CD81 and CD48 show different expression on blood eosinophils in systemic sclerosis: new markers for disease and pulmonary inflammation?

OBJECTIVES: In systemic sclerosis (SSc)-related interstitial lung disease (ILD), elevated eosinophil counts in bronchoalveolar lavage are associated with a worse outcome. We hypothesized that eosinophils may be activated in the peripheral circulation, thereby increasing their recruitment to affected tissues and contributing to inflammation and fibrosis. The aim of this study was to characterize the blood eosinophils in SSc patients. METHOD: Expression levels of surface markers CD11b, CD44, CD48, CD54, CD69, CD81, and HLA-DR on CD16(low)CD9(high)-expressing eosinophils were measured by flow cytometry in whole blood from SSc patients (n = 32) and controls (n = 11). RESULTS: Expression levels of CD54, CD69, and HLA-DR were undetectable in all groups. CD44 and CD11b expression levels were similar between groups. CD81 expression was lower in patients compared to controls independent of disease duration (p = 0.001). CD48 expression was increased in patients with a short disease duration (< 2 years) compared to both controls (p = 0.042) and patients with longer disease duration (≥ 2 years; p = 0.027). In patients with short disease duration, increased CD48 expression was associated with alveolar inflammation as measured by an increased concentration of alveolar nitric oxide (r = 0.76, p = 0.003). CONCLUSIONS: Blood eosinophils change phenotype during disease evolution in SSc, and CD48 expression may be used as a biomarker for pulmonary inflammation.

Increased serum type I interferon activity in early systemic sclerosis patients is associated with antibodies against Sjögren's syndrome antigens and nuclear ribonucleoprotein antigens.

OBJECTIVE: To study serum type I interferon (IFN) activity in patients with early systemic sclerosis (SSc). METHOD: Serum type I IFN activity was measured in 33 consecutive patients with SSc and a disease duration of < 2 years and in 13 healthy individuals by calculating a type I IFN score according to the induction of six IFN-α regulated genes in a reporter cell line. RESULTS: Twenty-seven per cent of the SSc patients had an increased type I IFN score compared to none of the healthy individuals (p < 0.05). The clinical SSc phenotype associated with high serum type I IFN activity did not differ from patients with low serum type I IFN activity regarding the presence of skin or lung fibrosis, pulmonary hypertension, or digital complications. Patients with high serum type I IFN activity were younger (p < 0.01) and had a lower frequency of cardiac involvement (p = 0.053), lower leucocyte count (p < 0.001), higher immunoglobulin (Ig)G levels (p < 0.05), and a higher amount of antibodies against extractable nuclear antigens (p < 0.01) than patients with low serum type I IFN activity. The presence of antibodies against topoisomerase I, Sjögren's syndrome antigen, and nuclear ribonucleoprotein antigens was associated with higher type I IFN activity (p < 0.05 for all comparisons). CONCLUSIONS: Our study indicates that increased serum type I IFN activity in early SSc patients is associated with an antibody and laboratory profile that may reflect a subclinical overlap of SSc with other type I IFN-driven connective tissue diseases (CTDs).

Scleroderma renal crisis in a Swedish systemic sclerosis cohort: survival, renal outcome, and RNA polymerase III antibodies as a risk factor.

