Serum levels of soluble programmed death‐1 and programmed death ligand‐1 in systemic sclerosis: Association with extent of skin sclerosis

The interaction of programmed death‐1 (PD‐1) with its ligand, programmed death ligand‐1 (PD‐L1), has been considered to play a key role in the negative regulation of immune responses. Patients with diffuse cutaneous systemic sclerosis (SSc) had higher levels of soluble PD‐1 (sPD‐1) than those with limited cutaneous SSc and healthy individuals. Serum sPD‐1 levels positively correlated with the severity of skin sclerosis. In contrast, serum sPD‐L1 levels were significantly increased in patients with SSc compared with healthy individuals. Moreover, serum sPD‐L1 levels were not associated with the extent of skin sclerosis and were elevated not only in patients with diffuse cutaneous SSc, but also in those with limited cutaneous SSc. These results suggested that serum sPD‐1 levels may increase in patients with SSc and correlate with the severity of skin sclerosis. PD‐1/PD‐L1 interaction may contribute to the development of skin sclerosis in SSc.     

Elevated plasma homocysteine level is possibly associated with skin sclerosis in a series of Japanese patients with systemic sclerosis

Homocysteine is a sulfhydryl‐containing amino acid that is derived from dietary methionine, and there has been increasing evidence that elevated plasma homocysteine levels are associated with increased risk of cardiovascular diseases, including carotid, coronary and peripheral arterial disease (PAD). The association of plasma homocysteine levels with peripheral vascular involvements, such as Raynaud phenomenon (RP), digital ulcers (DU) in systemic sclerosis (SSc) patients has not been well studied. The objective of this study was to examine plasma homocysteine levels and their clinical associations in patients with SSc. Plasma homocysteine levels in 151 Japanese patients with SSc and 20 healthy controls were examined. No significant differences were observed in plasma homocysteine levels between SSc patients and healthy individuals. Demographic and clinical features of the SSc patients revealed that severe skin sclerosis, anti‐topoisomerase I antibody positivity, complications of DU, acro‐osteolysis (AO) and interstitial lung disease (ILD) were significantly more prevalent among the patients with elevated plasma homocysteine levels. The plasma homocysteine levels were positively correlated with modified Rodnan total skin score. The plasma homocysteine levels in the SSc patients with DU, AO and ILD were significantly higher than those in the SSc without DU, AO and ILD, respectively. Plasma homocysteine levels did not correlate with either the mean or max intima‐media thickness (IMT) or plaque score, suggesting that plasma homocysteine levels might not be associated with carotid artery atherosclerosis in SSc patients. The measurement of plasma homocysteine levels in SSc patients might be useful for the risk stratifications of severe skin sclerosis, DU and AO.     

Increased production of soluble inducible costimulator in patients with diffuse cutaneous systemic sclerosis

Inducible costimulator (ICOS) is crucial for T cell proliferation, production of various cytokines, and T cell-dependent B-cell responses. To determine the serum soluble ICOS (sICOS) level and its association with clinical parameters in patients with systemic sclerosis (SSc), serum sICOS level was examined by enzyme-linked immunosorbent assay in 38 patients with SSc and 24 healthy individuals. The expression of ICOS and ICOS ligand in skin was examined immunohistochemically. There was no significant difference in serum sICOS level between patients with SSc and healthy individuals. Patients with diffuse cutaneous SSc had higher levels of sICOS than those with limited cutaneous SSc (P < 0.05) or healthy individuals (P < 0.05). Serum sICOS level correlated positively with the severity of skin sclerosis. Patients with SSc and elevated sICOS level more often had interstitial lung disease and decreased vital capacity than those with normal sICOS level. The serum sICOS level was significantly greater in patients with early phase SSc than those with late phase SSc. ICOS and ICOS ligand immunostaining were observed on infiltrating dermal mononuclear cells in lesional skin tissue. These results suggest that the serum level of sICOS is increased in patients with diffuse cutaneous SSc and correlates with the severity and activity of skin sclerosis and interstitial lung disease. ICOS may contribute to the development of SSc. In addition, measurement of serum sICOS level in patients with early SSc may offer an important means for further evaluation of SSc disease severity.     

