Prevalence Of Anti-endothelial Cell Antibodies Research Articles

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.

De novo development of circulating anti-endothelial cell antibodies rather than pre-existing antibodies is associated with post-transplant allograft rejection

Anti-endothelial cell antibodies (AECAs) are thought to be involved in the development of renal allograft rejection. To explore this further, we determine whether AECAs play a role both in predicting the incidence of allograft rejection and long-term outcomes by analysis of serum samples from 226 renal allograft recipients for AECAs pre- and post-transplant. Surprisingly, the presence of pre-existing AECAs was not associated with either an increased risk of rejection or a detrimental impact on recipient/graft survival. Subsequent de novo AECAs, however, were associated with a significantly increased risk of early acute rejection. Moreover, these rejections tended to be more severe with a significantly increased incidence of both steroid-resistant and multiple episodes of acute rejection. The acute rejections associated with de novo AECAs did not correlate with C4d deposition at the time of renal biopsy, but did demonstrate an association with the presence of glomerulitis and peritubular capillary inflammation. Significantly more patients with de novo AECAs developed graft dysfunction. Thus, our prospective study suggests the emergence of de novo AECAs is associated with transplant rejection that may lead to allograft dysfunction.

Prevalence of anti-endothelial cell antibodies in idiopathic pulmonary arterial hypertension: Table 1—

To the Editors: Pulmonary arterial hypertension (PAH) is a rare disease often resulting in right-sided heart failure and premature death 1. PAH is idiopathic (IPAH), heritable, or related to conditions such as connective tissue diseases (CTD) 2. IPAH prognosis remains poor despite improved patient survival with current treatment options. Therefore, elucidating the pathophysiology of IPAH is important for the discovery of novel therapeutic approaches. Inflammation and immune reactivity have been implicated in the pathophysiology of IPAH. In 2005, Tamby et al. 3 described the presence of anti-endothelial cell antibodies (AECA) in IPAH, pointing at the involvement of humoral immunity. AECA are a heterogeneous family of auto-antibodies capable of reacting with different endothelial cell (EC) structures 4. In PAH, pulmonary EC dysfunction is considered a key player in the initiation and progression of the disease 5. Systemic sclerosis (SSc) is a paradigm of autoimmune PAH, as 10–15% of these patients develop PAH 6. Interestingly, in SSc, immunoglobuliln (Ig)G AECA targeting cell-surface antigens have indeed been shown to induce EC dysfunction 7, 8. Thus, IgG AECA-induced endothelial dysfunction may be the initiating event in IPAH. Whereas IgG auto-antibodies are considered pathogenic in various autoimmune diseases, IgM auto-antibodies have been proposed to be protective in these diseases 9. Regarding a pathophysiological role of AECA, it is important to identify whether AECA are reactive with EC-surface antigens. To corroborate and further investigate the role of the humoral immune system in IPAH, we aimed to study the prevalence of IgG, as well as IgM AECA targeting cell-surface EC antigens using a cell-based ELISA with viable human umbilical vein EC (HUVEC). We screened five study cohorts for the presence of AECA. 1) 29 IPAH patients; mean pulmonary artery …

Prevalence of Anti-endothelial Cell Antibodies in Patients with Pulmonary Arterial Hypertension Associated with Connective Tissue Diseases

To investigate the prevalence of anti-endothelial cell antibodies (AECAs) in the sera of connective tissue diseases (CTD) patients with pulmonary arterial hypertension (PAH) and its correlation with clinical manifestations. AECAs in sera of 39 CTD patients with PAH, 22 CTD patients without PAH, and 10 healthy donors as controls were detected with Western blotting. The prevalence of different AECAs in different groups was compared and its correlation with clinical manifestations was also investigated. The prevalence of AECAs was 82.1% in CTD patients with PAH, 72.7% in CTD patients without PAH, and 20.0% in healthy donors. Anti-22 kD AECA was only detected in CTD patients with PAH (15.4%). Anti-75 kD AECA was more frequently detected in CTD patients with PAH than in those without PAH (51.3% vs. 22.7%, P < 0.05). In CTD patients with PAH, anti-75 kD AECA was more frequently detected in those with Raynaud's phenomenon or with positive anti-RNP antibody. AECAs could be frequently detected in CTD patients with or without PAH, while anti-22 kD and anti-75 kD AECA might be specific in CTD patients with PAH.

