Estimation of SLE activity based on the serum level of chosen cytokines and superoxide radical generation

Serum protein signatures differentiate paediatric autoimmune/inflammatory disorders

Because of their rarity, limited awareness among non-specialists, and significant overlaps in their clinical presentation, childhood autoimmune/inflammatory conditions represent a diagnostic and therapeutic challenge. Juvenile idiopathic arthritis (JIA), with its 7 sub-forms, is the most common paediatric "rheumatic" disease. Juvenile-onset systemic lupus erythematosus (jSLE) is a severe autoimmune/inflammatory disease that can affect any organ system and shares clinical features with JIA. To overcome issues around diagnostic approaches in the context of clinical overlap, we aimed at the definition of disease sub-form specific cytokine and chemokine profiles. Serum samples from patients with JIA (n = 77) and jSLE (n = 48), as well as healthy controls (n = 30), were collected. Samples were analysed using the Meso Scale Discovery (MSD) U-PLEX Biomarker Group 1 (hu) panel. Distinct serum protein signatures associate with JIA vs jSLE disease groups. Proteins with high discriminatory ability include IL-23, MIP-1β, MCP-1, M-CSF and MDC. Furthermore, serum IL-18, MIF, MIP-5 and YKL-40 discriminate between systemic JIA and other JIA subtypes. Thus, simultaneous quantification of serum proteins in a panel format may provide an avenue for the diagnosis and monitoring of childhood autoimmune/inflammatory conditions.

Binding of anti-dsDNA antibodies to proximal tubular epithelial cells contributes to renal tubulointerstitial inflammation

Immune deposits are often observed along the tubular basement membrane in patients with lupus nephritis, but the role of anti-dsDNA antibody (Ab) deposition on tubulointerstitial inflammation remains to be investigated. We examined the effect of human polyclonal anti-dsDNA Abs on inflammatory processes in cultured proximal renal tubular epithelial cells (PTEC, HK-2 cells) and their association with serum levels of interleukin (IL)-6, IL-8 and monocyte chemoattractant protein-1 (MCP-1) in patients. Binding of anti-dsDNA Abs to HK-2 cells was investigated by cellular ELISA, flow cytometry and immunohistochemistry. IL-6, IL-8 and MCP-1 secretion, mitogen-activated protein kinase (MAPK) activation and the effect of mycophenolic acid (MPA) were investigated by ELISAs and Western blot analysis. NZBWF1/J mice with active nephritis were randomized to receive either mycophenolate mofetil (MMF) (100 mg/kg per day) or vehicle for up to 12 weeks to study renal histopathology focusing on tubulointerstitial changes. Our results demonstrated that anti-dsDNA Abs bound to HK-2 cell surface and induced IL-6, IL-8 and MCP-1 secretion through distinct MAPK pathways. MPA inhibited anti-dsDNA Ab binding to HK-2 cells and suppressed apical and basolateral IL-6 and IL-8, but not MCP-1, secretion. Anti-dsDNA Ab level correlated with serum and tubulointerstitial expression of IL-6, IL-8 and MCP-1. MMF treatment in NZBWF1/J mice reduced anti-dsDNA Ab production and MAPK activation in the renal tubulointerstitium, together with decreased IL-6 and MCP-1 expression. Our data demonstrate that anti-dsDNA Abs contribute to inflammatory processes in the tubulointerstitium in lupus nephritis through their binding to proximal renal tubular epithelial cells and induction of pro-inflammatory mediators, and MPA ameliorates anti-dsDNA Ab induced IL-6 and IL-8 secretion in these cells.

Clinical associations of IL-10 and IL-37 in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by the development of autoantibodies to nuclear antigens and inflammatory responses mediated by multiple cytokines. Although previous studies have determined clinical associations between SLE and the anti-inflammatory cytokines IL-10 and IL-37, their role in the disease, or their potential as biomarkers, remains unclear. We examined serum levels of IL-10 and IL-37 in a large cohort of SLE patients, with detailed longitudinal clinical data. We demonstrate a statistically significant association of serum IL-10 with disease activity, with higher levels in active compared to inactive disease. High first visit IL-10 was predictive of high subsequent disease activity; patients with IL-10 in highest quartile at first visit were 3.6 times more likely to have active disease in subsequent visits. Serum IL-37 was also higher in SLE patients compared to control, and was strongly associated with Asian ethnicity. However, IL-37 was not statistically significantly associated with disease activity. IL-37 was significantly reduced in patients with organ damage but this association was attenuated in multivariable analysis. The data suggest that IL-10, but not IL-37, may have potential as a biomarker predictive for disease activity in SLE.

