Definitions of and contributions to cardiovascular disease in systemic lupus erythematosus

Abstract

Patients with systemic lupus erythematosus (SLE) have a significantly increased risk of cardiovascular disease (CVD). Increased prevalence of atherosclerosis may explain part of this enhanced risk, but SLE related CVD can also result from other mechanisms. Vascular events may be the result of several pathophysiologic mechanisms; some can be caused by atherosclerosis, others may be primarily thrombotic, and some may be due to ongoing inflammation. The traditional risk factors are of importance for the development of CVD in lupus. However, lupus-related factors, such as endothelial dysfunction and inflammation, renal impairment and disease activity, lupus phenotype, autoantibodies and genetic predisposition are equally or even more important. Risk factors may also contribute separately or in combination to increase the risk of atherosclerosis and clinical CVD in SLE. Studies investigating risk factors for CVD in SLE vary with respect to definition of outcome, it is, e.g. common that the terms atherosclerosis and clinical CVD are used interchangeably. Varying definitions and outcomes may thus explain divergent results of different studies and make comparisons difficult. This review summarizes some of the current knowledge regarding risk factors and mechanisms for atherosclerosis and clinical CVD in SLE. Aspects on the importance of CVD definitions and outcomes are briefly discussed.     

Annexin A5 in cardiovascular disease and systemic lupus erythematosus

Atherosclerosis, a major cause of disease and death from cardiovascular disease (CVD), is an inflammatory disease characterized by T cell and monocyte/macrophage infiltration in the intima of large arteries. During recent years and with improved treatment of acute disease manifestations, it has become clear that the risk of CVD is very high in systemic lupus erythematosus (SLE), often considered a prototypic autoimmune disease. A combination of traditional and non-traditional risk factors, including dyslipidemia, inflammation, antiphospholipid antibodies (aPL) and lipid oxidation are related to CVD in SLE. aPL are highly thrombogenic, and possible mechanisms include direct effects of aPL on endothelial and other cells, and interference with coagulation reactions.

More than a thousand proteins of the annexin-superfamily are expressed in eukaryotes. Annexins are ubiquitous, highly conserved, predominantly intracellular proteins, widely distributed in tissues. Annexin A5 (ANXA5) is an important member of the annexin family due to its antithrombotic properties. These are believed to be caused by it forming a two-dimensional protective shield, covering exposed potentially thrombogenic cell surfaces. Recently, ANXA5 has been implicated in SLE since aPL interfere with ANXA5 binding to placental trophoblasts, causing microthrombosis and miscarriage, a rather common complication in SLE. We recently demonstrated that ANXA5 may play a role in CVD and is abundant in late-stage atherosclerotic lesions. Sera from SLE-patients with a history of CVD inhibited ANXA5 binding to endothelium, caused by IgG antibodies, to a significant degree aPL. This review will focus on potential involvement of ANXA5 in pathogenesis of CVD, particularly caused by underlying atherosclerosis and atherothrombosis.     

Dyslipidemia in systemic lupus erythematosus

Cardiovascular disease is one of the major causes of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Accelerated atherosclerosis is related to traditional (age, hypertension, diabetes mellitus, dyslipidemia, obesity, smoking, and positive family history) and non-traditional, disease-related factors. Traditional risk factors are still more prominent in patients with lupus, as both hypertension and hypercholesterinemia were independently associated with premature atherosclerosis in several SLE cohorts. In this work, the authors summarize the epidemiology of dyslipidemia in lupus patients and review the latest results in the pathogenesis of lipid abnormalities. The prevalence of dyslipidemia, with elevations in total cholesterol (TC), low-density lipoprotein (LDL), triglyceride (TG), and apolipoprotein B (ApoB), and a reduction in low-density lipoprotein (LDL) levels are about 30% at the diagnosis of SLE rising to 60% after 3 years. Multiple pathogenetic mechanism is included, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) can suppress HDL and increase TG, auto-antibodies can cause the injury of the endothelium, lipoprotein lipase (LPL) activity can be reduced by circulating inflammatory mediators and antibodies, and increased oxidative stress may trigger a wide range of pro-atherogenic lipid modifications. As a major risk factor, dyslipidemia should be treated aggressively to minimize the risk of atherosclerosis and cardiovascular events. Randomized controlled trials with statins are controversial in the detention of atherosclerosis progression, but can be favorable by inhibiting immune activation that is the arterial wall and by decreasing lupus activity.     