Elevation of serum von Willebrand factor and anti‐endothelial cell antibodies in patients with immunoglobulin A nephropathy are associated with intrarenal arterial lesions

Recent studies suggest that intrarenal arterial lesions are frequently observed in patients with immunoglobulin A nephropathy (IgAN). However, the mechanisms of the injury have not been elucidated. The level of serum von Willebrand factor (vWF) and the prevalence of anti-endothelial cell antibodies (AECA) were investigated in patients with IgAN with different intrarenal arterial lesions. Sera from 28 patients with mild intrarenal arterial lesions (group 1) and 36 patients with severe intrarenal arterial lesions (group 2) were collected. Sera from 20 patients with idiopathic membranous nephropathy (group 3) and 50 healthy volunteers were also obtained as disease and normal controls, respectively. Serum vWF and AECA of both IgG and IgA isotype were detected. In comparison with normal controls, serum vWF was significantly higher in group 2 and group 3. Serum vWF was also significantly higher in group 2 than in group 1. Both IgG-AECA and IgA-AECA could be detected in three groups of patients. The prevalence of anti-87 kD IgG-AECA was greatest in patients in group 2. IgAN patients, especially those in group 2 with IgG-AECA or anti-87 kD IgG-AECA, had significantly higher serum creatinine and lower creatinine clearance than those without. No significant difference could be found for IgA-AECA. The level of serum vWF was higher in IgAN patients with IgG-AECA than that in patients without. Intrarenal arterial lesions are associated with endothelial cell damage in IgAN, and vWF is a useful serological biomarker of severe intrarenal arterial lesions. AECA, especially IgG-AECA, may play an important role in the pathogenesis of intrarenal arterial damage in IgAN.

Malignant hypertension in IgA nephropathy was not associated with background pathological phenotypes of glomerular lesions

It was reported that IgA nephropathy (IgAN) was the major cause of secondary malignant hypertension (MHT). However, the pathogenesis of MHT secondary to IgAN (IgAN-MHT) is unknown and its association with glomerular pathological phenotypes remains inconclusive. The present study aimed to investigate whether glomerular pathological phenotypes and anti-endothelial cell antibodies (AECA) were associated with the occurrence of IgAN-MHT. The glomerular pathological phenotypes of 45 patients with IgAN-MHT were analysed using Haas' histologic grading system of IgAN. Sera were collected from 34 of the 45 patients with IgAN-MHT, 19 patients with primary MHT, 41 patients with non-MHT IgAN and 10 healthy volunteers. AECA of both IgG and IgA isotypes were detected by western blot analysis using human umbilical vein endothelial cell lysate as antigen. In the 45 patients with IgAN-MHT, 7 (15.56%), 5 (11.11%), 13 (28.89%), 9 (20%) and 11 (24.44%) patients were graded as Hass I, II, III, IV and V, respectively. Although the severity of non-ischaemic sclerosis, crescents and mesangial proliferation were significantly different between patients with different grades, the levels of blood pressure, SCr and proteinuria at presentation were comparable. Eleven and four protein bands of endothelial proteins could be blotted by AECA-IgG and AECA-IgA in sera from patients with IgAN-MHT. The prevalences of anti-121 kD AECA-IgG (15/34) and anti-92 kD AECA-IgA (10/34) in IgAN-MHT were significantly higher than that of primary MHT, non-MHT IgAN and normal controls, respectively. Patients with anti-92 kD AECA-IgA had more severe glomerular ischaemic sclerosis (6.25-92.86%, median 39.61%) than those without (0-91.67%, median 18.18%, P = 0.035). There was no significant difference in the prevalence of AECA between IgAN-MHT patients with different background glomerular lesions. Only one IgAN patient with MHT was found with both anti-121 kD AECA-IgG and anti-92 kD AECA-IgA. No particular manifestations were found. The occurrence of IgAN-MHT was not associated with the background glomerular pathological phenotypes of IgAN. AECA might play a role in the pathogenesis of IgAN-MHT.