An anti-DNA antibody prefers damaged dsDNA over native

DNA-protein interactions, including DNA-antibody complexes, have both fundamental and practical significance. In particular, antibodies against double-stranded DNA play an important role in the pathogenesis of autoimmune diseases. Elucidation of structural mechanisms of an antigen recognition and interaction of anti-DNA antibodies provides a basis for understanding the role of DNA-containing immune complexes in human pathologies and for new treatments. Here we used Molecular Dynamic simulations of bimolecular complexes of a segment of dsDNA with a monoclonal anti-DNA antibody's Fab-fragment to obtain detailed structural and physical characteristics of the dynamic intermolecular interactions. Using a computationally modified crystal structure of a Fab-DNA complex (PDB: 3VW3), we studied in silico equilibrium Molecular Dynamics of the Fab-fragment associated with two homologous dsDNA fragments, containing or not containing dimerized thymine, a product of DNA photodamage. The Fab-fragment interactions with the thymine dimer-containing DNA was thermodynamically more stable than with the native DNA. The amino acid residues constituting a paratope and the complementary nucleotide epitopes for both Fab-DNA constructs were identified. Stacking and electrostatic interactions were shown to play the main role in the antibody-dsDNA contacts, while hydrogen bonds were less significant. The aggregate of data show that the chemically modified dsDNA (containing a covalent thymine dimer) has a higher affinity toward the antibody and forms a stronger immune complex. These findings provide a mechanistic insight into formation and properties of the pathogenic anti-DNA antibodies in autoimmune diseases, such as systemic lupus erythematosus, associated with skin photosensibilization and DNA photodamage.

Investigating the role of angiogenesis in systemic lupus erythematosus

OBJECTIVE

We aimed to elucidate the roles of six pro-angiogenic factors, namely, basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), placental growth factor (PlGF), hepatocyte growth factor (HGF), transforming growth factor-beta (TGF-beta) and tumor necrosis factor-alpha (TNF-alpha), in the pathogenesis of systemic lupus erythematosus (SLE).

METHODS

A group of 75 patients with SLE and a control group of 40 healthy volunteers were recruited. Angiogenic factors were tested through enzyme-linked immunosorbent assay (ELISA) measurement. The angiogenic activities of the patients with SLE and the healthy controls were assessed and a correlation analysis of these angiogenic factors was conducted.

RESULTS

A much higher level of angiogenic activity was shown in the serum of patients with SLE than that of the healthy controls, yet no statistically significant difference was found in the angiogenic activities of active SLE and inactive SLE. Serum VEGF level in the active SLE group was significantly higher than that in the control group and the inactive SLE group, and serum HGF level was strongly positively correlated with VEGF in all SLE groups; meanwhile, there was also a statistically significant positive correlation between TNF-alpha and VEGF in all SLE groups. There was a statistically significant positive correlation between serum VEGF level and bFGF level in the active SLE group. There was a slightly negative correlation between serum HGF level and TGF-beta level in the SLE group, but this negativity did not reach the significance level. Likewise, positive correlation was also shown in the serum VEGF level and PlGF level, yet not in bFGF with PlGF.

CONCLUSION

Circulating serum angiogenic cytokines may be disease markers of SLE activity. Anti-angiogenic agents such as thalidomide and endogenous angiogenesis inhibitors such as endostatin are potentially effective and promising therapies in the treatment of SLE.

Role of interleukin-10 and interleukin-10 receptor in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease characterized by excessive production of a variety of autoantibodies, accumulation of immune complexes, and multiple organ systems involvement. Interleukin-10 (IL-10) has an important role in the growth, survival, differentiation, and function of B cells. Abnormally increased IL-10 synthesis seems contributing to the spontaneous hyperactivity of the B cell compartment, so that it can directly result in autoantibody production by committed plasma cells, circulating immune complexes formation, and eventually in tissue and organ damage, suggesting it might associate with the development of SLE. A better understanding of the regulation of IL-10 and its receptors (IL-10R) can likely provide more valuable clues to the pathogenic mechanisms underlying specific forms of SLE, so as to pave the way toward more effective therapeutics.

