Anti-endothelial Cell Antibodies Research Articles

SAT0013 Lupus Enteritis: Clinical Characteristics and Risk Factors Associated with Recurrence

BackgroundLupus enteritis is a severe complication of systemic lupus erythematosus (SLE) cases with acute abdominal pain. Some studies have identified clinical characteristics and risk factors for relapse in lupus enteritis...

Increased levels of anti-heat-shock protein 60 (anti-Hsp60) indicate endothelial dysfunction, atherosclerosis and cardiovascular diseases in patients with mixed connective tissue disease.

Heat-shock protein 60 (Hsp60) has been shown to provoke inflammation, and anti-Hsp60 may facilitate the development of atherosclerosis. In this study, we have investigated 30 patients with mixed connective tissue disease (MCTD) and assessed anti-Hsp60 and their relationship to cardiovascular diseases (CVD). Out of 30 patients with MCTD, 15 had CVDs. Anti-Hsp60 antibody was determined by enzyme-linked immunosorbent assay. Since endothelial dysfunction and accelerated atherosclerosis are characteristic to MCTD, a wide array of MCTD-, endothelial dysfunction- and CVD-associated parameters was investigated: serum lipid levels, paraoxonase activity (PON1), rich nuclear ribonucleoprotein U1 (anti-U1RNP), anti-endothelial cell antibodies, anti-cardiolipin and anti-β2-glycoprotein I antibody isotypes (anti-CL and anti-β2GPI), endothelin-1 (ET-1) levels, also intima-media thickness (IMT), a quantitative indicator of atherosclerosis. In MCTD, anti-Hsp60 antibody levels were significantly higher than in healthy individuals (p<0.02). MCTD patients with CVD had significantly higher levels of anti-Hsp60 compared to MCTD without CVD (p=0.001). Patients with MCTD had significantly lower high-density lipoprotein cholesterol (p=0.02) and PON activity (p<0.001), and significantly increased systolic (p<0.0002) and diastolic (p<0.001) blood pressure compared to healthy individuals. Anti-U1RNP levels (p<0.002) and IMT were higher in patients compared to controls (p=0.002). The CVD-positive MCTD patients had increased anti-Hsp60 (p<0.0013), anti-CL IgG (p=0.0005), ET-1 serum concentration (p<0.05) and IMT levels (p<0.001) compared to MCTD patients without CVD. Anti-Hsp60 showed a strong correlation with anti-oxLDL (r=0.36, p=0.01) and serum ET-1 (r=0.62, p<0.001) and negative correlation with PON activity (r=-0.47, p=0.01). Anti-Hsp60 indicates endothelial injury, CVD, and can function as a novel atherosclerotic risk factor, also a valuable diagnostic marker in patients with MCTD.

Evaluation of antiendothelial cell antibodies in COPD patients, with and without corpulmonale

BackgroundAntiendothelial cell antibodies (AECA) were studied in the pathogenesis of emphysema in chronic obstructive pulmonary disease (COPD) and pulmonary hypertension (PH) in vasculitis, connective tissue disease and idiopathic pulmonary arterial hypertension. Aim of the studyThis study aimed to compare the level of AECA between COPD patients with corpulmonale and those without corpulmonale. MethodsThe study involved 30 male COPD patients without corpulmonale (group 1), 30 male COPD patients with corpulmonale (group 2) and 30 male healthy controls, (group 3). All subjects underwent spirometric pulmonary functions’ testing, echocardiography and measurement of AECA in serum. ResultsThere was highly significantly elevated AECA level in COPD patients with corpulmonale compared to other groups. This was associated with highly significant correlation of AECA level and right ventricular systolic pressure (RVSP), FEV1% of predicted and significant correlation with arterial oxygen tension (PaO2) and oxygen saturation (SapO2) in the same group. ConclusionThe significantly higher level of AECA in COPD patients with corpulmonale together with RVSP suggests a role for these autoantibodies in the pathogenesis of PH and corpulmonale complicating COPD.

Anti-endothelial cell antibodies in connective tissue diseases associated with pulmonary arterial hypertension.

