Autoantibodies against the chemokine receptor 3 predict cardiovascular risk.

BACKGROUND AND AIMS: Chronic inflammation and autoimmunity contribute to cardiovascular (CV) disease. Recently, autoantibodies (aAbs) against the CXC-motif-chemokine receptor 3 (CXCR3), a G protein-coupled receptor with a key role in atherosclerosis, have been identified. The role of anti-CXCR3 aAbs for CV risk and disease is unclear. METHODS: Anti-CXCR3 aAbs were quantified by a commercially available enzyme-linked immunosorbent assay in 5000 participants (availability: 97.1%) of the population-based Gutenberg Health Study with extensive clinical phenotyping. Regression analyses were carried out to identify determinants of anti-CXCR3 aAbs and relevance for clinical outcome (i.e. all-cause mortality, cardiac death, heart failure, and major adverse cardiac events comprising incident coronary artery disease, myocardial infarction, and cardiac death). Last, immunization with CXCR3 and passive transfer of aAbs were performed in ApoE(-/-) mice for preclinical validation. RESULTS: The analysis sample included 4195 individuals (48% female, mean age 55.5 ± 11 years) after exclusion of individuals with autoimmune disease, immunomodulatory medication, acute infection, and history of cancer. Independent of age, sex, renal function, and traditional CV risk factors, increasing concentrations of anti-CXCR3 aAbs translated into higher intima-media thickness, left ventricular mass, and N-terminal pro-B-type natriuretic peptide. Adjusted for age and sex, anti-CXCR3 aAbs above the 75th percentile predicted all-cause death [hazard ratio (HR) (95% confidence interval) 1.25 (1.02, 1.52), P = .029], driven by excess cardiac mortality [HR 2.51 (1.21, 5.22), P = .014]. A trend towards a higher risk for major adverse cardiac events [HR 1.42 (1.0, 2.0), P = .05] along with increased risk of incident heart failure [HR per standard deviation increase of anti-CXCR3 aAbs: 1.26 (1.02, 1.56), P = .03] may contribute to this observation. Targeted proteomics revealed a molecular signature of anti-CXCR3 aAbs reflecting immune cell activation and cytokine-cytokine receptor interactions associated with an ongoing T helper cell 1 response. Finally, ApoE(-/-) mice immunized against CXCR3 displayed increased anti-CXCR3 aAbs and exhibited a higher burden of atherosclerosis compared to non-immunized controls, correlating with concentrations of anti-CXCR3 aAbs in the passive transfer model. CONCLUSIONS: In individuals free of autoimmune disease, anti-CXCR3 aAbs were abundant, related to CV end-organ damage, and predicted all-cause death as well as cardiac morbidity and mortality in conjunction with the acceleration of experimental atherosclerosis.

Cross-sectional analysis reveals autoantibody signatures associated with COVID-19 severity.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is associated with increased levels of autoantibodies targeting immunological proteins such as cytokines and chemokines. Reports further indicate that COVID-19 patients may develop a broad spectrum of autoimmune diseases due to reasons not fully understood. Even so, the landscape of autoantibodies induced by SARS-CoV-2 infection remains uncharted territory. To gain more insight, we carried out a comprehensive assessment of autoantibodies known to be linked to diverse autoimmune diseases observed in COVID-19 patients in a cohort of 231 individuals, of which 161 were COVID-19 patients (72 with mild, 61 moderate, and 28 with severe disease) and 70 were healthy controls. Dysregulated IgG and IgA autoantibody signatures, characterized mainly by elevated concentrations, occurred predominantly in patients with moderate or severe COVID-19 infection. Autoantibody levels often accompanied anti-SARS-CoV-2 antibody concentrations while stratifying COVID-19 severity as indicated by random forest and principal component analyses. Furthermore, while young versus elderly COVID-19 patients showed only slight differences in autoantibody levels, elderly patients with severe disease presented higher IgG autoantibody concentrations than young individuals with severe COVID-19. This work maps the intersection of COVID-19 and autoimmunity by demonstrating the dysregulation of multiple autoantibodies triggered during SARS-CoV-2 infection. Thus, this cross-sectional study suggests that SARS-CoV-2 infection induces autoantibody signatures associated with COVID-19 severity and several autoantibodies that can be used as biomarkers of COVID-19 severity, indicating autoantibodies as potential therapeutical targets for these patients.

