Low levels of total cholesterol, high-density lipoprotein, and apolipoprotein A1 in association with anticardiolipin antibodies in patients with systemic lupus erythematosus

Exploring the Association Between Systemic Lupus Erythematosus and High-Density Lipoproteins: A Systematic Review and Meta-Analysis

OBJECTIVE

Systemic lupus erythematosus (SLE) is an autoimmune disease with inflammation as a critical feature. Recently, high-density lipoprotein cholesterol (HDLc) have been evidenced to have anti-inflammatory effects, suggesting a potential link between HDL and SLE that needs to be thoroughly studied. The aim was to explore the association between SLE and HDLc through a systematic review with meta-analysis.

METHODS

A systematic review with meta-analysis was conducted to assess mean differences in HDL levels between patients with SLE and healthy controls. Both qualitative and quantitative syntheses were performed, including an assessment of heterogeneity using I2, a publication bias evaluation, a methodologic quality assessment, and a forest plot under a random effects model. Subgroup analyses were conducted based on disease activity and the report of corticosteroid dosage.

RESULTS

A total of 53 studies were included in the qualitative synthesis, and 35 studies were included in the quantitative synthesis, comprising 3,002 patients with SLE and 2,123 healthy controls. Mean HDL levels were found to be lower in patients with SLE as follows: in the meta-analysis including all articles -6.55 (95% confidence interval [CI] -8.77 to -4.33); in patients with mild disease activity -5.46 (95% CI -8.26 to -2.65); in patients with moderate or severe disease activity -9.42 (95% CI -15.49 to -3.34); in patients using corticosteroids -5.32 (95% CI -10.35 to -0.29); and in studies with excellent methodologic quality -8.71 (95% CI -12.38 to -5.03).

CONCLUSION

HDL levels appear to be quantitatively altered in patients with SLE, suggesting a potential contribution to immune dysregulation, highlighting the importance of HDL in autoimmune diseases.

Lipid profile alterations in non-infectious uveitis: correlation with quantitative optical coherence tomography angiography parameters

BACKGROUND/AIMS

Lipid profiles have been changed in numerous chronic conditions. The impact of uveitis on lipid metabolism remains unclear.

METHODS

This is a cross-sectional study included 416 patients with non-infectious uveitis (NIU) and 416 healthy subjects. Standard techniques were used to measure total cholesterol (TC), triglycerides (TG), high-density lipoprotein-cholesterol (HDLc), low-density lipoprotein-cholesterol (LDLc) levels. Quantitative optical coherence tomography angiography (OCTA) parameters were obtained from 500 eyes in each group. Correlation analysis examined the relationship between lipid profile and OCTA parameters.

RESULTS

Patients with NIU exhibited significantly elevated TC, TG and LDLc levels compared with controls (p=0.003; p<0.001; p<0.001, respectively). Subgroup analysis revealed that HDLc was significantly lower in Behçet's disease (p=0.024) compared with controls. Vascular density (VD) in the superficial capillary plexus (SCP), deep capillary plexus (DCP), choriocapillaris and optic disk were significantly decreased in NIU eyes (p<0.05, respectively) compared with controls. HDLc exhibited a significant negative correlation with VDs in the whole and parafovea SCP (r=-0.489, p=0.008; r=-0.480, p=0.0026, respectively), while LDLc showed a significant positive correlation with VDs in the whole and parafovea DCP in NIU patients (r=0.576, p=0.032; r=0.267, p=0.034, respectively).

CONCLUSIONS

The lipid profile is altered in NIU, and there are correlations between HDLc and LDLc levels and VD as measured by OCTA. Lipid profile analysis may offer valuable insights into evaluating vascular and metabolic aspects of NIU.

Anti-apolipoprotein A-1 autoantibodies correlate with disease activity in systemic lupus erythematosus

OBJECTIVES

Apolipoprotein A-1 (ApoA-1) is a protein fraction of the high-density lipoproteins with anti-inflammatory and antioxidant properties that play a major role in reverse cholesterol transport. The presence of anti-ApoA-1 IgG has been reported in SLE to be variably associated with disease activity or cardiovascular events (CVEs). We assessed the clinical performance of anti-ApoA-1 IgG and of antibodies directed against its immunodominant F3L1 peptide (F3L1 IgG) in a well-characterized Swiss SLE cohort study.

METHODS

A total of 354 biological samples and interviews from 176 individuals were studied. SLEDAI, clinical characteristics, anamnestic CVEs and therapy details were recorded. Sera were tested for the presence of anti-ApoA-1 IgG, anti-F3L1 IgG, anti-dsDNA IgG and aPL.

RESULTS

Anti-ApoA-1 and anti-F3L1 IgG positivity was associated with higher SLEDAI, mostly due to concomitant positivity of dsDNA IgG and low complement. Variations in time of anti-ApoA-1 IgG correlated positively with variations of anti-dsDNA IgG and inversely to variations of C3 levels. No cross-reactivity was found between anti-ApoA-1 and anti-dsDNA IgG. Positivity for anti-Apo-A1 IgG was more frequent in individuals receiving 10 mg/day or more of prednisone. We did not find any significant association between anti-ApoA-1 IgG positivity and CVEs.

CONCLUSION

Anti-ApoA-1 and anti-F3L1 IgG in SLE correlate strongly with laboratory markers of activity, particularly with the presence and titre of dsDNA IgG. These results confirm and extend previous findings and support the use of anti-ApoA1 IgG in the clinical setting. Their role in CVEs deserves further investigation.

Humoral Immunity Against HDL Particle: A New Perspective in Cardiovascular Diseases?

BACKGROUND

Autoimmune diseases are closely associated with cardiovascular diseases (CVD). Over the last decades, the comprehension of atherosclerosis, the principal initiator of CVD, evolved from a lipidcentered disease to a predominant inflammatory and immune response-driven disease displaying features of autoimmunity against a broad range of auto-antigens, including lipoproteins. Among them, high density lipoproteins (HDL) are important actors of cholesterol transport and bear several anti-atherogenic properties, raising a growing interest as therapeutic targets to decrease atherosclerosis and CVD burden, with nevertheless rather disappointing results so far. Reflecting HDL composition complexity, autoimmune responses and autoantibodies against various HDL components have been reported.

RESULTS

In this review, we addressed the important complexity of humoral autoimmunity towards HDL and particularly how this autoimmune response could help improving our understanding of HDL biological implication in atherosclerosis and CVD. We also discussed several issues related to specific HDL autoantibody subclasses characteristics, including etiology, prognosis and pathological mechanisms according to Rose criteria.

CONCLUSION

Finally, we addressed the possible clinical value of using these antibodies not only as potential biomarkers of atherogenesis and CVD, but also as a factor potentially mitigating the benefit of HDL-raising therapies.

Dyslipidemia Might Be Associated with an Increased Risk of Osteoarthritis

Background

According to several studies, the autoimmune response may lead to osteoarthritis and dyslipidemia and may affect the homeostasis of the human body's internal environment and then cause its own immune regulation. Consequently, the risk of osteoarthritis might be increased by dyslipidemia, but this association is not universally acknowledged. Therefore, a systematic review and meta-analysis was conducted to study the relationship between dyslipidemia and the risk of osteoarthritis.

