T-Cell/B-Cell Interactions in Atherosclerosis

Atherosclerosis is a complex inflammatory disease in which the adaptive immune response plays an important role. While the overall impact of T and B cells in atherosclerosis is relatively well established, we are only beginning to understand how bidirectional T-cell/B-cell interactions can exert prominent atheroprotective and proatherogenic functions. In this review, we will focus on these T-cell/B-cell interactions and how we could use them to therapeutically target the adaptive immune response in atherosclerosis.

Non-invasive imaging in antiphospholipid syndrome to assess subclinical coronary artery disease

Antiphospholipid antibody syndrome (usually named antiphospholipid syndrome, APS) is an autoimmune disorder seen mainly in young people. Clinically, APS is described by pregnancy complications and/or a hypercoagulable state, including the venous or arterial vasculature, and strongly related to antiphospholipid antibodies. Although several cardiac manifestations have been involved with APS, and accelerated atherosclerosis is present in this condition, little is known about cardiovascular (CV) risk and the relation between APS. Several studies have used imaging markers to associate them with the main clinical features of patients with APS and the probability of having subclinical atherosclerosis. However, it has not yet been established which markers are most related to the risk of developing CV diseases (CVD) in these patients. In this narrative review, we focus on non-invasive imaging markers that can predict CVD, including carotid intima-media thickness and carotid plaques assessed by carotid ultrasonography or coronary artery calcium score, which usually by computed tomography. We also examine the evidence about vascular function markers used in APS, such as arterial flow-mediated brachial dilation and artery stiffness measured by the velocity of the pulse wave. We present the current status of non-invasive imaging markers, which suggest the existence of subclinical atherosclerosis in patients with APS. However, new prospective research is required to identify the predictive value of these findings and their modification by current treatments for APS.

Antibodies in action: the role of humoral immunity in the fight against atherosclerosis

The sequestering of oxidation-modified low-density lipoprotein by macrophages results in the accumulation of fatty deposits within the walls of arteries. Necrosis of these cells causes a release of intercellular epitopes and the activation of the adaptive immune system, which we predict leads to robust autoantibody production. T cells produce cytokines that act in the plaque environment and further stimulate B cell antibody production. B cells in atherosclerosis meanwhile have a mixed role based on subclass. The current model is that B-1 cells produce protective IgM antibodies in response to oxidation-specific epitopes that work to control plaque formation, while follicular B-2 cells produce class-switched antibodies (IgG, IgA, and IgE) which exacerbate the disease. Over the course of this review, we discuss further the validation of these protective antibodies while evaluating the current dogma regarding class-switched antibodies in atherosclerosis. There are several contradictory findings regarding the involvement of class-switched antibodies in the disease. We hypothesize that this is due to antigen-specificity, and not simply isotype, being important, and that a closer evaluation of these antibodies' targets should be conducted. We propose that specific antibodies may have therapeutical potential in preventing and controlling plaque development within a clinical setting.

Cardiovascular Involvement in Sjögren’s Syndrome

Sjögren Syndrome (SS) seems to be associated with a greater “overall risk” of cardiovascular (CV) and cerebrovascular events. Although not conventionally considered a feature of the disease, CV events represent a major burden in SS patients. CV risk is the consequence of a complex combination of multiple factors, including traditional risk factors and disease-related mechanisms. A complex relationships between disease-related features, endothelial dysfunction and traditional risk factor has been suggested. Several drugs are available for treating the systemic manifestations of SS, however they have shown positive effects on different outcomes of the disease, but until today the data on the role of these drugs on CV events are scarse. Given these data, the aim of this review was to evaluate the risk of CV risk in primary SS and the effect of the drugs on this manifestation.

Assessment and management of the heightened risk for atherosclerotic cardiovascular events in patients with lupus erythematosus or dermatomyositis

For patients with lupus erythematosus (LE) or dermatomyositis (DM), there is an urgent need to address a heightened risk of clinical events, chiefly heart attacks and strokes, caused by atherosclerotic cardiovascular disease (ASCVD). Patients with LE or DM frequently exhibit high levels of conventional risk factors for ASCVD events, particularly dyslipoproteinemia and hypertension; an amplified burden of atherosclerotic plaques; and increased age- and sex-adjusted rates of ASCVD events compared with the general population. The rate of ASCVD events exceeds what would be expected from conventional risk factors, suggesting that disease-specific autoimmune processes exacerbate specific, known pathogenic steps in atherosclerosis. Importantly, despite their heightened risk, patients with LE or DM are often undertreated for known causative agents and exacerbators of ASCVD. Herein, we propose an approach to assess and manage the heightened risk of ASCVD events in patients with LE or DM. Our approach is modeled in large part on established approaches to patients with diabetes mellitus or stage 3 or 4 chronic kidney disease, which are well-studied conditions that also show heightened risk for ASCVD events and have been explicitly incorporated into standard clinical guidelines for ASCVD. Based on the available evidence, we conclude that patients with LE or DM require earlier and more aggressive screening and management of ASCVD. We suggest that physicians consider implementing multipliers of conventional risk calculators to trigger earlier initiation of lifestyle modifications and medical therapies in primary prevention of ASCVD events, employ vascular imaging to quantify the burden of subclinical plaques, and treat to lower lipid targets using statins and newer therapies, such as PCSK9 inhibitors, that decrease ASCVD events in nonautoimmune cohorts. More clinical vigilance is needed regarding surveillance, prevention, risk modification, and treatment of dyslipidemias, hypertension, and smoking in patients with LE or DM. All of these goals are achievable.