ANTI-ENDOTHELIAL CELL ANTIBODIES AND CENTRAL NERVOUS SYSTEM INVOLVEMENT IN BEHÇET'S DISEASE

Previous studies have detected the presence of anti-endothelial cell antibodies (AECA) in patients with Behçet's disease (BD). However, no real evidence exists whether these antibodies exert any influence on clinical presentation and/or activity of this disease. To determine the frequency of AECA in patients with BD and analyze possible clinical associations. 50 patients with BD who fulfilled diagnostic criteria were selected. Thirty-seven patients were females, and 13 were males; the mean age was 44 +/- 9 years with a mean follow-up time of 10 +/- 7.5 years. AECA were assayed by ELISA using ECV-304 cells as the antigenic substrate. The prevalence of AECA was determined, and their possible relationships with present and past clinical features were investigated. AECA were detected in the sera of 38% of the patients (IgG in 13, IgM in four, and IgG plus IgM in two). An association was observed between AECA and a previous history of central nervous system involvement (OR= 5.4, p= 0.03). This association was more evident for IgG-AECA (OR= 6.0, p= 0.02). A trend of an increased risk of aneurysms was also observed in patients with IgG-AECA (OR= 2.58, p= 0.77). None of the other clinical characteristics showed a relevant association with these antibodies. Our data suggest that IgG-AECA may be a marker of more severe lesions in patients with BD based on the higher frequency of previous central nervous system manifestations in patients who presently display circulating AECA.

Anti-endothelial cell antibodies in patients with interstitial lung diseases

Anti-endothelial cell antibodies (AECA) are circulating antibodies that bind to endothelial antigens and induce endothelial cell damage. AECA have been detected in patients with collagen vascular disease (CVD) and their presence is associated with interstitial lung disease (ILD) in cases of CVD. However, the prevalence of AECA in patients with idiopathic interstitial pneumonias (IIPs) is not known. We investigated the prevalence of AECA in patients with IIPs. We also examined whether the expression of AECA differed among the histologic subgroups usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP), and compared the values with those of CVD-associated ILD (CVD-ILD). Twenty patients with IIPs and 24 patients with CVD-ILD were studied. Serum samples were examined for AECA by cellular enzyme-linked immunosorbent assay (ELISA) using human umbilical vein endothelial cells. Values are expressed as ELISA ratios (ER). All sera from patients with idiopathic pulmonary fibrosis (IPF)/UIP were negative for AECA, whereas 5 out of 10 with idiopathic NSIP, 5 out of 14 with CVD-UIP and 4 out of 10 with CVD-NSIP tested positive (p<0.05). ER values were significantly lower in patients with IPF/UIP than idiopathic NSIP, CVD-UIP or CVD-NSIP (p<0.05). Among idiopathic NSIP, CVD-NSIP and CVD-UIP patients, the ER values did not differ. Among IIP patients, only those with idiopathic NSIP, not IPF/UIP, tested positive for AECA. The prevalence of AECA in idiopathic NSIP patients was similar to that in CVD-ILD patients. These results may provide important information to understand the distinct pathophysiology of each form of IIPs.

Anti-endothelial cell antibodies are prevalent in juvenile idiopathic arthritis: implications for clinical disease course and pathogenesis

To determine the prevalence of anti-endothelial cell antibodies (AECA) in children with juvenile idiopathic arthritis (JIA) versus healthy control children. Twenty-eight children with active JIA were studied (ten each with polyarticular and oligoarticular disease, and eight with systemic onset disease). AECA were determined by a cell-based ELISA from samples obtained every 3 months over a 2 year period in each subject. These levels were compared against previously determined levels of von Willebrand factor antigen, fibrin d-dimer, and soluble forms of ICAM-1 and E-selectin, as well as clinical measures of disease activity. AECA were detected in 5/10 oligoarticular, 6/10 polyarticular, and 7/8 systemic JIA subjects and 0/14 controls. Mean levels of AECA were significantly higher in subjects with oligoarticular, and especially systemic disease as compared to polyarticular and control groups when analyzed by ANOVA. AECA are prevalent in JIA and are present more often and at higher levels in systemic disease.

Anti-endothelial cell antibodies in systemic vasculitis: detection and correlation with disease activity

To investigate the prevalence of anti-endothelial cell antibodies (AECA) in systemic vasculitis and to assess the correlation between AECA and disease activity, and try to discuss the classification of AECA. Cyto-ELISA with EA.hy926 and HMEC-1, two immortalized cell lines, as substrates, was applied to detect AECA in 122 cases of systemic vasculitis, including 43 cases of Behcet disease, 19 cases of Takayasu arteritis, 19 cases of Wegener's granulomatosis, 11 cases of microscopic polyangiitis, 9 cases of polyarteritis nodosa, 3 cases of Churg-Strause syndrome, 2 cases of giant cell arteritis and other 16 cases of which could not be classified clearly. Patients with SLE, RA, and fever of unknown origin, and normal persons were used as control groups. Then the associations of AECA to laboratory findings and clinical disease activity (scored by BVAS) were analyzed. Furthermore, the AECA value from the two different substrate cells were analyzed for correlation and difference. With either EA.hy926 or HMEC-1 as substrates, the AECA prevalence rates of systemic vasculitis (respectively 33.61% and 37.70%) were significantly higher than those of the normal and RA groups (less than 10%), and the prevalence of AECA in SLE (61.75%) was higher than that of systemic vasculitis (37.70%) when using HMEC-1 as substrates. AECA was found to correlate very well with ESR in 122 cases of systemic vasculitis and with BVAS in 40 cases of small systemic vasuculitides, including Wegener's disease, microscopic polyangiitis, Churg-Strause syndrome and so on. The pair AECA values with EA.hy926 and HMEC-1 as substrate cells were found to be correlated significantly, and the matching rate was 92.62%. Prevalence of AECA in systemic vasculitis is high. AECA indicates the clinical disease activity. As to the assumption of classification of AECA into antibodies against microvascular and macrovascular endothelial cells, further study need to be done to prove or disprove it.