OBJECTIVES: To study survival, renal outcome, and RNA polymerase III antibodies (RNAP Abs) as a risk factor for scleroderma renal crisis (SRC) in a Swedish cohort of systemic sclerosis (SSc) patients. METHODS: SRC was diagnosed in 16 SSc patients during the period from 1982 to 2010. For comparison, 112 (seven for each SRC patient) SSc patients without SRC were included. RNAP Abs were detected by a fully automated fluoroenzyme immunoassay (EliA). Values greater than 15 µg/L were considered positive. Frozen serum samples from the time of diagnosis of SSc were used. RESULTS: The 5- and 10-year survival rates were, respectively, 58% and 40% for SRC patients and 90% and 76% for patients without SRC (p < 0.001). The odds ratio (OR) for mortality was 4.39 [95% confidence interval (CI) 2.10-9.16, p < 0.001] in patients with SRC compared to those without SRC. Renal outcome was good in three patients. Haemodialysis was started in 10 patients and peritoneal dialysis in three. Renal function improved in three patients and dialysis was terminated. Four patients underwent renal transplantation. Seven SRC patients and nine without SRC were positive for RNAP Abs. Anti-RNAP Abs was a strong predictor of SRC. The sensitivity and specificity for development of SRC were 0.44 and 0.92, respectively. The OR for development of SRC was 8.90 (95% CI 2.68-29.6, p = 0.001) in RNAP-positive patients. CONCLUSIONS: RNAP positivity is a strong risk factor for SRC. Renal outcome was variable and survival is still notably decreased.

Progressive capillary loss over a decade in patients with systemic sclerosis, in particular in patients with early digital ischaemic manifestations.

OBJECTIVE: Characteristic capillary abnormalities occur early in systemic sclerosis (SSc). Our aim was to study the longitudinal development of capillary density in SSc patients. METHODS: Forty-eight consecutive patients with SSc fulfilling a follow-up of at least 8 years were retrospectively analysed for capillary loss over the observation period. Eleven had diffuse cutaneous SSc (dcSSc) and 37 limited cutaneous SSc (lcSSc). The median disease duration at first assessment was 2.5 years. Capillary density was determined by direct counting of capillaries in the distal row on eight fingers in a stereo-zoom microscope at 20× magnification. RESULTS: Capillary density decreased over the observation period in dcSSc (from median 5.1 to 4.4 loops/mm, p < 0.05) and in lcSSc (from 5.1 to 4.2 loops/mm, p < 0.001). No significant difference was found between the two forms at start or at follow-up. Digital ischaemic manifestations had already been found at the first assessment in 19 patients. They did not differ in capillary density from those without ischaemic manifestations at the first assessment (5.0 and 5.3 loops/mm), but did differ at follow-up (3.6 and 4.7 loops/mm, p < 0.001). Capillary loss was more pronounced in patients who already had digital ischaemic manifestations at the first assessment compared to those without (p < 0.02). CONCLUSION: In SSc, early digital ischaemic manifestations may precede a subsequent progressive capillary loss. The association between capillary loss and serious internal vascular complications remains to be studied.

Enlarged right-sided dimensions and fibrosis of the right ventricular insertion point on cardiovascular magnetic resonance imaging is seen early in patients with pulmonary arterial hypertension associated with connective tissue disease.

OBJECTIVES: To describe the findings of cardiovascular magnetic resonance (CMR) imaging in patients with pulmonary arterial hypertension (PAH) associated with connective tissue disease (CTD) and in consecutive patients with systemic sclerosis (SSc) without PAH. METHODS: The study comprised nine consecutive patients who were admitted for right heart catheterization (RHC) under a suspicion of CTD-PAH and 25 consecutive patients who were admitted for evaluation because of a clinical suspicion of SSc. In addition to the regular assessment, they also underwent examination by CMR. RESULTS: CMR measurements of right ventricular (RV) volumes and function showed severe pathology in patients with CTD-PAH. Patients with SSc without PAH had similar but much less severe findings. Right ventricular end-diastolic volume (RVEDV) and right ventricular ejection fraction (RVEF) were abnormal in all patients with CTD-PAH. In eight out of nine patients with CTD-PAH, fibrosis was seen in the RV insertion point, probably caused by increased tension, but only in one of the consecutive SSc patients. This patient was diagnosed with CTD-PAH 20 months later. CONCLUSIONS: In CTD-PAH, CMR shows severe changes in RV volumes and function, but also fibrosis in the RV insertion point. Similar abnormalities, although much less severe, may be seen at diagnosis of SSc. Further evaluation is warranted to determine whether these findings are of value in screening for early signs of PAH in SSc.