Modulation of Beta-Adrenergic Autoantibodies Over Time in Post-Viral ME/CFS is Related to Fatigue and Pain Symptoms.

BACKGROUND: Myalgic encephalomyelits/chronic fatigue syndrome (ME/CFS) is an acquired disease with symptoms of fatigue and pain. In pathogenesis, the induction of autoantibodies (AAB) against G-protein coupled receptors (GPCR), such as ß-adrenergic receptors (ß-AdR), has been suspected. GPCR-AAB correlate with symptom severity and autonomic dysfunction in ME/CFS. Objectives: To describe symptoms and treatment of a patient presenting with infection-triggered ME/CFS demonstrating that levels of ß-AdR-AAB underlie modulation over time, correlating with the severity of symptoms. METHODS: At T1 and T2, GPCR-AAB were measured and questionnaires assessing symptom severity were completed. TSHDS-IgM-AAB were tested, and SF density was analyzed via skin probe. RESULTS: At T2, elevated levels of ß-AdR-AAB were found, corresponding with an aggravation of fatigue and pain symptoms. Elevated TSHDS-IgM-AAB were found, which corresponded with reduced fiber density from the skin probe. CONCLUSIONS: The levels of ß-AdR-AAB in post-infectious ME/CFS can be modulated. Future studies might target interventions to reduce these AAB.

Possible Association Between Anti-Trisulfated-Heparin-Disaccharide (TS-HDS) Immunoglobulin M Autoantibody and Fibromyalgia Syndrome.

BACKGROUND: Fibromyalgia syndrome (FMS) is estimated to affect 2-4% of the general population. While FMS has some known environmental and genetic risk factors, the disorder has no clear etiology. A common coexisting disorder with FMS is small fiber neuropathy (SFN). High levels of serum immunoglobulin M (IgM) binding to trisulfated-heparin-disaccharide (TS-HDS) were recently found to be associated with SFN. OBJECTIVES: To evaluate potential differences in anti-TS-HDS antibody titers in women with FMS compared to healthy controls. METHODS: In this cross-sectional study, we evaluated 51 female participants: 30 with a diagnosis of FMS and 21 healthy controls who had been recruited at the Zabludowicz Center for Autoimmune Diseases, Sheba Medical Center, Israel. All of the participants were older than 18 years of age. Anti-TS-HDS IgM levels were measured in their sera using the enzyme immunoassay technique. RESULTS: The mean anti-TS-HDS IgM levels were significantly lower in the FMS group, compared with the control group (7.7 ± 5 vs. 13.2 ± 8.6 U/ml, respectively; P = 0.013). CONCLUSIONS: There is a possible association between FMS and anti-TS-HDS IgM. This association might be the missing link for the coexistence of SFN and FMS, but further study should be performed to assess this association and this auto-antibody characteristic.

Non-HLA antibodies targeting angiotensin II Type 1 receptor and endothelin-1 Type A receptors induce endothelial injury via ß2-arrestin link to mTOR pathway.

