosis and its function in TGF-β-regulated fibrosis-related genes expression

Uncontrolled fibrosis in multiple organs is the main cause of death in systemic sclerosis (SSc), and transforming growth factor-β (TGF-β) activation plays a fundamental role in the process. Our previous study demonstrated that miR-21 was significantly up-regulated in SSc fibroblasts. Here, we found that TGF-β regulated the expression of miR-21 and fibrosis-related genes, and decreased Smad7 expression. Over-expression of miR-21 in fibroblasts decreased the levels of Smad7, whereas knockdown of miR-21 increased its expression. Further study using a reporter gene assay demonstrated Smad7 was a direct target of miR-21. Similar to human SSc, the expression of miR-21 increased in the bleomycin induced skin fibrosis. Inhibition of fibrosis by treatment with anti-fibrosis drug bortezomib restored the levels of miR-21 and Smad7. MiR-21 may function in an amplifying circuit to enhance TGF-β signaling events in SSc fibrosis, and suggesting that miR-21 may act as a potential therapeutic target.

Affected and non-affected skin fibroblasts from systemic sclerosis patients share a gene expression profile deviated from the one observed in healthy individuals

OBJECTIVES

To evaluate the gene expression profile of fibroblasts from affected and non-affected skin of systemic sclerosis (SSc) patients and from controls.

MATERIALS AND METHODS

Labeled cDNA from fibroblast cultures from forearm (affected) and axillary (non-affected) skin from six diffuse SSc patients, from three normal controls, and from MOLT-4/HEp-2/normal fibroblasts (reference pool) was probed in microarrays generated with 4193 human cDNAs from the IMAGE Consortium. Microarray images were converted into numerical data and gene expression was calculated as the ratio between fibroblast cDNA (Cy5) and reference pool cDNA (Cy3) data and analyzed by R environment/Aroma, Cluster, Tree View, and SAM softwares. Differential expression was confirmed by real time PCR for a set of selected genes.

RESULTS

Eighty-eight genes were up- and 241 genes down-regulated in SSc fibroblasts. Gene expression correlation was strong between affected and non-affected fibroblast samples from the same patient (r>0.8), moderate among fibroblasts from all patients (r=0.72) and among fibroblasts from all controls (r=0.70), and modest among fibroblasts from patients and controls (r=0.55). The differential expression was confirmed by real time PCR for all selected genes.

CONCLUSIONS

Fibroblasts from affected and non-affected skin of SSc patients shared a similar abnormal gene expression profile, suggesting that the widespread molecular disturbance in SSc fibroblasts is more sensitive than histological and clinical alterations. Novel molecular elements potentially involved in SSc pathogenesis were identified.

Molecular subsets in the gene expression signatures of scleroderma skin

BACKGROUND

Scleroderma is a clinically heterogeneous disease with a complex phenotype. The disease is characterized by vascular dysfunction, tissue fibrosis, internal organ dysfunction, and immune dysfunction resulting in autoantibody production.

METHODOLOGY AND FINDINGS

We analyzed the genome-wide patterns of gene expression with DNA microarrays in skin biopsies from distinct scleroderma subsets including 17 patients with systemic sclerosis (SSc) with diffuse scleroderma (dSSc), 7 patients with SSc with limited scleroderma (lSSc), 3 patients with morphea, and 6 healthy controls. 61 skin biopsies were analyzed in a total of 75 microarray hybridizations. Analysis by hierarchical clustering demonstrates nearly identical patterns of gene expression in 17 out of 22 of the forearm and back skin pairs of SSc patients. Using this property of the gene expression, we selected a set of 'intrinsic' genes and analyzed the inherent data-driven groupings. Distinct patterns of gene expression separate patients with dSSc from those with lSSc and both are easily distinguished from normal controls. Our data show three distinct patient groups among the patients with dSSc and two groups among patients with lSSc. Each group can be distinguished by unique gene expression signatures indicative of proliferating cells, immune infiltrates and a fibrotic program. The intrinsic groups are statistically significant (p<0.001) and each has been mapped to clinical covariates of modified Rodnan skin score, interstitial lung disease, gastrointestinal involvement, digital ulcers, Raynaud's phenomenon and disease duration. We report a 177-gene signature that is associated with severity of skin disease in dSSc.