Interleukin (IL)-17F and IL-17E are related to fibrosis and vasculopathy in systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune disease that causes fibrosis and vasculopathy of the skin and internal organs against a background of autoimmune abnormalities. In recent years, the importance of the interleukin (IL)-17 family for inflammatory diseases has received much attention, but autoimmune diseases have not yet been fully explored. As for SSc, there is also no unified perspective on the involvement of the IL-17 family in its development, and few studies have been conducted linking IL-17F and IL-17E particularly to the disease severity. In the present study, we examined the correlation between serum IL-17F and IL-17E levels and disease severity in SSc patients. Moreover, the expression of the receptors for these cytokines, IL-17RB and IL-17RC, in skin tissues obtained by skin biopsy was examined by immunohistochemistry. Both cytokines were significantly elevated in the sera of patients with diffuse cutaneous SSc patients compared with healthy controls. Serum IL-17F levels correlated with modified Rodnan total skin thickness score, a semiquantitative measure of skin sclerosis, percent predicted forced vital capacity, percent predicted carbon monoxide lung diffusion capacity and serum levels of Krebs von den Lungen-6 and surfactant protein-D, serological markers of interstitial lung disease. Serum IL-17E levels were significantly correlated with percent predicted forced vital capacity and serum Krebs von den Lungen-6 levels. Serum levels of IL-17F and IL-17E also correlated with the prevalence of digital ulcers, and serum IL-17F levels were associated with elevated right ventricle systolic pressure values. In addition, IL-17RC and IL-17RB expression was increased in the skin tissues of diffuse cutaneous SSc patients. These results suggested that IL-17F and IL-17E could be involved in fibrosis and vasculopathy in SSc through their respective receptors in the affected organ tissues.     

Serum heparanase levels: A protective marker against digital ulcers in patients with systemic sclerosis

Heparanase is an endo‐β‐D‐glucuronidase cleaving heparan sulfate side‐chains of heparin sulfate proteoglycans, which is involved in wound healing, inflammation, neovascularization and tumor progression through the degradation and remodeling of the extracellular matrix and the release of sequestered pro‐angiogenic factors. Because heparanase‐mediated biological processes seem to be involved in the development of systemic sclerosis (SSc), we investigated the clinical correlation of serum heparanase levels in patients with this disease. Serum heparanase levels were significantly higher in SSc patients than in healthy individuals, while comparable between diffuse cutaneous SSc and limited cutaneous SSc subgroups. On the other hand, SSc patients with digital ulcers had serum heparanase levels significantly lower than those without. These results suggest that serum heparanase levels may be elevated in SSc patients reflecting the contribution of heparanase‐dependent biological processes to the development of SSc. SSc patients with high serum heparanase levels may be protected from the development of digital ulcers due to the increased release of sequestered pro‐angiogenic factors such as vascular endothelial growth factor. Therefore, serum heparanase levels may serve as a protective marker against digital ulcers in SSc patients.     

No association of atherosclerosis with digital ulcers in Japanese patients with systemic sclerosis: Evaluation of carotid intima‐media thickness and plaque characteristics

Patients with systemic sclerosis (SSc) usually develop Raynaud's phenomenon, persistent digital ischemia and sometimes develop digital ulcers (DU). Several studies have reported an association of carotid artery atherosclerosis with SSc by evaluating carotid intima‐media thickness (IMT) in SSc patients. However, none of those studies analyzed the association between DU and carotid artery atherosclerosis in SSc patients. We examined the association of carotid artery atherosclerosis with digital ulcers by comparing SSc patients with (n = 48, 29.5%) and without (n = 206, 70.5%) DU. The demographic and clinical features of the SSc patients showed that young age, male sex, anti‐topoisomerase I antibody positivity, severe skin sclerosis, interstitial lung disease complication and cardiac involvements were significantly prevalent in patients with DU. In addition, diffuse cutaneous type, anti‐RNA polymerase III antibody positivity and severe skin sclerosis are more frequent in SSc patients with DU at the extensor surface of joints than SSc patients with DU at the digital tip. There were no differences in serum lipid level, carotid IMT or plaque score between SSc patients with and without DU, suggesting that atherosclerotic changes are not primarily involved in the development of DU.     

