Endothelial cell markers reflecting endothelial cell dysfunction in patients with mixed connective tissue disease

Epipericardial fat necrosis in chest CT and MRI: a case report of an unusual cause of chest pain associated with the initial diagnosis of undifferentiated connective tissue disease

BACKGROUND

Epipericardial fat necrosis (EFN) is a benign and self-limited condition of unknown cause with a good prognosis, usually affecting otherwise healthy patients. Clinically, it presents with severe acute left pleuritic chest pain, often leading the patient to the Emergency Room (ER).

CASE PRESENTATION

A 23-year-old male, smoker (5 pack-years), was evaluated in the ER due to left pleuritic chest pain, worsening with deep breathing and Valsalva maneuver. It was not associated with trauma and did not present other symptoms. The physical examination was unremarkable. The arterial blood gases while breathing room air and the laboratory tests, including D-dimers and high-sensitivity cardiac Troponin T, were normal. The chest radiograph, electrocardiogram, and transthoracic echocardiogram showed no abnormalities. A computed tomography (CT) pulmonary angiogram showed no signs of pulmonary embolism but depicted at the left cardiophrenic angle a focal 3 cm ovoid-shaped fat lesion with stranding and thin soft tissue margins, consistent with necrosis of the epicardial fat, which was confirmed by magnetic resonance (MRI) of the chest. The patient was medicated with ibuprofen and pantoprazole, with clinical improvement in four weeks. At a two-month follow-up, he was asymptomatic and presented radiologic resolution of the inflammatory changes of the epicardial fat of the left cardiophrenic angle on chest CT. Laboratory tests revealed positive antinuclear antibodies, positive anti-RNP antibody, and positive lupus anticoagulant. The patient complained of biphasic Raynaud's phenomenon initiated five years ago, and a diagnosis of undifferentiated connective tissue disease (UCTD) was made.

CONCLUSIONS

This case report highlights the diagnosis of EFN as a rare and frequently unknown clinical condition, which should be considered in the differential diagnosis of acute chest pain. It can mimic emergent conditions such as pulmonary embolism, acute coronary syndrome, or acute pericarditis. The diagnosis is confirmed by CT of the thorax or MRI. The treatment is supportive and usually includes non-steroidal anti-inflammatory drugs. The association of EFN with UCTD has not been previously described in the medical literature.

Biomarker profiles of endothelial activation and dysfunction in rare systemic autoimmune diseases: implications for cardiovascular risk

OBJECTIVES

Vasculopathy is an important hallmark of systemic chronic inflammatory connective tissue diseases (CICTD) and is associated with increased cardiovascular risk. We investigated disease-specific biomarker profiles associated with endothelial dysfunction, angiogenic homeostasis and (tissue) inflammation, and their relation to disease activity in rare CICTD.

METHODS

A total of 38 serum proteins associated with endothelial (dys)function and inflammation were measured by multiplex-immunoassay in treatment-naive patients with localized scleroderma (LoS, 30), eosinophilic fasciitis (EF, 8) or (juvenile) dermatomyositis (34), 119 (follow-up) samples during treatment, and 65 controls. Data were analysed by unsupervised clustering, Spearman correlations, non-parametric t test and ANOVA.

RESULTS

The systemic CICTD, EF and dermatomyositis, had distinct biomarker profiles, with 'signature' markers galectin-9 (dermatomyositis) and CCL4, CCL18, CXCL9, fetuin, fibronectin, galectin-1 and TSP-1 (EF). In LoS, CCL18, CXCL9 and CXCL10 were subtly increased. Furthermore, dermatomyositis and EF shared upregulation of markers related to interferon (CCL2, CXCL10), endothelial activation (VCAM-1), inhibition of angiogenesis (angiopoietin-2, sVEGFR-1) and inflammation/leucocyte chemo-attraction (CCL19, CXCL13, IL-18, YKL-40), as well as disturbance of the Angiopoietin-Tie receptor system and VEGF-VEGFR system. These profiles were related to disease activity, and largely normalized during treatment. However, a subgroup of CICTD patients showed continued elevation of CXCL10, CXCL13, galectin-9, IL-18, TNFR2, VCAM-1, and/or YKL-40 during clinically inactive disease, possibly indicating subclinical interferon-driven inflammation and/or endothelial dysfunction.