Methods

In this study, PubMed, EMBASE, and the ISI Web of Science were used to identify related studies published before July 2018. The relationship between dyslipidemia and the risk of osteoarthritis was evaluated on the basis of relative risk (RR) values and the corresponding 95% confidence intervals (CIs). To further investigate this relationship, we also employed the random effects model proposed by DerSimonian and Laird.

Results

A total of nine studies were included to study the effect of dyslipidemia on the risk of osteoarthritis, including four cohort, three case-control, and two cross-sectional studies. Among these studies, six stated data for knee osteoarthritis, two reported on hand osteoarthritis, and one reported on hip osteoarthritis. A total of 53,955 participants were included in the meta-analysis, comprising 22,501 patients with OA (19,733 hand OA, 2,679 knee OA, and 89 hip OA). Based on the meta-analysis of case-control and cross-sectional studies, osteoarthritis was clearly higher in those with dyslipidemia compared to those who did not suffer from dyslipidemia (case-control: OR = 1.37; 95%CI = 1.27–1.46; cross-sectional: OR = 1.33; 95%CI = 1.21-1.46). In addition, the meta-analysis of cohort studies did not present any relationship between dyslipidemia and OA (RR = 1.00; 95%CI = 0.85–1.14).

Conclusions

Even though our meta-analysis of case-control and cross-sectional studies suggested a strong relationship between dyslipidemia and osteoarthritis; this relationship was not validated by our meta-analysis of only cohort studies. As a result, further investigation needs to be conducted on the relationship between dyslipidemia and osteoarthritis, considering the significant public health relevance of the topic.

Inflammation and the pathogenesis of atherosclerosis in systemic lupus erythematosus

Atherosclerosis is a complicated inflammatory process characterized by the interactions of numerous different moieties including lipids, enzymes, endothelial cells, cytokines, chemokines, leukocytes, adhesion molecules, complement and antibodies. As in the pathogenesis of many lupus disease processes, the increased risk of atherosclerosis seen in systemic lupus erythematosus (SLE) is likely due to the complex interplay of many of these inflammatory mediators. Expanding our understanding of the pathogenesis of atherosclerosis in SLE is critical if we are to improve the quality of care and reduce mortality in this vulnerable population.

Risk Factors for Recurrent Thrombosis: Prospective Study of a Cohort of Japanese Systemic Lupus Erythematosus

Not only antiphospholipid antibodies (aPLs) but also other factors should be considered in assessing the risk of thrombosis development in patients with systemic lupus erythematosus (SLE) and antiphospholipid antibodies (aPLs). The kinds of risk factors, including past history of thrombotic event (PHTE), hypertension, hypercholesterolemia, diabetes mellitus (DM), obesity, and smoking, in conjunction with aPLs, that contribute to the development of new thrombotic events in patients with SLE and aPLs were studied prospectively over a 5-year observation period. One-hundred and sixty-six Japanese patients with SLE (55 patients with aPLs and 111 patients without aPLs) were examined and followed up for 5 years. Five major risk factors for ischemic coronary disease and stroke according to the Framingham heart cohort study were evaluated objectively in these patients. A significant difference was seen for 4 factors: past history of thrombotic event (PHTE; odds ratio: 101.93; 95% confidence interval: 12.29-845.22; p<0.0001), hypertension (odds ratio: 8.87; 95% CI: 2.58-30.53; p<0.001), DM (odds ratio: 5.42; 95% CI: 1.44-20.46; p<0.05), and lupus anticoagulant (LAC; odds ratio: 47.41; 95% CI: 5.88-382.03, p<0.0001) as aPLs, when the incidence of these risk factors was compared between patients with and without new thrombotic events. Furthermore, PHTE (odds ratio: 30.19, 95% CI: 1.33-683.13), hypertension (odds ratio: 15.44; 95% CI: 1.77-134.80), and LAC (odds ratio: 14.11; 95% CI: 0.48-412.42) showed higher odds ratios than DM (odds ratio: 11.53; 95% CI: 0.83-159.94) on multivariate logistic analysis as well as analysis of the combination of risk factors, suggesting that these are important risk factors for the development of new thrombotic events in patients with SLE and aPLs.

The prevalence of dyslipoproteinemia in Thai patients with systemic lupus erythematosus

Fasting blood samples taken from 93 pairs of outpatient systemic lupus erythematosus (SLE) women and matched controls were assessed for total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL)- and low-density lipoprotein (LDL)-cholesterol. The demographic data, clinical manifestations, Mexican-SLE Disease Activity Index (MEX-SLEDAI), Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) damage index and medication prescribed in the SLE patients were reviewed. A significant elevation of TG levels was observed in the SLE patients compared to controls (mean ±SD 113.3 ±59.5 versus 77.7 ±45.7 mg/dL, P < 0.001). The HDL-c level was also significantly lower in SLE patients than controls (mean ±SD 49.7 ±12.7 versus 65.0 ±14.8 mg/dL, P < 0.001). The percentage of samples with low HDL-c (<35 mg/dL) was higher in the SLE group (9.7%) than controls (0%; P = 0.002). The LDL-c and TC levels were comparable in both groups. The use of antimalarial drugs was negatively associated with TC (OR 0.22, 95%CI 0.08-0.61) and LDL-c levels (OR 0.27, 95%CI 0.09-0.80). The increased prevalence of dyslipoproteinemia in SLE patients in this report has confirmed the results of previous studies and emphasized the importance of controlling this modifiable cardiovascular risk factor by the combination of lifestyle modification and medical treatments.

Dyslipidemia in systemic lupus erythematosus: just another comorbidity?

OBJECTIVE

Among traditional atherosclerotic risk factors, dyslipidemia is believed to decisively affect the long-term prognosis of lupus patients, not only with regard to cardiovascular events but also by influencing other manifestations, such as lupus nephritis. The aim of this study was to review the epidemiology, pathogenesis, evidence for its impact on atherosclerosis manifestations and management of dyslipidemia in lupus patients.

METHODS

English-restricted MEDLINE database search (Medical Subject Headings: lupus or systemic lupus erythematosus and dyslipidemia or hyperlipidemia).

RESULTS

The prevalence of dyslipidemia in systemic lupus erythematosus (SLE) ranges from 36% at diagnosis to 60% or even higher after 3 years, depending on definition. Multiple pathogenetic mechanisms are implicated, including antibodies against lipoprotein lipase and cytokines affecting the balance between pro- and anti-atherogenic lipoproteins. Dyslipidemia has a clear impact on clinical cardiovascular disease and surrogate markers for subclinical atherosclerosis. Moreover, it negatively affects end-organ damage (kidneys and brain). Treatment with statins yielded contradictory results as per minimizing cardiovascular risk.