CONCLUSIONS AND SIGNIFICANCE

Genome-wide gene expression profiling of skin biopsies demonstrates that the heterogeneity in scleroderma can be measured quantitatively with DNA microarrays. The diversity in gene expression demonstrates multiple distinct gene expression programs in the skin of patients with scleroderma.

TCRBV20S1 and TCRBV3S1 gene segment polymorphisms in systemic sclerosis

OBJECTIVE

To compare the frequencies of variants of TCRBV20S1 and TCRBV3S1 gene segments in patients with systemic sclerosis (SSc) and in controls. The null allele (allele 2) of TCRBV20S1 is associated with reduced levels of Vbeta20+ T-cells in the peripheral blood, while allele 1 of TCRBV3S1 is related to a low frequency of Vbeta3.1+ T-cells.

METHODS

One hundred thirty patients with SSc and 118 healthy volunteer controls were genotyped for TCRBV20S1, and 117 patients and 85 controls were genotyped for TCRBV3S1 variants by PCR-RFLP. Patients underwent clinical evaluation, serology, pulmonary function tests, high resolution computed tomography, and Doppler echocardiography.

RESULTS

The genotypic frequencies of TCRBV20S1 were 0.46 (allele 1/allele 1), 0.43 (allele 1/allele 2), and 0.11 (allele 2/allele 2) in SSc patients; in controls the frequencies were 0.70, 0.26, and 0.04, respectively (p < 0.001). The Mantel-Haenszel odds ratio (stratified by race and sex) of the allele 2 carrier state was 3.88 (95% CI 1.94 to 7.75). The allelic and genotypic frequencies of the TCRBV3S1 gene segment did not differ significantly in patients and controls. However, among patients, allele 1 (TCRBV3S1) carriers had a higher prevalence of interstitial lung disease (adjusted p = 0.032).

CONCLUSION

The null allele of the TCRBV20S1 and the allele 1 of TCRBV3S1 gene segments may be considered risk factors for the development of SSc and interstitial lung disease, respectively, suggesting a protective role of Vbeta20+ and Vbeta3.1+ cells in the pathogenic immune responses in SSc.

Association of polymorphisms in the IL1B and IL2 genes with susceptibility and severity of systemic sclerosis

OBJECTIVE

To investigate possible associations of 9 single-nucleotide polymorphisms in the IL10, IL1B, IL1A, IL1RN, IL2, LTA, and IL6 genes with susceptibility to systemic sclerosis (SSc), and with clinical subtype of SSc patients.

METHODS

A total of 78 patients with SSc [diffuse SSc (dcSSc), n = 31; limited SSc, (lcSSc), n = 47] and 692 healthy blood donors were genotyped for the following polymorphisms: IL10 T-3575A, IL10 A-1082G, IL1B C-31T, IL1B C-511T, IL1A C-889T, IL1RN A9589T, IL2 T-384G, LTA T-91G, and IL6 G-174C.

RESULTS

Alleles in IL1B-31 and IL1B-511 showed a significantly different distribution between cases and controls. Carriers of at least one copy of the IL1B-31-C allele had an increased risk of SSc [odds ratio (OR) 2.8, 95% confidence interval (CI) 1.6-5.2, p < 0.001], while a similar strong association was also evident for IL1B-511-T carriers (OR 3.1, 95% CI 1.7-5.7, p < 0.001). Interestingly, carriers of the IL2-384-G allele were significantly more frequent among patients with lcSSc (80.8%), compared to patients with the diffuse subtype (45.1%) (OR 5.1, 95% CI 1.8-14.3, p = 0.001) and in subjects positive to anticentromere antibodies (OR 4.2, 95% CI 1.5-11.9, p = 0.007). Lastly, the distribution of the IL2-384 genotype showed statistically significant differences between controls and patients with lcSSc (OR 3.5, 95% CI 1.7-7.4, p < 0.001). There were no differences between patients with dcSSc and controls.