Clinical significance of serum soluble T‐cell immunoglobulin and mucin domain 3 levels in systemic sclerosis: Association with disease severity

T‐cell immunoglobulin and mucin domain 3 (TIM‐3) has been thought to play a crucial role in the negative regulation of immune responses. Here, we examined the levels of serum soluble TIM‐3 (sTIM‐3) in patients with systemic sclerosis (SSc) and evaluated the results with respect to the clinical features of the disease. Patients with diffuse cutaneous SSc (dcSSc) had higher levels of sTIM‐3 than those with limited cutaneous SSc and healthy individuals. Serum sTIM‐3 levels were positively correlated with the severity of skin sclerosis in early phase dcSSc. Moreover, serum sTIM‐3 levels were increased more often in patients with renal crisis and cardiac involvement than in those with normal sTIM‐3 levels. These results suggest that serum sTIM‐3 levels may be increased in patients with early phase dcSSc and associated with cardiac involvement and renal crisis. Measurement of serum sTIM‐3 may be useful for risk stratification in the early stage of the disease.     

Rheumatoid factor isotypes and anti-agalactosyl IgG antibodies in systemic sclerosis

BACKGROUND: Rheumatoid factor isotypes and anti-agalactosyl IgG antibodies (anti-AG IgG) have been reported to be detected and correlated with the disease activity in some collagen diseases. OBJECTIVES: To study the frequency and the clinical significance of IgM, IgG and IgA rheumatoid factor (IgM-RF, IgG-RF and IgA-RF) and anti-AG IgG in patients with systemic sclerosis (SSc). METHODS: Seventy-nine serum samples from patients with SSc were examined by specific enzyme-linked immunosorbent assays. RESULTS: The levels of IgM-, IgG-, IgA-RF and anti-AG IgG were significantly higher in SSc patients than in normal healthy controls. The levels of IgM- and IgA-RF were significantly higher in patients with diffuse cutaneous SSc than in those with limited cutaneous SSc. IgM-, IgG- and IgA-RF and anti-AG IgG were significantly elevated in 39%, 32%, 23% and 35% of 79 SSc patients, respectively. The prevalence of pulmonary fibrosis, oesophageal involvement and cutaneous telangectasias in patients with elevated IgA-RF levels was significantly higher than in those with normal levels. The incidence of pitting scars of digits in those with elevated IgG-RF levels and the incidence of contracture of phalanges in those with elevated IgM-RF levels were significantly higher than in those with normal levels. The frequency of increased erythrocyte sedimentation rate in patients with elevated IgG-RF and the frequency of increased C-reactive protein in those with elevated IgM-RF were significantly greater than in those with normal levels. CONCLUSIONS: IgM-, IgG-, IgA-RF and anti-AG IgG can be serum indicators of specific clinical manifestations in SSc patients.     

Decreased MMP-9 activity in the serum of patients with diffuse cutaneous systemic sclerosis

Matrix metalloproteinase-9 (MMP-9) and its inhibitor, tissue inhibitors of metalloproteinases-1 (TIMP-1) are involved in tissue inflammation and fibrotic processes. We previously reported an elevated serum TIMP-1 level in patients with systemic sclerosis (SSc). We measured serum TIMP-1 and active MMP-9 levels in 62 patients with SSc, 10 patients with rheumatoid arthritis (RA) and 15 normal controls using a modified enzyme-linked immunosorbent assay. The active MMP-9 level in the serum of the patients with RA or SSc was not significantly different from that of controls. Serum MMP-9 activity in patients with diffuse cutaneous SSc was significantly decreased compared with that of limited cutaneous SSc or normal controls. The MMP-9 activity and modified-Rodnan total skin thickness score in patients with SSc were negatively correlated. Serum MMP-9 activity and TIMP-1 level in patients with SSc were not correlated. Serum MMP-9 activity might be a useful indicator of disease activity, especially skin severity, in SSc patients.     