Inflammation: a pivotal link between autoimmune diseases and atherosclerosis

Premature coronary heart disease has emerged as a major cause of morbidity and mortality in systemic autoimmune diseases. Recent epidemiologic and pathogenesis studies have suggested a great deal in common between the pathogenesis of prototypic autoimmune disease such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) and that of atherosclerosis. Some of the most remarkable data in support of a link between autoimmunity and atherosclerosis comes from epidemiological studies of patients with autoimmune disorders (RA and SLE). Many epidemiologic observations have linked systemic inflammation with the cardiovascular events in autoimmune disease such as RA and SLE. Inflammation is increasingly being considered central to the pathogenesis of atherosclerosis and an important risk factor for vascular disease. Systemic inflammation may be regarded as accelerating the atherosclerotic process. Systemic levels of soluble inflammatory mediators such as C-reactive protein (CRP) have been associated with cardiovascular risk in the general population. CRP, or more specifically high sensitivity-hsCRP, is a marker of systemic inflammation that has been identified as a valid biomarker of cardiovascular risk. Furthermore, the immunomodulatory and anti-inflammatory actions of statins may affect their utility in the context of chronic inflammatory autoimmune disease. Thus, effective control or dampening of inflammation, with such agents, should be included in the therapeutic armamentarium of autoimmune diseases with the aim of protecting against cardiovascular disease.     

Periodontal disease as a risk factor for cardiovascular disease: suggestion of a further link in systemic lupus erythematosus

Cardiovascular disease (CVD) is a major cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Due to either infection or disease activity, elevated levels of inflammatory markers and up-regulation of the autoimmune process can contribute to the development of atherosclerosis in SLE patients. Periodontal diseases are among the most prevalent chronic infections in humans and are characterized by pathogen-induced oral inflammatory disease affecting the supporting tissues of teeth. Several cytokines capable of inducing systemic effects are produced during the course of this infection. The presence of these cytokines can be verified by changes in the levels of C-reactive protein (CRP). Periodontal disease is a well-known risk factor for atherosclerosis. The potential for beneficial prevention of CVD events through the use of periodontal treatment has been previously recommended. This review reinforces the hypothesis that periodontal infection could be a risk factor for CVD in patients diagnosed with SLE, and suggests that by reducing the progression of this oral infection, levels of inflammatory markers common to both diseases (SLE and periodontal disease) would likely decrease.     

Oxygen free radicals and systemic autoimmunity

Reactive oxygen species generated during various metabolic and biochemical reactions have multifarious effects that include oxidative damage to DNA leading to various human degenerative and autoimmune diseases. The highly reactive hydroxy radical (*OH) can interact with chromatin and result in a wide range of sugar and base-derived products, DNA-protein cross-links and strand breaks. Studies from our laboratory have demonstrated that after modification the DNA becomes highly immunogenic and the induced antibodies exhibit variable antigen-binding characteristics. Systemic lupus erythematosus, a prototype autoimmune disease, is characterized by the presence of autoantibodies to multiple nuclear antigens. The detection of 8-hydroxyguanosine in the immune complex derived DNA of systemic lupus erythematosus patients reinforces the evidence that reactive oxygen species may be involved in its pathogenesis. Increased apoptosis and decreased clearance of apoptotic cells as observed in systemic lupus erythematosus (SLE) might well be a contributory factor in systemic autoimmunity. Clinically, titres of autoantibodies are closely related to the degree of renal inflammation. Anti-DNA antibodies may combine with circulating antigen and contribute to the deposition of immune complexes in renal glomeruli.     