CONCLUSION

IL1B and IL2 gene polymorphisms may be involved in susceptibility to SSc. Moreover, the IL2-384-G allele may be a marker for the limited phenotype of SSc.

KIRs and autoimmune disease: studies in systemic lupus erythematosus and scleroderma

We investigated killer immunoglobulin-like receptors (KIRs) and the human leukocyte antigen (HLA)-C ligands for the corresponding inhibitory KIRs in Caucasian patients, 304 with systemic lupus erythematosus (SLE) and 90 with scleroderma [or progressive systemic sclerosis (PSS)] compared with 416 Caucasian controls. Compared with controls, KIR2DS1 in the absence of KIR2DS2 was increased in both SLE (P= 0.04) and PSS (P= 0.02). Only 42% of KIR2DS1-positive PSS patients had the appropriate HLA-C ligand for the corresponding inhibitory KIR compared with 61% of KIR2DS1 positive controls (P= 0.02). In the PSS group the presence of at least either activating KIR2DS1 and/or 2DS2 was significantly increased in patients when compared with controls (P= 0.001). This suggests that KIR receptors play a role in susceptibility to both PSS and SLE.

Mutations of activin-receptor-like kinase 1 (ALK-1) are not found in patients with pulmonary hypertension and underlying connective tissue disease

Pulmonary arterial hypertension is a recognized clinical component of systemic autoimmune diseases, especially systemic sclerosis. Mutations in the bone morphogenetic protein receptor 2 gene reported in sporadic and familial primary pulmonary arterial hypertension have failed to be detected in patients with either scleroderma spectrum disease or underlying connective tissue diseases. Activin receptor-like kinase 1 (ALK-1) gene has recently been linked to the pathogenesis of pulmonary hypertension in patients with hereditary hemorrhagic telangiectasia, which has some resemblance with the CREST syndrome. The presence of mutations in the ALK-1 gene in ten patients with underlying connective tissue diseases was investigated.

Scleroderma in South Australia: further epidemiological observations supporting a stochastic explanation

The aim of this study was to determine the incidence, prevalence, survival and selective demographic characteristics of scleroderma occurring in South Australia over the 10-year period 1993-2002. Analysis of the database of the South Australian Scleroderma Register: a population-based register established in 1993. Patients with scleroderma resident in South Australia (n = 353 at 2002) were ascertained from multiple sources and clinical and demographic data were obtained from mailed questionnaire and from review of computerized hospital databases, case notes or referring letters. Time-space cluster analysis was carried out according to the Knox method. Control data were obtained from the Australian Bureau of Statistics census. The mean prevalence was 21.4 per 10(5) (95% confidence interval 20.2-22.6) and the mean cumulative incidence of 1.5 per 10(5) (95% confidence interval 1.32-1.73) with no significant change in incidence over the study period (P = 0.13). Cumulative survival improved over the study period, with patients with diffuse disease having significantly reduced survival (as compared with limited disease, P < 0.001). The proportion with diffuse disease ( approximately 22%) remained steady. There was a small but significant predisposition in patients with a continental European birthplace (P < 0.001). A family history of scleroderma was noted in 1.6% with lambda1 (familial risk) of 14.3 (95% confidence interval 5.9-34.5). However, a family history of systemic autoimmunity (especially rheumatoid arthritis) was more common (6%). No socioeconomic stratification, temporal clustering nor spatio-temporal clustering was observed either at time of initial symptom or at 10 years before disease onset. Scleroderma occurs relatively infrequently in South Australia with no significant change in incidence observed over the 10-year study period. However, cumulative survival has improved. Identified risk factors include family history of scleroderma (risk approximately 14-fold), female sex (risk approximately 5-fold) and European birthplace (risk approximately 2.5-fold); however, the majority of the disease variance appears unexplained. A stochastic explanation based on genetic instability is favoured to explain this paradox.

