Anti-La/SSB antiidiotypic antibodies in maternal serum: a marker of low risk for neonatal lupus in an offspring

Lupus Heart Disease Modeling with Combination of Induced Pluripotent Stem Cell-Derived Cardiomyocytes and Lupus Patient Serum

Background and Objectives

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease mainly affecting young women of childbearing age. SLE affects the skin, joints, muscles, kidneys, lungs, and heart. Cardiovascular complications are common causes of death in patients with SLE. However, the complexity of the cardiovascular system and the rarity of SLE make it difficult to investigate these morbidities. Patient-derived induced pluripotent stem cells (iPSCs) serve as a novel tool for drug screening and pathophysiological studies in the absence of patient samples.

Methods and Results

We differentiated CMs from HC- and SLE-iPSCs using 2D culture platforms. SLE-CMs showed decreased proliferation and increased levels of fibrosis and hypertrophy marker expression; however, HC-and SLE-monolayer CMs reacted differently to SLE serum treatment. HC-iPSCs were also differentiated into CMs using 3D spheroid culture and anti-Ro autoantibody was treated along with SLE serum. 3D-HC-CMs generated more mature CMs compared to the CMs generated using 2D culture. The treatment of anti-Ro autoantibody rapidly increased the gene expression of fibrosis, hypertrophy, and apoptosis markers, and altered the calcium signaling in the CMs.

Conclusions

iPSC derived cardiomyocytes with patient-derived serum, and anti-Ro antibody treatment could serve in effective autoimmune disease modeling including SLE. We believe that the present study might briefly provide possibilities on the application of a combination of patient-derived materials and iPSCs in disease modeling of autoimmune diseases.

Cardio-Rheumatology: Cardiovascular Complications in Systemic Autoimmune Rheumatic Diseases / Is Inflammation the Common Link and Target?

In the current Thematic Issue of Current Vascular Pharmacology (CVP), entitled "Systemic Autoimmune Rheumatic Diseases and Cardiology", presented in two parts, Part 1 and Part 2, review articles are included from specialists in cardiology, rheumatology, immunology and related fields. These reviews discuss the cardiovascular complications of the main systemic Autoimmune Rheumatic Diseases (ARDs). For example, the underlying pathogenetic mechanisms, the role of cardiovascular imaging and recommendations for prevention and management. These articles place inflammation as the key process, linking cardiovascular complications with ARDs. From all these reviews, the conclusion is the need for collaboration between the disciplines of Rheumatology and Cardiology to establish the emerging field of Cardio- Rheumatology. This will aid to fine-tune risk stratification and optimize preventive strategies and pharmacological therapies for patients with ARDs.

Primary Sjögren's Syndrome and Cardiovascular Disease

Sjögren's syndrome is a rheumatic autoimmune disease that primarily affects middle-aged women and runs a slowly progressing course with sicca symptoms being the prevalent manifestation. Premature atherosclerosis and increased cardiovascular (CV) morbidity and mortality are frequently encountered in rheumatic diseases characterized by significant systemic inflammation, such as the inflammatory arthritides, systemic vasculitides and systemic lupus erythematosus. In the same context, chronic inflammation and immune aberrations underlying Sjögren's syndrome are also reported to be associated with augmented risk of atherosclerosis. Increased CV disease (CVD) frequency has been found in recent meta-analyses. The involvement of the CV system is not a common feature of Sjögren's syndrome; however, specific manifestations, such as autoantibody-mediated heart block, pericarditis, pulmonary arterial hypertension and dysautonomia, have been described. This review focuses on studies addressing CV morbidity in Sjögren's syndrome and presents current data regarding distinct CV features of the disease.

Cardio-Rheumatology: Two Collaborating Disciplines to Deal with the Enhanced Cardiovascular Risk in Autoimmune Rheumatic Diseases

In Part 1 of this Thematic Issue entitled "Systemic Autoimmune Rheumatic Diseases and Cardiology", a panel of specialists and experts in cardiology, rheumatology, immunology and related fields discussed the cardiovascular complications of spondyloarthritides, rheumatoid arthritis, Sjogren's syndrome and vasculitides, as well as relevant cardiovascular issues related to non-biologic and biologic disease-modifying anti-rheumatic drugs (DMARDs), and provided their recommendations for prevention and management of these complications. In part 2 of this Thematic Issue, experts discuss the enhanced cardiovascular risk conferred by additional autoimmune rheumatic diseases (ARDs), including systemic lupus erythematosus, the antiphospholipid syndrome, psoriasis and psoriatic arthritis and juvenile idiopathic arthritis. These, and the previous articles, place inflammation as the key common link to explain the enhanced risk of cardiovascular complications in patients with ARDs. It follows that treatment should probably target inflammation. From all these contemporary reviews, the conclusion that is derived further supports the notion of the emerging field of Cardio- Rheumatology where physicians and experts from these two disciplines collaborate in risk stratification and optimization of preventive strategies and drug therapies in patients with ARDs.