Activation of the immune system and coronary artery disease: the role of anti-endothelial cell antibodies

On the basis of the role of immuno-mediated inflammation in atherosclerosis we investigated, (1) the prevalence of anti-endothelial cell antibodies (AECA) in ischaemic heart disease (IHD); (2) if β2-glycoprotein I (β2-GPI) was the target antigen of AECA; (3) the relationship between AECA, tissue factor (TF) and tissue factor pathway inhibitor (TFPI). In 93 consecutive IHD patients undergoing percutaneous transluminal coronary angioplasty (PTCA) and 105 controls AECA were detected by ELISA on human umbilical vein endothelial cells (HUVEC). AECA positive sera were evaluated for anti-β2-GPI antibodies by ELISA. TF and TFPI plasma levels were assessed by ELISA. Twelve of 93 (12.9%) IHD patients and only one of 105 controls (0.95%) were AECA positive. The prevalence of AECA was higher in unstable angina (UA) than in effort angina (EA) ( P=0.01). Three of 12 AECA positive sera resulted positive for anti-β2-GPI and showed a marked decrease in EC-binding when tested on HUVEC cultured in serum-free medium. The binding was restored by the addition of β2-GPI. TF and TFPI levels were similar in AECA positive and AECA negative patients. The rate of angiographically documented clinical recurrences was 66.7% in the AECA positive and 14.8% in the AECA negative group ( P=0.0004) with a significant relationship between restenosis and AECA ( P<0.0001), unchanged by the inclusion of cardiovascular risk factors in the regression model. Our results suggest a ‘role’ for AECA in the immune-mediated inflammation in UA β2-GPI is not the only AECA target antigen. AECA are not responsible for high TF and TFPI levels. The high rate of clinical recurrences after PTCA, confirmed by angiography, in AECA positive patients is in line with such a role and suggests further large-scale ‘ad hoc’ studies.

Prevalence of anti-endothelial cell antibodies in patients with Sneddon's syndrome

Background : Sneddon's syndrome consists of widespread livedo reticularis and ischemic cerebral manifestations. Its pathogenesis remains unclear. Endothelial cells could be the primary target tissue. Objective : Our aim was to determine the prevalence of anti-endothelial cell antibodies (AECA) in a large series of patients with Sneddon's syndrome. The results were compared with those of three groups of control subjects: 39 patients with active periarteritis nodosa, 20 patients hospitalized for stroke without livedo, and 28 healthy persons. Methods : AECA were detected with enzyme-linked immunosorbent assay with hybrid cells (EA.hy926) before and after absorption on epithelial cells ( A 549 8 ) to avoid false positivity from antibodies reacting with membranous epithelial antigens. Results : Twenty-two patients with Sneddon's syndrome had AECA (35%). Of the control subjects, 11 patients with active periarteritis nodosa (28%), 1 of 20 patients with a recent stroke without livedo, and no healthy persons had AECA. Conclusion : AECA were frequently found in patients with Sneddon's syndrome, in contrast to the patients with stroke without livedo. The clinical significance and involvement of these antibodies in the pathogenesis of endothelial lesions in Sneddon's syndrome remain to be ascertained.