Contribution of activin receptor–like kinase 5 (transforming growth factor β receptor type I) signaling to the fibrotic phenotype of scleroderma fibroblasts

OBJECTIVE

To use a specific transforming growth factor beta receptor type I (TGFbetaRI; activin receptor-like kinase 5 [ALK-5]) kinase inhibitor (SD208) to determine the role of activation of the TGFbetaRI kinase (ALK-5) in maintaining the profibrotic phenotype of dermal fibroblasts in systemic sclerosis (SSc).

METHODS

The effect of SD208 on the expression of key biochemical markers of the fibrotic phenotype was compared in fibroblasts cultured from clinically involved (lesional) and clinically uninvolved skin of patients with diffuse cutaneous SSc (dcSSc) and in fibroblasts from healthy controls matched for age, sex, and anatomic site. Protein expression was compared together with the ability of fibroblasts to adhere to the extracellular matrix and to remodel and contract a free-floating fibroblast-populated type I collagen lattice.

RESULTS

Inhibiting TGFbetaRI kinase reduced the expression of a cohort of fibrotic markers by dermal fibroblasts from patients with dcSSc, including type I collagen and beta1 integrin. Moreover, inhibition also attenuated the elevated adhesive and contractile abilities of dcSSc fibroblasts.

CONCLUSION

Our data suggest that some of the key profibrotic features of lesional SSc fibroblasts are dependent upon ALK-5 activity. Thus, TGFbetaRI kinase-mediated signaling may contribute to dermal fibrosis in dcSSc.

HLA markers for susceptibility and expression in scleroderma

OBJECTIVE

Reported associations between HLA alleles and both susceptibility to and features of scleroderma have been conflicting. Our objective was (1) to determine the role of HLA alleles in the susceptibility to scleroderma; and (2) to determine the role of HLA alleles in various aspects of disease expression.

METHODS

Consecutive patients were followed in the scleroderma clinic between 1996 and 1998. Clinical data were obtained through chart review. Healthy volunteers as well as cadaveric donors served as controls. Molecular HLA typing was performed (polymerase chain reaction/sequence-specific oligonucleotides). Statistical analysis included Fisher's exact test and multivariate analyses, using logistic and linear regression models.

RESULTS

Ninety-five Caucasian patients (75 women, 20 men, age 43.9 yrs, disease duration 11.9 yrs) with scleroderma and 416 controls were studied. HLA-DRB1*01 and HLA-DRB1*11 were associated with susceptibility to scleroderma, whereas HLA-DRB1*07 was protective. HLA-A*30 and HLA-A*32 were also associated with susceptibility to scleroderma, while HLA-B*57 and HLA-Cw*14 were protective. HLA-B*62 and HLA-DRB1*07 had a significant correlation with the presence of diffuse skin involvement in both univariate and multivariate analyses. HLA-DRB1*11 was associated with high skin score values, while lower values were related to the presence of HLA-Cw*14 and HLA-DQB1*06. Both alleles retained significance in a linear regression model. High skin score values were related to the absence of anticentromere antibodies. Pulmonary fibrosis was associated with HLA-B*62 and HLA-Cw*0602, whereas pulmonary hypertension was associated with HLA-B*13 and HLA-B*65.

CONCLUSION

HLA alleles play a role in susceptibility to scleroderma and its disease expression.