Anti-phospholipid antibody prevalence and association with subclinical atherosclerosis and atherothrombosis in the general population

BACKGROUND

There is no agreement on the prevalence of anti-phospholipid antibodies (aPLs) and the correlation with atherosclerosis and cardiovascular (CV) events in the general population.

METHODS

We performed a cross-sectional study on 1712 randomly enrolled subjects from a Northern Italian city to investigate the presence of aPLs and the association with subclinical atherosclerosis (using the carotid artery intima media thickness measured as inter-adventitia common carotid artery diameters - ICCAD) and retrospectively collected CV factors and events (i.e. acute myocardial infarction, stroke, and peripheral obliterans arterial vasculopathy) using physician-assisted questionnaires. We tested serum IgG, IgM, and IgA anti-cardiolipin, anti-beta2glycoprotein I (aGPI), and anti-phosphatidylserine-prothrombin antibodies.

RESULTS

Positive aPLs were found in 15.1% of the subjects, with no differences between sex but with higher rates in older subjects. Carotid subclinical atherosclerosis was more frequent in aPL positive subjects; more specifically, aGPI IgA were associated with higher ICCAD average (adjusted beta 0.51, 95% confidence interval (CI)0.17-0.84; p = 0.003). A positive history of CV events was also more frequent in aPL positive subjects (odds ratio (OR) 1.67, 95%CI 1.08-2.54; p = 0.012), particularly peripheral obliterans arterial vasculopathy (OR 2.02; 95%CI 1.14-3.57; p = 0.015). Among subjects with a Framingham risk score >20, and/or diabetes, and/or body mass index >35 kg/m², aPL positivity was associated to the highest risk of CV events (OR 2.52, 95%CI 1.24-5.11; p = 0.011).

CONCLUSIONS

APL prevalence in the general population is higher than previously reported. CV events and subclinical atherosclerosis are more frequent in the presence of aPL, particularly when a high CV risk coexists.

Atherosclerosis and autoimmunity: a growing relationship

Atherosclerosis is regarded as one of the leading causes of mortality and morbidity in the world. Nowadays, it seems that atherosclerosis cannot be defined merely through the Framingham traditional risk factors and that autoimmunity settings exert a remarkable role in its mechanobiology. Individuals with autoimmune disorders show enhanced occurrence of cardiovascular complications and subclinical atherosclerosis. The mechanisms underlying the atherosclerosis in disorders like rheumatoid arthritis, systemic lupus erythematosus, antiphospholipid syndrome, systemic sclerosis and Sjögren's syndrome, seem to be the classical risk factors. However, chronic inflammatory processes and abnormal immune function may also be involved in atherosclerosis development. Autoantigens, autoantibodies, infectious agents and pro-inflammatory mediators exert a role in that process. Being armed with the mechanisms underlying autoimmunity in the etiopathogenesis of atherosclerosis in rheumatic autoimmune disorders and the shared etiologic pathway may result in substantial developing therapeutics for these patients.

Lupus in Baltimore: evidence-based ‘clinical pearls’ from the Hopkins Lupus Cohort

The Hopkins Lupus Cohort is supported by RO1 AR 43727 and by the Outpatient General Clinical Research Center M01-RR00052. Received 6 June 2005; accepted 23 June 2005 The Hopkins Lupus Cohort is a prospective longitudinal study of lupus activity, organ damage, and quality of life in SLE patients. It is balanced between Caucasian and African-American SLE patients. This review highlights major findings from the cohort with implications for clinical care.

The Increase of Blood Anticardiolipin Antibody Depends on the Underlying Etiology in Cerebral Ischemia

Although anticardiolipin antibody (aCL) has been suggested to be a potent risk factor for thrombosis and atherosclerosis in multiple arterial beds, conflicting results exist between aCL and cerebral ischemia in the general stroke population. To elucidate if this discrepancy relates to the heterogeneity of underlying etiologies, the blood beta2-glycoprotein I dependent-aCL in 432 Taiwanese adults was examined. The associated cerebral ischemia in these patients was classified into five subtypes according to the cause of cerebral ischemia. The results were compared with those in 100 healthy controls. A definite increase of aCL-IgG isotype was found in 41 patients (9.35%) and four controls (4.0%). The relative risk was 2.52. The frequency of increased aCL-IgG was 12.2%, 12.8%, 8.8%, 3.9%, and 3.5% in patients with large-artery atherosclerotic disease, stroke of unknown etiology, small-artery occlusive disease, cardioembolism, and stroke of other known etiology, respectively. Only patients with large-artery atherosclerotic disease (p<0.025) and stroke of unknown etiology (p<0.05) had higher frequencies of increased aCL than those in control subjects. The frequencies of abnormal results of activated partial thromboplastin time, antinuclear factor, Coombs’ test, and venereal disease research laboratory were 2.84%, 1.22%, 1.02%, and 1.34% in these 41 patients, respectively. Accordingly, aCL-IgG selectively increases in patients with large-artery atherosclerosis and stroke of unknown etiology, reflecting selective activation of humoral immunity for aCL in the pathogenesis of cerebral ischemia.