CONCLUSION

CICTD-specific biomarker profiles revealed an anti-angiogenic, interferon-driven environment during active disease, with incomplete normalization under treatment. This warrants further investigation into monitoring of vascular biomarkers during clinical follow-up, or targeted interventions to minimize cardiovascular risk in the long term.

APPLICATION OF QUERCETIN FOR CORRECTION OF THE IMPAIRMENT OF THE FUNCTIONAL STATE OF THE ENDOTHELIUS OF VESSELS (CLINICAL AND EXPERIMENTAL STUDY)

OBJECTIVE

in the experiment, to investigate the effect of Quercetin on the NO-dependent reactions of isolated vessels involving endothelium and perivascular adipose tissue (PVAT) after a single X-ray irradiation of rats at a sublethal dose. In a clinical study, to investigate the effect of long-term use of Quercetin on the functional state of themicrovascular endothelium in the elderly patients with metabolic syndrome (MS).

MATERIAL AND METHODS

Experimental studies were performed on vascular fragments obtained from adult male rats(7-8 months) of the control group, in animals exposed to a single R-irradiation at a dose of 7 Gy and animals irradiated in the same dose, which received Quercetin orally for 14 days three times a week based on 10 mg/kg bodyweight. Fragments of the thoracic aorta (TA) and mesenteric artery (MA) were cleaned of perivascular adipose tissue (PVAT-) or left uncleaned (PVAT+), and then were cut into rings (up to 2 mm). The amplitude of the contractionof the rings TA and MA under the influence of phenylephrine (PE, 3 x 10-6 M), the amplitude of the contraction of therings TA and MA in the presence of a competitive blocker of NO-synthase methyl ester of N-nitro-L-arginine(L-NAME, 10-5 M), the amplitude of relaxation of the rings TA and MA in the presence of N-acetylcysteine (NAC, 10-4 M)were measured. The clinical study examined 110 patients with MS criteria in accordance with ATP III (2001).Patients in the main group for 3 months received Quercetin from the same manufacturer, 80 mg three times a day,patients in the control group received placebo.

RESULTS

Single R-irradiation disrupts the regulation of the contractile function of TA and MA, which is evidenced bychanges in the contractile reactions of isolated fragments of these vessels as a response to the action of vasoactivecompounds. Course use of Quercetin in irradiated rats leads to the normalization of contractile and dilatory vascular responses due to partial correction of NO metabolism in the endothelium and PVAT. For the majority of patients(69 %) who received Quercetin, a post-occlusive hyperemia test showed a statistically significant increase of maximal volumetric velocity of the skin blood flow rate and duration of the recovery period to the baseline, which indicates about improvement of vasomotor vascular endothelial function.

CONCLUSIONS

Course use of Quercetin improves the functional state of the microvascular endothelium among theelderly people with MS, normalizes contractile and dilatory vascular responses in irradiated rats due to partial correction of NO metabolism in the endothelium and PVAT.

Clinical aspects and risk factors of lupus nephritis: a retrospective study of 156 adult patients

Objective

To analyze the clinical manifestations, laboratory indexes, disease activity, and pathological types of lupus nephritis (LN) in adult patients.

Methods

We retrospectively analyzed the clinical manifestations, laboratory indexes, and pathological classifications of 156 adult patients first diagnosed with LN between July 2013 and November 2017. Patients were categorized according to the following criteria: active or inactive LN, LN with or without renal damage, and mild or severe LN.

Results

Immunoglobulin G and A levels, 24-hour proteinuria, and anti-dsDNA, anti-Sm, and anti-ribosomal P protein antibody positivity rates were all significantly increased in patients with active LN compared with inactive LN. Anti-dsDNA antibody positivity and 24-hour proteinuria were significantly increased, whereas hemoglobin, serum albumin, and C3 and C4 levels were significantly decreased in patients with LN and renal damage compared with those without renal damage. Anti-dsDNA and anti-Sm antibody positivity rates and 24-hour proteinuria were significantly increased, while hemoglobin, serum albumin, C3 and C4 levels, and estimated glomerular filtration rate were significantly decreased in patients with severe LN compared with patients with mild LN.

Conclusions

LN can display various clinical manifestations, laboratory indexes, levels of disease activity, and pathological types in adult patients.