Metabolic syndrome and systemic lupus erythematosus: the connection

ABSTRACT

Introduction: The metabolic syndrome (MetS) is now recognized as a chronic proinflammatory and prothrombotic state that aggravates insulin resistance, oxidative injury, and cardiovascular risk. MetS is more prevalent in patients with systemic lupus erythematosus (SLE), a prototype of systemic autoimmune disease associated with premature atherosclerosis that cannot be accounted by traditional vascular risk factors alone. Dysregulation of the cytokines and adipokines is a common feature in both SLE and MetS, suggesting a complex relationship among autoimmunity, obesity, inflammation, and atherosclerosis.

Areas covered: This review summarizes the prevalence of MetS and its effect on cardiovascular outcome and organ damage in patients with SLE. The pathophysiology of MetS and its relevance to SLE is also briefly discussed.

Expert opinion: Imbalance of adipokine production in MetS contributes to inflammation and atherosclerosis. MetS predisposes SLE patients to new cardiovascular events and vascular mortality, as well as the development of chronic kidney disease and diabetes mellitus. However, conflicting results have been reported in the literature regarding the levels of the proinflammatory leptin and anti-inflammatory adiponectin, and their relationship with disease activity in SLE patients. While lifestyle modifications and targeting dyslipidemia, hypertension and diabetes mellitus is essential, there is little information on the efficacy and safety of metformin and hydroxychloroquine in alleviating insulin resistance in SLE or MetS. Further research on adipokines in SLE and the role of anti-obesity medications and probiotics in MetS is necessary.     

Unmet Needs in the Pathogenesis and Treatment of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune rheumatic disease with a prevalence of approximately 1 in 1000. Over the last 30 years, advances in treatment such as use of corticosteroids and immunosuppressants have improved life expectancy and quality of life for patients with lupus and the key unmet needs have therefore changed. With the reduced mortality from disease activity, development of cardiovascular disease (CVD) has become an increasingly important cause of death in patients with SLE. The increased CVD risk in these patients is partly, but not fully explained by standard risk factors, and abnormalities in the immune response to lipids may play a role. Invariant natural killer T cells, which are triggered specifically by lipid antigens, may protect against progression of subclinical atherosclerosis. However, currently our recommendation is that clinicians should focus on optimal management of standard CVD risk factors such as smoking, blood pressure and lipid levels. Fatigue is one of the most common and most limiting symptoms suffered by patients with SLE. The cause of fatigue is multifactorial and disease activity does not explain this symptom. Consequently, therapies directed towards reducing inflammation and disease activity do not reliably reduce fatigue and new approaches are needed. Currently, we recommend asking about sleep pattern, optimising pain relief and excluding other causes of fatigue such as anaemia and metabolic disturbances. For the subgroup of patients whose disease activity is not fully controlled by standard treatment regimes, a range of different biologic agents have been proposed and subjected to clinical trials. Many of these trials have given disappointing results, though belimumab, which targets B lymphocytes, did meet its primary endpoint. New biologics targeting B cells, T cells or cytokines (especially interferon) are still going through trials raising the hope that novel therapies for patients with refractory SLE may be available soon.     

Anti-inflammatory and immunomodulating properties of statins. An additional tool for the therapeutic approach of systemic autoimmune diseases?

Cardiovascular diseases secondary to accelerated atherosclerosis are now accepted as a cause of mortality and morbidity in patients suffering from systemic lupus erythematosus and rheumatoid arthritis. More recently, atherosclerosis is emerging as one of the most serious complications in the anti-phospholipid syndrome, although large epidemiological studies, such as those performed in lupus and rheumatoid arthritis patients, have not been performed up to now. Classical risk factors (dislipidemia, hypertension, diabetes, smoking, etc.) and steroid therapy cannot completely explain the high prevalence of cardiovascular complications in systemic autoimmune diseases. Since the modern view defines atherosclerosis as a chronic inflammatory disorder, it has been suggested that systemic inflammation and soluble immune mediators (circulating autoantibodies, immune-complexes, complement activation products) might play a role in accelerating vessel pathology. The main target appears to be the endothelium because of its ability to switch to a pro-adhesive, pro-inflammatory and pro-coagulant surface in response to these mediators. Recent advances in the knowledge of the pharmacology of statins have indicated that these drugs rather than to be simple cholesterol lowering molecules display a pleiotropic effects on several mechanisms involved in the atherosclerotic plaque formation. Their anti-inflammatory activity and particularly their ability to downregulate endothelial cell activation induced by different stimuli strongly suggest their possible use in conditions in which the systemic inflammation and the endothelial activation/damage are through to represent key pathogenic mechanisms.     

