Systemic Sclerosis Serum Research Articles

AB0837 Circulating micrornas in systemic sclerosis patients reflect microrna profile of cultured scleroderma fibroblasts and correlate with distinct disease features

BackgroundMicroRNAs (miRs) play a role in many pathophysiologic processes, and have been proposed as tissue-based biomarkers, which are released and stably detectable in body fluids.ObjectivesTo analyse serum expression of miRs...

Toll-like receptor-mediated, enhanced production of profibrotic TIMP-1 in monocytes from patients with systemic sclerosis: role of serum factors

ObjectivesTo investigate whether monocytes contribute to matrix deposition in systemic sclerosis (SSc) by production of tissue-inhibitor of metalloproteinase-1 (TIMP-1).MethodsMatrix metalloproteinase-1 (MMP-1) and TIMP-1 expression and secretion were measured by qRT-PCR...

Antibodies recognising sulfated carbohydrates are prevalent in systemic sclerosis and associated with pulmonary vascular disease

BackgroundGlycosylation represents an important modification that regulates biological processes in tissues relevant for disease pathogenesis in systemic sclerosis (SSc), including the endothelium and extracellular matrix. Whether patients with SSc develop...

Bone marrow-derived mesenchymal stem cells from early diffuse systemic sclerosis exhibit a paracrine machinery and stimulate angiogenesis in vitro

ObjectiveTo characterise bone marrow-derived mesenchymal stem cells (MSCs) from patients with systemic sclerosis (SSc) for the expression of factors implicated in MSC recruitment at sites of injury, angiogenesis and fibrosis....

Dysregulated expression of MIG/CXCL9, IP-10/CXCL10 and CXCL16 and their receptors in systemic sclerosis

IntroductionSystemic sclerosis (SSc) is characterized by fibrosis and microvascular abnormalities including dysregulated angiogenesis. Chemokines, in addition to their chemoattractant properties, have the ability to modulate angiogenesis. Chemokines lacking the enzyme-linked receptor (ELR) motif, such as monokine induced by interferon-γ (IFN-γ) (MIG/CXCL9) and IFN-inducible protein 10 (IP-10/CXCL10), inhibit angiogenesis by binding CXCR3. In addition, CXCL16 promotes angiogenesis by binding its unique receptor CXCR6. In this study, we determined the expression of these chemokines and receptors in SSc skin and serum.MethodsImmunohistology and enzyme-linked immunosorbent assays (ELISAs) were used to determine chemokine and chemokine receptor expression in the skin and serum, respectively, of SSc and normal patients. Endothelial cells (ECs) were isolated from SSc skin biopsies and chemokine and chemokine receptor expression was determined by quantitative PCR and immunofluorescence staining.ResultsAntiangiogenic IP-10/CXCL10 and MIG/CXCL9 were elevated in SSc serum and highly expressed in SSc skin. However, CXCR3, the receptor for these chemokines, was decreased on ECs in SSc vs. normal skin. CXCL16 was elevated in SSc serum and increased in SSc patients with early disease, pulmonary arterial hypertension, and those that died during the 36 months of the study. In addition, its receptor CXCR6 was overexpressed on ECs in SSc skin. At the mRNA and protein levels, CXCR3 was decreased while CXCR6 was increased on SSc ECs vs. human microvascular endothelial cells (HMVECs).ConclusionsThese results show that while the expression of MIG/CXCL9 and IP-10/CXCL10 are elevated in SSc serum, the expression of CXCR3 is downregulated on SSc dermal ECs. In contrast, CXCL16 and CXCR6 are elevated in SSc serum and on SSc dermal ECs, respectively. In all, these findings suggest angiogenic chemokine receptor expression is likely regulated in an effort to promote angiogenesis in SSc skin.

Proteomic analysis of Systemic Sclerosis serum identifies the toll-like receptor agonists S100A8/A9 as a novel possible pathogenic marker

Background Systemic sclerosis (SSc) is an autoimmune disease characterized by fibrosis of the skin and the internal organs. The etiology is still unknown but prominent features are vascular injury and chronic inflammation resulting in fibrosis. There are no markers available that predict SSc susceptibility and/or prognosis. This study is the first study that exploits a proteome-wide profiling to identify new targets in the pathogenesis of SSc.