Functional non-HLA antibodies (antibodies to non-human leukocyte antigens) targeting the G protein-coupled receptors angiotensin II type 1 receptor (AT1R) and endothelin-1 type A receptor (ETAR) are implicated in the pathogenesis of transplant vasculopathy. While ERK signaling (a regulator of cell growth) may represent a general cellular response to agonist stimulation, the molecular link between receptor stimulation and development of vascular obliteration has not been fully established. Here we hypothesize involvement of the versatile adaptor proteins, ß-arrestins, and the major regulator of cell growth, PI3K/mTOR signaling, in impaired endothelial repair. To test this, human microvascular endothelial cells were treated with AT1R/ETAR antibodies isolated from patients with kidney transplant vasculopathy. These antibodies activated both mTOR complexes via AT1R and ETAR in a PI3K-dependent and ERK-independent manner. The mTOR inhibitor, rapamycin, completely abolished activation of mTORC1 and mTORC2 after long-term treatment with receptor antibodies. Imaging studies revealed that ß2- but not ß1-arrestin was recruited to ETAR in response to ET-1 and patient antibodies but not with antibodies isolated from healthy individuals. Silencing of ß2-arrestin by siRNA transfection significantly reduced ERK1/2 and mTORC2 activation. Non-HLA antibodies impaired endothelial repair by AT1R- and ETAR-induced mTORC2 signaling. Thus, we provide evidence that functional AT1R/ETAR antibodies induce ERK1/2 and mTOR signaling involving ß2-arrestin in human microvascular endothelium. Hence, our data may provide a translational rationale for mTOR inhibitors in combination with receptor blockers in patients with non-HLA receptor recognizing antibodies.

Induced antibodies directed to the angiotensin receptor type 1 provoke skin and lung inflammation, dermal fibrosis and act species overarching.

OBJECTIVE: To determine contributions and functions of autoantibodies (Abs) directed to the angiotensin receptor type 1 (AT1R), which are suggested to be involved in the pathogenesis of AT1R Abs-related diseases such as systemic sclerosis (SSc). METHODS: C57BL/6J mice were immunised with membrane-embedded human AT1R or empty membrane as control. Mice deficient for CD4+ or CD8+ T cells and B cells were immunised with membrane-embedded AT1R or an AT1R peptide proposed to be a dominant T cell epitope. A monoclonal (m)AT1R Ab was generated by hybridoma technique and transferred into C57BL/6J and AT1Ra/b knockout mice. The induced phenotype was examined by histology, immunohistochemistry, immunofluorescence, apoptosis assay and ELISA. In vitro, Abs responses towards AT1R were measured in cells of different origins and species. RESULTS: AT1R-immunised mice developed perivascular skin and lung inflammation, lymphocytic alveolitis, weak lung endothelial apoptosis and skin fibrosis accompanied by Smad2/3 signalling, not present in controls or mice deficient for CD4+ T and B cells. The AT1R peptide 149-172 provoked lung inflammation. Application of the mAT1R Ab induced skin and lung inflammation, not observed in AT1Ra/b knockout mice. In vitro, AT1R Abs activated rat cardiomyocytes and human monocytes, enhanced angiotensin II-mediated AT1R activation in AT1R-transfected HEK293 cells via AT1R binding and mAT1R Ab-activated monocytes mediated the induction of profibrotic markers in dermal fibroblasts. CONCLUSION: Our immunisation strategy successfully induced AT1R Abs, contributing to inflammation and, possibly, to fibrosis via activation of AT1R. Therefore, AT1R Abs are valuable targets for future therapies of SSc and other AT1R Ab-related diseases.

Molecular Effects of Auto-Antibodies on Angiotensin II Type 1 Receptor Signaling and Cell Proliferation.

The angiotensin II (Ang II) type 1 receptor (AT1R) is involved in the regulation of blood pressure (through vasoconstriction) and water and ion homeostasis (mediated by interaction with the endogenous agonist). AT1R can also be activated by auto-antibodies (AT1R-Abs), which are associated with manifold diseases, such as obliterative vasculopathy, preeclampsia and systemic sclerosis. Knowledge of the molecular mechanisms related to AT1R-Abs binding and associated signaling cascade (dys-)regulation remains fragmentary. The goal of this study was, therefore, to investigate details of the effects of AT1R-Abs on G-protein signaling and subsequent cell proliferation, as well as the putative contribution of the three extracellular receptor loops (ELs) to Abs-AT1R signaling. AT1R-Abs induced nuclear factor of activated T-cells (NFAT) signaling, which reflects Gq/11 and Gi activation. The impact on cell proliferation was tested in different cell systems, as well as activation-triggered receptor internalization. Blockwise alanine substitutions were designed to potentially investigate the role of ELs in AT1R-Abs-mediated effects. First, we demonstrate that Ang II-mediated internalization of AT1R is impeded by binding of AT1R-Abs. Secondly, exclusive AT1R-Abs-induced Gq/11 activation is most significant for NFAT stimulation and mediates cell proliferation. Interestingly, our studies also reveal that ligand-independent, baseline AT1R activation of Gi signaling has, in turn, a negative effect on cell proliferation. Indeed, inhibition of Gi basal activity potentiates proliferation triggered by AT1R-Abs. Finally, although AT1R containing EL1 and EL3 blockwise alanine mutations were not expressed on the human embryonic kidney293T (HEK293T) cell surface, we at least confirmed that parts of EL2 are involved in interactions between AT1R and Abs. This current study thus provides extended insights into the molecular action of AT1R-Abs and associated mechanisms of interrelated pathogenesis.

