Assessment and management of scleroderma lung disease:

Characterising the autoantibody repertoire in systemic sclerosis following myeloablative haematopoietic stem cell transplantation

OBJECTIVES

Results from the SCOT (Scleroderma: Cyclophosphamide Or Transplantation) clinical trial demonstrated significant benefits of haematopoietic stem cell transplant (HSCT) versus cyclophosphamide (CTX) in patients with systemic sclerosis. The objective of this study was to test the hypothesis that transplantation stabilises the autoantibody repertoire in patients with favourable clinical outcomes.

METHODS

We used a bead-based array containing 221 protein antigens to profile serum IgG autoantibodies in participants of the SCOT trial.

RESULTS

Comparison of autoantibody profiles at month 26 (n=23 HSCT; n=22 CTX) revealed antibodies against two viral antigens and six self-proteins (SSB/La, CX3CL1, glycyl-tRNA synthetase (EJ), parietal cell antigen, bactericidal permeability-increasing protein and epidermal growth factor receptor (EGFR)) that were significantly different between treatment groups. Linear mixed model analysis identified temporal increases in antibody levels for hepatitis B surface antigen, CCL3 and EGFR in HSCT-treated patients. Eight of 32 HSCT-treated participants and one of 31 CTX-treated participants had temporally varying serum antibody profiles for one or more of 14 antigens. Baseline autoantibody levels against 20 unique antigens, including 9 secreted proteins (interleukins, IL-18, IL-22, IL-23 and IL-27), interferon-α2A, stem cell factor, transforming growth factor-β, macrophage colony-stimulating factor and macrophage migration inhibitory factor were significantly higher in patients who survived event-free to month 54.

CONCLUSIONS

Our results suggest that HSCT favourably alters the autoantibody repertoire, which remains virtually unchanged in CTX-treated patients. Although antibodies recognising secreted proteins are generally thought to be pathogenic, our results suggest a subset could potentially modulate HSCT in scleroderma.

Anesthetic Management of a Patient With Systemic Sclerosis and Microstomia

Systemic sclerosis (SSc) is an autoimmune disease that can cause fibrosis in vital organs, often resulting in damage to the skin, blood vessels, gastrointestinal system, lungs, heart, and/or kidneys. Patients with SSc are also likely to develop microstomia, which can render dental treatment difficult and painful, thereby necessitating advanced anesthetic management. This is a case report of a 61-year-old woman with a history of SSc with microstomia, interstitial pneumonia, and gastroesophageal reflux disease in whom intravenous moderate sedation was performed using a combination of dexmedetomidine and ketamine for dental extractions. Both anesthetic agents are known to have analgesic effects while minimizing respiratory depression. Consequently, the increased discomfort caused by opening the patient's mouth and stretching the buccal mucosa was sufficiently managed, permitting an increase in maximum interincisal opening and completion of treatment without complications. Patients with SSc present with serious comorbidities that can negatively impact anesthetic management, so the implementation of an anesthetic plan that takes such risks into account is required. Furthermore, emergency airway management is likely to be difficult in patients with microstomia. For intravenous moderate sedation, combined use of dexmedetomidine and ketamine, which have analgesic effects while minimizing respiratory depression, may be particularly effective in patients with SSc and microstomia.

Therapeutic interleukin-6 blockade reverses transforming growth factor-beta pathway activation in dermal fibroblasts: insights from the faSScinate clinical trial in systemic sclerosis

OBJECTIVES

Skin fibrosis mediated by activated dermal fibroblasts is a hallmark of systemic sclerosis (SSc), especially in the subset of patients with diffuse disease. Transforming growth factor-beta (TGFβ) and interleukin-6 (IL-6) are key candidate mediators in SSc. Our aim was to elucidate the specific effect of IL-6 pathway blockade on the biology of SSc fibroblasts in vivo by using samples from a unique clinical experiment-the faSScinate study-in which patients with SSc were treated for 24 weeks with tocilizumab (TCZ), an IL-6 receptor-α inhibitor.

METHODS

We analysed the molecular, functional and genomic characteristics of explant fibroblasts cultured from matched skin biopsy samples collected at baseline and at week 24 from 12 patients receiving placebo (n=6) or TCZ (n=6) and compared these with matched healthy control fibroblast strains.

RESULTS

The hallmark functional and molecular-activated phenotype was defined in SSc samples and was stable over 24 weeks in placebo-treated cases. RNA sequencing analysis robustly defined key dysregulated pathways likely to drive SSc fibroblast activation in vivo. Treatment with TCZ for 24 weeks profoundly altered the biological characteristics of explant dermal fibroblasts by normalising functional properties and reversing gene expression profiles dominated by TGFβ-regulated genes and molecular pathways.