Differential expression of tissue kallikrein in the skin of systemic sclerosis

Systemic sclerosis (SSc) is characterised by ischemic damage, impaired angiogenesis and skin fibrosis. Tissue kallikrein (t-kallikrein) is involved through kinins in inflammation, vasorelaxation and angiogenesis. T-kallikrein is synthetised by endothelial, smooth muscle, and inflammatory cells and, in skin, also by dark cells of the sweat glands, where it is involved in sweat formation. Our aim was to analyse, by immunohistochemistry and RT-PCR, the expression of t-kallikrein in the skin of patients with different SSc subsets, limited (lSSc) and diffuse (dSSc), and phases, early and advanced. Skin biopsies were taken from 18 SSc patients and 10 controls. Immunohistochemistry was performed on paraffin sections with an antibody against human urinary t-kallikrein. For RT-PCR, cDNA from skin biopsies was amplified using primers specific for human t-kallikrein. In the control skin, dark cells of the secretory units of sweat glands showed immunopositivity for t-kallikrein as well as blood vessels. In the lSSc skin, immunoreactivity was observed only in some glands, with weak staining in the advanced phase. In early lSSc skin, immunoreactivity was observed in microvessel walls and in the inflammatory infiltrate. In dSSc skin, dark cells of the glandular fundus units, and the few remaining vessels showed scarcity (early phase) or lack (advanced phase) of immunoreactivity for t-kallikrein. RT-PCR confirmed a decrease of t-kallikrein mRNA levels from early to advanced phase in SSc subsets, reaching its lowest level in advanced dSSc. In conclusion, immunohistochemical and biomolecular results indicate that t-kallikrein is decreased in the skin of SSc patients and decreases progressively from the early to advanced phase of lSSc and dSSc. The decreased expression of t-kallikrein may be involved in the impairment of the sweating process, vessel functionality and angiogenesis.

Association of TAP1 and TAP2 Gene Polymorphisms With Systemic Sclerosis in Korean Patients

We sought to determine whether transporter associated with antigen processing (TAP) gene polymorphism is associated with susceptibility to systemic sclerosis (SSc). TAP1 and TAP2 gene polymorphisms were analyzed in 61 Korean patients with SSc and 100 ethnically matched healthy Koreans by polymerase chain reaction-restriction fragment length polymorphism. Human leukocyte antigen (HLA)-DRB1 genotyping data of the patients from our previous study was used for the assessment of independent role of TAP genes to SSc susceptibility. Patients were stratified according to anti-topoisomerase I (anti-topo I) antibody status and clinical subsets of diffuse and limited cutaneous SSc (dcSSc and lcSSc). TAP1 and TAP2 gene polymorphisms were associated with different subsets of SSc: TAP1*A/A genotype with anti-topo I-positive dcSSc (p = 0.01, p corrected = 0.04), TAP2*A1/C genotype with anti-topo I-positive lcSSc (p < 0.05), TAP2*Bky2 and *C alleles with anti-topo I-negative dcSSc (both p < 0.05), and TAP2*B/E genotype with anti-topo I-negative lcSSc (p = 0.004). Although TAP gene associations were generally weak, some associations (TAP2*A1/C, TAP2*C, and TAP2*B/E) with different subsets of SSc were independent of HLA-DR associations, revealing even stronger associations (TAP2*A1/C and TAP2*C) among individuals not possessing the risk HLA-DR alleles. These results suggest the possible role of TAP gene polymorphisms in the genetic susceptibility to SSc.

HLA allelic variants encoding DR11 in diffuse and limited systemic sclerosis in Caucasian women

OBJECTIVE

We investigated HLA class II alleles in women with systemic sclerosis (SSc), a rare disease that preferentially affects women.

METHODS

Specific alleles of DRB1, DQA1 and DQB1 were determined by DNA-based HLA typing for women with SSc (n = 102) and healthy women (n = 533). All study subjects were Caucasian. DRB1, DQA1 and DQB1 allele frequencies of women with SSc were compared with those of healthy women.