Monocytes from Irf5-/- mice have an intrinsic defect in their response to pristane-induced lupus

The transcription factor IFN regulatory factor (IRF)5 has been identified as a human systemic lupus erythematosus (SLE) susceptibility gene by numerous joint linkage and genome-wide association studies. Although IRF5 expression is significantly elevated in primary blood cells of SLE patients, it is not yet known how IRF5 contributes to SLE pathogenesis. Recent data from mouse models of lupus indicate a critical role for IRF5 in the production of pathogenic autoantibodies and the expression of Th2 cytokines and type I IFN. In the present study, we examined the mechanisms by which loss of Irf5 protects mice from pristane-induced lupus at early time points of disease development. We demonstrate that Irf5 is required for Ly6C(hi) monocyte trafficking to the peritoneal cavity, which is thought to be one of the initial key events leading to lupus pathogenesis in this model. Chemotaxis assays using peritoneal lavage from pristane-injected Irf5(+/+) and Irf5(-/-) littermates support an intrinsic defect in Irf5(-/-) monocytes. We found the expression of chemokine receptors CXCR4 and CCR2 to be dysregulated on Irf5(-/-) monocytes and less responsive to their respective ligands, CXCL12 and CCL2. Bone marrow reconstitution experiments further supported an intrinsic defect in Irf5(-/-) monocytes because Irf5(+/+) monocytes were preferentially recruited to the peritoneal cavity in response to pristane. Taken together, these findings demonstrate an intrinsic role for IRF5 in the response of monocytes to pristane and their recruitment to the primary site of inflammation that is thought to trigger lupus onset in this experimental model of SLE.

Oxidative stress promotes hypertension and albuminuria during the autoimmune disease systemic lupus erythematosus

Several lines of evidence suggest that essential hypertension originates from an autoimmune-mediated mechanism. One consequence of chronic immune activation is the generation of oxygen-derived free radicals, resulting in oxidative stress. Renal oxidative stress has direct prohypertensive actions on renal microvascular and tubular function. Whether oxidative stress contributes to the prevalent hypertension associated with autoimmune disease is not clear. We showed previously that female NZBWF1 mice, an established model of the autoimmune disease systemic lupus erythematosus (SLE), develop hypertension associated with renal oxidative stress. In the present study we tested the hypothesis that oxidative stress contributes to autoimmune-mediated hypertension by treating SLE and control (NZW/LacJ) mice with tempol (2.0 mmol/L) and apocynin (1.5 mmol/L) in the drinking water for 4 weeks. Although the treatment did not alter SLE disease activity (assessed by plasma double-stranded DNA autoantibodies), blood pressure and renal injury (urinary albumin) were reduced in the treated SLE mice. Tempol plus apocynin-treated SLE mice had reduced expression of nitrosylated proteins in the renal cortex, as well as reduced urinary and renal cortical hydrogen peroxide, suggesting that treatment reduced renal markers of oxidative stress. These data suggest that renal oxidative stress plays an important mechanistic role in the development of autoimmune-mediated hypertension.

Superoxide release in juvenile systemic lupus erythematosus

The objective of this study was to analyze the un-stimulated and stimulated release of superoxide anion (O(2) (-)) by granulocytes and monocytes in juvenile systemic lupus erythematosus (jSLE). The un-stimulated and phorbol myristate acetate (PMA, 30 nM)-induced O(2) (-)by granulocytes and monocytes were determined in six different times of incubation in patients with 23 jSLE and 28 controls. The analysis compared the jSLE group, which was classified into two subgroups by SLEDAI in one inactive subgroup (score <3) (n = 13 patients) and one active subgroup (score ≥3) (n = 10 patients) to the same control group. At time of blood withdrawal, 13 (56.52%) had inactive and 10 (43.47%) patients had active SLE. jSLE patients' granulocytes and monocytes had always a lower un-stimulated O(2) (-) production when compared to controls. Stimulated granulocytes had an increased O(2) (-) production at baseline followed by a significant lower production at 60 min in jSLE when compared to controls. Stimulated monocytes had a similar O(2) (-) production among patients with jSLE and controls. The results suggest a defect in phagocytic function in jSLE. The significant higher release of O(2) (-) in the assays of the stimulated granulocytes, in the initial instances, the so-called respiratory burst, could be attributed to the inflammatory state of phagocytes.