The Increase of Blood Anticardiolipin Antibody Depends on the Underlying Etiology in Cerebral Ischemia

Although anticardiolipin antibody (aCL) has been suggested to be a potent risk factor for thrombosis and atherosclerosis in multiple arterial beds, conflicting results still exist between aCL and cerebral ischemia in the general stroke population. To elucidate if this discrepancy relates to the heterogeneity of underlying etiologies, blood beta2-glycoprotein I dependent-aCL was evaluated in 432 Taiwanese adults associated with cerebral ischemia who were classified into five subtypes according to their causes of cerebral ischemia. The results were compared with those in 100 healthy controls. A definite increase of aCL-IgG isotype was found in 41 patients (9.35%) and four controls (4.0%). The relative risk was 2.52. The frequency of increased aCL-IgG was 12.2%, 12.8%, 8.8%, 3.9%, and 3.5% in patients with large-artery atherosclerotic disease, stroke of unknown etiology, small-artery occlusive disease, cardioembolism, and stroke of other known etiology, respectively. Only patient with large-artery atherosclerotic disease (p<0.025) and stroke of unknown etiology (p<0.05) had a higher frequency of increased aCL than control. The frequencies of abnormal result of activated partial thromboplastin time, antinuclear factor, Coombs’ test, and venereal disease research laboratory were 2.84%, 1.22%, 1.02%, and 1.34% in these 41 patients, respectively. Accordingly, aCL-IgG selectively increases in patients with large-artery atherosclerosis and stroke of unknown etiology, reflecting selective activation of humoral immunity for aCL in the pathogenesis of cerebral ischemia.

Pathogenetic potential of antiphospholipid antibodies

Antiphospholipid antibodies are autoantibodies that recognize phospholipid-binding proteins such as beta2 glycoprotein (beta2GP)-I, prothrombin or annexins. These antibodies have been associated with arterial or venous thrombotic events and pregnancy morbidity. The molecular mechanisms responsible for the pathogenetic potential of these antibodies include: resistance to activated protein C, acquired Factor XII deficiency resulting in suppression of intrinsic fibrinolytic activity, activation of endothelial cells through the nuclear factor kappaB pathway leading to tissue factor upregulation, adhesion molecule and cytokine expression and activation of platelets. Opposite effects, such as the potentiation of the inhibitory action of beta2GPI on the activation of Factor XI, make the dynamics of the interaction of these antibodies with the coagulation system rather complex. Many of the above functions can be mediated by signaling through molecules of the tumor necrosis factor receptor family, such as CD40, which is recognized by purified anti-beta2GPI antibodies.

Coronary involvement in Takayasu's arteritis

Coronary involvement may appear in up to a third of patients with Takayasu's arteritis. This affliction may have a dominant impact on the clinical manifestations of the patient. Occlusion of the ostia of the left main coronary artery and of proximal segments of the coronary arteries is the most frequent finding of the coronary vasculature in patients with Takayasu's arteritis. Beyond the vasculitic process enhanced atherosclerosis has a significant and detrimental impact on the disease development. Revascularizations are often unsuccessful particularly when the inflammatory disease is not under satisfactory control. New techniques have been developed in order to use vessels that have not been damaged by the disease as grafts.

Thickened carotid artery intima-media in rheumatoid arthritis is associated with elevated anticardiolipin antibodies

Antiphospholipid and anti-oxidized LDL (anti-oxLDL) antibodies are associated with thrombosis and atherosclerosis. Rheumatoid arthritis (RA) is characterized by excess atherosclerosis and cardiovascular diseases. Our aim was to determine whether antiphospholipid and anti-oxLDL antibodies are associated with early atherosclerotic changes in RA. The levels of IgG and IgM anticardiolipin, IgG and IgM anti-beta-2-glycoprotein-I and anti-oxLDL autoantibodies have been evaluated in 82 patients having RA. Carotid artery intima-media thickness (IMT) was measured in the carotid arteries in the common carotid, bifurcation and internal carotid arteries. Elevated levels of IgG anticardiolipin antibodies were detected in 17 of 82 (21%) RA patients, including 7 with medium-to-high levels considered being clinically relevant. These patients had significantly elevated mean carotid and carotid bifurcation IMT compared with RA patients without elevated anticardiolipin. No such association was found regarding other autoantibodies tested. Anticardiolipin antibodies are prevalent in RA and are associated with early atherosclerotic changes, supporting a rational for measuring them in RA, and upon detection treat the patients in order to decrease chances of atherosclerosis progression and thrombosis.