Autoimmune dysautonomia in women with silicone breast implants.

IMPORTANCE AND OBJECTIVES: There is unmet medical need to understand the pathogenic mechanism of the panoply of clinical manifestations associated with silicone breast implants (SBIs) such as severe fatigue, widespread pain, palpitations, dry mouth and eyes, depression, hearing loss etc. We aimed to determine whether autoantibodies against the autonomic nervous system receptors can explain the enigmatic and subjective clinical manifestation reported by women with SBIs. RESULTS: Circulating level of autoantibodies against G protein-coupled receptors (GPCRs) of the autonomic nervous system (adrenergic, muscarinic, endothelin and angiotensin receptors) have been evaluated in symptomatic women with SBIs using an ELISA method. These women with SBIs addressed our clinic due to various subjective and autonomic-related manifestations such as chronic severe fatigue, cognitive impairment, widespread pain, memory loss, sleep disorders, palpitations, depression, hearing abnormalities etc. We report for the first time, a significant reduction in the sera level of anti-ß1 adrenergic receptor (p < 0.001), anti-angiotensin II type 1 receptor (p < 0.001) and anti-endothelin receptor type A (p = 0.001) autoantibodies in women with SBIs (n = 93) as compared with aged matched healthy women (n = 36). Importantly, anti-ß1 adrenergic receptor autoantibody was found to significantly correlate with autonomic-related manifestations such as: sleep disorders and depression in women with SBIs. CONCLUSIONS: Chronic immune stimulation by silicone material may lead to an autoimmune dysautonomia in a subgroup of potentially genetically susceptible women with SBIs. The appearance of autoantibodies against GPCRs of the autonomic nervous system serve as an explanation for the subjective autonomic-related manifestations reported in women with SBIs.

Autoantibodies from Patients with Scleroderma Renal Crisis Promote PAR-1 Receptor Activation and IL-6 Production in Endothelial Cells.

BACKGROUND: Scleroderma renal crisis (SRC) is a life-threatening complication of systemic sclerosis (SSc). Autoantibodies (Abs) against endothelial cell antigens have been implicated in SSc and SRC. However, their detailed roles remain poorly defined. Pro-inflammatory cytokine interleukin-6 (IL-6) has been found to be increased in SSc, but its role in SRC is unclear. Here, we aimed to determine how the autoantibodies from patients with SSc and SRC affect IL-6 secretion by micro-vascular endothelial cells (HMECs). METHODS: Serum IgG fractions were isolated from either SSc patients with SRC (n = 4) or healthy individuals (n = 4) and then each experiment with HMECs was performed with SSc-IgG from a separate patient or separate healthy control. IL-6 expression and release by HMECs was assessed by quantitative reverse transcription and quantitative PCR (RT-qPCR) and immunoassays, respectively. The mechanisms underlying the production of IL-6 were analyzed by transient HMEC transfections with IL-6 promoter constructs, electrophoretic mobility shift assays, Western blots and flow cytometry. RESULTS: Exposure of HMECs to IgG from SSc patients, but not from healthy controls, resulted in a time- and dose-dependent increase in IL-6 secretion, which was associated with increased AKT, p70S6K, and ERK1/2 signalling, as well as increased c-FOS/AP-1 transcriptional activity. All these effects could be reduced by the blockade of the endothelial PAR-1 receptor and/or c-FOS/AP-1silencing. CONCLUSIONS: Autoantibodies against PAR-1 found in patients with SSc and SRC induce IL-6 production by endothelial cells through signalling pathways controlled by the AP-1 transcription factor. These observations offer a greater understanding of adverse endothelial cell responses to autoantibodies present in patients with SRC.