Proteomic analysis for the anti-apoptotic effects of cystamine on apoptosis-prone macrophage

Increased macrophage vulnerability is associated with progression of systemic lupus erythematosus. Our previous studies have shown that cystamine, an inhibitor of transglutaminase 2 (TG2), alleviated the apoptosis of hepatocyte and brain cell in lupus-prone mice NZB/W-F1. In present study, we further investigated the effects of cystamine on apoptosis-prone macrophages (APMs) in the lupus mice. Using two-dimensional gel electrophoresis (2-DE) analysis, we found that cystamine induced a differential protein expression pattern of APM as comparing to the PBS control. The protein spots presenting differential level between cystamine and PBS treatment were then identified by peptide-mass fingerprinting (PMF). After bioinformatic analysis, these identified proteins were found involved in mitochondrial apoptotic pathway, oxidative stress, and mitogen-activated protein (MAP) kinase-mediated pathway. Further investigation revealed that cystamine significantly decreased the levels of apoptotic Bax and Apaf-1 and the activity of caspase-3, and increased the levels of anti-apoptotic Bcl-2 in APM. We also found that these apoptotic mediators were up-regulated in a correlation with the progression of lupus severity in NZB/W-F1, which were little affected in BALB/c mice. We also found that the reduced serum glutathione was restored by cystamine in NZB/W-F1. Interestingly, the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) in APM and the phagocytic ability was diminished in presence of cystamine. In conclusion, our findings indicate that cystamine significantly inhibited mitochondrial pathway, induced antioxidant proteins, and diminished phosphorylation of extracellular ERK1/2, which may alleviate the apoptosis and the phagocytic ability of APM.

Tumor necrosis factor-alpha antagonist etanercept decreases blood pressure and protects the kidney in a mouse model of systemic lupus erythematosus

Chronic inflammation has been implicated in the pathology of hypertension; however, the role for specific cytokines remains unclear. We tested whether tumor necrosis factor-α blockade with etanercept (Etan) reduces mean arterial pressure in a female mouse model of systemic lupus erythematosus (SLE). SLE is a chronic inflammatory disorder with prevalent hypertension. Thirty-week-old SLE (NZBWF1) and control mice (NZW/LacJ) received Etan (0.8 mg/kg SC weekly) for 4 weeks or vehicle. Mean arterial pressure (in millimeters of mercury) was increased in SLE mice (150±5 versus 113±5 in controls; P<0.05) and was lower in Etan-treated SLE mice (132±3) but not controls (117±5). Albuminuria (in micrograms per milligram of creatinine) was elevated in SLE mice (28 742±9032 versus 1075±883; P<0.05) and was lower in Etan-treated SLE mice (8154±3899) but not control animals (783±226). Glomerulosclerosis (in percentage of glomeruli) was evident in SLE mice (2.5±1.6 versus 0.0±0.0 in controls; P<0.05) and was ameliorated in Etan-treated SLE mice (0.1±0.1). Renal cortex CD68(+) cell staining (in percentage of area) was elevated in SLE mice (4.75±0.80 versus 0.79±0.12 in controls; P<0.05) and was lower in Etan-treated SLE mice (2.28±0.32) but not controls (1.43±0.25). Renal cortex NADPH oxidase activity (relative light units per milligram of protein) was higher in SLE mice compared with controls (10 718±1276 versus 7584±229; P<0.05) and lowered in Etan-treated SLE mice (6645±490). Renal cortex nuclear factor κB (phosphorylated and nonphosphorylated) was increased in SLE mice compared with controls and lower in Etan-treated SLE mice. These data suggest that TNF-α mechanistically contributes to the development of hypertension in a chronic inflammatory disease through increased renal nuclear factor κB, oxidative stress, and inflammation.