CONCLUSIONS

We demonstrated the exceptional value of using explant dermal fibroblast cultures from a well-designed trial in SSc to provide a molecular framework linking IL-6 to key profibrotic pathways. The profound impact of IL-6R blockade on the activated fibroblast phenotype highlights the potential of IL-6 as a therapeutic target in SSc and other fibrotic diseases.

TRIAL REGISTRATION NUMBER

NCT01532869; Post-results.

Thrombin increases lung fibroblast survival while promoting alveolar epithelial cell apoptosis via the endoplasmic reticulum stress marker, CCAAT enhancer-binding homologous protein

Apoptosis of alveolar epithelial cells (AECs) and survival of lung fibroblasts are critical events in the pathogenesis of pulmonary fibrosis; however, mechanisms underlying the apoptosis of AECs and the resistance of lung fibroblasts to apoptosis remain obscure. Herein, we demonstrate that the fate of these two cell types depends on the expression of CCAAT enhancer-binding homologous protein (CHOP). We observed that thrombin, which is overexpressed in scleroderma (SSc; systemic sclerosis) and other interstitial lung diseases (ILDs), increases the expression of CHOP in primary AECs and in A549 cells via an Ets1-dependent pathway. In addition, thrombin activates caspase-3 in AECs and induces apoptosis of these cells in a CHOP-dependent manner. In contrast, thrombin decreases endoplasmic reticulum stress-induced CHOP in lung fibroblasts through Myc-dependent mechanisms and protects such cells from apoptosis. Furthermore, when lung fibroblasts are transfected with recombinant CHOP, they then undergo apoptosis, even in the presence of thrombin, suggesting that CHOP signaling pathways are downstream of thrombin. In accordance with the differential effects of thrombin on AECs and lung fibroblasts, we observed strong expression of CHOP in AECs in fibrotic lung tissue isolated from patients with SSc-associated ILD (SSc-ILD), but not in lung myofibroblasts nor in normal lung tissue. Expression of CHOP in SSc lung is accompanied by positive staining for the thrombin receptor, protease-activated receptor-1, and for terminal deoxynucleotidyl transferase dUTP nick end labeling, suggesting roles for both thrombin and CHOP in AEC apoptosis in SSc-ILD. We conclude that regulation of CHOP by thrombin directs AECs toward apoptosis while promoting survival of lung fibroblasts, ultimately contributing to the persistent fibroproliferation seen in SSc-ILD and other fibrosing lung diseases.

Serum interleukin 9 levels are increased in patients with systemic sclerosis: association with lower frequency and severity of pulmonary fibrosis

OBJECTIVE

To determine serum interleukin 9 (IL-9) levels and their clinical associations in patients with systemic sclerosis (SSc).

METHODS

Serum IL-9 levels were examined by ELISA in 71 patients with SSc, 15 with systemic lupus erythematosus (SLE), 15 with dermatomyositis (DM), 39 with atopic dermatitis, and 28 healthy individuals.

RESULTS

Serum IL-9 levels were significantly elevated in SSc patients (84.6 ± 76.0 pg/ml) compared with healthy individuals (40.4 ± 41.7 pg/ml; p < 0.001), and patients with SLE (50.7 ± 52.0 pg/ml; p < 0.05) or DM (50.6 ± 55.8 pg/ml; p < 0.05) or atopic dermatitis (41.8 ± 38.8 pg/ml; p < 0.001). Among SSc patients, there were no differences in serum IL-9 levels between those with limited cutaneous SSc and those with diffuse cutaneous SSc. Patients with SSc and raised IL-9 levels less often had pulmonary fibrosis and decreased percentage vital capacity than those with normal IL-9 levels. IL-9 levels were positively correlated with percentage vital capacity in patients with SSc.

CONCLUSION

Serum IL-9 level was increased in patients with SSc, and was associated with lower frequency and severity of pulmonary fibrosis in SSc. IL-9 could be a protective factor against the development of pulmonary fibrosis in this disease, and as such would be a possible therapeutic target.