Autoantibodies Targeting AT1- and ETA-Receptors Link Endothelial Proliferation and Coagulation via Ets-1 Transcription Factor.

Scleroderma renal crisis (SRC) is an acute life-threatening manifestation of systemic sclerosis (SSc) caused by obliterative vasculopathy and thrombotic microangiopathy. Evidence suggests a pathogenic role of immunoglobulin G (IgG) targeting G-protein coupled receptors (GPCR). We therefore dissected SRC-associated vascular obliteration and investigated the specific effects of patient-derived IgG directed against angiotensin II type 1 (AT1R) and endothelin-1 type A receptors (ETAR) on downstream signaling events and endothelial cell proliferation. SRC-IgG triggered endothelial cell proliferation via activation of the mitogen-activated protein kinase (MAPK) pathway and subsequent activation of the E26 transformation-specific-1 transcription factor (Ets-1). Either AT1R or ETAR receptor inhibitors/shRNA abrogated endothelial proliferation, confirming receptor activation and Ets-1 signaling involvement. Binding of Ets-1 to the tissue factor (TF) promoter exclusively induced TF. In addition, TF inhibition prevented endothelial cell proliferation. Thus, our data revealed a thus far unknown link between SRC-IgG-induced intracellular signaling, endothelial cell proliferation and active coagulation in the context of obliterative vasculopathy and SRC. Patients' autoantibodies and their molecular effectors represent new therapeutic targets to address severe vascular complications in SSc.

Complex syndromes of chronic pain, fatigue and cognitive impairment linked to autoimmune dysautonomia and small fiber neuropathy.

Chronic fatigue syndrome, postural orthostatic tachycardia syndrome, complex regional pain syndrome and silicone implant incompatibility syndrome are a subject of debate among clinicians and researchers. Both the pathogenesis and treatment of these disorders require further study. In this paper we summarize the evidence regarding the role of autoimmunity in these four syndromes with respect to immunogenetics, autoimmune co-morbidities, alteration in immune cell subsets, production of autoantibodies and presentation in animal models. These syndromes could be incorporated in a new concept of autoimmune neurosensory dysautonomia with the common denominators of autoantibodies against G-protein coupled receptors and small fiber neuropathy. Sjogren's syndrome, which is a classical autoimmune disease, could serve as a disease model, illustrating the concept. Development of this concept aims to identify an apparently autoimmune subgroup of the disputable disorders, addressed in the review, which may most benefit from the immunotherapy.

Y-box protein-1/p18 as novel serum marker for ovarian cancer diagnosis: A study by the Tumor Bank Ovarian Cancer (TOC).

INTRODUCTION: The cold shock Y-box binding protein-1 (YB-1) fulfills important roles in regulating cell proliferation and differentiation. Overexpression occurs in various tumor cells. Given the existence of extracellular YB-1 we set out to determine the diagnostic, predictive and prognostic role of serum YB-1/p18 for patients with primary epithelial ovarian cancer (EOC). METHODS: The protein fragment YB-1/p18 was quantified by sandwich ELISA in serum samples from 132 healthy female volunteers and 206 patients with histological diagnosis of primary EOC. The ELISA sensitivity and specificity to detect EOC were calculated using receiver operating curves. Survival data were calculated using Kaplan Maier curves. RESULTS: Median age at the time of diagnosis was 60years and follow-up ended with a mean of 44.8month. 188 (91%) patients were diagnosed at advanced stages (FIGO III/IV) and 188 patients (91%) suffered from high-grade serous ovarian carcinoma. YB-1/p18 levels were significantly decreased in older patients (p=0.021). Significantly lower serum levels of YB-1/p18 were detected in the EOC cohort when compared to the control group (p<0.0001, AUC=0.827; 95% CI, 0.787-0.867). Using the expression of serum YB-1/p18 in early stages I and II cases these could be differentiated from control cases (p<0.0001, AUC=0.816; 95% CI 0.704-0.929). No other significant associations between clinical prognostic factors and YB-1/p18 serum levels were detected. Immunoblotting results with serum samples suggest that masking of epitopes by the YB-1/p18 fragment in multiprotein-complexes under non reducing conditions leads to the observed reduced ELISA readings in the EOC cohort. CONCLUSIONS: The quantification of fragment YB-1/p18 derived from cold shock protein YB-1 in serum samples could be useful for the early diagnosis of EOC.