OxLDL/beta2GPI-anti-oxLDL/beta2GPI complex and atherosclerosis in SLE patients

It has been demonstrated that atherosclerosis (ATS) is enhanced in autoimmune rheumatic diseases, such as systemic lupus erythematosus (SLE). The reason for this accelerated process is still debatable and, although traditional risk factors are more prevalent in SLE patients than in general population, they do not seem to fully explain the enhanced risk. ATS has the characteristics of an autoimmune chronic disease, involving both the innate and the adaptive immunity. Moreover, it satisfies the four criteria defining an autoimmune disease, proposed by Witebsky and Rose. It has been shown that some autoantibodies, including anti-oxLDL, anti-beta(2)GPI, anti-HSP60/65, and more recently anti-oxLDL/beta(2)GPI, play a key role in the pathogenesis of ATS. However the role of these autoantibodies in accelerated ATS in SLE patients is still controversial. In fact, some of them seem to be proatherogenic and other protective; moreover, it has been demonstrated that induced oral tolerance has a protective role against ATS. We have recently observed that the levels of oxLDL/beta(2)GPI antigenic complexes and their antibodies were higher in patients with SLE than in healthy subjects, but we did not find a clear association between oxLDL/beta(2)GPI complexes and IgG or IgM anti-oxLDL/beta(2)GPI autoantibodies and subclinical ATS in SLE patients. Many other studies are required to explain the role of autoantibodies in the pathogenesis of ATS in SLE patients, because the characteristics of SLE seem to mask their effects for atherogenesis.     

Preventive strategies in systemic lupus erythematosus

Despite the improvement of systemic lupus erythematosus (SLE) survival observed in the last decades, the long-term prognosis of these patients remains poor mainly due to complications of the disease and/or of its treatment. Therefore, in order to improve SLE prognosis, we should try to avoid long-term complications by adopting, early in the disease course, some strategies directed to prevent infections, atherosclerosis and cancer. Moreover, since it has been shown that autoantibodies appear before clinical manifestations in SLE, the question of whether or not asymptomatic individuals with a reliable positive serology should be treated arises. Other than advising these individuals to avoid sun exposure, drugs implicated in drug-induced lupus and cigarette smoking, the use of vitamin D and hydroxychloroquine could be considered. Finally, early SLE diagnosis has led to a modification of disease clinical spectrum at disease onset with an increased frequency of mild disease manifestations over severe ones. Thus great effort should be made in order to identify early in the disease course risk factors for the development of severe SLE manifestations. Finally patients with mild disease carrying factors predictive of severe manifestations should be treated more aggressively than we have done up to now.     

Environment and systemic lupus erythematosus: An overview

Systemic lupus erythematosus (SLE) is an autoimmune disease of unknown etiology that manifests as a pleomorphic systemic disease mainly affecting females. The variety of autoantibodies found in the serum of patients indicate that SLE is an autoimmune disease, but the mechanisms leading to the aberrant responses are not clearly understood although it is thought that a number of genetic and environmental factors may be involved. Environmental (or non-genetic) exposures could include infectious agents, chemicals or other compounds capable of modulating immune responses such as occupational/environmental pollutants or drugs, and behavioural factors such as smoking and diet. Environmental exposures may lead to the production of autoreactive T cells and autoantibodies, the stimulation of pro- and antiinflammatory cytokines, and target end-organ damage, but are not so convincing as agents causing SLE. Exposure to viruses increases antibody titres, but these may be the result of polyclonal B cell activation. The amount and timing of exposure to different environmental factors may play a significant and complex role in the pathogenesis of SLE and other autoimmune diseases. A better understanding of the etiopathogenetic mechanism of SLE is required in order to clarify the multiple interactions between environmental exposures and genetic factors.     