CONCLUSIONS

Dyslipidemia is a significant comorbidity of lupus patients with multiple negative effects in the long term. Its treatment represents a modifiable risk factor; prompt and adequate treatment can minimize unnecessary burden in lupus patients, thus reducing hospitalizations and their overall morbidity and mortality.

mTOR activation is a biomarker and a central pathway to autoimmune disorders, cancer, obesity, and aging

The mechanistic target of rapamycin (mTOR) is a ubiquitous serine/threonine kinase, which plays pivotal roles in integrating growth signals on a cellular level. To support proliferation and survival under stress, two interacting complexes that harbor mTOR, mTORC1 and mTORC2, promote the transcription of genes involved in carbohydrate metabolism and lipogenesis, enhance protein translation, and inhibit autophagy. Although rapamycin was originally developed as an inhibitor of T cell proliferation for preventing organ transplant rejection, its molecular target, mTOR, has been subsequently identified as a central regulator of metabolic cues that drive lineage specification in the immune system. Owing to oxidative stress, the activation of mTORC1 has emerged as a central pathway for the pathogenesis of systemic lupus erythematosus and other autoimmune diseases. Paradoxically, mTORC1 has also been identified as a mediator of the Warburg effect that allows cell survival under hypoxia. Rapamycin and new classes of mTOR inhibitors are being developed to block not only transplant rejection and autoimmunity but also to treat obesity and various forms of cancer. Through preventing these diseases, personalized mTOR blockade holds promise to extend life span.

The problem of accelerated atherosclerosis in systemic lupus erythematosus: insights into a complex co-morbidity

Rheumatic autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus (SLE), are associated with antibodies to "self" antigens. Persons with autoimmune diseases, most notably SLE, are at increased risk for developing accelerated cardiovascular disease. The link between immune and inflammatory responses in the pathogenesis of cardiovascular disease has been firmly established; yet, despite our increasing knowledge, accelerated atherosclerosis continues to be a significant co-morbidity and cause of mortality in SLE. Recent animal models have been generated in order to identify mechanism(s) behind SLE-accelerated atherosclerosis. In addition, clinical studies have been designed to examine potential treatments options. This review will highlight data from recent studies of immunity in SLE and atherosclerosis and discuss the potential implications of these investigations.

Dyslipidaemia in rheumatological autoimmune diseases

Autoimmunity forms the basis of many rheumatological diseases, and may contribute not only to the classical clinical manifestations but also to the complications. Many of the autoimmune rheumatological diseases, including rheumatoid arthritis and systemic lupus erythematosus are associated with an excess cardiovascular morbidity and mortality. Much of this excess cardiovascular risk can be attributed to atherosclerotic disease. Atherosclerosis is a complex pathological process, with dyslipidaemia and inflammation fundamental to all stages of plaque evolution. The heightened inflammatory state seen in conjunction with many rheumatological diseases may accelerate plaque formation, both through direct effects on the arterial wall and indirectly through inflammation-mediated alterations in the lipid profile. Alongside these factors, antibodies produced as part of the autoimmune nature of these conditions may lead to alterations in the lipid profile and promote atherosclerosis. In this review, we discuss the association between several of the rheumatological autoimmune diseases and dyslipidaemia, and the potential cardiovascular impact this may confer.

Review on anti-lipoprotein lipase antibodies

Lipoprotein lipase (LPL) is a member of the lipase family, and LPL is known to hydrolyze triglyceride molecules found in lipoprotein particles. Understanding the pathogenesis of atherosclerosis in autoimmune diseases, particularly systemic lupus erythematosus (SLE), is vital to reduce morbidity and mortality of this disease. It is now recognized that SLE has a particular pattern of dyslipoproteinemia characterized by low HDL levels and increased triglycerides, which is aggravated by flare. Antilipoprotein lipase (anti-LPL) antibodies have been recently described in rheumatic diseases, mainly in SLE and systemic sclerosis (SSc). Several studies have reported a close link between antibodies, inflammation and lipoprotein levels and an increased risk of cardiovascular damage in this particular group of patients. These studies have emphasized the importance of rigorous clinical control of disease activity and prevention of cardiovascular risk factors. This review summarized the studies that have discussed the presence of anti-LPL in rheumatic diseases and other conditions and analyzed the importance of this antibody in the complex atherosclerotic process in autoimmune diseases.

Plasma from systemic lupus patients compromises cholesterol homeostasis: a potential mechanism linking autoimmunity to atherosclerotic cardiovascular disease

Atherosclerotic cardiovascular disease (ASCVD) contributes to morbidity and mortality in systemic lupus erythematosus (SLE). Immunologic derangements may disrupt cholesterol balance in vessel wall monocytes/macrophages and endothelium. We determined whether lupus plasma impacts expression of cholesterol 27-hydroxylase, an anti-atherogenic cholesterol-degrading enzyme that promotes cellular cholesterol efflux, in THP-1 human monocytes and primary human aortic endothelial cells (HAEC). THP-1 monocytes and HAEC were incubated in medium containing SLE patient plasma or apparently healthy control human plasma (CHP). SLE plasma decreased 27-hydroxylase message in THP-1 monocytes by 47 +/- 8% (p < 0.008) and in HAEC by 51 +/- 5.5% (n = 5, p < 0.001). THP-1 macrophages were incubated in 25% lupus plasma or CHP and cholesterol-loaded (50 microg ml(-1) acetylated low density lipoprotein). Lupus plasma more than doubled macrophage foam cell transformation (74 +/- 3% vs. 35 +/- 3% for CHP, n = 3, p < 0.001). Impaired cholesterol homeostasis in SLE provides further evidence of immune involvement in atherogenesis. Strategies to inhibit or reverse arterial cholesterol accumulation may benefit SLE patients.

Intestinal angina due to atherosclerosis in a 45-year-old systemic lupus erythematosus patient

We report a patient with systemic lupus erythematosus (SLE) who developed progressive emaciation and postprandial abdominal pain with a 27-year history of corticosteroid treatment. The patient was diagnosed as having intestinal angina based on computed tomography that showed severe stenosis of the superior mesenteric artery (SMA) in addition to complete occlusion of the celiac and inferior mesenteric arteries. Histopathology of the SMA and abdominal aorta showed atherosclerosis with no vasculitis or thrombus formation. Intestinal angina should actively be considered as a possible cause of recurrent abdominal pain in SLE patients, particularly in those with a long history of disease.

Dysfunctional proinflammatory high-density lipoproteins confer increased risk of atherosclerosis in women with systemic lupus erythematosus

OBJECTIVE

Women with systemic lupus erythematosus (SLE) have an increased risk of atherosclerosis. Identification of at-risk patients and the etiology underlying atherosclerosis in SLE remain elusive. The antioxidant capacity of normal high-density lipoproteins (HDLs) is lost during inflammation, and these dysfunctional HDLs might predispose individuals to atherosclerosis. The aim of this study was to determine whether dysfunctional proinflammatory HDL (piHDL) is associated with subclinical atherosclerosis in SLE.