To investigate the prevalence of anti-endothelial cell antibodies (AECA) in connective tissue diseases (CTD) associated with pulmonary arterial hypertension (PAH) and to corroborate the pathologic function of AECA in PAH-associated CTDs. AECA were detected by cellular enzyme-linked immunosorbent assay (ELISA) in sera of 19 PAH-associated CTD patients, 22 CTD patients without PAH involvement, and 20 age- and sex-matched healthy individuals as controls. Using IgG purified from the sera of AECA-positive, AECA-negative, and healthy subjects, the effects of AECA on the expression of ICAM-1 and the chemokine regulated upon activation normal T-cell expressed and secreted (RANTES) in cultured endothelial cells were also evaluated. A total of 12 of the 19 (63.2%) CTD patients with PAH, 9 of the 22 (40.9%) CTD patients without PAH, and 1 of the 20 (5%) healthy controls were positive for AECA, which were calculated as ELISA ratio (ER) values. ER values in PAH-associated CTD patients were significantly higher than those with CTD without PAH (3.68±2.05 versus 1.67±1.07, P<0.001). IgG purified from AECA-positive sera induced a significantly increased level of ICAM-1 expression after 48 h incubation (795.2±32.5 pg/mL) compared with AECA-negative or healthy control IgG (231.5±27.1 and 192.8±33.4 pg/mL, respectively; P<0.001). In addition, RANTES production by cultured human pulmonary arterial endothelial cells (HPAECs) increased in both a time- and concentration-dependent manner in response to incubation with purified AECA-positive IgG. AECA could be involved in CTD and might participate in the pathogenesis of PAH-associated CTD.

Susac's syndrome during pregnancy — The first Croatian case

Susac's syndrome (SS) is an infrequent neurological disorder characterized by the clinical triad of encephalopathy, branch retinal artery occlusion and hearing loss due to an autoimmune endotheliopathy associated with anti-endothelial cell antibodies. At the onset of the disease SS rarely appears with the complete clinical triad. The most important diagnostic procedures involved in the diagnosis of SS are brain MRI, audiometric testing and retinal fluorescein angiography. Presence of at least two components of the SS clinical triad accompanied by specific brain MRI findings is highly suggestive of SS.We report a case of a young pregnant woman with a history of encephalopathy, hearing loss and walking impairment. Brain MRI revealed a spectrum of findings previously described in patients with SS. We induced labor at 37weeks' gestation to start with immunosuppressive treatment and avoid possible fetal toxicity. To the best of our knowledge this is the first report of SS in Croatia.

Identification of target antigens of anti-endothelial cell antibodies in patients with anti-neutrophil cytoplasmic antibody-associated vasculitides: A proteomic approach

Anti-endothelial cell antibodies (AECAs) have been reported to cause endothelial cell dysfunction, but their specific targets have never been identified in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAVs). Proteins from human umbilical vein endothelial cells (HUVECs) were separated by 2-dimensional electrophoresis (2-DE). 2-D immunoblots were used to compare serum IgG reactivities from 30 patients with AAV and 12 healthy controls (HCs). Proteins identified as target antigens by MALDI- TOF-TOF mass spectrometry included lamin A/C, vimentin, α-enolase, far upstream binding protein 2 (FUBP2) and protein disulfide-isomerase A3 precursor (PDIA3). Antibodies targeting lamin A, vimentin, α-enolase, FUBP2 and PDIA3 were identified in 57.1%, 64.3%, 35.7%, 50% and 0% of patients with microscopic polyangiitis and 8%, 3.3%, 7.2%, 0% and 6.7% of HCs respectively. IgG from patients with microscopic polyangiitis had stronger reactivity against HUVEC than other groups and HCs and induced stronger Erk phosphorylation in HUVECs than IgG from HCs.

Changes in IgG sialylation and glycosylation in pulmonary arterial hypertension (1089.3)

Rationale: Anti‐endothelial cell antibodies are found in both idiopathic and connective tissue disease associated pulmonary arterial hypertension (PAH). IgG is the most abundant immunoglobulin and is heavily glycosylated. Sialic acid is a monosaccharide often found on the end of glycan chains, and sialylation of IgG can alter IgG binding to its receptors. Changes in IgG sialylation and N‐linked glycan composition occur in numerous diseases, but it is unknown whether changes occur in PAH. We sought to determine whether IgG sialylation and glycosylation are altered in PAH patients, and if these changes affect IgG binding to endothelial cells (EC). Methods: We purified IgG from healthy volunteers (HV), idiopathic PAH (IPAH), or connective tissue disease‐associated PAH (CTD) patients. Lectin blots were used to analyze IgG sialic acid linkages and glycosylation residues. IgG was treated with sialidases to remove sialic acids or glycosidases to remove N‐linked glycans. The cleaved glycans were analyzed by ESI mass spectrometry. Both untreated IgG and sialidase‐treated IgG were used in a cell based ELISA to examine the effect of sialylation on IgG binding to EC. Results: Lectin blots and mass spec show marked differences between HV and PAH IgG. PAH IgG treated with sialidase has decreased binding to EC, whilst untreated PAH IgG has increased binding to EC as compared to HV IgG. These data suggest that sialylation and glycosylation differences in IgG from PAH patients affect binding to EC.Grant Funding Source: Supported by R01HL107778