RESULTS

Among women with SSc, 29.4% (30/102) and among healthy women 10.7% (57/533) had DRB1*11. Allele frequencies were compared for women with SSc and healthy women (each woman has two alleles). The allele frequency of DRB1*11 was 15.7% (32/204 alleles) in SSc women and 5.8% (62/1066 alleles) in healthy women (P = 0.000002). The increase of DRB1*11 was found both in diffuse (P = 0.0001) and limited SSc (P = 0.002) (allele frequencies 15.0 and 17.2%, respectively). Among women with diffuse SSc, there was a disproportionate increase of the DRB1*1104 allele (P = 0.0004) with no increase of DRB1*1101 (P = 1.00). In contrast, in limited SSc the strongest association was with DRB1*1101 (P = 0.008), with a less significant increase of DRB1*1104 (P = 0.04).

CONCLUSIONS

An increase of DRB1*11 in SSc is consistent with other reports. Although present in both diffuse and limited SSc disease subsets, the increase was predominantly due to over-representation of DRB1*1104 in women with diffuse SSc. Women with limited SSc had a preponderance of DRB1*1101, the most common allele in healthy women. DRB1*1104 and DRB1*1101 differ by a single amino acid at position 86, where the former has valine and the latter glycine.

Single-nucleotide polymorphisms in the SPARC gene are not associated with susceptibility to scleroderma

OBJECTIVE

SPARC (secreted protein, acidic and rich in cysteine) is a matricellular protein that modulates cell-cell and cell-extracellular matrix interactions. SPARC expression is restricted mainly to sites of tissue remodelling and wound repair, and is prominent in fibrotic disorders. Single-nucleotide polymorphisms (SNPs) in the SPARC gene are reportedly linked to scleroderma in four ethnic groups: Choctaw Indians, Caucasians, African Americans and Mexican Americans. We set out to reproduce and to positionally clone these disease associations in a set of UK Caucasian scleroderma patients and ethnically matched controls.

METHODS

One hundred and twenty-one scleroderma subjects and 200 controls were genotyped by polymerase chain reaction with sequence-specific primers differing only in the 3' nucleotide corresponding to each allele of the biallelic SNPs. Scleroderma patients were analysed against controls and on the basis of their fibrosing alveolitis status as judged by high-resolution computed tomography evaluation and the extent of cutaneous involvement.

RESULTS

Eight biallelic SNPs were genotyped: three from the last untranslated exon, which had been described previously, and an additional five novel SNPs: two in the promoter region, one in exon three and two in the 3' untranslated region. Six major haplotypes were constructed across all eight SNP positions. No significant differences in genotype, allele or haplotype frequency were observed between scleroderma and controls or within scleroderma subgroups.

CONCLUSIONS

SNPs in the SPARC gene are not associated with susceptibility to scleroderma. This research adds to the genetic knowledge of the SPARC gene by identifying five novel SNPs spanning the whole gene and inserting these within the context of clearly defined haplotypes.

Analysis of the 5' flanking region of the interleukin 10 gene in patients with systemic sclerosis

OBJECTIVES

Fibrosis, a feature of systemic sclerosis (SSc), is more severe in the diffuse compared with the limited disease variant. Interleukin 10 (IL-10) is an anti-inflammatory cytokine which reduces type 1 collagen mRNA levels in human fibroblasts. The 5' flanking region of the IL-10 gene is highly polymorphic, with three single base pair substitutions at position -1082(G/A), -819(C/T) and -592(C/A), which results in differential IL-10 production. The GCC/GCC genotype is associated with high IL-10 production while the ATA/ATA genotype with low production. We postulated that there would be a difference in IL-10 polymorphisms in patients with limited (lSSc) and diffuse (dSSc) disease.

METHODS

Patients with limited (lSSc, n = 89) or diffuse (dSSc, n = 51) disease plus controls (n = 94) were recruited. DNA was isolated from peripheral blood and polymorphisms analysed using amplification refractory mutation system (ARMS) polymerase chain reaction (PCR).