METHODS

Carotid artery ultrasound was performed in 276 women with SLE to identify carotid plaques and measure intima-media thickness (IMT). The antioxidant function of HDL was measured as the change in oxidation of low-density lipoprotein after the addition of HDL cholesterol. Two antiinflammatory HDL components, paraoxonase 1 and apolipoprotein A-I, were also measured.

RESULTS

Among the SLE patients, 48.2% were determined to have piHDL on carotid ultrasound, while 86.7% of patients with plaque had piHDL compared with 40.7% of those without plaque (P<0.001). Patients with piHDL also had a higher IMT (P<0.001). After multivariate analysis, the only factors found to be significantly associated with plaque were the presence of piHDL (odds ratio [OR] 16.1, P<0.001), older age (OR 1.2, P<0.001), hypertension (OR 3.0, P=0.04), dyslipidemia (OR 3.4, P=0.04), and mixed racial background (OR 8.3, P=0.04). Factors associated with IMT measurements in the highest quartile were the presence of piHDL (OR 2.5, P=0.02), older age (OR 1.1, P<0.001), a higher body mass index (OR 1.07, P=0.04), a cumulative lifetime prednisone dose>or=20 gm (OR 2.9, P=0.04), and African American race (OR 8.3, P=0.001).

CONCLUSION

Dysfunctional piHDL greatly increases the risk of developing subclinical atherosclerosis in SLE. The presence of piHDL was associated with an increased prevalence of carotid plaque and with a higher IMT. Therefore, determination of piHDL may help identify patients at risk for atherosclerosis.

Body composition, lipid and lipoprotein levels in childhood‐onset systemic lupus erythematosus

OBJECTIVES

Systemic inflammation, corticosteroid therapy, and reduced physical activity are risk factors for altered body composition in patients with systemic lupus erythematosus (SLE). The aim of this study was to assess whether body composition differs between childhood-onset SLE patients and healthy controls, and to investigate the impact of disease characteristics and lifestyle factors on body fat mass, serum lipids, and lipoproteins.

METHODS

Fat mass and lean tissue mass were measured in a cross-sectional study of 68 childhood-onset SLE patients and 68 matched healthy controls by dual-energy X-ray absorptiometry (DXA). The influence of disease, glucocorticosteroids, disease activity and severity, physical activity, and dietary intake on fat mass was evaluated by multiple linear regression analysis. Serum lipid and lipoprotein levels were measured.

RESULTS

Patients had a significantly higher fat mass [mean (SD) 35.3 (10.8) vs. 30.9 (11.1)%; p = 0.024] and lower lean mass [39.7 (9.8) vs. 44.4 (1.5) kg; p = 0.003] than controls. Corticosteroid use and the disease itself were significant independent predictors of greater fat mass, while disease activity, physical activity, and dietary intake had only a minor influence. Mean high density lipoprotein (HDL) cholesterol and apolipoprotein A1 (apo A1) levels were significantly lower (p<0.001), and the mean apo B/apo A1 ratio significantly higher (p = 0.004), in patients than in controls.

CONCLUSION

Childhood-onset SLE patients had a higher fat mass and lower lean mass than healthy controls and corticosteroid use was an independent predictor of increased fat mass. Patients had a more proatherogenic lipid profile, which will contribute to the increased risk of coronary heart disease in SLE patients.

Accelerated atherosclerosis in inflammatory rheumatic diseases

Over recent years it has become clear that patients with inflammatory rheumatic diseases are at increased risk of developing atherosclerosis. The exact causes for this are probably related in part to a general adverse effect of inflammation on atherogenesis, and in part to immune mechanisms specific to individual rheumatic diseases. This review discusses proposed mechanisms of accelerated atherosclerosis, including abnormal lipid and lipoprotein profiles, oxidative stress, enhanced apoptosis, thrombophilia, immune complexes, and increased mononuclear cell infiltration of atherosclerotic lesions, and local generation of cytokines.

Anti-atherogenic and anti-inflammatory properties of high-density lipoprotein are affected by specific antibodies in systemic lupus erythematosus

OBJECTIVE

To determine whether antibodies against high-density lipoprotein (aHDL) and apolipoprotein A-I (aApo A-I) interfere with the anti-atherogenic functions of high-density lipoprotein (HDL) and relate to disease activity and damage in SLE.

METHODS

Seventy-seven SLE patients were compared with an age- and sex-frequency matched control group. Immunoglobulin G (IgG) aHDL, IgG aApoA-I, soluble vascular cell and intracellular cell adhesion molecules (VCAM-1 and ICAM-1, respectively) were measured by ELISA, paraoxonase (PON) activity by spectrophotometry, nitric oxide (NOx) metabolites by the Griess reaction, and total anti-oxidant capacity (TAC) by chemiluminescence.

RESULTS

Compared with controls, SLE patients showed higher titres of IgG aHDL (P < 0.0001) and IgG aApo A-I (P < 0.0001), lower PON activity (P < 0.0001), increased NOx (P < 0.0001), VCAM-1 (P < 0.0001) and ICAM-1 (P = 0.0008) and lower TAC (P = 0.0006). Titres of IgG aHDL positively correlated with IgG aApo A-I (r = 0.64, P < 0.0001), NOx (r = 0.32, P = 0.007), inversely correlated with PON activity (r = -0.34, P = 0.002) and TAC (r = -0.43, P = 0.0004) and were independently associated with ICAM-1 (t = 3.509, P = 0.001). IgG aApo A-I titres correlated positively with NO (r = 0.37, P = 0.007), inversely with PON activity (r = -0.31, P = 0.006), TAC (r = -0.47, P < 0.0001) and were independently associated with HDL (t = -2.747, P = 0.008) and VCAM-1 (t = 3.311, P = 0.002), the latter alongside NOx (T = 2.271, P = 0.02). Elevated titres of IgG aHDL and IgG aApo A-I and reduced PON activity related to increased disease score (BILAG) and damage index (SLICC/ACR DI).

CONCLUSION

In SLE, IgG aHDL and aApo A-I associate with disease activity and damage and interfere with the anti-oxidant and anti-inflammatory functions of HDL favouring atherogenesis.

Antibodies toward high-density lipoprotein components inhibit paraoxonase activity in patients with systemic lupus erythematosus

Patients with systemic lupus erythematosus (SLE) have an increased incidence of vascular disease, and oxidative stress is recognized as an important feature in this condition, despite the underlying mechanisms not being fully understood. In these patients, an interaction between lipoproteins and the immune system has been suggested, but most studies have only looked at antibodies against oxidized low-density lipoproteins. This study was undertaken to determine the presence of antibodies directed against high-density lipoproteins (HDL) and to identify a possible association between these antibodies and paraoxonase (PON), an antioxidant enzyme present in HDL. Plasma from 55 patients with SLE was collected and IgG aHDL and antiapolipoprotein A-I (aApo A-I) antibodies were assessed by enzyme-linked immunosorbent assay. Standardization of the method was performed in a control population of 150 healthy subjects. Plasma levels above 5 standard deviations of the mean of the control population were considered positive. PON activity was assessed by quantification of p-nitrophenol formation (micromol/mL/min). Patients with SLE had higher titers of aHDL (P < 0.0001) and aApo A-I (P < 0.0001) antibodies, and lower PON activity (P < 0.0001) than healthy controls. There was also a direct correlation between the titers of aHDL and aApo A-I antibodies (r = 0.61; P < 0.0001). PON activity was inversely correlated with aApo A-I (P = 0.0129) antibody levels. Anti-HDL and aApo A-I antibodies from patients with high titers were isolated and subsequently incubated with human HDL. These antibodies reduced PON activity up to a maximum of 70.2% and 78.4%, respectively. This study showed the presence of aHDL and aApo A-I antibodies in patients with SLE. These antibodies were associated with reduced PON activity in plasma, and the in vitro inhibition assay confirmed a direct inhibition of the enzyme activity.