A Functional Idiotype/Anti-Idiotype Network Is Active in Genetically Gluten-Intolerant Individuals Negative for Both Celiac Disease-Related Intestinal Damage and Serum Autoantibodies

An unbalance between Abs that recognize an autoantigen (idiotypes; IDs) and Igs that bind such Abs (anti-IDs) is considered a functional event in autoimmune disorders. We investigated the presence of an ID/anti-ID network in celiac disease (CD), a condition in which antitissue transglutaminase 2 (TG2) Abs are suspected to contribute to CD pathogenesis. To characterize the ID side, we reproduced by in vitro yeast display the intestine-resident Abs from CD and control patients. These TG2-specific IDs were used to identify potential anti-IDs in the serum. We observed elevated titers of anti-IDs in asymptomatic patients with predisposition to CD and demonstrated that anti-ID depletion from the serum restores a detectable humoral response against TG2. Our study provides an alternative approach to quantify CD-related autoantibodies in cases that would be defined "negative serology" with current diagnostic applications. Therefore, we suggest that developments of this technology could be designed for perspective routine tests.

Maternal antibodies and developing blood-brain barrier

We briefly review the protective role of maternal antibodies during fetal development and at early postnatal stages. We describe antibody delivery to fetuses, particularly in the context of the developing blood-brain barrier (BBB), and present the essential concepts regarding the adult BBB, together with existing information on the prenatal developing BBB. We focus on maternal antibody transfer to the developing brain and the consequences of the presence of pathogenic antibodies at early stages of brain development on subsequent brain dysfunction.

Autoantigen complementarity and its contributions to hallmarks of autoimmune disease

The question considered is, "What causes the autoimmune response to begin and what causes it to worsen into autoimmune disease?" The theory of autoantigen complementarity posits that the initiating immunogen causing disease is a protein complementary (antisense) to the self-antigen, rather than a response to the native protein. The resulting primary antibody elicits an anti-antibody response or anti-idiotype, consequently producing a disease-inciting autoantibody. Yet, not everyone who developes self-reactive autoantibodies will manifest autoimmune disease. What is apparent is that manifestation of disease is governed by the acquisition of multiple immune-compromising traits that increase susceptibility and drive disease. Taking into account current cellular, molecular, and genetic information, six traits, or 'hallmarks', of autoimmune disease were proposed: (1) Autoreactive cells evade deletion, (2) Presence of asymptomatic autoantibodies, (3) Hyperactivity of Fc-FcR pathway, (4) Susceptibility to environmental impact, (5) Antigenic modifications of self-proteins, (6) Microbial Infections. Presented here is a discussion on how components delineated in the theory of autoantigen complementarity potentially promote the acquisition of multiple 'hallmarks' of disease.

A comprehensive review of autoantibodies in primary Sjögren's syndrome: clinical phenotypes and regulatory mechanisms

Sjögren's syndrome (SS) is a systemic autoimmune disease characterized by periepithelial lymphocytic infiltrates in affected tissues and the production of plethora of autoantibodies. Among them autoimmune responses against Ro/SSA and La/SSB are of major importance since their detection is routinely used for disease diagnosis and clinical characterization. Although the exact mechanisms underlying disease pathogenesis are not fully understood, the important role of salivary gland epithelial cells (SGEC) in the initiation and development of the local immune responses is well-established. SGECs are also capable to mediate the exposure of the Ro/SSA and La/SSB autoantigens to the immune system by elevated apoptosis and autoantigen release in apoptotic bodies and/or by the secretion of autoantigen-containing exosomes. The expression of these autoantigens in epithelial cells appears to be tightly regulated. Up-to-date, signaling of certain innate immunity receptors, such as TLR3, appear to be implicated in the regulation of Ro/SSA and La/SSB expression by SGECs, whereas the deregulated expression of certain miRNAs that are predicted to target them in SS patients suggests a regulatory feedback at the post-transcriptional level. In the periphery, the humoral autoimmune responses are further regulated by the development of an active network of idiotypic-antiidiotypic antibodies. The plethora of mechanisms suggests that autoimmune humoral responses in SS are tightly regulated. In this review, the major humoral autoimmune responses, recent advances on the role of epithelial cells in their development, as well as possible regulatory mechanisms will be discussed.