The Predictive Value of Autoantibody Spectrum on Organ Damage in Patients With Systemic Lupus Erythematosus

OBJECTIVES

This study aims to investigate the positive detection rate and predictive value of autoantibodies, including anti-double stranded deoxyribonucleic acid (anti-dsDNA) antibodies, anti-histone antibodies (AHAs), anti-ribosomal (anti-Rib) P antibodies, anti-Smith (anti-Sm) antibodies, anti-U1 ribonucleoprotein (anti-U1RNP) antibodies, anti-Sjögren's syndrome type A antibodies and anti-Sjögren's syndrome type B antibodies, on organ damage in patients with systemic lupus erythematous (SLE).

PATIENTS AND METHODS

A total of 225 patients with SLE (37 males, 188 females; mean age 37.4±15.9 years; range, 7 to 80 years) were evaluated retrospectively. Statistical analysis was performed to obtain the positive detection rate of autoantibodies and to investigate the predictive value.

RESULTS

There were statistically significant differences of positive anti-dsDNA antibodies in renal damage, photosensitization, hematological abnormalities and serositis (p<0.05) and a statistically significant difference of positive AHAs in photosensitization (p<0.05). There was statistically significant difference of positive anti-U1RNP antibodies in renal damage (p<0.05). There were also statistically significant differences of positive anti-Smith antibodies in renal damage, arthritis, photosensitization, oral ulcers, hematological abnormalities and serositis (p<0.05) and of positive anti-Rib antibodies in renal damage, arthritis, photosensitization, malar rash, hematological abnormalities and serositis (p<0.05). However, there were no statistically significant differences of positive anti-Sjögren's syndrome type B antibodies and anti-Sjögren's syndrome type A antibodies in renal damage, arthritis, malar rash, neuropsychiatric disorders, hematological abnormalities and serositis (p>0.05).

CONCLUSION

Autoantibody spectrum is an important serological basis for SLE diagnosis. There are differences in the autoantibodies distribution of SLE patients with different organ damage, suggesting a certain clinical value for prediction of organ damage in SLE.

Effect on Cardiac Function of Longstanding Juvenile-onset Mixed Connective Tissue Disease: A Controlled Study

OBJECTIVE

To assess cardiac function in patients with juvenile mixed connective tissue disease (JMCTD) compared to matched controls, and to investigate possible associations between cardiac impairment and disease variables and cardiovascular risk factors.

METHODS

Fifty JMCTD patients (86% female) examined median 14.9 (6.6-23.0) years after disease onset were compared with 50 age- and sex-matched controls. Electrocardiogram and echocardiography [including e' as a marker for diastolic dysfunction and long-axis strain (LAS) and left ventricular (LV) ejection fraction (EF) as markers of systolic function] were performed. LV dysfunction (LVD) was defined as low EF, low LAS, or low e'. Right ventricular function was assessed with tricuspid annular plane systolic excursion (TAPSE). Cardiovascular risk factors and disease variables were assessed.

RESULTS

LVD was found in 16% of patients and 4% of controls (p = 0.035). EF and LAS were lower in patients compared to controls (6% lower, p < 0.001, and 4% lower, p = 0.044, respectively). TAPSE was 8% lower in patients versus controls (p = 0.008). No patients had signs of pulmonary hypertension. Patients had longer corrected QT time than controls (p = 0.012). LVD was associated with higher levels of apolipoprotein B, higher disease activity measured by physician's global assessment, longer prednisolone treatment, and more organ damage assessed with the Myositis Damage Index.

CONCLUSION

Patients with JMCTD had impaired left and right ventricular function compared to matched controls after median 15 years disease duration. High disease activity and longer treatment with prednisolone were factors associated with LVD.

Preclinical Carotid Atherosclerosis in Patients With Juvenile-Onset Mixed Connective Tissue Disease

BACKGROUND

This study investigated preclinical atherosclerosis in patients with juvenile mixed connective tissue disease (JMCTD), which is a chronic inflammatory disease with a varied phenotype. Mixed connective tissue disease (MCTD) has well known associations with other autoimmune diseases known to have increased risk of cardiovascular disease. However, the cardiovascular risk for patients with the juvenile form remains unclear.

MATERIALS AND METHODS

Forty-nine patients with JMCTD and 45 age-and sex-matched controls took part in this study. They underwent blood tests, clinical examination, and ultrasound measurement of the carotid arteries.