Serum omentin levels: A possible contribution to vascular involvement in patients with systemic sclerosis

Adipokines have been shown to be potentially involved in various pathological processes of systemic sclerosis (SSc), including inflammation, vasculopathy and fibrosis, through their pleiotropic effects. Omentin is a member of the adipokines, and has a protective effect against vascular inflammation and pathological remodeling leading to atherosclerosis as well as a vasodilatory effect. To assess the potential role of omentin in the development of SSc, we determined serum omentin levels by enzyme‐linked immunosorbent assay in 66 SSc and 21 control subjects and evaluated their clinical correlation. Serum omentin levels were significantly decreased in diffuse cutaneous SSc patients compared with limited cutaneous SSc patients, while comparable between total SSc patients and healthy controls. In diffuse cutaneous (dc)SSc, patients with a disease duration of 5 years or less had serum omentin levels significantly lower than those with a disease duration of more than 5 years. In total SSc, serum omentin levels were significantly higher in patients with elevated right ventricular systolic pressure than in the others, while serum omentin levels did not correlate with fibrotic and systemic inflammatory parameters. These results suggest that a loss of omentin‐dependent protection against vascular inflammation and remodeling may be related to pathological vascular events of early dcSSc. The elevation of serum omentin levels may serve as a marker of vascular involvement leading to pulmonary arterial hypertension in SSc, which is possibly due to the compensatory induction of omentin against the increased pulmonary vascular tone.     

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.     

Augmented production of soluble CD93 in patients with systemic sclerosis and clinical association with severity of skin sclerosis

Background The cell surface protein CD93, expressed on endothelial and myeloid cells, mediates phagocytosis, inflammation and cell adhesion. A soluble form of CD93 (sCD93) is released during inflammation. Objectives To determine the serum sCD93 level and its association with clinical parameters in patients with systemic sclerosis (SSc). Methods Serum sCD93 levels were examined by enzyme‐linked immunosorbent assay in 59 patients with SSc, 24 patients with systemic lupus erythematosus and 47 healthy individuals. The expression of CD93 in skin tissues was examined immunohistochemically. In a retrospective longitudinal study, sera from 11 patients with SSc were analysed. Results Serum sCD93 levels were increased in patients with SSc compared with healthy individuals (P < 0·001). Patients with diffuse cutaneous SSc showed greater levels of sCD93 than those with limited cutaneous SSc (P < 0·01) or systemic lupus erythematosus (P < 0·01). Serum sCD93 levels correlated positively with the severity of skin sclerosis. Strong CD93 immunostaining was observed on endothelial cells in lesional skin tissues. In the longitudinal study, sCD93 levels decreased in parallel with improvement in skin sclerosis. Conclusions Serum sCD93 levels are increased in patients with SSc and correlate with the severity and activity of skin sclerosis. CD93 may contribute to the development of skin fibrosis in SSc.     

Possible association of decreased serum CXCL14 levels with digital ulcers in patients with systemic sclerosis

CXCL14 serves as a chemoattractant for activated macrophages, immature dendritic cells and natural killer cells, as well as an antiangiogenic factor by preventing the migration of endothelial cells. CXCL14 also exerts an inhibitory effect on the CXCL12/CXCR4 signaling pathway, which is involved in the maintenance of T‐helper (Th)2 bias, and promotes Th1 immune response under the physiological and pathological conditions. Because CXCL14‐mediated biological processes seem to be involved in the development of systemic sclerosis (SSc), which is characterized by Th2/Th17‐skewed immune polarization and impaired neovascularization, we investigated the clinical correlation of serum CXCL14 levels in patients with this disease. Serum CXCL14 levels were significantly decreased in SSc patients compared with healthy individuals and in diffuse cutaneous SSc patients relative to limited cutaneous SSc patients. SSc patients with digital ulcers had serum CXCL14 levels significantly lower than those without. Furthermore, i.v. cyclophosphamide pulse significantly increased serum CXCL14 levels as compared with the baseline in SSc patients with interstitial lung disease successfully treated with this therapy. These results indicate that decreased CXCL14 expression may contribute to the maintenance of Th2‐skewed immune polarization and dysregulated neovascularization, both of which underlie the developmental process of SSc.     