Inflammation and Accelerated Atherosclerosis: Basic Mechanisms

This article summarizes knowledge of the pathogenic mechanisms in autoimmune rheumatic diseases as risk factors for accelerated atherosclerosis. The studies described support a role for immunologic-inflammatory mechanisms in the pathogenesis of atherosclerosis. This immunologic-inflammatory state is evident in many autoimmune diseases, but also in the general population lacking an overt autoimmune disease. The ability to immunomodulate atherosclerosis (currently only experimental) should lead to future research into the mechanisms and treatment of atherosclerosis, the leading cause of death in the Western world.

Antiphospholipid antibodies in patients with lupus nephritis

The aim of this study was to compare the prevalence of anticardiolipin antibodies with other types of antiphospholipid antibodies (aPL) (antiphosphatidylserine--aPS, antiphosphatidylinositol--aPI, antiphosphatidylethanolamine--aPE) in patients with lupus nephritis and to find if the examination of a panel of various aPL is valuable for further diagnosis of patients. Additionally we determined the levels of autoantibodies against beta2-glycoprotein I (beta2GPI) and oxidized low-density lipoprotein (anti-oxLDL) and also investigated the relationship between antibodies against beta2GPI and oxLDL, which were assessed by ELISA methods. Twenty-two patients with lupus nephritis were studied. The control group consisted of 62 healthy blood donors. A statistically significant higher occurrence of all aPLs in the patients with lupus nephritis in comparison to the control group was found. The prevalence of polyspecific antibodies, which reacted with at least two various phospholipids, was 82% in the group of SLE patients. Significantly higher levels of IgG anti-beta2GPI in the sera of SLE patients (p = 0.0003) was detected. The levels of anti-oxLDL in the sera of the patients group did not differ significantly from the control one. Some positive samples for anti-beta2GPI and negative for aCL or anti-oxLDL and vice versa were found. It ca be concluded that the production of aPL including anti-beta2GPI and anti-oxLDL in the lupus nephritis patients is higher in comparison with healthy blood donors. We assume that the estimation of various types of aPL may be important in the selection of the group patients with renal diseases. The synthesis of aPL can reflect the spreading of the autoimmune response for several antigens modified on the vessel wall.

Peripheral vascular disease in antiphospholipid syndrome

Atherosclerosis has been considered an inflammatory disease based on the finding that atherosclerotic lesion contains activated T lymphocytes reacting with oxidized low-density lipoproteins (oxLDL) and heat shock proteins (HSP); it also contains autoantigens like beta2GPI, a target of antibodies occurring in an immune-mediated thrombophilia called antiphospholipid syndrome (APS). Further support to this hypothesis comes from the cross-reactivity, which occurs between antiphospholipid antibodies (aPL) and antibodies to oxLDL. Animal experiments have shown that aPL are associated with atheroma. In addition, accelerated atherosclerosis has been detected in patients with a prototype systemic autoimmune disease, such as systemic lupus erythematosus (SLE). However, the association of APS or aPL with atherosclerosis is a matter of debate due to the small numbers of patients studied, and the fact that traditional risk factors for atherosclerosis coexist. The prevalence of APS ranges from 1.7% to 6%, and that of aPL reaches to 14% among patients with peripheral vascular disease defined on the basis of clinical outcomes. On the other hand, the prevalence of asymptomatic atherosclerosis, defined in terms of plaques in ultrasonography, reaches to 15% of patients with APS compared to 9% of SLE patients and 3% of normal controls. Among SLE patients with aPL, the prevalence of plaques ranges from 6% in premenopausal women to 31% in unselected patients. Less than 10% of APS patients express premature atherosclerosis in the absence of other risk factors. Which APS patient will develop atherosclerosis is unpredictable.

The lupus anticoagulant is a risk factor for myocardial infarction (but not atherosclerosis): Hopkins Lupus Cohort

Antiphospholipid antibodies, both anticardiolipin and lupus anticoagulant, are common in SLE. We asked, in a prospective cohort, whether these antibodies are predictive of atherosclerosis and/or coronary artery disease.

METHODS

Three hundred eighty patients, 92% female, 49% Caucasian, 51% African-American, mean age 46.4+/-12.3 years are followed quarterly, with assessment of both anticardiolipin and lupus anticoagulant (dRVVT). These patients underwent both helical CT and carotid duplex.