Primer: the practical use of biological markers of rheumatic and systemic inflammatory diseases

The assessment of systemic inflammation by means of laboratory tests often complements the results of medical examination. Traditionally, the erythrocyte sedimentation rate and leukocytosis with left shift are diagnostic markers for inflammatory and infectious diseases. The levels of acute-phase proteins--especially C-reactive protein--are used to assess both the presence of inflammation and any response to treatment. The determination of C-reactive protein levels may be advised in three types of pathological situation: infection, acute or chronic inflammation, and evaluation of metabolic risk. Procalcitonin is useful as a marker of sepsis and severe infection. The concentration of serum amyloid A predicts the chances of survival of patients with secondary (AA) amyloidosis. Ferritin and its glycosylated form are of interest in the study of specific diseases such as adult-onset Still's disease. Markers of cartilage and bone turnover are complementary to these markers of inflammation. Although cytokine serum levels are transiently crucial to the generation of inflammation, their usefulness in the clinic is still under investigation. Serum concentrations of cytokine inhibitors or soluble cytokine receptors, as well as the clinical response of patients to treatment with cytokine antagonists, might generate important information for monitoring autoinflammatory diseases.

African-American and Hispanic ethnicities, renal involvement and obesity predispose to hypertension in systemic lupus erythematosus: results from LUMINA, a multiethnic cohort (LUMINAXLV)

OBJECTIVE

To examine the predictors of the occurrence of hypertension in a large multiethnic US cohort.

PATIENTS AND METHODS

There were 614 patients with systemic lupus erythematoses (SLE; > or = 4 American College of Rheumatology revised criteria) with < or = 5 years of disease duration at entry into the cohort (T0) and of Hispanic (Texan or Puerto Rican), African-American or Caucasian ethnicity. T0 variables were compared between patients who did and did not develop hypertension (blood pressure > or = 140/90 mm Hg on at least two occasions and/or the use of antihypertensive drugs) after T0. Significant and clinically relevant variables were then examined by a stepwise logistic regression model.

RESULTS

A total of 379 patients without hypertension at T0 were included (patients who developed hypertension prior to SLE diagnosis (n = 126) or before T0 (n = 109) were excluded). Predictors of hypertension were African-American and Texan-Hispanic ethnicities, renal involvement and a higher body mass index.

CONCLUSIONS

Traditional cardiovascular risk factors, disease-related factors and ethnicity play a role in the occurrence of hypertension in patients with SLE. Controlling renal involvement and optimising body weight may prevent the occurrence of hypertension.

Proinflammatory high-density lipoprotein as a biomarker for atherosclerosis in patients with systemic lupus erythematosus and rheumatoid arthritis

OBJECTIVE

Women with systemic lupus erythematosus (SLE) have a 7-50-fold increased risk of coronary artery disease (CAD). In the general population, oxidized low-density lipoprotein (ox-LDL) increases the risk for CAD. Normal high-density lipoproteins (HDLs) protect LDL from oxidation; proinflammatory HDLs do not. This study was undertaken to determine whether patients with SLE, who have chronic inflammation that causes oxidative damage, have more proinflammatory HDL and higher levels of ox-LDL, thus predisposing them to atherosclerosis.

METHODS

One hundred fifty-four women with SLE, 48 women with rheumatoid arthritis (RA), and 72 healthy controls were studied. The ability of the patients' HDL to prevent oxidation of normal LDL was measured. Values >1.0 (the value assigned for LDL oxidation in the absence of HDL) after the addition of HDL indicated proinflammatory HDL. Plasma ox-LDL levels were measured as the amount of oxidation produced by the patient's LDL after the removal of HDL.

RESULTS

SLE patients had more proinflammatory HDL (mean +/- SD score 1.02 +/- 0.57, versus 0.68 +/- 0.28 in controls [P < 0.0001] and 0.81 +/- 0.22 in RA patients [P = 0.001 versus SLE patients]). A higher proportion of SLE patients had proinflammatory HDL: 44.7% of SLE patients versus 4.1% of controls and 20.1% of RA patients had scores >1.0 (P < 0.006 between all groups). Levels of ox-LDL correlated with levels of proinflammatory HDL (r = 0.37, P < 0.001). SLE patients with CAD had significantly higher proinflammatory HDL scores than patients without CAD (P < 0.001).

CONCLUSION

HDLs are proinflammatory in a significant proportion of SLE patients and are associated with elevated levels of ox-LDL. Abnormal HDLs impair the ability to prevent LDL oxidation and may predispose to atherosclerosis.

Dyslipoproteinemia during the active course of systemic lupus erythematosus in association with anti-double-stranded DNA (anti-dsDNA) antibodies

Dyslipoproteinemia is common in lupus patients. In this study, we investigated the pattern of dyslipoproteinemia in the course of active systemic lupus erythematosus (SLE) in possible association with anti-double-stranded DNA (anti-dsDNA) antibodies. Forty-six lupus patients under 45 years old who fulfilled the American College of Rheumatology revised criteria for the classification of SLE were selected. The exclusion criteria were renal failure, nephrotic syndrome, thyroid or liver disease, diabetes mellitus, obesity, pregnancy and taking drugs that induce dyslipidemia. Disease activity was measured by Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Comparison of the lipid profiles, between active and inactive groups determined high levels of serum TG and VLDL and low levels of serum HDL in active group in comparison with inactive group (P < 0.05). The results indicated that the levels of TG and VLDL were significantly elevated in the patients with positive anti-dsDNA (P < 0.05). Although, the mean of serum HDL levels was also lower in patients with positive anti-dsDNA, the difference was not significant. This pattern of dyslipoproteinemia in active SLE may be associated with the autoimmune mechanisms especially in relation to the presence of anti-dsDNA antibodies.

Atherogenesis and autoimmune disease: the model of lupus

Accelerated atherosclerosis is a major cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Certain 'classic' risk factors are associated with atherosclerosis risk in SLE. However, these factors alone do not fully explain the excess risk observed. Atherosclerosis is increasingly recognized as a chronic inflammatory condition and in SLE, complement activation and immune complex formation may promote atheroma development. Similarly, autoantibody production, especially those in the anticardiolipin (ACLA) family are gaining increasing attention. The role of steroids may not be completely straightforward, low doses may have a beneficial anti-inflammatory role whereas higher doses may exacerbate metabolic factors. In contrast, antimalarials have a beneficial effect on lipids as well as anti-inflammatory and anti-platelet effects. The aetiology of atherosclerosis in SLE is therefore multifactorial. A better understanding of the interface of autoimmunity and atherogenesis in the context of SLE will benefit lupus patients and will also help us better understand the pathogenesis of atherosclerosis in general.