Serum interleukin‐34 levels in patients with systemic sclerosis: Clinical association with interstitial lung disease

Interleukin (IL)‐34 is a hematopoietic cytokine promoting proliferation and differentiation of macrophages. Because abnormal activation of macrophages is involved in the development of systemic sclerosis (SSc), we investigated serum IL‐34 levels in patients with SSc. Serum IL‐34 levels were significantly increased in diffuse cutaneous SSc compared with limited cutaneous SSc and healthy controls, while there were no significant differences between limited cutaneous SSc and healthy controls. In addition, SSc patients with increased serum IL‐34 levels more often had interstitial lung disease (ILD) than those with normal levels. Moreover, in SSc patients, serum IL‐34 levels negatively correlated with the percentage of predicted vital capacity, while they positively correlated with ground‐glass opacity score and fibrotic score on chest computed tomography. Collectively, increased serum IL‐34 levels were associated with greater frequency and severity of ILD in SSc patients. Serum IL‐34 levels may be a useful serological marker for SSc‐associated ILD.     

Serum aminoterminal propeptide of type III procollagen in systemic sclerosis. A follow-up--investigations in subclasses and during therapy.

Fifty-seven patients with systemic sclerosis were investigated for connective tissue turn-over related to type III collagen. Sera from 13 patients with diffuse cutaneous systemic sclerosis and 44 patients with limited cutaneous systemic sclerosis were analysed for aminoterminal propeptide of type III procollagen (PIIINP) by a radioimmunoassay based on human propeptide. Increased levels of PIIINP in serum correlated with skin involvement and the clinical course. All patients with diffuse cutaneous systemic sclerosis had levels above the normal range, and in limited cutaneous systemic sclerosis elevated PIIINP levels seemed to be correlated with rapid progression and with extension of lesions. Immunosuppressive drugs, cyclosporin A, and prednisone with or without cyclophosphamide, which were given to patients with rapid disease progression, significantly reduced PIIINP. This was also the case with penicillamine, but to a lesser degree. Our data support the suggestion that immunosuppressive agents are justified in rapidly progressive, life-threatening or disabling disease, when used with the necessary precautions. Serum PIIINP may be utilized as a marker of type III collagen fibrogenesis in systemic sclerosis and be of prognostic value. PIIINP may also be of use in the differential diagnosis between diffuse cutaneous systemic sclerosis and scleredema.     

Serum periostin levels are correlated with progressive skin sclerosis in patients with systemic sclerosis

Background Periostin, a matricellular protein, serves as a regulator of wound healing and fibrosis. The role of periostin in the pathogenesis of systemic sclerosis (SSc) is unknown. Objective To determine periostin levels in association with severity of skin fibrosis in patients with SSc. Methods Expression of periostin was immunohistochemically examined in skin obtained from patients with SSc and healthy controls. Enzyme‐linked immunosorbent assay was performed to evaluate serum periostin levels in association with clinical characteristics in 56 patients with SSc [diffuse cutaneous SSc (dSSc), n = 16; and limited cutaneous SSc (lSSc), n = 40] and 66 healthy controls. Results Periostin was strongly expressed in the affected dermis from patients with SSc. Periostin was colocalized in α‐smooth muscle actin‐positive myofibroblasts and platelet endothelial cell adhesion molecule‐1‐positive endothelial cells in SSc dermis. Serum levels of periostin in patients with dSSc were markedly elevated compared with those in patients with lSSc and control subjects. Patients with lSSc had increased periostin levels compared with healthy controls. In addition, significantly higher levels of periostin were observed in patients with dSSc with disease duration ≤ 5 years compared with those with disease duration > 5 years. Furthermore, the modified Rodnan total skin thickness score (MRSS) was positively correlated with periostin levels in patients with SSc. Serial analysis revealed a correlation between periostin and MRSS; namely, MRSS decreased in line with decreased periostin levels in some patients with dSSc as the disease progressed. Conclusion An elevated periostin level in patients with SSc is associated with severity of skin sclerosis. Periostin may be a potential biomarker for progressive skin fibrosis in SSc.     

A possible contribution of elevated serum clusterin levels to the inhibition of digital ulcers and pulmonary arterial hypertension in systemic sclerosis

Clusterin has been demonstrated to be one of the anti-inflammatory and anti-apoptotic factors, suggesting the potential to be involved in the development of systemic sclerosis (SSc). The aim of this study is to determine serum clusterin levels and their clinical associations in patients with SSc. Serum clusterin levels were examined by enzyme-linked immunosorbent assay in 61 SSc patients and 24 healthy individuals. Serum clusterin levels were significantly elevated in SSc patients compared with healthy individuals (P < 0.001). Among SSc patients, there were no differences in serum clusterin levels between those with limited cutaneous SSc (n = 30) and those with diffuse cutaneous SSc (n = 31). SSc patients with raised clusterin levels had digital ulcers and pulmonary arterial hypertension less often than those with normal clusterin levels. The results show that the serum clusterin levels were increased in patients with SSc, and associated with a lower frequency of digital ulcers and pulmonary arterial hypertension. Clusterin could be a protective factor against the development of digital ulcers and pulmonary arterial hypertension in this disease and as such would be a possible therapeutic target.     