RESULTS

Both the lupus anticoagulant and anticardiolipin are predictive of later venous or arterial thrombosis. Twenty years after diagnosis, SLE patients with the lupus anticoagulant (LA) have a 50% chance of a venous thrombotic event. Myocardial infarction occurs significantly more often in those with LA 22% vs. 9%, p=0.04. Neither anticardiolipin nor LA are associated with carotid IMT, carotid plaque, nor coronary calcium by helical CT. In aCL positive patients carotid IMT was 0.57+/-0.01 vs. 0.58+/-0.01 in aCL negative patients (p=NS); carotid plaque 0.47+/-0.13 vs. 0.32+/-0.10 (p=NS); and coronary calcium 65.4+/-37.4 vs. 65.4+/-30.2 (p=NS). In LA positive patients, carotid IMT was 0.59+/-0.03 vs. 0.59+/-0.02 in LA negative patients (p=NS); carotid plaque 0.07+/-0.02 (SE) vs. 0.80+/-0.02 (SE) (p=0.06); and coronary calcium 28.1+/-3.7 (SE) vs. 85.7+/-2.6 (SE) (p=NS).

CONCLUSION

Antiphospholipid antibodies are not associated with subclinical atherosclerosis (carotid IMR, carotid plaque, helical CT coronary calcium), but are associated with actual thrombotic sequelae (myocardial infarction).

Antiphospholipid antibodies: are they pro-atherogenic or an epiphenomenon of atherosclerosis?

Antiphospholipid antibodies are the hallmark of the antiphospholipid syndrome which is characterized by thrombosis. There are currently data supporting an association between these autoantibodies and atherosclerosis as well. Human studies suggest that anti-cardiolipin and anti-beta2-glycoprotein-I antibodies are elevated in patients having coronary artery disease compared with controls. Anti-cardiolipin antibodies are also associated with typical chest pain, significant coronary artery stenosis on angiography and prediction of myocardial infarction. Laboratory studies and murine models support the pro-atherogenic role of these autoantibodies, as they are involved in uptake of oxidized LDL into macrophages, and immunization of mice with them results in enhanced atherosclerosis. There is some evidence that high anti-beta2-glycoprotein-I antibodies can present a risk factor for atherosclerosis, but more epidemiological data are required in order to confirm whether the pro-atherogenic properties of anti-phospholipid antibodies signifies an independent risk factor for atherosclerosis and its complications.

The antiphospholipid syndrome

The antiphospholipid (aPL) antibody syndrome is an autoimmune condition in which vascular thrombosis and/or recurrent pregnancy losses occur in patients with laboratory evidence for antibodies that bind to phospholipids. There have been significant advances in the recognition of the role of phospholipid-binding cofactors, primarily beta2GPI, as the true immunologic targets of the antibodies. Recent evidence suggests that the antibodies disrupt phospholipid-dependent anticoagulant mechanisms and/or that aPL antibodies induce the expression of procoagulant and proadhesive molecules on endothelial cells. Current diagnosis is based on clinical findings and empirically derived tests, such as assays for antibodies that bind to phospholipids or putative cofactors and coagulation assays that detect inhibition of phospholipid-dependent coagulation reactions. Current treatment relies primarily on anticoagulant therapy. Research advances are expected to bring mechanistically based diagnostic tests and improved therapy that target the roots of the disease process.

[Antiphospholipid syndrome with only antiphosphatidylethanolamine antibodies: report of 20 cases]

PURPOSE

The association of antiphosphatidylethanolamine antibodies (aPE) as the only antiphospholipid antibody with antiphospholipid syndrome (APS) is discussed. The aPE was described as the sole antibody in many cases suggesting APS. aPE was not included in the Sapporo criteria for the classification of APS.

METHODS

We investigated the clinical features of 20 patients with aPE only; 17 patients had symptoms potentially related to APS (group 1) and three had other manifestations (group 2).

RESULTS

There were 15 women and five men, mean age was 35 +/- 12 years at the beginning. In group 1 (n = 17), ten patients presented arterial thrombosis, nine venous thrombosis (five had both), and six microvascular thrombosis (livedo reticularis, lacunar pathology). The aPE positivity was persistent in 13 patients. A subgroup of four patients (three women) presented arteriosclerosis with peripheral arteriopathy which started before 45 years of age. They had another atherosclerosis risk factor associated with aPE persistence. In group 2 (n = 3), there was no thrombotic event, one demyelinating pathology, one microvascular pathology, and one arterial dysplasia. The aPE positivity was never confirmed. Finally, 13 patients presented an APS with aPE only, confirmed at least 8 weeks later.

CONCLUSIONS

Our study points out that testing for aPE would be of interest for patients when symptoms were potentially related to APS, particularly when other antiphospholipid antibodies were negative. This description questions the enlargement of the APS biological criteria defined in Sapporo. The role of aPE in atherosclerosis is considered.

Are antiphospholipid antibodies an independent risk factor for atherosclerosis?

The purpose of this study was to check whether antiphospholipid antibodies (aPL) could be an independent risk factor for atherosclerosis. Eighty-five subjects were studied: 45 with primitive antiphospholipid antibody syndrome and 40 controls affected by deep vein thrombosis secondary to known causes. The two groups were homogeneous for age, sex, and risk factors for atherosclerosis. All the subjects submitted to echo-color doppler of the carotid arteries, femoral arteries, and abdominal aorta. The cases were then subdivided into three subgroups on the basis of the positivity to the three subpopulations of aPL. Results demonstrate that there is no correlation between aPL and atherosclerosis. The different positivity to aPL does not modify this conclusion.