Clinical significance of anti-endothelial cell antibody in allogeneic hematopoietic stem cell transplantation recipients with graft-versus-host disease

Anti-endothelial cell antibody (AECA) is well known to reflect endothelial injury. Graft-versus-host disease (GVHD), a major complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT), is also closely associated with endothelial injury. We hypothesized that AECA may be associated with GVHD. To investigate the clinical significance of AECA in allo-HSCT recipients with GVHD, we detected AECA by cyto-enzyme-linked immunosorbent assay (cyto-ELISA) in allo-HSCT recipients with acute and/or chronic GVHD (aGVHD and cGVHD). Incidences of anti-HMEC-1 AECA (anti-HMEC) and anti-EA.hy926 AECA (anti-EAHY) were significantly higher in patients with grade II-IV than grade 0-I aGVHD (P = 0.049, P = 0.011, respectively). There was no difference in the incidence of AECA between patients with and without cGVHD. Patients with anti-EAHY positive in the early stage post-transplant demonstrated a higher incidence of cGVHD (P = 0.044). In patients with grade 0-I aGVHD, AECA-positive patients had higher overall survival and disease-free survival (P < 0.05), and tended to have lower incidences of relapse and transplant-related mortality. Our data suggest that AECA plays an important role in the pathogenesis of GVHD.

Clinical Impact of Anti-Endothelial Cell Antibodies in Kidney and Pancreas Transplantation

Background Anti-endothelial cell antibodies (AECA) have been associated with graft dysfunction and rejection, but lack of scalable, cheap testing has hindered routine screening. Indirect immunofluorescence on human umbilical vein endothelial cells (HUVEC) aims to fill this niche, and a high incidence of severe multiple rejections has been reported in a large study of deceased-donor kidney transplant recipients. Methods We retrospectively studied 119 kidney transplants and 21 pancreas transplants consecutively performed in 128 recipients at our Centre. Results 13% showed positive pretransplant AECA. Of them, 47% showed negativization of AECA at various posttransplant times. At a median follow-up of 14 months (range : 6-24), patients with positive pretransplant AECA showed a higher risk of biopsy-proven acute cell-mediated pancreas rejection (OR = 24; P = 0.02); post-transplant persistence of AECA correlated with an even higher risk of pancreas rejection (OR = 78 ; P = 0.01). No correlation between pretransplant AECA and risk of kidney rejection or graft loss was found. De novo AECA developed in 4% of all patients, but did not correlate with any transplant-related event. Conclusion Our study demonstrates a lack of importance of pretransplant and de novo AECA screening in kidney transplantation. Larger studies on pancreas transplantation will be necessary to confirm the relevance in such setting.

Heterogeneous Nuclear Ribonucleoprotein K Autoantibodies in Patients who Suffered Severe Traumatic Brain Injury

The immune-inflammatory response as well as cerebral endothelial activation has been described after Traumatic Brain Injury (TBI). Although inflammation can have both beneficial and detrimental effects in TBI, the mechanisms underlying this dichotomy are mostly unknown. Moreover, emerging data indicates that chronic alterations produced after TBI are probably the result of systemic and persistent inflammation that activates immune response, culminating in the production of different specific auto antibodies against central nervous system antigens. In the previous study we demonstrated the production of anti-hnRNPK antibodies, belonging to Anti-Endothelial Cell Antibodies (AECA), in heart transplanted patients who developed Cardiac Allograft Vasculopathy (CAV). These antibodies could be produced in response to the vascular endothelial damage that is also present in TBI patients. In the current study we analyse the presence of AECA by Indirect Immunofluorescence assay (IFI) and anti-hnRNPK IgG antibodies by Enzyme-Linked Immunosorbent Assay (ELISA) in a cohort of 19 patients who suffered TBI. We detected a significant increase in the number of patients with AECA and anti-hnRNPK antibodies after TBI. Moreover, anti-hnRNPK antibody levels were also higher during follow-up, being the values obtained after TBI significantly higher than those detected at the time of trauma (p = 0.001). We also found that AECA and anti-hnRNPK antibodies were mostly present in the sera of patients with a worse outcome (p = 0.018 and p = 0.04 respectively). Taking into account, measuring these auto antibodies could be useful for evaluating endothelial injury and/or the outcome after TBI.