Apolipoprotein A-I induces IL-10 and PGE2 production in human monocytes and inhibits dendritic cell differentiation and maturation

Apolipoprotein A-I (apoA-I), the major protein component of serum high-density lipoprotein, exhibits anti-inflammatory activity in atherosclerosis. In this study, we demonstrate that apoA-I inhibits DC differentiation and maturation. DC differentiated from monocytes in the presence of apoA-I showed a decreased expression of surface molecules such as CD1a, CD80, CD86, and HLA-DR. In addition, these DC exhibited decreased endocytic activity and weakened allogeneic T-cell activation. During DC differentiation in the presence of apoA-I, PGE(2) and IL-10, which are known to be DC differentiation inhibitors and/or modulators of DC function, were produced at remarkable rates, whereas IL-12 production in the cells after stimulation with CD40 mAb and IFN-gamma was significantly decreased in comparison with the control DC. T cells stimulated by apoA-I-pretreated DC produced significantly low levels of IFN-gamma, and apoA-I inhibited cross-talk between DC and NK cells, in terms of IL-12 and IFN-gamma production. Therefore, apoA-I appears to play an important role in modulating both innate immune response and inflammatory response. The novel inhibitory function of apoA-I on DC differentiation and function may facilitate the development of new therapeutic interventions in inflammatory diseases.

‘Not only…but also’: factors that contribute to accelerated atherosclerosis and premature coronary heart disease in systemic lupus erythematosus

Premature coronary heart disease (CHD) has emerged as a major cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Overall SLE patients have a 5-6-fold increased risk of CHD and this excess risk is especially pronounced in younger women where the excess risk may be >50-fold. Studies from our group and others have also demonstrated that SLE patients have a higher prevalence of subclinical atherosclerosis compared with controls, with approximately 30% having evidence of subclinical involvement. It is important to consider what factors may underlie this excess risk. We have found that certain 'classic' risk factors, i.e. hypertension and diabetes mellitus, are more prevalent in SLE and that persistent hypercholesterolaemia independently predicts patients who will develop CHD. These risk factors alone do not completely explain the excess risk observed, and after adjusting for classic risk factors SLE remains independently associated with both clinical and subclinical outcomes. Certain other metabolic changes also occur more frequently in SLE, namely premature menopause, renal impairment, high triglycerides and higher plasma homocysteine. In addition, insulin resistance is more pronounced in patients with SLE, and approximately 18% have the metabolic syndrome. It is also increasingly accepted that atherosclerosis is a chronic inflammatory condition, and in SLE systemic complement activation as well as immune complex formation can result in changes that promote the development of atheroma. Similarly, autoantibody production, especially antibodies directed against lipoprotein subtypes and those in the antiphospholipid (APLA) family, are gaining increasing attention. The role of the latter are particularly controversial as different subtypes have been shown to both promote and protect against atherogenesis. In a study looking at carotid plaque in SLE, we found that APLA was independently associated with the presence of plaque; this study also found that patients with plaque had higher white cell counts, suggesting ongoing chronic inflammation. We have also noted a negative correlation between activation of transforming growth factor beta-1 and carotid intima-medial thickness. This cytokine, which is known to be a potent anti-inflammatory molecule, has also been shown to be protective against atherogenesis. With regard to therapy, steroids may be a true double-edged sword, with low doses exerting a beneficial anti-inflammatory role whereas higher doses may be detrimental through exacerbation of metabolic risk factors. In contrast, we have found that antimalarials have a beneficial effect on lipids especially when co-prescribed with steroids, and this, along with anti-inflammatory and proposed antiplatelet effects, may confer protection against CHD in lupus. The risk of premature CHD in SLE is therefore mediated by a number of factors that involve not only classic risk factors but also a range of factors associated with SLE itself. Preventative strategies will therefore need to address all potential risk factors of relevance. A more through understanding of the interplay between autoimmunity and atherogenesis should be possible by the study of SLE, and this may not only benefit lupus patients but also may have implications for our understanding of atherosclerosis in general.

Cardiovascular disease in lupus patients: Should all patients be treated with statins and aspirin?

Premature coronary heart disease (CHD) is a major cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). In certain age groups, the risk can be >50 times that of an age-matched population. This population also has an increased prevalence of several key classic risk factors that contribute to the CHD development. Chronic inflammation, anti-phospholipid antibodies and exposure to steroid therapy are also likely to have an impact. We have adopted a proactive approach to classic risk factor management with 'ideal targets' based on viewing SLE as a CHD equivalent condition. In this context, a significant proportion of SLE patients (approximately 30%) will require statins and the majority would be treated with aspirin prophylaxis. Better control of the underlying inflammatory disease is also likely to play an important role and the relative safety of anti-malarials allows their consideration as an adjunct in a large proportion of patients. Well-conducted clinical trials are now needed to advance beyond these initial recommendations.

[T cell-dependent monocyte activation, TNFalpha and apolipoprotein A-I in autoimmunity and inflammation]

Rheumatoid arthritis is characterized by a massive overproduction of monokines like TNFalpha, IL-6 and IL-1beta, which are predominantly produced by monocytes and macrophages. To date, the exact mechanisms of monocyte/macrophage activation have not been fully elucidated. One possible mechanism is their cell contact-dependent activation by activated T cells. The direct cell contact of monocytes/macrophages and T cells leads to an increased production of pro-inflammatory cytokines such as TNFalpha and IL-1beta. Stringent control of this mechanism by inhibitory factors appears mandatory under physiological conditions in order to avoid systemic cytokine release syndromes. The presence of inhibitory factors in the serum could represent such a mechanism. In healthy donors, apolipoprotein A-I was identified as such an inhibitory serum protein. In patients with rheumatoid arthritis, apolipoprotein A-I is found in decreased concentrations, possibly due to its role as a negative acute phase protein. The role of this and other inhibitory serum molecules are discussed.

Antiphospholipid syndrome in systemic lupus erythematosus: is the whole greater than the sum of its parts?

This article compares the manifestations of systemic lupus erythematosus (SLE) in the presence and absence of antiphospholipid antibodies (aPLs), the hallmark autoantibodies of antiphospholipid syndrome (APS). The combination of SLE and APS appears to be of greater concern than either entity alone. APS complicates SLE by adding a vaso-occlusive factor to the inflammatory component that adversely affects the prognosis of those who have lupus and aPLs. The increase in both morbidity and mortality when both are present has significant therapeutic implications. Anticoagulation may be a safer and more appropriate therapeutic option than instituting a regimen of corticosteroids and immunosuppressive agents with all their attendant adverse effects. It falls upon the physician to clearly define the disease entity and fully evaluate the disease process.