Fine specificity of anti-citrullinated peptide antibodies discloses a heterogeneous antibody population in rheumatoid arthritis

Anti-citrullinated peptide antibodies (ACPA) are highly specific for rheumatoid arthritis (RA). However, the predominant B cell epitopes have not yet been defined. The aim of this study was to examine the reactivity of ACPA against different peptides derived from citrullinated proteins and to investigate whether or not these antibodies constitute a homogeneous population. For this purpose, sera from patients with RA (n = 141), systemic lupus erythematosus (SLE) (n = 60), Sjögren's syndrome (SS) (n = 54) and healthy controls (n = 100) were tested for their reactivity against six citrullinated peptides derived from peptidyl arginine deiminase (PAD), vimentin (vim), alpha-enolase (enol), fibrin, type II collagen (col-II) and filaggrin, respectively. A non-citrullinated control peptide derived from PAD was used as control (ctrlPAD(621-40)). Antibody reactivity against each individual peptide was evaluated by enzyme-linked immunosorbent assay (ELISA). Specificity and cross-reactivity of ACPA were tested by using two prototype sera with homologous and cross-inhibition assays. Specificity of ACPA from two prototype sera was confirmed by purification of anti-peptide antibodies and homologous-inhibition experiments. We found that sera from patients with RA reacted diversely with the six citrullinated peptides. More specifically, PAD(211-30) displayed 29·08% sensitivity, vim(60-75) 29·08%, enol(5-21) 37·59%, fibrin(617-31) 31·21%, col-II(358-75) 29·97% and filaggrin(306-24) 28·37%, while control ctrlPAD(621-40) showed no reactivity. All reactive peptides were found to be highly specific for RA. A notable cross-reaction (>70%) was found mainly between filaggrin and the majority of anti-citrullinated peptide antibodies. We concluded that ACPA in RA constitute a heterogeneous population with limited cross-reactivity and without a predominant epitope.

Autoantibodies in Sjögren's syndrome: clinical presentation and regulatory mechanisms

Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease mostly affecting the exocrine glands. A large number of autoantibodies have been detected in the serum of patients with pSS. Among them, anti-Ro/SSA and anti-La/SSB autoantibodies are the most common; they serve as disease markers and are involved in the pathogenesis of neonatal lupus syndrome (NLS). Other autoantibodies are associated with significant clinical phenotypes, such as cryoglobulins with development of non-Hodgkin's lymphoma, anti-centromere antibodies with Raynaud's phenomenon and anti-mitochondrial antibodies with liver pathology. As a result, pSS patients can be schematically categorized in subgroups according to their serological profile. Although the clinical utility of these autoantibodies is appreciated, little is known about the mechanisms related to their production and the regulation of the autoimmune response. In the present review, the clinical subsets of patients with pSS related to different autoantibodies as well as the regulating mechanisms of their production with special emphasis on idiotypic/anti-idiotypic network are discussed.

Protective role of anti-idiotypic antibodies in autoimmunity--lessons for type 1 diabetes