The pathogenesis of systemic sclerosis

Systemic sclerosis (SSc), also known as scleroderma, is a rare connective tissue disease characterized by vascular and immune dysfunction, leading to fibrosis that can damage multiple organs. Its pathogenesis is complex and poorly understood. Two major clinical subtypes are the limited and diffuse forms. Research into SSc has been hampered by its rarity, its clinical heterogeneity, and the lack of mouse models that accurately recapitulate the disease. Clinical and basic studies have yielded some mechanistic clues regarding pathogenesis. Recent insights gained through the use of microarrays have revealed distinctive subsets of SSc within and beyond the limited and diffuse subsets. In this review, we discuss potential mechanisms underlying the vascular, autoimmune, and fibrotic points of dysregulation. Proper categorization of SSc patients for research studies by use of microarrays or other biomarkers is critical, as disease heterogeneity may explain some of the inconsistencies of prior studies.

Elevated Circulating TWEAK Levels in Systemic Sclerosis: Association with Lower Frequency of Pulmonary Fibrosis

Objective.

To determine serum levels of tumor necrosis factor-related weak inducer of apoptosis (TWEAK) and its clinical associations in patients with systemic sclerosis (SSc).

Methods.

Serum TWEAK levels from 70 patients with SSc were examined by ELISA. In a retrospective longitudinal study, sera from 23 patients with SSc were analyzed (followup 0.8–7.2 yrs).

Results.

Serum TWEAK levels were elevated in patients with SSc (n = 70) compared with healthy controls (n = 31) and patients with systemic lupus erythematosus (n = 22). Among patients with SSc, there were no differences in serum TWEAK levels between limited cutaneous SSc and diffuse cutaneous SSc. Patients with SSc who had elevated TWEAK levels less often had pulmonary fibrosis and decreased vital capacity than those with normal TWEAK levels. In the longitudinal study, SSc patients with inactive pulmonary fibrosis or without pulmonary fibrosis consistently exhibited increased TWEAK levels, while those with active pulmonary fibrosis showed decreased TWEAK levels during the followup period.

Conclusion.

TWEAK levels were increased in patients with SSc, and associated with a lower frequency of pulmonary fibrosis in patients with SSc. TWEAK could be a protective factor against the development of pulmonary fibrosis in this disease and as such would be a possible therapeutic target.

The proadhesive phenotype of systemic sclerosis skin promotes myeloid cell adhesion via ICAM-1 and VCAM-1

OBJECTIVE

SSc is characterized by microvascular abnormalities and leucocyte infiltration. Previous studies have suggested a proadhesive phenotype in SSc skin, but the functional consequences of this phenotype are not fully understood. Molecules known to mediate leucocyte adhesion include those present at intracellular junctions, such as junctional adhesion molecule-B (JAM-B), JAM-C and CD99, as well as intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). The aim of this study was to examine adhesive interactions in SSc skin.

METHODS

The expression of JAM-B, JAM-C, CD99, ICAM-1 and VCAM-1 in SSc skin was determined by immunohistology and cell surface ELISA. Myeloid U937 cell-SSc dermal fibroblast adhesion assays or in situ adhesion assays to SSc skin were performed.

RESULTS

JAM-C and CD99 expression on endothelial cells (ECs) in SSc skin was decreased compared with expression on normal ECs. CD99 was overexpressed on mononuclear cells in SSc skin and on SSc dermal fibroblasts. Neutralizing ICAM-1 inhibited the binding of U937 cells to SSc dermal fibroblasts. In addition, blocking both ICAM-1 and VCAM-1 inhibited U937 cell adhesion to either proximal (less involved) or distal (more involved) SSc skin.

CONCLUSIONS

These studies show that JAM-C and CD99 are aberrantly expressed in SSc skin. However, these adhesion molecules do not mediate myeloid cell-SSc skin adhesion. In contrast, we demonstrate an important role for ICAM-1 and VCAM-1 in the retention of myeloid cells in SSc skin, suggesting that targeting these molecules may be useful SSc therapies.

Elevated serum concentrations of polymorphonuclear neutrophilic leukocyte elastase in systemic sclerosis: association with pulmonary fibrosis

OBJECTIVE

To determine the serum concentrations and clinical association of polymorphonuclear neutrophilic leukocyte (PMN) elastase in patients with systemic sclerosis (SSc).

METHODS

Serum PMN elastase levels from 21 patients with limited cutaneous SSc (lSSc) and 32 with diffuse cutaneous SSc (dSSc) were examined by ELISA.

RESULTS

Serum PMN elastase levels were elevated in patients with SSc, especially dSSc, compared to healthy controls. SSc patients with elevated serum PMN elastase levels had more frequent presence of pulmonary fibrosis, arthritis, contracture of phalanges, and diffuse pigmentation. Anticentromere antibody was detected less frequently in SSc patients with elevated serum PMN elastase levels than in controls. Consistently, serum PMN elastase levels also correlated positively with serum levels of KL-6 and surfactant protein-D, serological markers for pulmonary fibrosis. Serum PMN elastase levels were also associated with levels of serum 8-isoprostane, an oxidative stress marker in SSc.