Increased Alveolar Concentration of Nitric Oxide Is Related to Serum-induced Lung Fibroblast Proliferation in Patients with Systemic Sclerosis

Lung inflammation is present in patients with systemic sclerosis (SSc) and interstitial lung disease (ILD), but the mechanisms linking inflammatory and fibrotic processes in ILD are unknown. Our aim was to investigate whether alveolar inflammation, reflected by increased alveolar concentration of exhaled nitric oxide (C(A)NO), is related to the ability of serum from patients with SSc to induce pulmonary fibroblast proliferation (PFP) and myofibroblast conversion. C(A)NO was measured in all subjects (37 patients with SSc and 10 healthy controls) whose sera were used to stimulate PFP (assessed by BrdU labeling index) and myofibroblast conversion (detected by alpha-smooth muscle actin expression). The PFP index in patients with SSc was compared to control values, and between patients with SSc who had elevated (> 4.3 ppb) and normal (<or= 4.3 ppb) C(A)NO values. Both C(A)NO and the PFP index were significantly greater in patients with SSc compared to controls. In patients with SSc, the PFP index was directly related to C(A)NO levels (r = 0.48; p = 0.002). The median PFP index was significantly higher in patients with SSc who had elevated C(A)NO (> 4.3 ppb; n = 25, median 1.1, range 0.98-1.23) than in patients with SSc who had normal C(A)NO (<or= 4.3 ppb; n = 12, median 0.93, range 0.82-1.08; p = 0.01). Similarly, myofibroblast conversion induced by SSc serum was significantly greater in patients with C(A)NO > 4.3 ppb than in patients whose C(A)NO was <or= 4.3 ppb (p < 0.001) and controls (p < 0.001). Alveolar inflammation reflected by increased nitric oxide production was related to serum-induced PFP and myofibroblast conversion, linking the active alveolitis process to cell proliferation and lung fibrosis in patients with SSc.

Autoantibody-mediated regulation of B cell responses by functional anti-CD22 autoantibodies in patients with systemic sclerosis.

Studies have demonstrated that B cells play important roles in systemic sclerosis (SSc), especially through the CD19/CD22 autoimmune loop. CD22 is a B cell-specific inhibitory receptor that dampens B cell antigen receptor (BCR) signalling via tyrosine phosphorylation-dependent mechanism. In this study, we examined the presence and functional property of circulating autoantibodies reacting with CD22 in systemic sclerosis. Serum samples from 10 tight skin (TSK/+) mice and 50 SSc patients were assessed for anti-CD22 autoantibodies by enzyme-linked immunosorbent assays using recombinant mouse or human CD22. The association between anti-CD22 antibodies and clinical features was also investigated in SSc patients. Furthermore, the influence of SSc serum including anti-CD22 autoantibodies for CD22 tyrosine phosphorylation was examined by Western blotting using phosphotyrosine-specific antibodies reacting with four major tyrosine motifs of CD22 cytoplasmic domain. Anti-CD22 autoantibodies were positive in 80% of TSK/+ mice and in 22% of SSc patients. Patients positive for anti-CD22 antibodies showed significantly higher modified Rodnan skin thickness score compared with patients negative for anti-CD22 antibodies. Furthermore, anti-CD22 antibodies from patients' sera were capable of reducing phosphorylation of all four CD22 tyrosine motifs, while sera negative for anti-CD22 antibodies did not affect CD22 phosphorylation. Thus, a subset of SSc patients possessed autoantibodies reacting with a major inhibitory B cell response regulator, CD22. Because these antibodies can interfere CD22-mediated suppression onto B cell activation in vitro, SSc B cells produce functional autoantibodies that can enhance their own activation. This unique regulation may contribute to the autoimmune aspect of SSc.