Cytokine-induced monocyte characteristics in SLE

Monocytes in SLE have been described as having aberrant behavior in a number of assays. We examined gene expression and used a genome-wide approach to study the posttranslational histone mark, H4 acetylation, to examine epigenetic changes in SLE monocytes. We compared SLE monocyte gene expression and H4 acetylation with three types of cytokine-treated monocytes to understand which cytokine effects predominated in SLE monocytes. We found that γ-interferon and α-interferon both replicated a broad range of the gene expression changes seen in SLE monocytes. H4 acetylation in SLE monocytes was overall higher than in controls and there was less correlation of H4ac with cytokine-treated cells than when gene expression was compared. A set of chemokine genes had downregulated expression and H4ac. Therefore, there are significant clusters of aberrantly expressed genes in SLE which are strongly associated with altered H4ac, suggesting that these cells have experienced durable changes to their epigenome.

Selected angiogenic cytokines in systemic lupus erythematosus patients

The objective of this study was to determine the serum concentration of angiogenic factors (vascular endothelial growth factor, VEGF; transforming growth factor beta, TGF-beta1; hepatic growth factor, HGF; basic fibroblast growth factor, bFGF; tumor necrosis factor alpha, TNF-alpha; soluble vascular endothelial growth factor receptor 1, sVEGF-R1; soluble vascular endothelial growth factor receptor 2, sVEGF-R2), the relationships among them and to assess the relation of their levels with the applied therapy in 48 females with systemic lupus erythematosus (SLE; 37 long-term treated +11 newly diagnosed). The control group consisted of 24 healthy women. A statistically significant increase of sVEGF-R2 and significant decrease of sVEGF-R1 were observed in the subgroup of newly diagnosed SLE patients as compared to the control subjects. No significant differences were found between serum angiogenic factors in the long-term treated subgroup and the control, the long-term treated subgroup and the newly diagnosed SLE patients after a 3-month treatment, and the subgroup of newly diagnosed SLE patients before therapy and after a 3-month treatment. The significant decrease in the serum of sVEGF-R2 was revealed in the subgroup treated for a long-time as compared to the subgroup of newly diagnosed untreated SLE patients. The analysis of relationships between serum concentration of sVEGF-R1 and other cytokines levels revealed positive correlation with concentration of VEGF and TNF-alpha in the total group of patients. In the newly diagnosed untreated subgroup, a strong positive correlation between concentration of sVEGF-R1 and bFGF was observed. Furthermore, a moderate positive correlation between concentration of sVEGF-R1 and the level of VEGF was revealed in the long-term treated patients. The association between sVEGF-R2 and HGF was also noted in this subgroup. The obtained data suggest the necessity of further investigations to determine the importance of angiogenic factors in pathogenesis and therapy of SLE.

Disparate distribution of activating and inhibitory killer cell immunoglobulin-like receptor genes in patients with systemic lupus erythematosus

The genes of killer cell immunoglobulin-like receptors (KIRs), which are involved in the activation of T cells and natural killer cells, are highly variable. In recent years, the role of KIRs in autoimmune diseases has received increasing attention. The present study was undertaken to determine the association of the polymorphism of KIR genes with the susceptibility to systemic lupus erythematosus (SLE). The polymorphism of KIR genes of 93 patients with SLE together with 123 healthy donors as the control group was determined by polymerase chain reaction with sequence-specific primers. Twenty-seven novel gene combinations were found. Genotypic frequencies of KIR2DL2 (p < 0.001) and KIR2DS1 (p < 0.001) were much higher in patients with SLE than in control subjects. Individuals with two and more than two activating KIR genes were found more frequently in patients than in control subjects (80.7% versus 66.7%, p = 0.022). The results suggest that a genetic disturbance between activating and inhibitory KIR genes may be one of the key factors underlying the pathogenesis of SLE.