Atherosclerosis and connective tissue diseases

Large increases in mortality related to premature atherosclerosis with coronary artery disease and stroke have been reported in patients with systemic lupus erythematosus (SLE), antiphospholipid syndrome (APLS), or rheumatoid arthritis (RA). Studies found relative risks of 5 for myocardial infarction, 6 to 10 for stroke in SLE patients, and 3.6 for cardiovascular deaths in RA patients. The main risk factors for atherosclerosis included not only the classic factors identified in epidemiological studies such as the Framingham study (advanced age, high cholesterol levels, hypertension, diabetes mellitus, and obesity), but also prolonged glucocorticoid therapy, long duration of SLE, postmenopausal status, and heart failure. SLE per se is an independent risk factor. The current pathogenic hypothesis for atherosclerosis involves an inflammatory response (erythrocyte sedimentation rate, C-reactive protein, and fibrin), autoantibodies, immune complexes (containing antibodies to phospholipids, to oxidized LDLs, and to endothelial cells), cytokine-producing activated T cells, and bacterial or viral infections responsible for an immune response against heat shock proteins (endogenous HSP60 and its equivalent, bacterial HSP65). Early risk factor intervention and effective control of inflammation should be incorporated into the management of connective tissue disease with the goal of protecting patients against atherosclerosis.

Catastrophic antiphospholipid syndrome: remission following leg amputation in 2 cases

OBJECTIVE

The antiphospholipid syndrome is characterized by venous and arterial thrombotic events that are often recurrent, thrombocytopenia, recurrent fetal loss, and elevated titers of antiphospholipid antibodies. A subtype of patients with a particularly overwhelming clinical picture has been termed catastrophic antiphospholipid syndrome (CAPS). In this report, we present 2 patients who exhibited a similar multisystem disorder associated with gangrenous changes in the lower extremities.

METHODS

Two patients with CAPS are presented, highlighting the impact of this disorder on the patients and the response to various therapeutic modalities.

RESULTS

Both patients had pulmonary, cardiac, cutaneous, and neurologic findings consistent with CAPS. In addition, they had large purulent leg ulcers associated with livedo reticularis. Amputation of the legs in each case induced remission of the systemic illness.

CONCLUSIONS

We believe that infection plays a significant role in the pathogenesis and amplification of the antiphospholipid syndrome. In certain patients, this association probably is mediated via immune mechanisms, which also enhance the genesis of atherosclerosis. After the foci of infection (suppurative leg ulcers) were removed, the underlying illness improved. These case studies provide an opportunity to study the interrelationship between several confounding factors that converge and lead to the development of this autoimmune condition.

Accelerated atheroma, antiphospholipid antibodies, and the antiphospholipid syndrome

Indirect data coming from animal studies and in vitro observations support the contention that the mere presence of antiphospholipid antibodies may be sufficient to increase atheroma development, regardless of other predisposing factors. It seems that humoral and cellular immune responses to beta 2-glycoprotein I can play an important role in mediating the increased propensity to atherosclerosis.

Induction and treatment of the antiphospholipid syndrome--lessons from animal models

The diagnosis of antiphospholipid syndrome (APS) is based on a combination of clinical and serological criteria. This review summarizes the literature regarding animal models of APS. Animal models of this syndrome help to elucidate pathogenic roles of the characteristic antiphospholipid antibodies in pregnancy morbidity, vascular thrombosis, neurologic disease and atherosclerosis. Furthermore, these models also provide measures to evaluate novel therapies for APS. These include bone-marrow transplantation, intravenous immunoglobulin, anticoagulation, interleukin-3, in addition to other therapies. Experimental induction and treatment of APS largely contributes to our understanding of the disease and to better management of its clinical characteristics.

Coronary calcium and anti-cardiolipin antibody are elevated in patients with typical chest pain

The aim of this study was to examine whether detection of coronary calcium and the autoimmune response associated with atherosclerosis, either solely or in combination, are different in patients with typical and atypical chest pain. Coronary calcium as detected by spiral computerized tomography and levels of antibodies against cardiolipin (CL), oxidized low-density lipoprotein (ox-LDL), and beta2-glycoprotein-I (beta2-GPI) were studied in patients with typical chest pain (n = 52), atypical chest pain (n = 19), or without chest pain (n = 21). Patients with typical chest pain had higher mean levels of coronary calcium (expressed as natural transformation of total coronary calcium score) compared with patients with atypical chest pain and controls (5.04 vs 3.21 and 2.75, respectively; p < 0.001). The levels of anti-CL were (mean +/- SD of optical density multiplied by 1,000): 262 +/- 140, 170 +/- 82, and 230 +/- 115 for patients with typical chest pain, atypical chest pain, and controls, respectively (p = 0.016). No significant difference was found between groups regarding anti-ox-LDL and anti-beta2-GPI autoantibody levels. In the typical chest pain group, there was a higher prevalence of high total coronary calcium scores (p = 0.03) and high anti-CL levels (p = 0.01) than in the atypical chest pain group. Eighteen of 52 patients with typical chest pain (35%) had both high calcium scores and high antibody levels, whereas none of the 19 patients (0%) who had atypical chest pain had high levels of both (p = 0.003). A combination of both coronary calcium and anti-CL was associated with higher area under the receiver operator characteristic curves than for each separately. High coronary calcium scores or high anti-CL levels are found more often in typical than in atypical chest pain patients, but a combination of high levels of both can better differentiate typical from atypical chest pain patients.