Imagerie thoracique

A patulous esophagus on high-resolution computed tomography (HRCT) of the thorax is frequently observed in patients with systemic sclerosis (SSc). Microaspiration has been purported to play a role in the development and progression of SSc interstitial lung disease (ILD), but studies examining the role of microaspiration in SSc ILD have yielded conflicting results. This study was conducted to determine the association between esophageal diameter and SSc ILD.A cross-sectional study of Northwestern Scleroderma Registry patients with available HRCT exams was conducted. The predictor variable was the widest esophageal diameter (WED) on HRCT, and the primary and secondary outcome variables were radiographic ILD and pulmonary function tests respectively. The degree of radiographic ILD was assessed using a semi-quantitative score adapted from published methods. Estimated regression coefficients adjusted for age, sex, race, body mass index, smoking; SSc disease subtype, serum autoantibodies, and disease duration; modified Rodnan skin score, proton pump inhibitor, and immune suppressant medication use and erythrocyte sedimentation rate were calculated.A total of 270 subjects were studied. In the adjusted analyses, there were positive associations between WED and total ILD score (β = 0.27; 95% CI: 0.09–0.41), fibrosis (β = 0.15; 95% CI: 0.07–0.23), and ground glass opacities (β = 0.12; 95% CI: 0.04–0.20); there were negative associations between WED and FVC % predicted (β = −0.42; 95% CI: −0.69 to −0.13), and adjusted DLCO % predicted (β = −0.45; 95% CI: −0.80 to −0.09) after adjusting for potential confounders.Increasing esophageal diameter on HRCT in patients with SSc is associated with more severe radiographic ILD, lower lung volumes, and lower DLCO % predicted. Longitudinal studies are needed to determine if esophageal dilatation is associated with the incidence and/or progression of ILD in patients with SSc.

Autoantibody-mediated regulation on B cell responses by functional anti-CD22 autoantibodies in patients with systemic sclerosis (137.42)

Abstract Objectives. Studies have demonstrated that B cells play important roles in systemic sclerosis (SSc), especially through the gCD19/CD22 autoimmune loop h. In this study, we examined the presence and functional property of circulating autoantibodies reacting with CD22. Methods. Serum samples from 10 tight skin (TSK/+) mice and 50 SSc patients were assessed for anti-CD22 autoantibodies by enzyme-linked immunosorbent assays using recombinant mouse or human CD22. The association between anti-CD22 antibodies and clinical features was also investigated in SSc patients. Furthermore, the influence of SSc serum including anti-CD22 autoantibodies for CD22 tyrosine phosphorylation was examined by western blotting using phospho-tyrosine specific antibodies reacting with four major tyrosine motifs of CD22 cytoplasmic domain. Results. Anti-CD22 autoantibodies were positive in 80% of TSK/+ mice and in 22% of SSc patients. Patients positive for anti-CD22 antibodies showed significantly higher modified Rodnan skin thickness score compared with patients negative for anti-CD22 antibodies. Furthermore, anti-CD22 antibodies from patients' sera were capable of reducing phosphorylation of all four CD22 tyrosine motifs, while sera negative for anti-CD22 antibodies did not affect CD22 phosphorylation. Conclusions. A subset of SSc patients possessed autoantibodies reacting with a major inhibitory B cell response regulator, CD22. Since these antibodies can interfere CD22-mediated suppression onto B cell activation in vitro, SSc B cells produce functional autoantibodies that can enhance their own activation. This unique regulation may contribute to the autoimmune aspect of SSc.

Tumor-associated antigens in systemic sclerosis and systemic lupus erythematosus: Associations with organ manifestations, immunolaboratory markers and disease activity indices