Survival in patients with pulmonary arterial hypertension associated with systemic sclerosis from a Swedish single centre: prognosis still poor and prediction difficult.

OBJECTIVES: To describe the survival rate in a cohort of systemic sclerosis (SSc) patients with pulmonary arterial hypertension (PAH) and to evaluate possible predictors for SSc-PAH in a cohort of SSc patients. METHODS: Thirty patients with SSc-PAH and 150 SSc patients without PAH were included. Survival and survival on therapy were calculated. Clinical features at baseline were correlated to the risk for development of PAH during follow-up. RESULTS: The 1-, 2-, 3-, and 4-year survival rates were 86, 59, 39, and 22%, respectively, from diagnosis of PAH. The hazard ratio for total mortality in the SSc-PAH group was 3.2 [95% confidence interval (CI) 1.8-5.7] compared to SSc without PAH (p < 0.001). Risk factors at baseline for the development of PAH were: limited skin involvement, low diffusing capacity of the lung for carbon monoxide (DL(CO)), high N-terminal pro-brain natriuretic peptide (NTProBNP), increased estimated systolic pulmonary arterial pressure (ESPAP), and the presence of teleangiectases. Severe peripheral vascular disease requiring iloprost treatment during follow-up was associated with an eightfold increased risk of PAH. CONCLUSION: Despite modern treatment and yearly screening by echocardiography, the survival in SSc-PAH is still low in our cohort. The identified risk factors should be assessed to select patients eligible for right heart catheterization (RHC) to make an earlier diagnosis.

Increased alveolar nitric oxide in early systemic sclerosis.

OBJECTIVES: Assessment of inflammatory activity in interstitial lung disease of systemic sclerosis (SSc) is difficult. Nitric oxide (NO) has gained attention in the pathogenesis of SSc. The aim of the study was to investigate alveolar NO concentration (CA(NO)) in SSc patients with short disease duration and to relate CA(NO) to radiologic findings. METHODS: In a prospective study, 34 consecutive patients with disease duration of less than 2 years from onset of first non-Raynaud symptom and 26 healthy controls were enrolled. Exhaled NO was measured and CA(NO) was calculated. CA(NO) levels were related to the radiologic extent of pulmonary fibrosis measured as the extent of traction bronchiectasis within areas of ground glass opacities and reticulations. RESULTS: CA(NO) levels were increased in patients with early SSc compared to healthy controls (3.52 (2.94-4.09) versus 2.08 (1.6-2.6); p<0.001). Both SSc patients with SSc-ILD (3.56 (3.04-4.73), p<0.001) and SSc patients without SSc-ILD (2.98 (2.68-3.98), p<0.01) had higher CA(NO) levels compared with healthy controls (2.08 (1.6-2.6)). CA(NO) levels did not differ between SSc patients without SSc-ILD and SSc patients with SSC-ILD. CA(NO) levels did not correlate to the extent of pulmonary fibrosis but were associated with the extent of ground glass opacities (rs=0.37, p<0.05) and reticulations (rs=0.37, p<0.05) on HRCT. CA(NO) levels were not correlated to lung function tests. CONCLUSIONS: In patients with early SSc, alveolar NO is increased and may precede radiological changes of SSc-ILD. CA(NO) may therefore be a marker of early lung involvement.

Distinct evolution of TLR-mediated dendritic cell cytokine secretion in patients with limited and diffuse cutaneous systemic sclerosis.