Heat shock protein 60/65, beta 2-glycoprotein I and oxidized LDL as players in murine atherosclerosis

We have made consecutive studies to prove that autoimmune factors can influence the progression of atherosclerosis in inbred and transgenic mice. C57BL/6 as well as LDL-receptor deficient mice were immunized with heat shock protein 65. LDL-RD and apolipoprotein E knockout (apoE KO) mice were immunized with human B-glycoprotein I. ApoE KO mice were immunized with oxidized LDL. In all immunized mice, a sustained humoral response to the provided antigen was elicited evident by high titers of antibodies by ELISA. A primary cellular immune response was also shown by thymidine incorporation studies employing the antigens in vitro. Immunization with hsp-65 and with beta 2-GPI served to enhance the progression atherosclerosis and led to an increase in the infiltration of CD3 in the subendothelial regions of the early plaques. Transfer of hsp-65 and beta 2-GPI reactive lymphocytes to syngenic mice led to enhancement of fatty streak formation. However, immunization with homologous oxLDL in apoE KO mice led to attenuation of lesion progression concomitant with the production of anti-oxLDL antibodies. Thus, autoimmune factors appear to influence early artherosclerosis progression in mice. If proven in humans these antigen specific responses may be harnessed for selective immunomodulation of the atherosclerotic plaque.

Autoimmune antiphospholipid antibodies and cryoglobulinemia

In addition to their role in the thrombotic manifestations of the antiphospholipid syndrome (APS), autoimmune antiphospholipid (aPL) antibodies may also be responsible for direct injury to the blood vessel wall, although the mechanism is unclear. Cryoglobulinemia has been reported infrequently in patients with APS and is one potential means of blood vessel injury. The aim of the present study was to determine if autoimmune aPL antibodies and their target antigens contribute to the formation of cryoprecipitates. Cryoglobulins were identified and isolated from 5 of 8 patients with autoimmune aPL antibodies. Using identical concentrations of immunoglobulins isolated from matched sera and washed cryoprecipitates there was a significant enrichment (at least 100%) of aCL antibodies in the cryoprecipitates from 4 of 5 patients. This involved IgG, IgM and IgA isotypes with specificity for both beta2-glycoprotein I (GPI) and prothrombin (PT). The target antigens were detected in cryoprecipitates from all 5 aPL positive patients and in cryoprecipitates from 3 controls. These results suggest that anti-beta2-GPI and anti-PT antibodies in association with their target antigens are integrally involved in the formation of cryoprecipitates in patients with autoimmune aPL antibodies and provide insight into a potential mechanism for blood vessel injury.

Lipids, cardiovascular disease and atherosclerosis in systemic lupus erythematosus

Systemic lupus erythematosus is commonly associated with early onset cardiovascular disease and is often associated with hyperlipidaemia. This review examines the evidence for an increased prevalence of both CHD and hyperlipidaemia in SLE and mechanisms by which autoimmunity in SLE could accelerate the progression of atheroma. It postulates how lipid lowering therapies used in cardiological disease might help reduce the incidence of CHD in SLE.

How accelerated atherosclerosis in SLE has changed our management of the disorder

Basic science insights along with the assessment of risk factors so clearly documented by the Canadian and Hopkins cohorts in earlier papers of this special issue have clearly led to a change in the way rheumatologists manage SLE. This review will highlight specific ways it should alter our day to day treatment of lupus patients.

Autoimmunity in atherosclerosis: lessons from experimental models

The modern view of atherosclerosis is of a chronic inflammatory disorder. In accord with this paradigm, the process of uninhibited influx of fat to the vessel wall results from an 'adequate' response to various forms of injury (i.e. turbulence, infections, modified lipoproteins). This idea has been further extended by several groups, to assume that the atherosclerotic lesion can be the target of an autoimmune mediated attack. According to this hypothesis, the site of initiation of the plaque should bear/express the target autoantigen, whereas concomitantly a respective immune response is generated in the periphery. The examples illuminating this notion are beta2GPI as a target autoantigen, HSP60/65 an oxidized-LDL. Herein we present evidence to support the involvement of autoimmune mechanisms in atherogenesis based on the experience from experimental models and human studies.