RESULTS

We found that patients had significantly higher average carotid intima-media thickness (IMT) as compared to controls (mean 0.57 ± 0.09 versus 0.53 ± 0.06, P = .03). IMT also increased with both increasing disease duration (years from diagnosis), and severity as assessed by the physicians global assessment score, after adjustment for age.

CONCLUSIONS

This is the first study to demonstrate increased preclinical atherosclerosis in juvenile MCTD. Our findings suggest that the atherosclerotic burden in this patient group, which was independent of traditional cardiovascular risk factors, might be secondary to the underlying connective tissue disease.

Coronary artery ectasia in Crohn's disease

Coronary artery ectasia (CAE) can be ascribed, in the majority of cases, to coronary atherosclerosis. Nevertheless, the presence of isolated ectatic lesions without obstructive coronary artery disease and the association of CAE with several autoimmune diseases characterised by systemic vascular involvement suggest that the pathogenesis of CAE may extend beyond coronary atherosclerosis. We herein report the case of a 56-year-old male patient with Crohn's disease and isolated CAE, who has been found positive for IgM and IgA antiendothelial cell antibodies, and discuss a potential pathogenic mechanism.

Anti-High-Density Lipoprotein Antibodies and Antioxidant Dysfunction in Immune-Driven Diseases

Introduction

Impaired high-density lipoprotein (HDL) levels and antioxidant functionality of HDL, mainly attributed to a decreased paraoxonase-1 (PON1) functionality, have been described in autoimmune conditions. In this setting, a role for humoral response in cardiovascular disease is emerging. This study evaluates the role of immunoglobulin G (IgG) antibodies against HDL and disease-related autoantibodies on HDL dysfunction in immune-driven diseases.

Methods

Serum IgG anti-HDL antibodies, PON1 activity, and total antioxidant capacity (TAC) were quantified in 381 patients with different immune-driven diseases [18 mixed connective tissue disease (MCTD), 35 primary Sjögren syndrome (pSS), 38 systemic sclerosis (SSc), 33 ANCA-associated vasculitis (AAV), 60 diabetes mellitus 1, 29 autoimmune B12 deficiency/pernicious anemia, 29 primary biliary cirrhosis, 46 IBD/Crohn, 54 IBD/UC, and 39 celiac disease (CD)] and 138 healthy controls.

Results

IgG anti-HDL antibodies were increased in MCTD, pSS, AAV, and inflammatory bowel disease (IBD) [Crohn and ulcerative colitis (UC)], even after correcting for total IgG levels, but not in organ-specific autoimmune diseases. Anti-HDL antibodies were negatively associated with PON1 activity in MCTD (r = −0.767, p < 0.001) and AAV (r = −0.478, p = 0.005), whereas both anti-HDL and anti-neutrophil cytoplasm antibod levels were related to an impaired PON1 activity and TAC in IBD/UC. In SSc, anti-centromere antibodies correlated PON1 activity. anti-Saccharomyces cerevisiae antibodies levels were negatively associated with PON1 activity (r = −0.257, p = 0.012) and PON1/TAC ratio (r = −0.261, p = 0.009) in IBD/Crohn. HDL dysfunction in CD was only related to anti-transglutaminase levels.

Conclusion

IgG anti-HDL antibodies and HDL dysfunction are common hallmarks of systemic autoimmunity. Anti-HDL and disease-related autoantibodies account for the HDL antioxidant dysfunction in immune-driven conditions, mainly in systemic autoimmune disorders.

Mixed connective tissue disease-enigma variations?

In 1972, Sharp et al. described a new autoimmune rheumatic disease that they called MCTD, characterized by overlapping features of SSc, SLE, PM/DM, high levels of anti-U1snRNP and low steroid requirements with good prognosis. MCTD was proposed as a distinct disease. However, soon after the original description, questions about the existence of such a syndrome as well as disputes over the features initially described began to surface. The conundrum of whether MCTD is a distinct disease entity remains controversial. We undertook a literature review, focusing on the articles reporting new data about MCTD published in the last decade, to determine whether any new observations help to answer the conundrum of MCTD. After reviewing recent data, we question whether the term MCTD is appropriately retained, preferring to use the term undifferentiated autoimmune rheumatic disease.