Efficacy and safety of infliximab in active SLE: a pilot study

Tumour necrosis factor-alpha (TNF-alpha) plays a major role in propagating the inflammatory processes responsible for tissue damage in systemic lupus erythematosus (SLE) and is overexpressed both systemically and locally in this disease. Hence, this pilot study was carried out to assess the safety and efficacy of TNF blockade in patients with active SLE. A total of 46 individuals (27 patients with active SLE and 19 healthy control volunteers) were the subjects of this study. Nine patients with SLE were allocated to treatment arm and 18 were allocated to control arm. In addition to conventional treatment, treatment arm received infliximab infusions 3 mg/kg body weight at 0, 2, 6 weeks and then q 8 weeks for a total of 24 weeks, that is, a total of five doses. Patients were closely monitored for infection. Clinical, laboratory and treatment data were entered into a pre-designed proforma. Health status (SF-36), patient global assessment (PGA) of disease activity, disease activity scores by SLEDAI and organ damage by SLICC/ACR-DI (American College Rheumatology) were measured at baseline and end of the study. Relevant immunological studies included serum levels of TNF-alpha and soluble TNF receptors-1 (p55 srTNF-alpha) and -2 (p75 srTNF-alpha), C3 and C4 complement levels, anti-dsDNA antibody titres (IgM, IgG and IgA isotypes), anti-cardiolipin titres (IgM, IgG and IgA isotypes) and anti-beta2GPI (Glycoprotein I) antibody titres (IgM, IgG and IgA isotypes). Four patients from treatment arm dropped out due to infliximab infusion reaction and 12 patients dropped out from the control arm. The treatment group showed significantly greater improvement in Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Improvements in several SF-36 subscales, PGA and VAS-Fatigue (Visual Analogue Scale) were also greater in the treatment group but did not achieve statistical significance. The mean levels of TNF-alpha, soluble TNF receptors-1 (p55 srTNF-alpha) and -2 (p75 srTNF-alpha) were higher in the SLE group compared with the healthy controls but did not change significantly over the study period. We did not face any safety issues with infliximab in this study. In view of improvement in several SLE parameters and good safety profile of infliximab, anti-TNF-alpha therapy is an interesting candidate approach for treating SLE.

Monocytes and T lymphocytes contribute to a predominance of interleukin 6 and interleukin 10 in systemic lupus erythematosus

OBJECTIVE

To investigate the contribution of T lymphocytes and monocytes to cytokine production in systemic lupus erythematosus (SLE).

METHODS

Forty-five SLE patients and 19 healthy volunteers were included. Serum levels of tumor necrosis factor alpha (TNFalpha), interferon gamma (IFN gamma), interleukin (IL)-6, and IL10 were quantified by ELISA. The cytokine production capacities of peripheral blood mononuclear cells were assessed by culturing in vitro with PMA+Ionomycin or LPS. The intracellular cytokine expression was measured by flow cytometry in T lymphocytes and monocytes, respectively. The influence of the disease activity (measured as the SLE-disease activity index; SLEDAI) and the treatment the patients were receiving was evaluated.

RESULTS

Serum IL10, IL6, and TNFalpha levels were increased in patients (P <or= 0.01), and a higher spontaneous (without stimuli) intracellular expression of IL10 in CD4+ and CD8+ T lymphocytes (P < 0.05) and of IL6 in monocytes (P = 0.01) were found. After stimulation, patients presented a higher percentage of CD4+ and CD8+ T lymphocytes producing IL4 and IL10 (P <or= 0.01), and of monocytes producing IL6 (P = 0.04) and IL10 (P = 0.008). The SLEDAI score was positively correlated with the percentage of CD4+IL10+ and CD8+IL10+ T lymphocytes (P < 0.01), and inversely correlated with CD8+TNFalpha+ (P= 0.02), CD4+IFN gamma+ (P = 0.04) and CD8+ IFN gamma+ (P = 0.002) T lymphocytes. Patients receiving high dose prednisone produced higher IL10, but they also were the patients with a more active disease.

CONCLUSION

Monocytes and T lymphocytes (CD4+ and CD8+) contribute to an overproduction of IL6 and IL10 in SLE; this correlates with the disease activity but is independent of the treatment the patients are receiving.

The pathophysiology of hypertension in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune inflammatory disorder that predominantly affects women during their reproductive years. Although SLE can affect any organ system, the kidneys are prominently involved in the form of immune complex glomerulonephritis. In addition, in women with SLE, risk for the development of cardiovascular disease is dramatically increased. Hypertension is a major risk factor for cardiovascular disease and is highly prevalent in women with SLE. Nevertheless, there has been little exploration of the pathophysiological mechanisms that promote SLE hypertension. This review discusses the role of several mechanisms, with an emphasis on the kidney, in SLE hypertension. These mechanisms include the renin-angiotensin system, endothelin, oxidative stress, sex steroids, metabolic changes, peroxisome proliferator-activated receptor-gamma, and, perhaps most importantly, chronic inflammation and cytokines. Growing evidence suggests a link between chronic inflammation and hypertension. Therefore, elucidation of mechanisms that promote SLE hypertension may be of significant value not only for patients with SLE, but also for a better understanding of the basis for essential hypertension.