Clinical, paraclinical and serological findings in Susac syndrome: an international multicenter study

BackgroundSusac syndrome (SuS) is a rare disorder thought to be caused by autoimmune-mediated occlusions of microvessels in the brain, retina and inner ear leading to central nervous system (CNS) dysfunction, visual disturbances due to branch retinal artery occlusions (BRAO), and hearing deficits. Recently, a role for anti-endothelial cell antibodies (AECA) in SuS has been proposed.ObjectivesTo report the clinical and paraclinical findings in the largest single series of patients so far and to investigate the frequency, titers, and clinical relevance of AECA in SuS.Patients and methodsA total of 107 serum samples from 20 patients with definite SuS, 5 with abortive forms of SuS (all with BRAO), and 70 controls were tested for AECA by immunohistochemistry employing primate brain tissue sections.ResultsIgG-AECA >1:100 were detected in 25% (5/20) of patients with definite SuS and in 4.3% (3/70) of the controls. Median titers were significantly higher in SuS (1:3200, range 1:100 to 1:17500) than in controls (1:100, range 1:10 to 1:320); IgG-AECA titers >1:320 were exclusively present in patients with SuS; three controls had very low titers (1:10). Follow-up samples (n = 4) from a seropositive SuS patient obtained over a period of 29 months remained positive at high titers. In all seropositive cases, AECA belonged to the complement-activating IgG1 subclass. All but one of the IgG-AECA-positive samples were positive also for IgA-AECA and 45% for IgM-AECA. SuS took a severe and relapsing course in most patients and was associated with bilateral visual and hearing impairment, a broad panel of neurological and neuropsychological symptoms, and brain atrophy in the majority of cases. Seropositive and seronegative patients did not differ with regard to any of the clinical or paraclinical parameters analyzed.ConclusionsSuS took a severe and protracted course in the present cohort, resulting in significant impairment. Our finding of high-titer IgG1 and IgM AECA in some patients suggest that humoral autoimmunity targeting the microvasculature may play a role in the pathogenesis of SuS, at least in a subset of patients. Further studies are warranted to define the exact target structures of AECA in SuS.

Clinical and autoimmune profile of scleroderma patients from Western India.

Background. Systemic sclerosis (SSc, scleroderma) is a disorder characterized by fibrosis of skin and visceral organs. Pathogenesis of scleroderma is complex and is incompletely understood as yet. Autoantibodies in SSc represent a serologic hallmark which have clinical relevance, with diagnostic and prognostic potential. Objectives. To study distribution of clinical manifestations and to identify frequency of autoantibodies among subtypes of scleroderma patients from Western India. Methodology. One hundred and ten scleroderma patients were clinically classified according to the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) criteria. All these patients were in active stage of disease. Clinical manifestations were recorded at the time of presentation. Autoantibodies were tested in them by indirect immunofluorescence test and ELISA. Immunoglobulin levels were estimated by nephelometer. These parameters were further correlated with clinical presentation of the disease. Results. Scleroderma patients had M : F ratio of 1 : 10 where mean age at evaluation was 34.7 ± 10.7 years and a mean disease duration was 43.7 ± 35 months. Clinical subtypes showed that 45 patients (40.9%) had diffused cutaneous (dcSSc) lesions, 32 patients (29.1%) had limited cutaneous (lcSSc) lesions, and 33 patients (30%) had other autoimmune overlaps. The overall frequency of ANA in SSc patients studied was 85.5%. The frequency of anti-Scl70, anti-centromere, anti-endothelial cell antibodies (AECA), and anti-keratinocyte antibodies (AKA) was 62.7%, 22.7%, 30%, and 40.9%, respectively. Anti-Scl70 antibodies were significantly high (75.6% versus 46.9%) among dcSSc patients (P < 0.0115) whereas anti-centromere antibodies were significantly high (9% versus 38%) among lcSSc patients when these two subtypes were compared (P < 0.0044). Conclusion. This study supports that there are geoepidemiological variations among scleroderma patients for their clinical presentation, autoantibody profile, and immune parameters across the country.