Circulating autoantibodies to beta cell antigens are present in the majority of patients with Type 1 diabetes. These autoantibodies can be detected before and at time of clinical diagnosis of disease. Although the role of autoantibodies in the pathogenesis of the disease is debated, their presence indicates a dysregulation of the humoral immune response. Mechanisms regulating autoantibodies in Type 1 diabetes are not well understood. In contrast, in other autoimmune diseases there is acceptance that autoantibodies are regulated not only by antigen but also by other antibodies that bind to the antigen-binding site of these autoantibodies (anti-idiotypic antibodies). The proposed purpose of this network is to maintain an equilibrium between autoantibodies and their anti-idiotypic antibodies, preventing autoimmunity, while allowing a robust response to exogenous antigen. Anti-idiotypic antibodies regulate both autoantibody binding and their levels by a) neutralizing autoantibodies, and b) inhibiting the secretion of autoantibodies. Because it has been proposed that the B lymphocytes that produce autoantibodies function as autoantigen presenting cells, inhibiting their binding to autoantigen by anti-idiotypic antibodies may prevent development of autoimmune disease. This hypothesis is supported by the presence of anti-idiotypic antibodies in healthy individuals and in patients in remission from autoimmune diseases, and by the lack of anti-idiotypic antibodies during active disease. We recently reported the presence of autoantibodies to glutamate decarboxylase in the majority of healthy individuals, where their binding to autoantigen is prevented by anti-idiotypic antibodies. These anti-idiotypic antibodies are absent at clinical diagnosis of Type 1 diabetes, revealing the presence of autoantibodies. Type 1 diabetes (T1D) is an autoimmune disease characterized by the dysfunction and destruction of insulin-producing beta cells by autoreactive T cells. Although much progress has been made towards understanding the respective roles of effector and regulatory T cells in this beta cell destruction, the development of autoantibodies to beta cell proteins is widely considered simply a by-product of the autoimmune destruction of the beta cells, rather than having an active role in the pathogenesis. This view is starting to change based on increasing recognition that autoantibodies can have defined roles in other autoimmune diseases, and the emergence of new data on their role in T1D. This exploration of the role of autoantibodies in autoimmune disease has been spurred, in part, by increasing recognition that development of autoimmune diseases is influenced by regulatory antibodies (anti-idiotypic antibodies) directed against the unique binding site of autoantibodies. This review provides an overview of the development and function of these anti-idiotypic antibodies, and present evidence supporting their role in the development of autoimmune diseases. Finally, we conclude this review with a model of the events that may cause loss of anti-idiotypic antibodies and the implications for the development of T1D.

Association of the idiotype:antiidiotype antibody ratio with the efficacy of intravenous immunoglobulin treatment for the prevention of recurrent autoimmune-associated congenital heart block

OBJECTIVE

Congenital heart block (CHB), a manifestation of neonatal lupus, is associated with maternal anti-Ro/SSA and anti-La/SSB autoantibodies and recurs in ∼18% of subsequent pregnancies. This study was undertaken to investigate the effect of the idiotype:antiidiotype (Id:anti-Id) antibody ratio in the ability of intravenous immunoglobulin (IVIG) administered during subsequent pregnancies to prevent CHB.

METHODS

We studied 16 anti-Ro/SSA and anti-La/SSB-positive pregnant women from the Preventive IVIG Therapy for Congenital Heart Block study who had previously given birth to a child with neonatal lupus. In 3 of the mothers, the study pregnancy resulted in the birth of a child with neonatal lupus (2 with CHB and 1 with rash). Sequential serum samples were obtained from all mothers immediately before the administration of IVIG during pregnancy and were evaluated for antibodies against the major B cell epitope 349-364aa of La/SSB (idiotype) and its antiidiotypic antibodies.

RESULTS

Following IVIG treatment, serum titers of anti-La(349-364) (Id antibodies) decreased in 80% of the mothers, and in 60% an increase in anti-Id antibodies against anti-La(349-364) was observed. The Id:anti-Id ratio was significantly higher in mothers whose offspring developed neonatal lupus compared to mothers who gave birth to a healthy child (P<0.0001). Removal of anti-Id antibodies substantially increased the reactivity against La(349-364) in sera from 5 of 7 mothers tested. All IVIG preparations were examined for Id and anti-Id antibody activity. IVIG from batches administered to mothers who gave birth to a healthy child had an Id:anti-Id activity ratio of <1, in contrast to that given to mothers who gave birth to a child with neonatal lupus. Addition of the IVIG preparations to the maternal sera further enhanced antiidiotypic activity (by up to 4.7-fold) in 11 of 13 patients studied.

CONCLUSION

This is the first study in humans to demonstrate that IVIG influences the Id-anti-Id network of a specific pathogenic autoantibody. Specifically, we showed that IVIG enhanced the anti-Id antibody response in pregnant women with anti-La/SSB antibodies. A high Id:anti-Id ratio in both the IVIG preparation and the maternal serum may explain the absence of an effect of IVIG in preventing recurrent neonatal lupus in some cases.