Serum protein oxidation and apolipoprotein CIII levels in people with systemic lupus erythematosus with and without nephritis

Increased oxidative stress is a hallmark of the autoimmune disease systemic lupus erythematosus (SLE). This study compares serum protein oxidation levels in SLE patients without and with renal involvement (lupus nephritis); the latter have a significantly poorer prognosis. Similar increases in protein carbonyls and decreases in protein thiols were observed in both SLE groups compared to controls. Protein carbonyl distribution, determined by Western blotting of 2D gels, was similar in both SLE groups, suggesting factors other than oxidation also play a role in SLE complications. 2D electrophoresis examined the serum proteome further. Six proteins were significantly decreases in non-renal SLE patients compared to controls; five were identified by mass spectrometry, including one isoform of pro-atherogenic apoCIII. Total apoCIII levels (assessed by ELISA) in lupus nephritis patients were significantly elevated compared to controls or non-renal SLE patients. Thus, levels of oxidized proteins and apoCIII may be useful biomarkers in SLE studies.

Interleukin-10 promoter polymorphisms in patients with systemic lupus erythematosus from the Canary Islands

The purpose of this study was to examine whether several allelic variants in the polymorphic interleukin (IL)-10 promoter region were related with an increased risk of developing systemic lupus erythematosus (SLE) in Spanish patients from Canary Islands. Microsatellites (MS) at positions -4000 and -1200 (IL10R and IL10G, respectively) and single nucleotide polymorphisms (SNPs) (MS) at positions -1082G/A, -819C/T and -592C/A of the IL-10 promoter were analysed in patients with SLE and healthy controls from Canary Islands (Spain). We found that SNPs but not MS were associated with SLE. The GCC haplotype frequency was significantly higher in SLE patients (0.43) than in healthy donors (0.33) [P = 0.02; OR = 1.50 (95% CI = 1.06-2.14)], whereas the ACC haplotype was less represented in patients (0.28 vs. 0.37) [P = 0.02; OR = 0.64 (95% CI = 0.44-0.92)]. To assess the functional role of genotypes, serum IL-10 levels from patients and controls were quantified by ELISA. Also, the lipopolysaccharide-induced IL-10 secretion by monocytes from healthy controls was evaluated in vitro. Serum IL-10 levels were higher in patients [median (interquartile range) = 2.8 pg/mL (1.8-4.2)] than in controls [0.9 pg/mL (0-3.5)] (P = 0.02), but no association was observed between serum IL-10 levels or lipopolysaccharide-induced IL-10 secretion and the IL-10 promoter haplotypes. These data suggest that the IL-10 promoter haplotype that produces higher levels of cytokine is associated with SLE in patients from Canary Islands.

Safety and efficacy of infliximab in a patient with active WHO class IV lupus nephritis

Because disease activity in systemic lupus erythematosus correlates well with increased serum levels and activity of the cytokine tumor necrosis factor alpha (TNF-alpha), we report on the safety and efficacy of infliximab, a chimeric monoclonal antibody directed against TNF-alpha, given to a patient with active lupus with diffuse proliferative nephritis (WHO Class IV). This patient who failed to remit with a combination of full-dose steroids, mycophenolate mofetil, and cyclosporine, went into sustained remission with the addition of infliximab infusions.

Therapeutic efficacy and safety profile of infliximab in active systemic lupus erythematosus

Since levels of the proinflammatory cytokine tumor necrosis factor alpha (TNFalpha) are significantly increased in systemic lupus erythematosus (SLE) and may be involved in the disease pathogenesis, we report on the safety and efficacy of infliximab, a chimeric monoclonal antibody directed against TNFalpha, given to a patient with difficult-to-treat active nonrenal SLE. This patient, who failed to remit with full doses of glucocorticoids, hydroxychloroquine, methotrexate, and azathioprine, went into sustained remission with the addition of infliximab infusions. Glucocorticoids could be tapered off completely.