Immunoglobulin G anti-endothelial cell antibodies: inducers of endothelial cell apoptosis in pulmonary arterial hypertension?

Endothelial cell (EC) apoptosis seems to play an important role in the pathophysiology of pulmonary arterial hypertension (PAH). We aimed to test the hypothesis that circulating anti-endothelial cell antibodies (AECA) of PAH patients induce EC apoptosis. Immunoglobulin (Ig)G was purified from sera of PAH patients (n = 26), patients with systemic lupus erythematosus (SLE) nephritis without PAH (n = 16), patients with systemic sclerosis (SSc) without PAH (n = 58) and healthy controls (n = 14). Human umbilical vein endothelial cells (HUVECs) were incubated with patient or healthy control IgG for 24 h. Thereafter, apoptosis was quantified by annexin A5 binding and hypoploid cell enumeration by flow cytometry. Furthermore, real-time cell electronic sensing (RT-CES™) technology was used to monitor the effects of purified IgG from patient and healthy control IgG on HUVECs. As demonstrated previously, IgG of AECA-positive SLE nephritis patients (n = 7) induced a higher percentage of apoptosis of HUVECs compared to IgG of AECA-negative SLE nephritis patients and healthy controls. Furthermore, IgG of AECA-positive SLE nephritis patients induced a marked decrease in cell index as assessed by RT-CES™ technology. IgG of AECA-positive PAH patients (n = 12) and SSc patients (n = 13) did not alter the percentage of HUVEC apoptosis or cell index compared to IgG of AECA-negative PAH and SSc patients and healthy controls. AECA-positive PAH patients, in contrast to SLE nephritis patients, do not have circulating IgG AECA that enhances apoptosis of HUVECs in vitro. Further studies should focus on other mechanisms by which AECA may enhance EC apoptosis in PAH, such as antibody-dependent cell-mediated cytotoxicity.

A novel autoantibody against ephrin type B receptor 2 in acute necrotizing encephalopathy

Acute necrotizing encephalopathy (ANE) is characterized by symmetrical brain necrosis, suggested to be due to breakdown of the blood–brain barrier (BBB). We experienced a rare case of ANE complicated with systemic lupus erythematosus (SLE), and found that the patient’s serum (V10-5) had binding activity to human umbilical vein endothelial cells (HUVECs). By SARF (Serological identification system for Autoantigens using a Retroviral vector and Flow cytometry) method using V10-5 IgG, a clone bound to V10-5 IgG was isolated. This cell clone was integrated with cDNA identical to EphB2, which plays critical roles in neuronal cells and endothelial cells. HUVECs and human brain microvascular endothelial cells expressed EphB2 and the V10-5 IgG bound specifically to EphB2-transfected cells. Anti-EphB2 antibody was not detected in other SLE patients without ANE. In this report, we identified EphB2 as a novel autoantigen, and anti-EphB2 antibody may define a novel group of brain disorders. Anti-EphB2 antibody can interfere not only with endothelial cells including those of the BBB (acting as an anti-endothelial cell antibody), but also neuronal cells (acting as an anti-neuronal antibody) if the BBB has been breached. Future studies should determine the clinical prevalence and specificity of anti-EphB2 antibody, and the molecular mechanisms by which anti-EphB2 antibody mediates neuronal and vascular pathological lesions.