Antibodies to ß adrenergic and muscarinic cholinergic receptors in patients with Chronic Fatigue Syndrome.

Infection-triggered disease onset, chronic immune activation and autonomic dysregulation in CFS point to an autoimmune disease directed against neurotransmitter receptors. Autoantibodies against G-protein coupled receptors were shown to play a pathogenic role in several autoimmune diseases. Here, serum samples from a patient cohort from Berlin (n=268) and from Bergen with pre- and post-treatment samples from 25 patients treated within the KTS-2 rituximab trial were analysed for IgG against human α and ß adrenergic, muscarinic (M) 1-5 acetylcholine, dopamine, serotonin, angiotensin, and endothelin receptors by ELISA and compared to a healthy control cohort (n=108). Antibodies against ß2, M3 and M4 receptors were significantly elevated in CFS patients compared to controls. In contrast, levels of antibodies against α adrenergic, dopamine, serotonin, angiotensin, and endothelin receptors were not different between patients and controls. A high correlation was found between levels of autoantibodies and elevated IgG1-3 subclasses, but not with IgG4. Further patients with high ß2 antibodies had significantly more frequently activated HLA-DR+ T cells and more frequently thyreoperoxidase and anti-nuclear antibodies. In patients receiving rituximab maintenance treatment achieving prolonged B-cell depletion, elevated ß2 and M4 receptor autoantibodies significantly declined in clinical responder, but not in non-responder. We provide evidence that 29.5% of patients with CFS had elevated antibodies against one or more M acetylcholine and ß adrenergic receptors which are potential biomarkers for response to B-cell depleting therapy. The association of autoantibodies with immune markers suggests that they activate B and T cells expressing ß adrenergic and M acetylcholine receptors. Dysregulation of acetylcholine and adrenergic signalling could also explain various clinical symptoms of CFS.

Angiotensin II type 1 receptor antibodies in childhood kidney transplantation.

Angiotensin II type 1 receptor antibodies (AT1 RAb) have emerged as non-HLA Ab present in patients with acute AMR and risk of graft loss. Furthermore, AT1 RAb have been shown to increase angiotensin II sensitivity which may play a role in the development of CVD and hypertension. Data on AT1 RAb in stable transplant recipients are lacking. The aim of this study was to analyze the levels of AT1 RAb in a cohort of stable patients after kidney transplantation (tx) in childhood. A cross-sectional study of 30 children (median age 14, range 3-19 yr, median time since tx five yr) and 28 adults who were transplanted in childhood (median age 26, range 20-40 yr, median time since tx 18 yr) transplanted between 1993-2006 and 1983-2002, respectively, was performed. Healthy controls were 51 healthy children (5-8 yr) and 199 healthy donors (median age 56.5 yr, range 42-83 yr). Plasma AT1 RAb were analyzed by immunoassay. Median total AT1 RAb IgG concentration was significantly higher in the pediatric-tx group as compared to the adult-tx group (40.0 and 10.95 U/mL, p < 0.0001). For both groups, the tx group showed higher levels: the pediatric-tx group vs. control group (40.0 vs. 13.3 U/mL, p = 0.0006) and the adult-tx group vs. adult control group (10.95 vs. 6.5 U/mL, p < 0.0001). Age was the strongest indicator of high levels of AT1 RAb IgG (p = 0.0003). AT1 RAb total IgG levels are significantly higher in a stable pediatric-tx cohort as compared to adult-tx patients and healthy controls of comparable age groups. The relevance of our findings in relation to age, time since tx, previous or future rejection, and CVD risk merits future studies.