RESULTS

dSSc patients were less likely to carry the genotype indicative of high IL-10 production when compared with controls (controls vs dSSc; 29 vs 4%, chi2 = 15.7, 5 df, P = 0.005) and lSSc patients (lSSc vs dSSc; 21 vs 4%, chi2 = 17.5, 5 df, P = 0.002). There was no difference between control and lSSc patients. While there was no difference between controls and lSSc haplotypes, the GCC haplotype distribution did differ significantly between controls and dSSc patients (controls vs dSSc; 54 vs 36%, chi2 = 11.2, 2 df, P = 0.001). A significant difference was also observed between lSSc and dSSc haplotype distribution (lSSc vs dSSc; 48 vs 36%, chi2 = 13.5, 2 df, P < 0.001).

CONCLUSION

We demonstrate that IL-10 genotypes associated with high IL-10 production are under-represented in dSSc. This may have implications in the disease pathology.

Transcriptional inhibition of type I collagen gene expression in scleroderma fibroblasts by the antineoplastic drug ecteinascidin 743

We previously showed that COL1A1 expression is up-regulated at the transcriptional level in systemic sclerosis (SSc) fibroblasts and that the CCAAT-binding factor (CBF) is involved in this increased expression. Ecteinascidin 743 (ET-743) is a chemotherapeutic agent that binds with sequence specificity to the minor groove of DNA and inhibits CBF-mediated transcriptional activation of numerous genes. Therefore, we examined the effects of ET-743 on the increased COL1A1 expression in SSc fibroblasts. The drug caused a potent and dose-dependent inhibition of type I collagen biosynthesis, which reached 70-90% at 700 pM without affecting cell viability. The same drug concentration caused 60-80% reduction in COL1A1 mRNA levels. The stability of the corresponding transcripts was not affected. In vitro nuclear transcription assays demonstrated a 54% down-regulation of COL1A1 transcription. Transient transfections with COL1A1 promoter constructs containing the specific CBF binding sequence into SSc cells previously treated with 700 pM ET-743 failed to show an effect on COL1A1 promoter activity. Furthermore, ET-743 did not affect the binding of CBF or Sp1 transcription factors to their cognate COL1A1 elements. However, treatment with 700 pM ET-743 of stably transfected NIH 3T3 cells expressing a human type II procollagen gene under the control of the human COL1A1 promoter caused a greater than 50% reduction in the production of type II procollagen and a similar decrease in the corresponding type II procollagen transcripts. These results indicate that ET-743 is a potent inhibitor of COL1A1 transcription. However, this effect cannot be explained by a direct effect on CBF binding to the COL1A1 promoter. Although the exact mechanisms responsible for the transcriptional inhibition of COL1A1 by ET-743 are not apparent, our observations suggest that the drug may be an effective agent to decrease collagen overproduction in SSc and other fibrotic diseases.

Systemic and cell type-specific gene expression patterns in scleroderma skin

We used DNA microarrays representing >12,000 human genes to characterize gene expression patterns in skin biopsies from individuals with a diagnosis of systemic sclerosis with diffuse scleroderma. We found consistent differences in the patterns of gene expression between skin biopsies from individuals with scleroderma and those from normal, unaffected individuals. The biopsies from affected individuals showed nearly indistinguishable patterns of gene expression in clinically affected and clinically unaffected tissue, even though these were clearly distinguishable from the patterns found in similar tissue from unaffected individuals. Genes characteristically expressed in endothelial cells, B lymphocytes, and fibroblasts showed differential expression between scleroderma and normal biopsies. Analysis of lymphocyte populations in scleroderma skin biopsies by immunohistochemistry suggest the B lymphocyte signature observed on our arrays is from CD20+ B cells. These results provide evidence that scleroderma has systemic manifestations that affect multiple cell types and suggests genes that could be used as potential markers for the disease.