Background Some tumor-associated antigens (TAAs) are expressed on inflammatory cells. We previously detected increased production of CA15-3, CA19-9 and CA125 in rheumatoid arthritis (RA). The production of some TAAs may also be increased in patients with systemic sclerosis (SSc), systemic lupus erythematosus (SLE) and other connective tissue diseases. Some of these TAAs contain sialylated carbohydrate motifs and they are involved in tumor-associated cell adhesion and metastasis. Objectives We assessed levels of TAAs in the sera of SSc, SLE patients, patients with infectious diseases and healthy subjects. Serum TAA levels were correlated with each other, as well as with disease activity markers and organ involvement. Methods TAAs including CEA, CA15-3, CA72-4, CA125 and CA19-9 were assessed by immunoassay in the sera of 92 patients with SSc, 40 patients with SLE, 50 age- and sex-matched healthy controls, as well as with 40 patients with current bacterial or viral infections. Normal upper limits for these TAAs were 3.4 mg/l, 25 kU/l, 6.9 kU/l, 35 kU/l and 34 kU/l, respectively. Results There were significantly more SSc patients showing abnormally high levels of CA19-9 (8.8% vs 2.0%), CA125 (11.0% vs 6.0%) and CA15-3 (28.4% vs 14.0%) in comparison to controls ( p < 0.05). In SLE, significantly more patients had elevated levels of CEA (32.5% vs 20.0%), CA19-9 (7.5% vs 2.0%), CA125 (15.0% vs 6.0%) and CA72-4 (15.0% vs 8.0%) than did controls ( p < 0.05). The mean absolute serum levels of CEA (6.6 ± 1.7 vs 1.8 ± 1.4 mg/l) and CA15-3 (22.9 ± 1.8 vs 18.6 ± 2.2 kU/l) were also significantly higher in SSc compared to controls ( p < 0.05). We found numerous correlations between the serum levels of different TAAs within the SSc and SLE population. Among SSc patients, serum CEA ( R = 0.290; p = 0.005), CA15-3 ( R = 0.260; p = 0.020) and CA19-9 ( R = 0.257; p = 0.013) correlated with renal involvement. Serum CA15-3 also correlated with joint involvement ( R = 0.329; p = 0.003), ANA positivity ( R = 0.288; p = 0.010) and CRP levels ( R = 0.407; p < 0.001). Within the SLE population, serum CA72-4 correlated with central nervous involvement ( R = 0.624; p = 0.004) and CA125 correlated with the SLEDAI composite activity index ( R = 0.666; p = 0.002). Patients with infections exerted serum TAA patterns similar to healthy controls. Conclusion The concentration of some TAAs may be elevated in the sera of patients with SSc or SLE in comparison to healthy subjects. Pathogenically, most of these TAAs contain carbohydrate motifs and thus they may be involved in inflammation-associated adhesive events. Furthermore, the production of some TAAs may correlate with organ involvement or disease activity in scleroderma or lupus.

Abnormal nitric oxide metabolism in systemic sclerosis: increased levels of nitrated proteins and asymmetric dimethylarginine

Endothelial dysfunction is a primary event in systemic sclerosis; however, the aetiology of events and the role of nitric oxide (NO) is still unclear. The aim of the present study is to investigate whether there are abnormalities in NO metabolism in plasma from patients with primary Raynaud's phenomenon (RP) and in the pathogenesis of systemic sclerosis (SSc): limited SSc (lSSc) and diffuse (dSSc). We also wanted to investigate the effect of factors within patients' SSc serum on NO metabolism in human microvascular endothelial cells (HMECs). Plasma (n=89) or serum (n=80) was assayed for total nitrate and nitrite (NOx), nitration of proteins and the NO inhibitor asymmetric dimethylarginine (ADMA). HMECs were treated with patients' SSc serum and assayed for indicators of NO metabolism. Plasma NOx was elevated in patients with RP or lSSc (P<0.002), but not in patients with dSSc, compared with controls. Nitrated proteins in plasma, however, were found to be very high in dSSc patients (P<0.03), compared with RP, lSSc or controls. Patients with dSSc also showed increased levels of serum ADMA (P<0.05). The high level of nitrated proteins in dSSc was strongly associated with the severity and duration of dSSc disease. Skin biopsy sections from dSSc patients also showed enhanced nitrotyrosine staining compared with controls. In HMECs, pre-incubation with SSc serum impaired the activity of nitric oxide synthase (NOS) but not the expression of inducible or endothelial NOS. SSc serum also induced a reduction in intracellular cGMP synthesis, and NOx production in the cell culture medium, but was not associated with increased cell cytotoxicity. NO formation is increased in patients with primary RP or lSSc, but nitration of proteins and elevated ADMA is a particular feature of dSSc and may reflect abnormal NO regulation and/or contribute to endothelial dysfunction in SSc.

Molecular recognition patterns of serum anti-DNA topoisomerase I antibody in systemic sclerosis.