Clinical Significance of Anti-endothelial Cell Antibodies in Systemic Vasculitis: A Longitudinal Study Comparing Anti-endothelial Cell Antibodies and Anti-neutrophil Cytoplasm Antibodies

Ten patients with systemic vasculitis, all positive for anti-neutrophil cytoplasm antibody (ANCA), were followed for a mean of 36 weeks to determine the prevalence of anti-endothelial cell antibodies (AECAs) and the relationship between AECAs, ANCAs, and disease activity. Anti-endothelial cell antibodies were detected in eight (80%) patients at some time during the study. The levels of both AECAs and ANCAs changed with time, and these autoantibodies were present in 48% and 63% of the total 100 serum samples, respectively. Eighteen clinical remissions were observed; in 16 (88.9%) cases the level of ANCAs dropped. Fifteen (83.3%) of the 18 remissions were among the AECA-positive patients and the level of AECAs decreased in 13 (86.7%) instances (P = not significant). There were 11 episodes of disease relapse; all were associated with an increase in the level of ANCAs. Nine (81.8%) of the 11 relapses were among AECA-positive patients, and the level of AECAs increased in eight (88.9%) cases (P = not significant). Serum levels of AECAs appeared less suppressible by cyclophosphamide therapy compared with ANCAs, and patients who were persistently positive for AECAs despite being ANCA-negative during remissions were at risk of subsequent relapse. Disease recrudescense was not observed in patients persistently tested negative for both AECAs and ANCAs. Intravenous immunoglobulin therapy was used in four patients and resulted in clinical improvement in all cases, but with variable changes in the levels of AECAs and ANCAs. We conclude that AECAs are commonly detected in patients with systemic vasculitis and their levels show a relationship to disease activity similar to that for ANCAs.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies to Endothelial Cells in Patients with Behçet's Disease

Autoantibodies that bind to endothelial cells have been identified in patients with several forms of vasculitis. Behçet's disease—a multisystem inflammatory disorder of unknown etiology—is associated with thrombosis in addition to systemic manifestations resulting from small and large vessel vasculitis. We studied 72 Turkish patients (33 female, 39 male) with Behçet's disease in order to investigate the prevalence of antiendothelial cell antibodies (AECA) and to examine their possible relationship with clinical and laboratory features of the illness. Sera from 30 healthy Turkish people were used as controls. Human umbilical vein endothelial cells were cultured and used unfixed in a cellular ELISA to detect AECA. IgG and/or IgM AECA were found in 13 (18.1%) patients but not in healthy controls. Antiendothelial cell antibodies did not induce complement-mediated cytotoxicity as assessed by 51Cr release assay and the binding was not due to immune complexes. The prevalences of acute thrombotic events and retinal vasculitis at the time of the AECA assay among patients with AECA were significantly higher than those in patients without AECA. Laboratory parameters of active disease were higher in patients with AECA. There was no correlation between other clinical and laboratory features of Behçet's disease and AECA. Anticardiolipin and antineutrophil cytoplasmic antibodies were negative in our series, excluding a possibility of crossreaction with AECA. Our results suggest a possible role of AECA in association with thrombosis and vasculitis in patients with Behçet's disease.

Prevalence of anti-endothelial cell antibodies in patients with autoimmune diseases.

The prevalence of anti-endothelial cell antibodies (AECA) of IgA, IgG and IgM classes was studied by means of enzyme-linked immunosorbent assays (ELISA) in 466 patients with autoimmune/inflammatory disorders. The reference limits in the ELISAs for the AECA were determined from a random population sample of 249 subjects. The frequency of AECA was highest in patients with SLE (n = 42), 14.6% mainly of IgG class, and the presence of AECA correlated with disease activity in these patients. In the RA patient group (n = 200), 9.5% had AECA, mostly of IgA type. We found no association between the presence of AECA and extra-articular manifestations of RA or survival rate. In patients with undefined connective tissue disease (n = 57), ankylosing spondylitis (n = 109), and psoriatic arthritis (n = 58), the frequency of AECA corresponded to that of the random population sample. In a cohort of samples sent to the laboratory for determination of anti-nuclear antibodies (ANA) there was a correlation between the presence of ANA and AECA. Our findings indicate that RA patients are characterized by IgA class AECA, whereas SLE patients have IgG class AECA also correlating to disease activity.

Anti-endothelial cell antibodies in retinal vasculitis.

Auto-antibodies to endothelial cells are found in a variety of vasculitic disorders including two diseases associated with retinal vasculitis: Behcet's disease and multiple sclerosis. In this study we have examined the prevalence of anti-endothelial cell antibodies [AECA] in 15 patients with retinal vasculitis [RV] associated with Behcet's disease, multiple sclerosis or sarcoidosis and 20 patients with idiopathic retinal vasculitis. 47% of patients with RV associated with systemic disease and 35% of patients with idiopathic RV had AECA, compared to 1% of 70 normal controls. The mean levels of AECA were similar in both groups of patients, and comparable to levels found in other systemic vasculitides.