Vascular receptor autoantibodies in pulmonary arterial hypertension associated with systemic sclerosis.

RATIONALE: Systemic sclerosis (SSc)-associated pulmonary arterial hypertension (PAH) portends worse outcome than other forms of PAH. Vasoconstrictive and vascular remodeling actions of endothelin (ET) 1 and angiotensin (Ang) II via endothelin receptor type A (ETAR) and Ang receptor type-1 (AT1R) activation are implicated in PAH pathogenesis. OBJECTIVES: We hypothesized that stimulating autoantibodies (Abs) targeting and activating AT1R and ETAR may contribute to SSc-PAH pathogenesis, and tested their functional and biomarker relevance. METHODS: Anti-AT1R and -ETAR Abs were detected by ELISA in different cohorts of patients and tested in vitro and in an animal model for their pathophysiological effects. MEASUREMENTS AND MAIN RESULTS: The Abs were significantly higher and more prevalent in patients with SSc-PAH (n = 81) and connective tissue disease-associated PAH (n = 110) compared with other forms of PAH/pulmonary hypertension (n = 106). High anti-AT1R and anti-ETAR Abs predicted development of SSc-PAH and SSc-PAH-related mortality in a prospective analysis. Both Abs increased endothelial cytosolic Ca(2+) concentrations in isolated perfused rat lungs, which could be blocked by respective specific receptor antagonists. Ab-mediated stimulation of intralobar pulmonary rat artery ring segments increased vasoconstrictive responses to Ang II and ET-1, and implicated cross-talk between both pathways demonstrated by reciprocal blockade with respective antagonists. Transfer of SSc-IgG containing both autoantibodies into healthy C57BL/6J mice led to more abundant vascular and airway α-smooth muscle actin expression and inflammatory pulmonary vasculopathy. CONCLUSIONS: Anti-AT1R and -ETAR Abs are more frequent in SSc-PAH/connective tissue disease-PAH compared with other forms of pulmonary hypertension, and serve as predictive and prognostic biomarkers in SSc-PAH. Both antibodies may contribute to SSc-PAH via increased vascular endothelial reactivity and induction of pulmonary vasculopathy.

In arterial occlusive disease autoantibodies against ETAR and AT(1)R correlate with each other but are not associated with classical cardiovascular risk factors.

BACKGROUND: Autoantibodies (Abs) against angiotensin-II type 1 (AT(1)R) and endothelin-1 type A receptors (ETAR) are investigated in the present study as B-cell originated humoral factors that may activate the respective receptors on endothelial cells. The prevalence of the Abs was determined in patients with peripheral arterial occlusive disease (PAD). PATIENTS AND METHODS: In a prospective observational study 200 patients undergoing angiography and proven advanced PAD were enrolled. Serum samples, clinical data and laboratory values for classical cardiovascular risk factors were collected. Autoantibody titers for AT(1)R and ETAR were determined by solid-phase ELISA and correlative analyses with laboratory parameters and clinical data for common cardiovascular risk factors were performed. RESULTS: Anti-ETAR antibody titers were detected in 57 % of the patients, elevated anti-AT(1)R titers in 61.5 %. About 50 % were positive for both Abs. A strong intercorrelation between ETAR and AT(1)R titers was present (r2 0.79). In patients with positive titers for both Abs females presented significantly higher titers for ETAR (p = 0.045) and AT(1)R (p = 0.02). Autoantibody titers directed against surface receptors ETA and AT(1) are highly correlated in PAD. Titers were independent from classical risk factors in any patient subgroup. CONCLUSIONS: This study opens a new perspective on the involvement of the immune system, hereby represented by functional autoantibodies, in the atherosclerotic pathophysiology, leaving behind the common background of classical risk factors.

Palpitation in women with silicone breast implants: association with autoantibodies against autonomic nervous system.