A clue for telangiectasis in systemic sclerosis: elevated serum soluble endoglin levels in patients with the limited cutaneous form of the disease

BACKGROUND: The transforming growth factor-beta (TGF-beta) system plays a critical role both in systemic sclerosis (SSc) and hereditary hemorrhagic telangiectasia (HHT). Endoglin, known as a gene responsible for HHT, is a TGF-beta receptor preferentially expressed on endothelial cells. The role of endoglin in SSc is potentially intriguing since limited cutaneous SSc (lcSSc) and HHT share several symptoms, including telangiectasia. OBJECTIVE: To determine serum levels of soluble endoglin (sEndoglin) and clinical associations in patients with SSc. METHODS: Serum sEndoglin levels were examined by ELISA in 70 patients with SSc, 20 patients with systemic lupus erythematosus and 20 healthy individuals. RESULTS: Serum sEndoglin levels were significantly elevated in patients with lcSSc compared with diffuse cutaneous SSc and systemic lupus erythematosus patients as well as normal controls. Patients with elevated sEndoglin levels had telangiectasia more frequently than those with normal sEndoglin levels. Furthermore, pulmonary artery pressure was positively correlated with sEndoglin levels in patients with lcSSc. CONCLUSION: Abnormal expression/function of endoglin may be linked to lcSSc-specific manifestations.     

Serum levels of interleukin-6 and interleukin-10 correlate with total skin thickness score in patients with systemic sclerosis

Various growth factors and cytokines have been suggested to play a central role in initiating and developing fibrosis in systemic sclerosis (SSc). To determine which serum levels of soluble mediators are the most relevant to the degree of skin sclerosis in SSc, serum levels of various soluble mediators were examined by ELISA and correlated with skin thickening that was measured using modified Rodnan total skin thickness scoring (TSS) system. Serum levels of IL-4, IL-12, IL-13, tumor necrosis factor-alpha, connective tissue growth factor (CTGF), vascular endothelial growth factor, monocyte chemotactic protein-1, macrophage inflammatory protein-1beta, soluble IL-6 receptor, and soluble L-selectin were higher in SSc patients than normal controls. Levels of IL-6, IL-10, and CTGF in patients with diffuse cutaneous SSc were higher than patients with limited cutaneous SSc and controls. Serum levels of IL-6 and IL-10 positively correlated with TSS in patients with SSc (r=0.625, P<0.0001 and r=0.663, P<0.0001, respectively). In addition, IL-10 levels significantly correlated with pulmonary fibrosis. Thus, serum levels of IL-6 and IL-10 most strongly reflect the extent of skin thickening in SSc, suggesting that levels of IL-6 and IL-10 are useful serological indicators for skin fibrosis in SSc.     

Clinical significance of serum decoy receptor 3 levels in patients with systemic sclerosis

Decoy receptor 3 (DcR3) is associated with autoimmunity and altered angiogenesis in certain pathological conditions. We herein measured serum DcR3 levels in 51 patients with systemic sclerosis (SSc) and 19 healthy controls and evaluated their clinical significance in this disorder. Serum DcR3 levels were significantly higher in diffuse cutaneous SSc (dcSSc) patients than in limited cutaneous SSc patients and in healthy controls. In dcSSc, serum DcR3 levels were significantly elevated in patients with disease duration of ≤6?years compared with healthy controls, but not in those with disease duration of >6?years. Serum DcR3 levels correlated negatively with the percentage of predicted diffusion lung capacity for carbon monoxide and positively with right ventricular systolic pressure. Furthermore, serum DcR3 levels positively correlated with C-reactive protein, erythrocyte sedimentation rate and immunoglobulin G. Collectively, the elevation of serum DcR3 levels is associated with the development of pulmonary arterial hypertension and systemic inflammation in SSc.