IgG placental transfer in healthy and pathological pregnancies

Placental transfer of maternal IgG antibodies to the fetus is an important mechanism that provides protection to the infant while his/her humoral response is inefficient. IgG is the only antibody class that significantly crosses the human placenta. This crossing is mediated by FcRn expressed on syncytiotrophoblast cells. There is evidence that IgG transfer depends on the following: (i) maternal levels of total IgG and specific antibodies, (ii) gestational age, (iii) placental integrity, (iv) IgG subclass, and (v) nature of antigen, being more intense for thymus-dependent ones. These features represent the basis for maternal immunization strategies aimed at protecting newborns against neonatal and infantile infectious diseases. In some situations, such as mothers with primary immunodeficiencies, exogenous IgG acquired by intravenous immunoglobulin therapy crosses the placenta in similar patterns to endogenous immunoglobulins and may also protect the offspring from infections in early life. Inversely, harmful autoantibodies may cross the placenta and cause transitory autoimmune disease in the neonate.

Cutaneous lupus in infancy and childhood

Cutaneous lupus may occur in infancy as transient lesions associated with and probably caused by maternal autoantibodies, or later in childhood, associated with the endogenous development of autoimmunity. In this review, clinical findings, diagnosis, management, and pathogenesis of neonatal lupus are discussed, and the management of cutaneous lupus in children is detailed.

Idiotype, anti-idiotype network of autoantibodies: pathogenetic considerations and clinical application

A common serologic finding in autoimmune diseases is the presence of autoantibodies against intracellular autoantigens. Recent data suggest that an anti-idiotypic network exists in these diseases, regulating the production of autoantibodies (idiotypic response). The anti-idiotypic antibodies can be monitored using complementary epitopes, designed according to the “molecular recognition” theory. The role of antiidiotypic antibodies in neonatal lupus and type 1 diabetes are discussed. In neonatal lupus, mothers with high anti-idiotypic antibody activity against anti-La autoantibodies are at lower risk of giving birth to an un-healthy child, as compared with mothers without anti-idiotypic antibodies. Similarly,the lack of particular anti-idiotypic antibodies against anti-GAD65 autoantibodies predispose in type 1 diabetes. These findings imply that antiidiotypic antibodies may confer protection from the harmful effect of autoantibodies in certain autoimmune diseases [corrected].

Modulation of diabetes in NOD mice by GAD65-specific monoclonal antibodies is epitope specific and accompanied by anti-idiotypic antibodies

Type 1 diabetes is caused by the autoimmune destruction of pancreatic beta cells. Here we show that administration of a human monoclonal antibody (b96.11) specific to the 65-kDa isoform of glutamate decarboxylase (GAD65) to prediabetic non-obese diabetic (NOD) mice significantly delays the onset of autoimmune diabetes. We found this effect to be epitope-specific, as only b96.11 showed this therapeutic property, while a GAD65-specific human monoclonal control antibody (b78) derived from the same patient, but specific to a different determinant of GAD65, had no significant effect on the progression of disease. Administration of b96.11 or b78 to NOD mice was accompanied by the generation of anti-idiotypic antibodies. Importantly, the induced anti-idiotypic antibodies were specific for the immunizing antibody and blocked the binding of GAD65 by the respective antibody. These findings suggest a potential role for the internal image of the GAD65 determinant recognized by b96.11 in the anti-idiotypic antibody, supporting an immunomodulatory role for GAD65-specific autoantibodies, as originally postulated by Jerne.

Neonatal lupus erythematosus: case report and review of the literature

A neonatalis lupus erythematosus (NLE) az újszülöttek első néhány hónapjának megbetegedése, melyet az édesanya autoimmun betegségének (SLE, Sjögren, rheumatoid arthritis stb.) kapcsán termelődő, placentán átjutó anti-SSA- és anti-SSB-ellenanyagok okoznak. Ritka megbetegedés. Tünetei érinthetik a bőrt (jellegzetes annuláris, erythemás plakkok), a szívet, a májat és a vérképzést. Legsúlyosabb következménye a 20–30%-os mortalitásért elsősorban felelős III. fokú AV-blokk, mely maradandó károsodás, s pacemaker beültetését teszi szükségessé. A tünetek általában kezelés nélkül megszűnnek az anyai ellenanyagok kiürülésével párhuzamosan a csecsemő 6–9 hónapos korára. Esetünkben a tipikus bőrtünetek az egész testet érintették, már születéskor fennálltak, de szívblokk nem alakult ki. A diagnózist jelentősen nehezítette, hogy az édesanya betegsége nem volt ismert a szülés idején. A jelentős thrombocytopenia, progrediáló bőrtünetek és emelkedett májfunkciós értékek miatt szisztémás szteroid adására kényszerültünk.