CONCLUSION

Serum PMN elastase levels were elevated in patients with SSc, and it was more prominent in patients with pulmonary fibrosis, suggesting that serum PMN elastase is a novel serological marker for SSc-related pulmonary fibrosis.

Statins as Immunomodulators in Systemic Sclerosis

Systemic sclerosis (SSc) has the highest case-specific mortality among the rheumatic diseases. Vascular dysfunction and structural wall abnormalities are among the earliest and fundamental alterations in SSc. Statins have a number of immunomodulating effects on vascular wall cells, which may modify the progression of vascular injury. The aim of this study was to evaluate the potential efficacy of statin therapy in ameliorating endothelial dysfunction (ED) in SSc by investigating the effect of statins on some markers that reflect endothelial activation in SSc. Forty patients with SSc were randomized into two groups to receive 6 months' treatment with atorvastatin (n = 20; dose, 40 mg/day) or placebo (n = 20) as an adjuvant to existing therapy. Markers of ED including ET-1, plasma nitrate levels, and thrombomodulin (TM) were evaluated by the enzyme-linked immunosorbent assay (ELISA) technique. Fibrinogen, high-sensitivity C-reactive protein (hsCRP), ESR, lipid peroxide (LP), and malonylaldehyde (MDA) levels were also assessed. Brachial flow-mediated vasodilatation was assessed by ultrasonography. Patients were studied at base line and after 6 months of statin therapy. After 6 months of therapy, ET-1, ICAM-1, sE-selectin, vWF, fibrinogen, ESR, hsCRP as well as LP and MDA levels declined and NO increased significantly in the statin-treated SSc group when compared to the placebo-treated group. Endothelium-dependent vasodilatation (EDV) improved significantly in the atorvastatin-treated group. The findings of this study demonstrated statin-mediated improvements in the endothelial function of SSc patients as well as immunomodulating effects. Statins may thus prove to be an invaluable addition to the therapy of the vasculopathy of SSc.

Taxane-induced scleroderma

We report five women who presented with scleroderma due to taxanes, mimicking systemic sclerosis. All five patients had received taxane chemotherapy for the treatment of metastatic breast cancer. Marked oedema began first, followed by skin sclerosis occurring mainly at the distal ends of the extremities 6-12 months after the administration of taxane in all patients. Skin biopsies showed full-layer dermal fibrosis with thickened collagen bundles, and perivascular monocytic cell infiltration. These cases resemble systemic sclerosis in terms of their clinical course and histological findings. However, clinical findings including Raynaud's phenomenon and pulmonary fibrosis as well as immunological abnormalities associated with systemic sclerosis were not detected in any of the patients. Although the mechanisms have not been clarified, it should be noted that taxane is causally involved in the formation of scleroderma-like skin conditions.

[B cell abnormalities and autoantibody production in systemic sclerosis]

The pathogenetic roles of autoantibodies remain unknown in systemic sclerosis (SSc). CD19, a cell-surface critical signal transduction molecule of B lymphocytes, augments signaling through B cell antigen receptor and CD19 overexpression in mice induces various autoantibody production. Peripheral B cells from SSc patients exhibit 20%-increase in CD19 expression. Furthermore, B cells from a tight-skin (TSK) mouse, a genetic murine model of SSc, show augmented signaling through CD19. The deficiency of CD19 expression in TSK mice results in inhibition of autoantibody production, reduced skin fibrosis, and inhibition of augmented IL-6 production by splenic B cells. Collectively, a new model that could explain the relationship between autoantibody and the development of fibrosis is proposed. CD19 overexpression observed in SSc patients breaks down peripheral tolerance of B cells, which results in autoantibody production. Furthermore, it is also possible that in vivo chronic B cell activation probably due to CD19 overexpression results in the development of fibrosis through production of fibrogenic cytokines, such as IL-6. This model indicates that B cells or CD19 would be potential therapeutic targets in SSc.