BACKGROUND: Systemic sclerosis (SSc) is an autoimmune disease and accumulating evidence suggests a role for Toll-like receptor (TLR)-mediated activation of dendritic cells (DCs). OBJECTIVE: To map TLR-mediated cytokine responses of DCs from patients with SSc. METHODS: 45 patients with SSc were included. Patients were stratified as having diffuse cutaneous SSc (dSSc) or limited cutaneous SSc (lSSc) according to the extent of skin involvement, and further divided into those with late (>3 years) or early disease (<2 years). DCs were stimulated with ligands for TLR2, TLR3, TLR4, TLR7/8 or combinations. Plasma samples were collected from patients with SSc (n=167) and measured for interleukin 6 (IL-6), tumour necrosis factor alpha (TNFalpha), IL-12, IL-10 and interferon gamma. RESULTS: Stimulation of DC subsets from patients with early lSSc and dSSc with ligands for TLR2, TLR3 or TLR4 resulted in higher secretion of IL-6 and TNFalpha compared with those having late disease or healthy controls. Remarkably, the production of IL-12 was lower upon stimulation with TLR ligands in most patients with SSc, whereas the secretion of IL-10 was very high in patients with the dSSc phenotype, particularly in those having early dSSc. The combination of various TLR ligands led to reduced cytokine secretion in all patients with SSc. Circulating levels of these cytokines further underscored the presence of differences between various SSc phenotypes. DISCUSSION: The altered TLR-mediated activation of DCs may be responsible for Th2 skewed T-cell activation in SSc that may be orchestrated by fibrogenic T-cell cytokines, such as IL-4 and IL-13. DC targeting could thus offer new avenues for therapeutic intervention.

Renal function is mostly preserved in patients with systemic sclerosis.

OBJECTIVE: Chronic renal disease other than scleroderma renal crisis (SRC) is not well documented in systemic sclerosis (SSc). We examined the occurrence of decreased glomerular filtration rate (GFR) in a large consecutive SSc cohort and analysed whether it was related to SSc or could be related to other causes. METHODS: During 1983-2004 GFR was measured by chromium-51-ethylenediaminetetraacetic acid (51Cr-EDTA) or iohexol clearance in 461 patients with SSc according to the American College of Rheumatology (ACR) criteria [356 with limited cutaneous SSc (lcSSc) and 105 with diffuse cutaneous SSc (dcSSc)] and the measurements were repeated once a year. Decreased GFR was defined as GFR<70% of the age-adjusted values. SRC was diagnosed in 4/360 lcSSc (1.1%) and in 10/115 dcSSc (8.7%). These patients were excluded from further analyses. RESULTS: At the latest follow-up at a median duration of 7.7 (range 0.5-54) years, decreased GFR was found in 39 lcSSc (11%) and nine (8.6%) dcSSc patients. Among the 48 SSc patients with GFR< 70p% (percentage of predicted value = p%), hypertension was diagnosed in 29 (60%) and cardiac involvement in 25 (52%). Different nephropathies were found in eight (19%) patients by renal biopsy. Fifteen patients with decreased GFR were followed up for > or = 4 years and no progress was seen in 11/15. CONCLUSIONS: A minority of patients with SSc develop renal dysfunction other than SRC. Decreased GFR was associated with other manifestations such as hypertension and cardiac involvement indicating possible pre-renal causes.

Expression of interleukin-15 in mouse and human atherosclerotic lesions.

Atherosclerotic lesions are characterized by prominent macrophage and T-cell infiltration and atherosclerosis is widely recognized as an inflammatory disease. The cytokine interleukin-15 (IL-15) has T-cell chemotactic and pro-inflammatory properties and promotes the recruitment of T cells to sites of inflammation. We have therefore examined IL-15 expression in the atherosclerotic ApoE-deficient mouse model as well as in human atherosclerotic lesions. In gene expression arrays, a transcript corresponding to IL-15 mRNA was elevated in atherosclerotic aortas of ApoE-deficient mice fed a Western diet for 10 and 20 weeks, corresponding to lesions of the fatty streak and fibrofatty plaque stage, respectively. Immunostaining for IL-15 localized to aortic smooth muscle cells in nonatherosclerotic C57BL/6 mice, whereas both macrophages and smooth muscle cells stained positive for IL-15 in atherosclerotic lesions of ApoE-deficient mice. Finally, advanced atherosclerotic lesions of human carotid arteries were immunostained to determine whether IL-15 is involved in human disease. IL-15 protein was present also in the human lesions with a distribution primarily overlapping that of macrophages. In conclusion, IL-15 is up-regulated in both human and animal atherosclerotic lesions and may contribute to the recruitment of T cells and their activation during atherogenesis.