Therapy Insight: systemic lupus erythematosus as a risk factor for cardiovascular disease

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease with a strong female predilection. Cardiovascular morbidity and mortality is a frequent complication, particularly in females aged 35-44 years, in whom the risk of myocardial infarction is raised 50-fold. The mechanisms underlying this increased risk are not fully understood. Certain traditional risk factors, such as hypertension and diabetes mellitus, are more common in SLE patients than in the general population. These factors do not, however, completely account for the increased cardiovascular risk; factors such as renal impairment, increased homocysteine levels and early menopause probably have a role. In addition, several factors more specifically related to lupus are proposed to be of importance, including chronic inflammation, antiphospholipid antibodies and therapy, especially corticosteroid use. Thus, we need to be proactive in our approach to risk-factor management in SLE patients. Here, we propose that, like diabetes mellitus, SLE should be considered a coronary heart disease equivalent condition for baseline risk and that assessment of cardiovascular risk should be done routinely. In addition to lifestyle modifications, blood pressure and cholesterol levels should be stringently controlled, and administration of aspirin should be considered in selected patients. The increased use of certain interventions, such as statins, also needs to be more widely investigated in this population.

Lipid Profile and Anticardiolipin Antibodies in Behcet's Disease

BACKGROUND

Behcet's disease (BD) is a multisystem disorder characterized by a relapsing inflammatory process of unknown etiology. It is well known that atherothrombosis in systemic inflammatory disorders is closely related to coagulation and lipid metabolism abnormalities. The purpose of this study was to investigate some parameters of lipid metabolism, lipoprotein (a) [Lp(a)] and anticardiolipin antibody (ACA) levels and the relationship of these parameters with the clinical activity of BD.

METHODS

Thirty three patients with BD (15 active, 18 inactive cases) and 20 healthy controls participated in the study. After performing a detailed physical exam, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), very-low-density lipoprotein cholesterol (VLDL-C), apoprotein A and B (apo-A, apo-B), Lp(a), and ACA levels (ACA-IgG and IgM) were measured in all participants.

RESULTS

Patients with active BD had higher ESR, CRP and Lp(a) levels, and lower apo-A and HDL-C levels compared with the patients with inactive BD and healthy controls. ACA-IgG and IgM levels were higher in patients with active BD than healthy controls but not higher than patients with inactive BD. On the other hand, ACA-IgG level was higher in active and inactive cases with vascular involvement than in those of active and inactive cases without vascular involvement. In the analyses of correlation, in active BD patients we found a positive correlation between CRP and Lp(a) levels.

CONCLUSIONS

Our findings suggest that Lp(a) behaves as an acute phase reactant and ACA levels are increased in patients with active BD. Data from patients with active BD may be compatible with the serum profile, which is accepted as a risk for the development of atherothrombosis.

Presence of autoantibodies to apolipoprotein A-1 in patients with acute coronary syndrome further links autoimmunity to cardiovascular disease

Anti-apolipoprotein A-1 (Apo A-1) autoantibodies were described in autoimmune disorders such as systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) and might be involved in the genesis of arterial and venous thrombotic events. To investigate the presence of these autoantibodies in patients with acute coronary syndrome (ACS) without other features of autoimmunity, we set up an enzyme-linked immunosorbent assay (ELISA) for anti-Apo A-1 antibodies. We used it to investigate their prevalence in ACS as compared to SLE and APS and correlated them to plasma Apo A-1 and serum amyloid A protein (SAA) concentrations. The prevalence of anti-Apo A-1 autoantibodies in the healthy control group was 1% (1/92), but was significantly higher in other groups: 21% (11/53) in ACS group (P=0.001), 13% (12/92) in SLE and/or APS group (P=0.005). Multiple linear regression revealed a significant correlation between plasma Apo A-1 (r=-0.72, P=0.013), plasma SAA concentration (r=0.76, P=0.0066) and anti-Apo A-1 IgG titre in ACS patients. The presence of anti-Apo A-1 autoantibodies in patients with ACS highlights an additional link between autoimmunity, inflammation and atherosclerosis.

Infection with Toxoplasma gondii increases atherosclerotic lesion in ApoE-deficient mice

Toxoplasma gondii is an intracellular protozoan that elicits a potent inflammatory response during the acute phase of infection. Herein, we evaluate whether T. gondii infection alters the natural course of aortic lesions. ApoE knockout mice were infected with T. gondii, and at 5 weeks of infection, serum, feces, and liver cholesterol; aortic lesion size, cellularity, and inflammatory cytokines; and levels of serum nitrite and gamma interferon (IFN-gamma) were analyzed. Our results showed that serum cholesterol and atherogenic lipoproteins were reduced after T. gondii infection. The reduction of serum levels of total cholesterol and atherogenic lipoproteins was associated with increases in the aortic lesion area, numbers of inflammatory cells, and expression of monocyte chemoattractant protein 1 and inducible nitric oxide synthase mRNA in the site of lesions as well as elevated concentrations of IFN-gamma and nitrite in sera of T. gondii-infected animals. These results suggest that infection with T. gondii accelerates atherosclerotic development by stimulating the proinflammatory response and oxidative stress, thereby increasing the area of aortic lesion.

The antiphospholipid syndrome and atherosclerosis: clue to pathogenesis

Regulation of blood vessels is intrinsically tied to inflammatory signaling. Recent research suggests that chronic inflammation is associated with atherosclerosis risk. The antiphospholipid syndrome is a prototypic autoimmune disease. Disturbance of blood vessel homeostasis in this disorder may increase risk for atherosclerosis by mechanisms that are direct (through antibody targeting of blood vessel-regulating proteins) or indirect (via inflammatory mechanisms that have recently been implicated in autoantibody-mediated thrombosis).

Atherosclerosis, oxidative stress and auto-antibodies in systemic lupus erythematosus and primary antiphospholipid syndrome

Overwhelming evidence spanning three decades has consistently shown that coronary artery disease is a major cause of morbidity and mortality in Systemic Lupus Erythematosus. Traditionally this was explained by abnormalities of the lipid profile induced by prolonged steroid treatment. Subsequently, antiphospholipid antibodies were presented as an additional cardiovascular risk factor. Recently, antibodies towards high-density lipoprotein and antiapolipoprotein A-I have been identified. These, together with anti-beta2 glycoprotein-1, interfere with the major antioxidant defence of patients with SLE and with primary antiphospholiqid syndrome exposing them to the atherogenic potential of enhanced oxidative stress. The present review discusses how the latter auto-antibodies, together with abnormalities of their target lipid auto-antigens, could enhance the risk of atherosclerosis in SLE and APS.

Antibodies to high-density lipoprotein and beta2-glycoprotein I are inversely correlated with paraoxonase activity in systemic lupus erythematosus and primary antiphospholipid syndrome

OBJECTIVE

To determine the prevalence of anti-high-density lipoprotein (anti-HDL) antibodies and to establish a possible relationship between anti-HDL, anticardiolipin antibodies (aCL), anti-beta(2)-glycoprotein I (anti-beta(2)GPI), and paraoxonase (PON) activity in patients with systemic lupus erythematosus (SLE) and primary antiphospholipid syndrome (APS).