Serum nitric oxide (NO) levels in systemic sclerosis patients: correlation between NO levels and clinical features

Vascular damage in systemic sclerosis (SSc) may be a factor in the abnormal regulation of several vasoactive agents. It has been well confirmed that plasma endothelin-1, as a vasoconstrictive factor, is elevated in patients with SSc. However, it is still controversial whether the levels of serum nitric oxide (NO), a strong vasodilator, are increased or decreased in SSc patients compared to healthy donors. In this study, we measured the levels of serum NO metabolites in SSc patients and determined the contribution of the excessive production of NO synthase (NOS)-2 by skin fibroblasts to NO synthesis. Serum NO levels of 45 patients with SSc were significantly higher than those of 20 healthy volunteers. In addition, some clinical features of SSc (the extent of skin fibrosis, short disease duration, and the complication of active fibrosing alveolitis) were all correlated positively with the levels of NO metabolites in SSc patients. To evaluate the levels of NOS-2 produced by skin fibroblasts, skin fibroblast cultures were established from SSc patients and healthy volunteers. Reverse transcription-polymerase chain reaction indicated that NOS-2 mRNA was spontaneously expressed in cultured fibroblasts derived from SSc patients, but not in those derived from healthy normal controls. Immunohistochemical staining also showed that NOS-2 proteins were detected in SSc fibroblasts but not in normal fibroblasts. The production of NO by cultured fibroblasts was visualized directly by a reagent (DAF-2 DA) used for the fluorescent detection of NO. Cultured SSc fibroblasts were capable of NO synthesis in culture media containing L-arginine, whereas normal fibroblasts (with no expression of NOS-2) did not synthesize detectable NO. These observations indicate that NO production is increased markedly in early-stage diffuse cutaneous SSc patients with active fibrosing alveolitis, and that constitutive NOS-2 expression in SSc fibroblasts may contribute to increased NO production.

Murine sclerodermatous graft-versus-host disease, a model for human scleroderma: cutaneous cytokines, chemokines, and immune cell activation

Murine sclerodermatous graft-vs-host disease (Scl GVHD) models human scleroderma, with prominent skin thickening, lung fibrosis, and up-regulation of cutaneous collagen mRNA. Fibrosis in Scl GVHD may be driven by infiltrating TGF-beta1-producing mononuclear cells. Here we characterize the origin and types of those cutaneous effector cells, the cytokine and chemokine environments, and the effects of anti-TGF-beta Ab on skin fibrosis, immune cell activation markers, and collagen and cytokine synthesis. Donor cells infiltrating skin in Scl GVHD increase significantly at early time points post-transplantation and are detectable by PCR analysis of Y-chromosome sequences when female mice are transplanted with male cells. Cutaneous monocyte/macrophages and T cells are the most numerous cells in Scl GVHD compared with syngeneic controls. These immune cells up-regulate activation markers (MHC class II I-A(d) molecules and class A scavenger receptors), suggesting Ag presentation by cutaneous macrophages in early fibrosing disease. Early elevated cutaneous mRNA expression of TGF-beta1, but not TGF-beta2 or TGF-beta3, and elevated C-C chemokines macrophage chemoattractant protein-1, macrophage inflammatory protein-1alpha, and RANTES precede subsequent skin and lung fibrosis. Therefore, TGF-beta1-producing donor mononuclear cells may be critical effector cells, and C-C chemokines may play important roles in the initiation of Scl GVHD. Abs to TGF-beta prevent Scl GVHD by effectively blocking the influx of monocyte/macrophages and T cells into skin and by abrogating up-regulation of TGF-beta1, thereby preventing new collagen synthesis. The Scl GVHD model is valuable for testing new interventions in early fibrosing diseases, and chemokines may be new potential targets in scleroderma.

Elevated serum KL-6 levels in patients with systemic sclerosis: association with the severity of pulmonary fibrosis

BACKGROUND

Serum KL-6 has been suggested to be a useful marker for the evaluation of interstitial lung disease activity.

OBJECTIVE

To determine the correlation between serum KL-6 levels and pulmonary fibrosis in patients with systemic sclerosis (SSc).

METHODS

Serum samples from patients with limited cutaneous SSc (lSSc; n = 19), diffuse cutaneous SSc (dSSc; n = 26) and normal individuals (n = 15) were examined by ELISA.

RESULTS

Serum KL-6 levels in SSc patients were significantly higher than those in normal controls. KL-6 levels in dSSc patients were significantly elevated compared with those in lSSc patients. Elevated KL-6 levels were associated with the presence of pulmonary fibrosis in SSc patients or dSSc patients. Furthermore, KL-6 levels inversely correlated with percentages of diffusion capacity of carbon monoxide and vital capacity in SSc patients or dSSc patients.

CONCLUSION

KL-6 may be a simple, serologic indicator for the severity of pulmonary fibrosis in SSc.