We explored a possible association between palpitation manifestation in women with silicone breast implants (SBIs) with circulating level of autoantibodies directed against autonomic nervous system (ANS) receptors. The study was conducted in 93 women with SBIs who arrived to our clinic with diverse symptoms thought to be associated with their implants. Titers of 11 various autoantibodies were measured in the sera of women with SBIs who experienced palpitations (Palpitations, n = 47), did not experience palpitations (Non, n = 46), and healthy women (Control, n = 36). A significant reduction in anti-α2-adrenergic receptor (A2AR, P = 0.035), anti-ß2-adrenergic receptor (B2AR, P = 0.027), antimuscarinic receptors M1R (P = 0.048), and anti-M2R (P = 0.039) autoantibodies was found in the 'Palpitations' group as compared with the 'Non' group. Anti-B2AR (P = 0.042), anti-M1R (P = 0.017), and anti-M2R (P = 0.0015) autoantibodies were also significantly reduced in 'Palpitations' as compared with the 'Control' group. Our study shows possible association between autoantibodies directed against ANS receptors, with existing complaints of palpitations in women with SBIs.

Intensive receptor blockade and plasma exchange to treat refractory scleroderma renal crisis in patients with agonistic autoantibodies targeting the angiotensin II type 1 and endothelin-1 type A receptors.

Scleroderma renal crisis is a rare complication of systemic sclerosis characterized by a rapid decline in kidney function due to acute renal vascular injury. Recently, activating autoantibodies targeting the angiotensin II type 1 receptor and the endothelin-1 type A receptor have been implicated in the pathophysiology of scleroderma renal crisis by sensitizing the angiotensin II type 1 receptor and endothelin-1 type A receptor in renal resistance arteries to their natural ligands. Here, we describe a cohort of 10 patients with scleroderma renal crisis refractory to standard treatment, including blockade of the renin-angiotensin system. Multimodal therapy was initiated, targeting at the removal of anti-angiotensin II type 1 receptor and anti-endothelin-1 type A receptor autoantibodies by plasma exchange and the reduction of vasoconstrictive activity. Further treatment options included angiotensin II type 1 receptor and endothelin-1 type A receptor blockade, iloprost, intravenous immunoglobulins, and immunosuppression. Six patients were hypertensive. On kidney biopsy, concentric intimal sclerosis was present in all patients, whereas acute vascular injury was evident in eight. Levels of anti-angiotensin II type 1 receptor and anti-endothelin-1 type A receptor autoantibodies were significantly reduced by multimodal treatment. Kidney function improved in three patients with histological signs of severe acute renal vascular damage. This report demonstrates that intensive multimodal therapy taking account of potentially pathogenic anti-angiotensin II type 1 receptor and anti-endothelin-1 type A receptor autoantibodies in concert with other vasodilatory interventions provides a salvage option for patients with refractory scleroderma renal crisis.

Allergic manifestations in women with silicone breast implants.

INTRODUCTION: Silicone breast implants (SBI) result in immune dysregulation and are associated with autoimmune diseases. Recently, we reported dysregulated levels of IgG autoantibodies directed against G protein-coupled receptors (GPCRs) of the autonomic nervous system which were linked to the autoimmune dysautonomia in silicone breast implant illness (SBII). AIMS: We aimed to explore the possible association between allergy with dysregulated IgE autoantibodies directed against GPCRs of the autonomic nervous system in women with SBI. METHODS: Circulating levels of IgE autoantibodies against GPCRs of the autonomic nervous system (adrenergic, muscarinic, endothelin and angiotensin receptors) have been evaluated in women with SBIs who complained of allergic symptoms, and compared to subjects with SBI without allergic manifestations and to age-matched healthy women without SBI. RESULTS: We report a significant dysregulation in three circulating autoantibodies: IgE-beta1 adrenergic receptor (B1AR), IgE-alpha 1 adrenergic receptor (A1AR) and IgE-muscarinic acetylcholine receptor type 1 (M1R) autoantibodies in women with SBI who complained of allergic symptoms. CONCLUSIONS: Allergic reactions associated with SBI are not uncommon. Imbalance of circulating levels of IgE autoantibodies against GPCRs of the autonomic nervous system might play a role not only in allergic reactions, but also in other enigmatic aspects of SBII such as autoimmune dysautonomia.