The anti-phospholipid antibody syndrome: clinical and serological aspects

The association of thromboses and/or cytopenias with anti-phospholipid antibodies (aPL), the anti-phospholipid syndrome (APS), is well recognized. The syndrome may be primary or occur within systemic lupus erythematosus (SLE). The notion of the syndrome occurring within SLE is important since patients found to have aPL may be at risk for developing APS manifestations, those who develop some manifestations may be at risk for developing others and, finally, SLE patients with this syndrome may need special treatment. There are subtle differences between the primary and the secondary forms, mostly due to the frequently higher and more persistent autoantibody levels in the primary and the influence of lupus in the secondary. These syndromes may be related to various antigen/antibody systems in which phospholipids participate either directly or through their effect on the proteins that bind them. Similar clinical manifestations also occur in patients who have serum antibodies to such proteins (e.g. beta2-glycoprotein-I) in the absence of phospholipid. Some of these antibodies may even be more important pathogenically than the antibodies against cardiolipin that were originally described. Testing for the latter is, however, still the first choice when suspecting an antiphospholipid syndrome. If this is negative in this situation, a search for the other autoantibodies is indicated.

The involvement of beta2-glycoprotein I (beta2-GPI) in human and murine atherosclerosis

Atherosclerosis is a multifactorial process, the hallmark of which is fat deposition in the vessel wall. Autoimmune factors have recently been shown to play an important role in the initiation and progression of atherosclerosis; candidate autoantigens are oxidized lipids and heat shock proteins. beta2-glycoprotein I (beta2-GPI) is a highly glycosylated plasma protein that serves as a major antigenic target for autoimmune type antiphospholipid antibodies. Its major relevant property is binding to negatively charged phospholipids/surfaces. In the set of studies presented in this paper, we provide evidence pointing towards beta2-GPI as an influential determinant in murine and human atherogenesis. Thus, immunization of transgenic atherosclerosis-prone mice (apolipoprotein E and low-density lipoprotein receptor knockouts) with human beta2-GPI results in a brisk and sustained respective response that extends to cross-react with the 'self' murine beta2-GPI. Atherosclerosis is accelerated in both strains concomitant with the infiltration of CD4 lymphocytes in the aortic sinus of the mice. When human plaques were studied, it was found that beta2-GPI resides in the subendothelial regions and co-localizes with CD4 lymphocytes. Thus, the immune response towards beta2-GPI may play an important role in atherogenesis, serving as a possible target for antigen specific therapies.

Atherosclerosis-related markers in systemic lupus erythematosus patients: the role of humoral immunity in enhanced atherogenesis

Systemic Lupus Erythematosus (SLE) patients experience premature atherosclerosis. A deranged lipid metabolism and use of immunosuppressive medications accounts partially for the accelerated process. The role of autoimmunity in atherosclerosis has recently been highlighted. Autoantigenic determinants thought to play a role in the development of atherosclerosis include: modified lipoproteins, heat shock proteins and beta2-glycoprotein I (a target of 'autoimmune' anticardiolipin antibodies). In this present work we determined autoimmune markers which may be associated with premature atherosclerotic process found in SLE patients. We have found that antibodies to oxLDL were raised in the sera of lupus patients and cross-reacted with cardiolipin and with beta2GPI. OxLDL containing immune-complexes of the IgG and IgM isotypes were both elevated in the SLE patients as compared with healthy controls. Patients with high Lipoprotein (a) concentrations (>30 mg/dl) had higher levels of IgM oxLDL-containing immune-complexes. IgM but not IgG anti-HSP-65 antibodies were elevated in the lupus patients and levels of oxLDL containing immune-complexes correlated positively with the presence of anti-HSP 65 antibodies. Lysophosphatidylcholine (LPC) is a peroxide-derivative formed during LDL oxidation, was shown to evoke a humoral response in healthy subjects. Antibodies to lysophosphatidylcholine of the IgG but not the IgM isotype were reduced in SLE patients compared with controls, suggesting it may be 'consumed' into oxLDL containing immune complexes. Therefore, SLE patients exhibit a humoral autoimmune response towards the antigenic candidates incriminated in the progression of atherosclerosis. These findings may help identify factors that are involved in accelerating atherogenesis in SLE patients.

Atherosclerosis and the antiphospholipid syndrome: a link unravelled?

Atherosclerosis is a multifactorial disease that involves the arterial system. Recent data suggest that immune and autoimmune factors play a dominant role in mediating the progression of atherosclerosis. Among these factors, humoral response to modified forms of LDL and heat-shock proteins has been shown to be influential. The antiphospholipid syndrome (APS) entails clinical manifestations that result from a hypercoagulable state. Antibodies to phospholipids and to beta2-glycoprotein I have been suggested to confer the tendency to thrombosis. In a set of recent studies, we have been able to show that generation of antiphospholipid antibodies in mice is associated with enhanced atherosclerosis. These findings imply that APS and atherosclerosis may share a common etiologic background, which may have direct implications for the management of both conditions.