Environment and systemic lupus erythematosus: an overview

Systemic lupus erythematosus (SLE) is an autoimmune disease of unknown etiology that manifests as a pleomorphic systemic disease mainly affecting females. The variety of autoantibodies found in the serum of patients indicate that SLE is an autoimmune disease, but the mechanisms leading to the aberrant responses are not clearly understood although it is thought that a number of genetic and environmental factors may be involved. Environmental (or non-genetic) exposures could include infectious agents, chemicals or other compounds capable of modulating immune responses such as occupational/environmental pollutants or drugs, and behavioural factors such as smoking and diet. Environmental exposures may lead to the production of autoreactive T cells and autoantibodies, the stimulation of pro- and antiinflammatory cytokines, and target end-organ damage, but are not so convincing as agents causing SLE. Exposure to viruses increases antibody titres, but these may be the result of polyclonal B cell activation. The amount and timing of exposure to different environmental factors may play a significant and complex role in the pathogenesis of SLE and other autoimmune diseases. A better understanding of the etiopathogenetic mechanism of SLE is required in order to clarify the multiple interactions between environmental exposures and genetic factors.     

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

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

Cardiac manifestations in antiphospholipid syndrome

Antiphospholipid syndrome (APS) is a systemic autoimmune disease associated with arterial and venous thrombotic events and recurrent fetal loss. Cardiac manifestations in APS primarily include accelerated atherosclerosis leading to cardiovascular disease. There is increased cardiovascular mortality in APS. Cardiovascular risk is even higher in secondary APS in lupus patients. Several traditional and disease-related, autoimmune-inflammatory risk factors are involved in APS-associated atherosclerosis and its clinical manifestations. Antiphospholipid antibodies (APA), lupus anticoagulant, anti-oxLDL and other antibodies have been implicated in vascular events underlying APS. The primary and secondary prevention of atherosclerosis and CAD in these diseases includes drug treatment, such as the use of statins and aspirin, as well as lifestyle modifications. Apart from atherosclerosis and CVD, other cardiac manifestations may also be present in these patients. Among these conditions, valvular disease including thickening and vegetations is the most common. APA are involved in the pathogenesis of Libman-Sacks endocarditis usually associated with SLE. In addition, ventricular dysfunction, intracardiac thrombi and myxomas, pulmonary hypertension may also exist in APS patients. Early diagnosis of APS, thorough examination of the heart, control of traditional risk factors by lifestyle modifications and pharmacotherapy, probably anti-inflammatory treatment, and close follow-up of APS patients may help to minimize cardiovascular risk in these individuals.     

Atherosclerosis in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune rheumatic disease that has a late mortality phase owing mainly to cardiovascular manifestations. Atherosclerosis itself is characterized by inflammatory components, fulfilling the criteria of Witebsky and Rose for an autoimmune disease. SLE patients have increased risk for cardiovascular events, and these are the result of both atherosclerosis and thromboembolic events. Risk factors for atherosclerosis in SLE include “traditional” risk factors (mainly the Framingham risk factors), as well as disease-related factors including disease duration, steroid therapy, and renal disease, and inflammatory mechanisms that specifically contribute to enhanced atherosclerosis in SLE. These include specific antibodies to β2GPI; anticardiolipin antibodies; anti-oxidized low-density lipoprotein; and antibodies to heat shock proteins, complement activation, impaired ability to activate TGF-β1, and elevated levels of CRP. These findings stress the importance of surveillance and preventive strategies to control atherosclerosis in SLE.     

Role of the innate and adaptive immune responses in the pathogenesis of systemic lupus erythematosus

Objective

Systemic lupus erythematosus (SLE), the most common form of lupus, is a multisystemic rheumatic disease with different clinical features that generally affect women of childbearing age. The common symptoms of SLE are very similar to other autoimmune and non-autoimmune disorders, thereby it is known as a thousand faces disease. In this article, we are going to discuss some of the most updated information about immune system-related factors, cells, and cytokines involved in SLE pathogenesis.