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Aim To determine the changes in gene expression in Endothelial Precursor Cells (EPC) exposed to Anti Endothelial Cell Antibodies (AECA) that are Non-HLA-specific. Methods Magnetic-bead column isolation followed by XM-One crossmatch procedure using reagents from Absorber Inc. was employed to identify serum samples with non-HLA AECA. For Gene expression assays, EPCs were obtained from T and B cell depleted PBL using reagents from Absorber Inc. The endothelial cell gene expression was performed on total RNA using Real-Time RT-PCR profiler reagents from QIAGEN Inc. Results EPCs exposed to a combination of IgM and IgG AECAs, affected the expression of more endothelial cell genes than EPCs exposed to IgM or IgG alone. Exposure of EPCs to IgM AECA alone caused changes in a few genes while exposure to IgG AECA alone did not significantly alter expression of any endothelial cell genes. In all, the genes which were up-regulated (ANXA5; APOE; BAX; BCL2L1; CALCA; CFLAR; COL18A1; EDN1; EDN2; EDNRA; FLT1; HIF1A; HMOX1; ICAM1; ITGAV; ITGB1; KDR; OCLN; PF4; SELE; THBS1) were those associated with pro-apoptotic, thrombocytic and or hemolytic events. One of the highly down-regulated genes was the Tissue inhibitor of Matrix Metalloproteinase (TIMP) that inhibit the matrix metalloproteinases which leads to increased extracellular protein deposition resulting in excessive extracellular connective tissue deposition, which is a hallmark of fibrosis which in turn is associated with chronic allograft rejection. Conclusions Human EPCs seem to respond to non-HLA antibodies by altering the gene expressions of endothelial cell biology which might be associated with events leading to allograft injury in a complement independent way. More detailed gene expression studies with organ specific endothelial cells and IgM/IgG specific non-HLA endothelial cell antibodies are needed to assess the full significance of AECA in allograft rejection.

Unilateral central retinal artery occlusion as the sole presenting sign of Susac syndrome in a young man: case report

Correspondence address: Mario Luiz Ribeiro Monteiro. Neuro-Ophthalmology Service. Escola de Me dicina da Universidade de Sao Paulo. Av. Angelica, 1.757 Conj. 61 Sao Paulo (SP) 01227-200 Brazil E-mail: mlrmonteiro@terra.com.br I read with interest the report of “Unilateral central retinal artery occlusion as the sole presenting sign of Susac syndrome in a young man: case report” by Apostolos-Pereira et al. Central retinal artery occlusion is very rare in Susac syndrome as evidenced by the paucity of reports in the clinical literature. The corpus callosum findings in this case are pathognomonic for the disease with the central callosal lesion and the 2 small spoke lesions in the posterior callosum. However, the fundus appearance is somewhat odd with the significant platelet-like embolic material in the arterioles. These are not Gass plaques as has been described previously. Did they disappear after his initial presentation? There are also characteristic fluorescein angiographic findings described previously. Was the typical autofluorescense pattern located remotely from the retinal artery occlusion? I am particularly interested in learning if the right eye showed this pattern prior to infarction; if so, can this be published? Were anti-en dothelial cell antibodies sent?

Streptococcal–vimentin cross-reactive antibodies induce microvascular cardiac endothelial proinflammatory phenotype in rheumatic heart disease

Rheumatic heart disease (RHD) is characterized by the presence of anti-streptococcal group A antibodies and anti-endothelial cell antibodies (AECA). Molecular mimicry between streptococcal antigens and self proteins is a hallmark of the pathogenesis of rheumatic fever. We aimed to identify, in RHD patients, autoantibodies specific to endothelial autoantigens cross-reactive with streptococcal proteins and to evaluate their role in inducing endothelial damage. We used an immunoproteomic approach with endothelial cell-surface membrane proteins in order to identify autoantigens recognized by AECA of 140 RHD patients. Cross-reactivity of purified antibodies with streptococcal proteins was analysed. Homologous peptides recognized by serum cross-reactive antibodies were found through comparing the amino acid sequence of streptococcal antigens with human antigens. To investigate interleukin (IL)-1R-associated kinase (IRAK1) and nuclear factor-κB (NF-κB) activation, we performed a Western blot analysis of whole extracts proteins from unstimulated or stimulated human microvascular cardiac endothelial cells (HMVEC-C). Adhesion molecule expression and release of proinflammatory cytokines and growth factors were studied by multiplex bead based immunoassay kits. We observed anti-vimentin antibodies in sera from 49% RHD AECA-positive patients. Cross-reactivity of purified anti-vimentin antibodies with heat shock protein (HSP)70 and streptopain streptococcal proteins was shown. Comparing the amino acid sequence of streptococcal HSP70 and streptopain with human vimentin, we found two homologous peptides recognized by serum cross-reactive antibodies. These antibodies were able to stimulate HMVEC-C inducing IRAK and NF-κB activation, adhesion molecule expression and release of proinflammatory cytokines and growth factors. In conclusion, streptococcal-vimentin cross-reactive antibodies were able to activate microvascular cardiac endothelium by amplifying the inflammatory response in RHD.