Gene expression in atherosclerotic lesion of ApoE deficient mice.

BACKGROUND: Atherosclerosis, the major cause of mortality and invalidity in industrialized countries, is a multifactorial disease associated with high plasma cholesterol levels and inflammation in the vessel wall. Many different genes have previously been demonstrated in atherosclerosis, although limited numbers of genes are dealt with in each study. In general, data on dynamic gene expression during disease progress is limited and large-scale evaluation of gene expression patterns during atherogenesis could lead to a better understanding of the key events in the pathogenesis of atherosclerosis. We have therefore applied a mouse gene filter array to analyze gene expression in atherosclerotic ApoE-deficient mice. MATERIALS AND METHODS: ApoE-deficient mice were fed atherogenic western diet for 10 or 20 weeks and aortas isolated. C57BL/6 mice on normal chow were used as controls. The mRNAs of 15 animals were pooled and hybridized onto commercially available Clontech mouse gene array filters. RESULTS: The overall gene expression in the ApoE-deficient and control mice correlated well at both time points. Gene expression profiling showed varying patterns including genes up-regulated at 10 or 20 weeks only. At 20 weeks of diet, an increasing number of up-regulated genes were found in ApoE-deficient mice. CONCLUSIONS: The gene expression in atherogenesis is not a linear process with a maximal expression at advanced lesion stage. Instead, several genes demonstrate a dynamic expression pattern with peaks at the intermediate lesions stage. Thus, detailed evaluation of gene expression at several time points should help understanding the development of atherosclerosis and establishment of preventive intervention.

T-cell recognition of lipid peroxidation products breaks tolerance to self proteins.

Peroxidation of polyunsaturated fatty acids in lipoproteins and cell membrane phospholipids occurs in many situations in the body, both under normal and pathological conditions. Low-density lipoprotein is particularly prone to oxidation and is believed to be a pathogenetic component in atherogenesis. Both antibody responses and T-cell responses to oxidatively modified lipoproteins have been demonstrated in humans as well as in animal models. However, little is known about how these responses arise or how T cells recognize these antigens. In the present study, mice were immunized with homologous albumin covalently modified with a series of defined aldehydes which are known to be generated during lipid peroxidation. T-cell hybridomas from immunized animals demonstrated major histocompatibility complex-restricted and protein sequence-dependent responses to modified albumin, but not to native albumin. In addition to the response to modified epitopes, some aldehyde modifications resulted in strong antibody responses also to the non-modified protein. This T-cell-dependent break of tolerance constitutes a novel pathway for induction of autoimmunity by lipid peroxidation. The findings have implications in many situations where lipid peroxidation products are generated, including atherosclerosis and inflammatory and infectious diseases.

Effects of in vitro addition of captopril on copper-induced low density lipoprotein oxidation.

Low density lipoprotein (LDL) was incubated with 20 microM of the angiotensin converting enzyme (ACE) inhibitors captopril, fosinopril and quinapril or ethanol. Oxidation of LDL was initiated by addition of CuSO4 and monitored for production of conjugated dienes, thiobarbituric acid reactive substances (TBARS) and lipid peroxides. The inhibition of production of conjugated dienes was expressed as the lag phase in minutes. The lag phase for control samples was 55.2 +/- 6.1 (mean +/- s.e. mean) min and for captopril 86.4 +/- 7.0 min (P = 0.0058). Quinapril had a small but nonsignificant effect, fosinopril and ethanol had no effect. LDL incubated with captopril showed only 13.8% of TBARS and 22.7% of lipid peroxides produced by control (100%) after 1 h. Increasing concentrations of captopril showed a linear increase in the lag phase. We conclude that captopril increases the resistance of LDL to copper-induced oxidation.