Pediatric Mixed Connective Tissue Disease

Pediatric-onset mixed connective tissue disease is among the rare disease entities in pediatric rheumatology and includes features of arthritis, polymyositis/dermatomyositis, systemic lupus erythematosus, and systemic sclerosis. Accurate recognition and diagnosis of the disease is paramount to prevent long-term morbidity. Advances in the genetic and immunologic understanding of the factors involved in the etiopathogenesis provide an opportunity for improvements in prognostication and targeted therapy. The development of a multinational cohort of patients with mixed connective tissue disease would be invaluable to provide more updated data regarding the clinical presentation, to develop a standardized treatment approach, disease activity and outcome tools, and to provide data on long-term outcomes and comorbidities.

Posterior reversible encephalopathy syndrome in a patient with mixed connective tissue disease: a case report

Background

Posterior reversible encephalopathy is a syndrome highly associated with hypertension and cytotoxic therapy. The syndrome typically presents with headache, visual abnormality, seizures and characteristic vasogenic edema on magnetic resonance imaging. The entity warrants a prompt diagnosis to avoid deteriorating consequences.

Case presentation

In this report, we describe a 15-year-old Iranian boy who was diagnosed with mixed connective tissue disease, and cyclophosphamide pulse therapy was administered. Three days after the second pulse of cyclophosphamide, when he was receiving prednisolone and hydroxycholoroquine, our patient developed generalized tonic-clonic seizures. Magnetic resonance imaging findings showed high signal intensities in the posterior areas of his brain. After 8 days, the brain magnetic resonance imaging abnormalities were resolved following the control of his blood pressure and antiepileptic treatment. These observations have been indicative of posterior reversible encephalopathy syndrome. Nevertheless, our patient developed uncontrollable respiratory distress and eventually died.

Conclusions

To the best of our knowledge, this case is the first report of posterior reversible encephalopathy syndrome in a patient with mixed connective tissue disease. As the patient developed posterior reversible encephalopathy syndrome 3 days after cyclophosphamide pulse therapy to reduce the disease activity, it is hard to accurately determine whether posterior reversible encephalopathy syndrome in this case is a complication of cyclophosphamide or a condition that resulted from the mixed connective tissue disease flare-up.

Decreased flow-mediated dilatation with increased arterial stiffness and thickness as early signs of atherosclerosis in polymyositis and dermatomyositis patients

Several autoimmune rheumatic diseases have been associated with accelerated atherosclerosis or other different types of vasculopathy depending on the underlying disease, leading to increased cardio- and cerebrovascular disease risk. Polymyositis (PM) and dermatomyositis (DM), members of idiopathic inflammatory myopathies (IIMs), a group of systemic autoimmune diseases are also associated with elevated risk of cardiovascular diseases (CVD). Up until now, no specific data is known on the mechanisms, risk factors, or possible vasculopathy leading to increased CVD risk. The aims of the present study were to assess the flow-mediated dilatation of the brachial artery by a TensioClinic arteriograph and to measure the thickness of carotid artery intima-media, the augmentation index, and the pulse wave velocity using high-resolution ultrasonography in a cohort of PM and DM patients. We also investigated the correlation of these parameters with the traditional risk factors of atherosclerosis and overall cardiovascular status within PM and DM patients. Twenty-seven patients (21 females, six males) with IIMs were enrolled in this study, and 38 healthy individuals matched for sex and age served as controls. We found a decreased flow-mediated dilatation in the brachial artery (6.36 vs. 8.39 %) with increased arterial stiffness and carotid artery thickness in our patients compared to healthy controls. We found significantly decreased flow-mediated dilatation of the brachial artery (5.57 vs. 8.39 %) in DM patients. We also detected a correlation between these parameters and the traditional cardiovascular risk factors, as well as hypertriglyceridemy, hypertension, and peripheral arterial disease. In DM, overall, more vascular abnormalities were found than in PM. Our findings suggest that flow-mediated dilatation of the brachial artery, arterial stiffness, and carotid artery thickness measurements could be beneficial for predicting the CVD risk in myositis patients. Further investigations need to find the potential differences and role of inflammation and immune mechanisms in atherosclerotic processes in DM and PM.