Functional implications of IgG anti-endothelial cell antibodies in pulmonary arterial hypertension

The objective of this study was to research the functionality of anti-endothelial cell antibodies (AECA) in pulmonary arterial hypertension (PAH) by assessing the effects of IgG from AECA-positive PAH patients on the induction of adhesion molecules on human umbilical vein endothelial cells (HUVECs) and on the production of pro-inflammatory cytokines and chemokines by HUVECs. To achieve this purified IgG from 28 PAH patients were included. IgG from systemic sclerosis (SSc) (n = 58) and systemic lupus erythematosus (SLE) (n = 16) patients without PAH were included as disease controls. Intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin expression on HUVECs, incubated with patient IgG, were quantified by flow cytometry. Production of interleukin (IL)-1β, -6, -8, and CC chemokine ligand 2 (CCL2) by HUVECs, incubated with patient IgG, were quantified by multiplex flow cytometry. Our results showed that IgG from AECA-positive PAH, SSc and SLE patients induced significantly higher expression of ICAM-1, VCAM-1, and E-selectin and production of IL-6, -8, and CCL2 compared to IgG from AECA-negative patients and IgG from healthy controls. Like in SLE and SSc, IgG from AECA-positive PAH patients can activate endothelial cells to a pro-adhesive and pro-inflammatory state. Therefore, IgG AECA could play a pathogenic role by inducing inflammatory injury of vascular endothelium which is considered a key player in the initiation and progression of PAH.

Endothelial cell adhesion molecule CD146: implications for its role in the pathogenesis of COPD

CD146 is an adhesion molecule localized at endothelial cell junctions and facilitates cell-cell interactions. The circulating soluble form (sCD146) lacks both the intracellular and the transmembrane domains. In this study we show that CD146 expression was significantly decreased in the lung tissue of smokers with chronic obstructive pulmonary disease (COPD) and also in rats exposed to second-hand smoke (SHS). Concurrently, levels of sCD146 were increased in both the plasma and bronchoalveolar lavage fluid (BALF) of COPD patients as well as in BALF from rats exposed to SHS. Decreased or abolished CD146 protein expression in rat pulmonary micro- and macrovascular endothelial cells was found after treatment with cigarette smoke extract (CSE), proinflammatory cytokine interleukin 18 (IL-18) or after silencing CD146 expression with siRNA. The decrease in CD146 protein was accompanied by increased endothelial monolayer permeability and enhanced macrophage infiltration in vitro. In CD146 knockout (KO) mice, distinct perivascular oedema was seen and increased numbers of inflammatory cells, along with increased protein levels in BALF. Increased sCD146 was found in BALF and plasma from patients with COPD. The circulating plasma levels of sCD146 correlated positively with the presence of anti-endothelial cell antibodies (AECAs). sCD146 in combination with AECAs may be useful markers for early detection of COPD. Our study indicates that loss of CD146 function damages pulmonary endothelial integrity. This damage may represent part of the pathophysiological processes that are involved in the basic aetiology of COPD/emphysema.

A prospective study evaluating the role of donor-specific anti-endothelial crossmatch (XM-ONE assay) in predicting living donor kidney transplant outcome

Anti-endothelial cell antibodies (AECAs) may play a role in allograft rejection. We prospectively tested 150 consecutive living donor kidney transplant recipients, with transplants performed at Northwestern Memorial Hospital between January and December 2010, using the donor-specific endothelial (XM-ONE) crossmatch. 88/150 Patients received standard of care (SOC) immunosuppression and analyzed separately, in addition to the complete study cohort. Patients were followed for one year and XM-ONE results were analyzed in relation to occurrence of acute rejection, proteinuria, serum creatinine levels, and biopsy proven fibrosis. No correlation was found between XM-ONE results and protocol or "for-cause" biopsy proven acute rejection or vasculopathy at 12 months. When IgG+ and IgM+ results of the XM-ONE assay were combined, a correlation with proteinuria at 12 months was observed (p=0.047). Although IgG+XM-ONE results were associated with significantly higher creatinine at 6 months (p=0.018), significance was lost at 12 months. Conversely, patients with an IgM+XM-ONE crossmatch had significantly lower creatinine at 1 month (p=0.019), 3 months (p=0.0045), and 6 months (p=0.038) post-transplant, but lost statistical significance at 12 months (p=0.67) post-transplant. In summary, the presence of AECAs as determined by a positive XM-ONE result was not predictive of overall poorer graft outcome after one year in our center.