Methods

Different electronic databases, especially PubMed/MEDLINE, Scopus, and Google Scholar, were searched to review and analyze relevant literature on the role of innate and adaptive immune cells and cytokines in the pathogenesis of SLE. A search for relevant literature was accomplished using various keywords including systemic lupus erythematosus, apoptosis, autoantibodies, immunopathogenesis of SLE, adaptive and innate immune cells, inflammatory cytokines, hormones, etc.

Results and conclusion

The most important characteristic of SLE is the production of antibodies against different nuclear autoantigens like double-strand DNA and RNA. The depositions of the immune complexes (ICs) that are generated between autoantibodies and autoantigens, along with aberrant clearance of them, can lead to permanent inflammation and contribute to tissue or organ damage. Related mechanisms underlying the initiation and development of SLE have not been clarified yet. Although, defects in immune tolerance, enhanced antigenic load, hyperactivity of T cells, and inappropriate regulation of B cells contribute to the pathogenic autoantibodies generation. Besides, sex hormones that influence the immune system seem to act as triggers or protectors of SLE development.

     

Cardiovascular involvement in systemic autoimmune diseases

Autoimmune diseases, including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), primary antiphospholipid syndrome (APS), systemic sclerosis and systemic vasculitis, affect a large number of people in whom one of the leading causes of morbidity and mortality is cardiovascular disease. Cardiovascular disease is associated with the development of accelerated atherosclerosis. It seems to occur at a younger age than in the general population, is often asymptomatic and, in addition to traditional risk factors, also involves specific risk factors as chronic inflammation, the duration and activity of the autoimmune disease, and immunosuppressive therapy. The early phases of cardiovascular involvement in patients with autoimmune diseases may be clinically silent, with only a microcirculation disorder present. There are various means of detecting morphological cardiac damage: coronary angiography remains the gold standard for diagnosing coronary stenosis, but new, non invasive and more reliable methods have been introduced into clinical practice in order to detect subclinical microcirculation abnormalities.     

Recent advances in the genetics of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by the production of antinuclear autoantibodies and the inflammatory infiltration of many organ systems. SLE is a complex disorder in which multiple genetic variants, together with environmental and hormonal factors, contribute to disease risk. In this article, we summarize our current understanding of the genetic contribution to SLE in light of recent genome-wide association studies, which have brought the total number of confirmed SLE susceptibility loci to 29. In the second section, we explore the functional implications of these risk loci and, in particular, highlight the role that many of these genes play in the Toll-like receptor and type I interferon signaling pathways. Finally, we discuss the genetic overlap between SLE and other autoimmune and inflammatory conditions as several risk loci are shared among multiple disorders, suggesting common underlying pathogenic mechanisms.     

Selfie: Autoimmunity,boon or bane

The immune system provides protection to tissues damaged by infectious microrganisms or physical damage. In autoimmune diseases, the immune system recognizes and attacks its own tissues, i.e., self-destruction. Various agents such as genetic factors and environmental triggers are thought to play a major role in the development of autoimmune diseases. A common feature of all autoimmune diseases is the presence of autoantibodies and inflammation, including mononuclear phagocytes, autoreactive T lymphocytes, and autoantibody producing B cells (plasma cells). It has long been known that B cells produce autoantibodies and, thereby, contribute to the pathogenesis of many autoimmune diseases. Autoimmune diseases can be classified as organ-specific or non-organ specific depending on whether the autoimmune response is directed against a particular tissue or against widespread antigens as in chronic inflammatory autoimmune diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Both SLE and RA are characterized by the presence of autoantibodies which play a major role in their etiopathogenesis. SLE is characterized by circulating antibodies and immune complex deposition that can trigger an inflammatory damage in organs. RA is a progressive inflammatory disease in which T cells, B cells, and pro-inflammatory cytokines play a key role in its pathophysiology.