Relationship of CD146 expression to activation of circulating T cells: exploratory studies in healthy donors and patients with connective tissue diseases

The endothelial cell adhesion molecule, CD146, is expressed on ≈ 2% of normal circulating T cells, correlating with T cell activation, endothelial interactions and T helper type 17 (Th17) effector functions. In this study, we have characterized CD146 expression in circulating T cells from healthy controls and patients with stable, well-controlled autoimmune connective tissue diseases (CTDs). In vitro, anti-CD3/anti-CD28 stimulation induced CD146 expression in both CD4 and CD8 T cells. In healthy controls and CTD patients, CD146 was associated with expression of recent and chronic activation markers (CD25(+), OX-40(+), CD69(+), CD27(-)) and was confined to CD45RO(+)/RA(-)/CD28(+) populations within the CD4 subset. Except for CD69, these markers were not associated with CD146 in the CD8 subset. Surprisingly, most CTD patients exhibited no T cell hyperactivation ex vivo. In five of five patients with secondary Sjögren's syndrome circulating T cells appeared activated despite therapy, and CD146 up-regulation, associated with activation markers, was observed both on CD4 and CD8 T cells. There was no association between CD146 and putative pro-atherogenic T cell subsets. In conclusion, the relationship of CD146 expression to T cell activation differs between T cell subsets in healthy subjects and correlates with systemic hyperactivity, where present, in patients with CTDs, as exemplified by the patients with secondary Sjögren's syndrome in this study.

Clinical course, prognosis, and causes of death in mixed connective tissue disease

OBJECTIVE

To study the survival rate and prognostic indicators of mixed connective tissue disease (MCTD) in a Hungarian population.

METHODS

Two hundred eighty patients with MCTD diagnosed between 1979 and 2011 were followed prospectively. Clinical features, autoantibodies, and mortality data were assessed. Prognostic factors for survival were investigated and survival was calculated from the time of the diagnosis by Kaplan-Meier method.

RESULTS

A total of 22 of 280 patients died: the causes of death were pulmonary arterial hypertension (PAH) in 9 patients, thrombotic thrombocytopenic purpura in 3, infections in 3, and cardiovascular events in 7. The 5, 10, and 15-year survival rates after the diagnosis was established were 98%, 96%, and 88%, respectively. The deceased patients were younger at the diagnosis of MCTD compared to patients who survived (35.5 ± 10.4 vs 41.8 ± 10.7 yrs; p < 0.03), while there was no difference in the duration of the disease (p = 0.835). Our cohort study showed that the presence of cardiovascular events (p < 0.0001), esophageal hypomotility (p = 0.04), serositis (p < 0.001), secondary antiphospholipid syndrome (p = 0.039), and malignancy (p < 0.001) was significantly higher in the deceased patients with MCTD. The presence of anticardiolipin (p = 0.019), anti-β2-glycoprotein I (p = 0.002), and antiendothelial cell antibodies (p = 0.002) increased the risk of mortality.

CONCLUSION

Overall, PAH remained the leading cause of death in patients with MCTD. The prevalence of cardiovascular morbidity and mortality, malignancy, and thrombotic events increased during the disease course of MCTD. The presence of antiphospholipid antibodies raised the risk of mortality.

A novel autoantibody against fibronectin leucine-rich transmembrane protein 2 expressed on the endothelial cell surface identified by retroviral vector system in systemic lupus erythematosus

Introduction

Anti-endothelial cell antibodies (AECAs) are thought to be critical for vasculitides in collagen diseases, but most were directed against molecules localized within the cell and not expressed on the cell surface. To clarify the pathogenic roles of AECAs, we constructed a retroviral vector system for identification of autoantigens expressed on the endothelial cell surface.

Methods

AECA activity in sera from patients with collagen diseases was measured with flow cytometry by using human umbilical vein endothelial cells (HUVECs). A cDNA library of HUVECs was retrovirally transfected into a rat myeloma cell line, from which AECA-positive clones were sorted with flow cytometry. cDNA of the cells was analyzed to identify an autoantigen, and then the clinical characteristics and the functional significance of the autoantibody were evaluated.

Results

Two distinct AECA-positive clones were isolated by using serum immunoglobulin G (IgG) from a patient with systemic lupus erythematosus (SLE). Both clones were identical to cDNA of fibronectin leucine-rich transmembrane protein 2 (FLRT2). HUVECs expressed FLRT2 and the prototype AECA IgG bound specifically to FLRT2-transfected cells. Anti-FLRT2 antibody activity accounted for 21.4% of AECAs in SLE. Furthermore, anti-FLRT2 antibody induced complement-dependent cytotoxicity against FLRT2-expressing cells.