Increased levels of serum protein oxidation and correlation with disease activity in systemic lupus erythematosus

OBJECTIVE

To examine protein oxidation in systemic lupus erythematosus (SLE) and to correlate levels of protein oxidation products with disease activity.

METHODS

Serum was collected from SLE patients and healthy control subjects. Protein-bound carbonyls and the pro-oxidant enzyme myeloperoxidase (MPO) were quantified by enzyme-linked immunosorbent assay. Protein thiols were quantified using 5,5'-dithionitrobenzoic acid. Protein-bound amino acids and methionine, tyrosine, and phenylalanine oxidation products were quantified by acid hydrolysis and high-performance liquid chromatography. Disease activity was assessed by the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Levels of anti-double-stranded DNA (anti-dsDNA) antibodies were measured by radioimmunoassay.

RESULTS

Compared with control subjects, SLE patients exhibited elevated levels of protein carbonyls (0.108 +/- 0.078 versus 0.064 +/- 0.028 nmoles/mg of protein; P = 0.046), decreased levels of protein thiols (3.9 +/- 1.1 versus 4.9 +/- 0.7 nmoles/mg of protein; P = 0.003), decreased levels of protein-bound methionine (P = 0.0007), and increased levels of protein-bound methionine sulfoxide (P = 0.0043) and 3-nitrotyrosine (P = 0.0477). SLE patients with high SLEDAI scores or elevated anti-dsDNA antibody levels exhibited increased oxidation compared with patients with low SLEDAI scores or low antibody levels. Serum MPO levels were decreased in SLE patients (P = 0.03), suggesting that this enzyme is not responsible for the enhanced protein oxidation.

CONCLUSION

We found elevated levels of multiple markers of protein oxidation in sera from SLE patients compared with controls, and these levels correlated with disease activity. The findings suggest that protein oxidation may play a role in the pathogenesis of chronic organ damage in SLE.

Raised levels of interleukin 6 in systemic lupus erythematosus correlate with anaemia

OBJECTIVES

Raised levels of the cytokines interleukin (IL) 6 and IL10 have been reported in patients with systemic lupus erythematosus (SLE).

OBJECTIVE

To determine if levels of IL6 and IL10 correlate with organ/system-specific disease activity in SLE, using the British Isles Lupus Assessment Group (BILAG) Disease Activity Index.

METHODS

Levels of IL6 and IL10 in serum samples from 171 patients with SLE and 50 normal controls were determined by enzyme linked immunosorbent assay (ELISA). Levels of cytokines in individual patients with SLE were compared with the presence or absence of active disease in eight organ/systems using the BILAG index.

RESULTS

Levels of IL6 were significantly higher (p = 0.005) in patients with active compared with inactive haematological disease, as scored by the BILAG index. Further analysis showed that this association was dependent on an inverse correlation (p = 0.002, r = -0.26) between IL6 levels and haemoglobin levels in patients with SLE. In contrast, IL10 levels did not correlate with individual organ/system disease activity.

CONCLUSIONS

Raised levels of IL6 in SLE may influence the development of anaemia in this disease. These findings are in agreement with an increasing number of studies, which support physiological links between IL6 and anaemia. Importantly, with the exception of the haematological system, our studies do not provide evidence of any individual organ/system which would respond to therapeutic manipulation of either IL6 or IL10 levels.

The role of interleukin-10 in autoimmune disease: systemic lupus erythematosus (SLE) and multiple sclerosis (MS)

Interleukin-10 (IL-10) is an immunoregulatory cytokine that plays a crucial role in inflammatory and immune reactions. It has potent anti-inflammatory and immunosuppressive activities on myeloid cell functions which forms a solid basis for its use in acute and chronic inflammatory diseases. Here, we discuss the role of IL-10 in autoimmune diseases and examine its beneficial effects in cellular-based autoimmune diseases such as multiple sclerosis (MS) or its involvement in humoral-based autoimmune diseases such as systemic lupus erythematosus (SLE). Inhibition of the immune stimulatory activities of IL-10 may provide novel approaches in the treatment of humoral autoimmune diseases, infectious diseases and cancer.