METHODS

Thirty-two patients with SLE and 36 with primary APS were enrolled in a cross-sectional study. Twenty age- and sex-matched healthy subjects were used as controls. Serum levels of IgG and IgM aCL, anti-beta(2)GPI, and antiprothrombin antibodies and IgG anti-HDL were measured by enzyme-linked immunosorbent assay. Total cholesterol, HDL cholesterol, HDL(2), and HDL(3) were determined by standard enzymatic techniques. PON activity was assessed by quantification of nitrophenol formation, and total antioxidant capacity (TAC) by chemiluminescence.

RESULTS

Levels of total HDL, HDL(2), and HDL(3) were reduced in patients with SLE compared with controls (mean +/- SD 0.51 +/- 0.3, 0.37 +/- 0.3, and 0.14 +/- 0.1 mmoles/liter, respectively, versus 1.42 +/- 0.9, 1.01 +/- 0.7, and 0.40 +/- 0.2). Patients with SLE and primary APS had higher titers of anti-HDL antibodies and lower PON activity than controls. In the SLE population, PON activity was inversely correlated with IgG anti-HDL titers (r = -0.48, P = 0.005) whereas in the primary APS population, IgG anti-beta(2)GPI was the only independent predictor of PON activity (r = -0.483, P = 0.003). In the SLE group, anti-HDL was inversely correlated with TAC (r = -0.40, P < 0.02), and PON activity was positively correlated with TAC (r = 0.43, P < 0.02).

CONCLUSION

IgG anti-HDL and IgG anti-beta(2)GPI antibodies are associated with reduced PON activity in patients with SLE and primary APS. Since the physiologic role of PON is to prevent low-density lipoprotein oxidation with its attendant atherogenic effects, the reported interactions may be relevant to the development of atherosclerosis in SLE and primary APS.

Cytokines, acute-phase proteins, and hormones: IL-1 and TNF-alpha production in contact-mediated activation of monocytes by T lymphocytes

The cytokine network is a homeostatic system that has to be perceived in an analogous fashion to the acid/base equilibrium. The level of any cytokine in biological fluids can be interpreted correctly only by taking into account the levels of other synergistic cytokines, of their respective inhibitors, and of each cytokine receptor. Due to their potent activities in many different processes (including cell growth and differentiation, development, and repair processes leading to the restoration of homeostasis), the cytokine activities have to be tightly controlled by natural inhibitory mechanisms. Since one of the main functions of cytokines is to mediate interactions between the immune and inflammatory system, it is thought that chronic immuno-inflammatory diseases might be caused in part by the uncontrolled production of cytokines. Depending on the stage of inflammation or the biological effect determined, the same cytokine might be pro- or anti-inflammatory. This applies, for instance, to IL-4, IL-10, and TGFbeta. An important mechanism that triggers the production of pro-inflammatory cytokines in chronic inflammatory diseases is the direct cellular contact between stimulated T cells and monocyte-macrophages. This mechanism is blocked at the systemic level by the "negative" acute-phase protein apolipoprotein A-I (apo A-I). The levels of expression of cytokines and cytokine inhibitors and acute-phase proteins are ruled by hormones. Estrogens as well as androgens inhibit the production of IL-1beta and TNF-alpha on monocyte-macrophages. However, androgens antagonize estrogen stimulatory effects on apo A-I synthesis by the liver. Other studies suggest that estradiol is more inhibitory to Thl cytokines (e.g., IFNgamma, IL-2), while testosterone is inhibitory to Th2 cytokines (e.g., IL-4). Cytokines also control the axis of the hypothalamic-hypophyseal-adrenal glands as well as the sexual hormones. The discrepancy between studies would suggest that the mechanisms are different in physiological and pathophysiological conditions.

Serum amyloid A and high-density lipoprotein cholesterol: serum markers of inflammation in sarcoidosis and other systemic disorders

Hypocholesterolemia has been observed in several inflammatory diseases such as rheumatoid arthritis, myeloproliferative disorders, systemic lupus erythematosus and sarcoidosis. Serum amyloid A is an acute-phase reactant that is related to the high-density lipoprotein cholesterol. This review discusses the relationship between the activation of the cells of the monocyte-macrophage system, determined by the serum amyloid A levels, and the lipid metabolism, measured as alterations in plasma lipoprotein concentrations. The mechanisms of this association during acute inflammation are also discussed in this review.

Lipid and lipoprotein levels in premenopausal systemic lupus erythematosus patients

The purpose of this study was to assess the prevalence of dyslipoproteinemia and to analyze the clinical variables that are associated with it in a sample of premenopausal systemic lupus erythematosus (SLE) patients. We studied 53 premenopausal (34.5 y) SLE outpatients and 45 controls. Clinical variables studied included patient age, weight, height, body mass index (BMI), age at disease onset, disease duration, clinical activity of SLE, renal involvement and drug therapy. Total cholesterol (TC), high- and low-density lipoprotein cholesterol (HDL-C and LDL-C), and triglycerides were measured using standard enzymatic techniques. Apolipoproteins (apo) A-I and B were determined by radial immunodiffusion. Twenty-nine patients (55%) and 14 controls (30%) had dyslipoproteinemia. An increase in TC, triglycerides, HDL3-C, apo A-I and apo B, and a decrease in HDL2-C and HDL-C/TC index was found in SLE patients in comparison with controls. TC (P = 0.007), apo B (P = 0.02), LDL-C (P = 0.03) and triglycerides (P = 0.0001) were significantly correlated with proteinuria. Patients on prednisone therapy had higher triglycerides levels (P = 0.03) than untreated patients. TC (P = 0.01), LDL-C (P = 0.006) and triglycerides (P = 0.04) were also correlated with the dose of prednisone. Dyslipoproteinemia is a common feature in adult SLE premenopausal patients which is characterized by an increase in TC, triglycerides and apo B, and an abnormal distribution of HDL subclasses. Corticosteroid therapy and proteinuria are the best predictors of dyslipoproteinemia in these patients.

What causes the antiphospholipid syndrome?

The antiphospholipid syndrome (APS) is characterized by unpredictable, sporadic, thrombotic events. The cause of the thrombosis is probably multifactorial and may involve disparate effects of the autoantibodies associated with the syndrome, which are known to interfere with various protein regulators of hemostasis. An integrated theory of pathogenesis that accounts for the diversity of autoantibodies and their effects suggests that cellular inflammation or apoptosis within the vasculature may lead to oxidation or turnover in phospholipid membranes. Thus, normally cryptic, functionally important epitopes of phospholipid-binding proteins are subjected to increased exposure to immune surveillance.

A swollen leg unmasks longstanding SLE

We report a case of long-standing SLE which presented with symptomatic muscle vasculitis on a background of photosensitivity, arthralgia and myalgia. The diagnosis was complicated by cardiomyopathy, nephrotic syndrome and diabetes. We highlight the benefits of aggressive treatment in severe disease and the importance of recognising and treating comorbidity especially ih relation to atherosclerosis.