Conclusions

We identified the membrane protein FLRT2 as a novel autoantigen of AECAs in SLE patients by using the retroviral vector system. Anti-FLRT2 antibody has the potential to induce direct endothelial cell cytotoxicity in about 10% of SLE patients and could be a novel molecular target for intervention. Identification of such a cell-surface target for AECAs may reveal a comprehensive mechanism of vascular injury in collagen diseases.

Comparative assessment of vascular function in autoimmune rheumatic diseases: considerations of prevention and treatment

Numerous autoimmune-inflammatory rheumatic diseases have been associated with accelerated atherosclerosis or other types of vasculopathy leading to increased cardio- and cerebrovascular disease risk. Traditional risk factors, as well as the role of systemic inflammation including cytokines, chemokines, proteases, autoantibodies, adhesion receptors and others have been implicated in the development of these vascular pathologies. The characteristics of vasculopathies may significantly differ depending on the underlying disease. While classical accelerated atherosclerosis has been associated with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) or spondyloarthropathies (SpA), obliterative vasculopathy may rather be characteristic for systemic sclerosis (SSc) or mixed connective tissue disease (MCTD). Antiphospholipid antibodies have been implicated in vasculopathies underlying SLE, antiphospholipid syndrome (APS), RA and MCTD. There is also heterogeneity with respect to inflammatory risk factors. Cytokines, such as tumor necrosis factor-α (TNF-α) or interleukin 6 (IL-6) and immune complexes are primarily involved in arthritides, such as RA, SpA, as well as in SLE. On the other hand, autoantibodies including anti-oxLDL anti-cardiolipin and anti-β2GPI are rather involved in SLE- and APS-associated vasculopathies. Regarding the non-invasive assessment of vascular function, endothelial dysfunction, overt atherosclerosis and vascular stiffness may be indicated by brachial artery flow-mediated vasodilation (FMD), common carotid intima-media thickness (ccIMT) and aortic pulse-wave velocity (PWV), respectively. These abnormalities have been described in most inflammatory rheumatic diseases. While ccIMT and stiffness are relatively stable, FMD may be influenced by many confounding factors. In addition to traditional vasculoprotection, immunosuppressive agents including corticosteroids, traditional and biologic DMARDs may have significant vascular and metabolic effects. The official EULAR recommendations on the assessment and management of cardiovascular disease in arthritides have just been published, and similar recommendations in connective tissue diseases are to be developed soon.

Vitamin D insufficiency in a large MCTD population

OBJECTIVES

The aim of the present study was to evaluate the vitamin D status in patients with mixed connective tissue disease (MCTD) and to determine which clinical symptoms, laboratory parameters and endothelial cell markers are associated with low vitamin D levels.

METHODS

125 female MCTD patients and 48 age- and sex-matched healthy controls were enrolled in the study. The clinical symptoms, autoantibodies (anti-U1-RNP, anti-cardiolipin - anti-CL and anti-endothelial cell antibody - AECA), serum cytokines (IFN-γ, IL-6, IL-12, IL-23, IL-17 and IL-10), soluble endothelial cell markers (endothelin, thrombomodulin - TM, and von Willebrand factor antigen - vWFAg) and serum lipids (total cholesterol, triglyceride, LDL-C, HDL-C, apolipoprotein A1, and apolipoprotein B) were investigated for an association with vitamin D levels by univariate and multivariate statistical analyses.

RESULTS

The mean vitamin D levels were significantly lower in MCTD patients, as compared with the control group (26.16±13.50ng/ml vs. 34.92±9.64ng/ml; p<0.001). In laboratory parameters, vitamin D levels were inversely associated with serum IL-6 (p<0.001), IL-23 (p=0.011), IL-10 (p=0.033) cytokine levels, TM (p=0.001) and endothelin (p=0.033) levels. Low vitamin D levels were also significantly associated with carotid artery intima media thickness (p<0.001), fibrinogen (p=0.010), total cholesterol (p=0.042) and ApoA1 (p=0.004) levels. Among the clinical symptoms, the cardiovascular involvement showed an inverse correlation with vitamin D status in MCTD (p<0.001).

CONCLUSIONS

The prevalence of vitamin D insufficiency is high in patients with MCTD. We assume that vitamin D insufficiency along with inflammatory parameters and lipid abnormalities may provoke cardiovascular events.