Autoreactive anti-DNA topoisomerase I (anti-Topo I) Abs are commonly detected in sera of systemic sclerosis (SSc) patients. Our studies have established a positive correlation between the levels of serum anti-Topo I Abs and both disease severity and activity of SSc. The molecular targets of anti-Topo I Ab on Topo I domains remain to be further defined. In this report, we studied the molecular recognition pattern of serum anti-Topo I Ab in 52 SSc patients. The highest reactivity of serum anti-Topo I Abs was against the core subdomains I and II (aa 207-441) and, to a lesser extent, against the core subdomain III (aa 433-636) of Topo I. The linker domain (aa 636-712) and the C-terminal domain (aa 713-765) had much less reactivity than the core domain (aa 207-636). Strikingly, very little reactivity was directed against the N-terminal domain (aa 1-213) by serum anti-Topo I Ab. This molecular recognition pattern was consistent among all SSc serum samples studied. Results from patients with serial serum samples indicated that this pattern remained unchanged over time. Interestingly, some naive B cells from healthy controls, upon transformation by EBV, produced IgM Abs against Topo I. These Abs had low affinity for Topo I and reacted equally to all domains of Topo I. The molecular recognition pattern of serum anti-Topo I Ab in SSc suggests the presence of a unique antigenic stimulation in vivo in this disease.

A novel protein highly expressed in testis is overexpressed in systemic sclerosis fibroblasts and targeted by autoantibodies.

Nearly all autoantibody specificities in sera from patients with systemic sclerosis (SSc) target proteins distributed ubiquitously, and Abs against proteins whose expression is restricted to the affected sites have not been identified. In this study we describe SSc-specific autoantibody to a novel testicular Ag, termed protein highly expressed in testis (PHET), which is ectopically overexpressed in SSc dermal fibroblasts. A partial cDNA encoding PHET was isolated by immunoscreening of a HepG2 cDNA library with an SSc serum. PHET appeared to be a member of the UniGene cluster Hs.129872, but had a unique exon composition and a characteristic mRNA expression profile restricted to the testis. Serum Abs to a recombinant PHET fragment were detected in nine (8.4%) of 107 SSc patients, but in none of 50 systemic lupus erythematosus patients or 77 healthy controls. In SSc patients, the presence of anti-PHET Abs was associated with diffuse cutaneous SSc and lung involvement (p = 0.02 and 0.01, respectively). PCR-based quantitative analysis of PHET mRNA expression in cultured dermal fibroblasts showed increased expression of PHET mRNA in SSc fibroblasts compared with control fibroblasts. PHET-reactive Abs purified from SSc sera stained the cytoplasm of SSc dermal fibroblasts, and the staining intensity tended to be more prominent on SSc compared with control fibroblasts. These findings suggest that the autoantibody response to PHET can be induced by ectopic overexpression of PHET in dermal fibroblasts in SSc patients.

Systemic sclerosis immunoglobulin G autoantibodies bind the human cytomegalovirus late protein UL94 and induce apoptosis in human endothelial cells.

Systemic sclerosis is an autoimmune disease characterized by immunological and vascular abnormalities. Autoantibodies against intracellular antigens are associated with particular clinical features of the disease, whereas autoantibodies against cell surface antigens may be pathogenic by inducing endothelial cell damage, considered the primary event in the pathogenesis of the disease. Latent human cytomegalovirus infection may contribute to progression of systemic sclerosis through its ability to infect endothelial cells; however, direct links between human cytomegalovirus infection and systemic sclerosis are still lacking. Molecular mimicry is one of the mechanisms that account for the link between infection and autoimmunity. Here we have identified an immunodominant peptide using systemic sclerosis serum screening of a random peptide library; such peptide shares homology with autoantigens and with the human cytomegalovirus late protein UL94 (ref. 9). Immunoglobulin G antibodies against the peptide affinity-purified from the sera of patients with systemic sclerosis specifically recognized the viral product and autoantigens; moreover, such antibodies induced endothelial cell apoptosis through specific interaction with the cell surface integrin-NAG-2 protein complex. Our results provide evidence that antibodies against human cytomegalovirus cause apoptosis of endothelial cells, considered the initial pathogenic event of systemic sclerosis, and indicate a previously unknown mechanism for the etiological link between human cytomegalovirus infection and autoimmunity.