Systems biology in systemic lupus erythematosus: Integrating genes, biology and immune function

Recent advances in pathogenesis, diagnosis, and therapeutic approaches for digestive system involvement in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by the presence of large amounts of autoantibodies and immune complex formation. Because of their atypical clinical symptoms, SLE patients with digestive system involvement may not be recognized or treated precisely and extensively. Clinicians should pay close attention to SLE with digestive system involvement, as these conditions can easily worsen the condition and possibly endanger the patient's life. In this review we summarized the pathogenesis, pathological characteristics, clinical manifestations, diagnosis, and therapies for digestive system involvement in SLE.

Systemic Lupus Erythematosus and the Ratio of Omega-3 to Omega-6 Fatty Acids Consumption among Women in the Adventist Health Study-2

OBJECTIVE

To assess the associations of omega-3 and omega-6 fatty acids consumption, and the ratio between the two, with self-reported doctor told Systemic Lupus Erythematosus (SLE) diagnosis. Further, to assess whether initiation of omega-3 supplements intake was related to time/year of SLE diagnosis.

METHODS

Data from 42,398 women in the Adventist Health Study-2 cohort were used for this cross-sectional study. Unconditional logistic regression modeling was used for all analyses with the following candidate covariates: age, race, education, smoking, and body mass index (BMI).

RESULTS

Compared to non-cases, participants with a diagnosis of SLE reported higher intakes of total omega-3 fatty acids and about the same intakes of omega-6 fatty acids. Overall, they had higher ratios of omega-3 to omega-6 fatty acids. When assessing odds ratios of SLE diagnosis by quartiles of omega-3 to omega-6 and DHA+EPA to omega-6, there was a positive significant trend (p trend = 0.005). Additionally, among those reporting intake of fish oil, 87% had initiated fish oil consumption around the time of SLE diagnosis. SLE was more likely to occur among Black women compared to White women, among ever smokers compared to never smokers, among overweight women compared to women with normal/underweight, and among women 50-59 years compared to those 30-49 year old. When a smaller 6 year follow-up study identified 64 incident SLE cases and assessed their omega-3 intake at baseline (6 years earlier and before the SLE diagnosis) their intake of omega-3 and fish oil was no different than among non-cases.

CONCLUSION

We observed a significant positive association between the ratio of omega-3 to omega-6 fatty acids consumption and prevalence of SLE. Among those with prevalent SLE, their year of starting supplementation of omega-3 and fish oil was closely linked to year of SLE diagnosis. Further, baseline intake of omega-3 fatty acids was not increased among 64 incident SLE cases identified during 6 years of follow-up. Our surprising finding can best be explained by reverse causation. This could be an example of how public health information is assimilated and acted upon by a health conscious public.

Steroids in Lupus: Enemies or Allies

Glucocorticoids are the gold standard treatment for reducing immune activation and inflammation in a wide range of inflammatory and systemic autoimmune diseases. Glucocorticoids have potent and fast actions that quickly relieve some symptoms and lower mortality in some life-threatening conditions, but they also have side effects that limit the duration of treatment and the dose used. Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by the involvement of numerous organs and systems and the production of autoantibodies. Most current treatments include the use of corticosteroids and immunosuppressive medications. Glucocorticoids in SLE have been classically used not only to induce remission or treat an acute situation but also as maintenance therapy. During the last decades, new approaches to managing SLE have emerged, but corticosteroids continue to be part of all therapeutic regimes. There is more and more evidence about the side effects related to the use (or abuse) of steroids and their relationship with the accrual damage. In this manuscript, we try to make a critical review of the published literature about the benefit and side effects/damage that can be attributed to the use of glucocorticoids.

Correlation between serum β2-microglobulin level and systemic lupus erythematosus disease activity: A PRISMA-compliant meta-analysis

BACKGROUND

Numerous studies have explored whether serum beta 2-microglobulin (β2-MG) can be used as a biomarker for monitoring systemic lupus erythematosus (SLE) disease activity, but the results are conflicting. Therefore, we performed a systematic meta-analysis to further investigate the correlation between serum β2-MG level and SLE disease activity.

METHODS

PubMed, Web of Science, Embase, and CNKI databases were thoroughly searched for eligible studies through April 2022. Standardized mean differences with 95% confidence intervals (95% CIs) were used to depict the differences in serum β2-MG levels between groups compared in the studies. The correlation between serum β2-MG level and SLE disease activity was assessed using Fisher z-values.

RESULTS

Sixteen articles with combined 1368 SLE patients were included in this meta-analysis. Serum β2-MG levels were significantly higher in SLE patients than in healthy controls (pooled standardized mean difference: 3.98, 95% CI: 2.50-5.46, P < .01). In addition, patients with active SLE had an increased serum β2-MG concentration compared to their inactive SLE counterparts. Furthermore, a positive correlation was observed between serum β2-MG levels and SLE disease activity (pooled Fisher z = 0.78, 95% CI: 0.61-0.96, P < .01).

CONCLUSIONS

This study suggests that patients with SLE have higher serum β2-MG levels than healthy controls and that serum β2-MG levels are positively correlated with SLE disease activity. Thus, serum β2-MG level may be a promising biomarker for monitoring SLE disease activity.

Serum Leptin Serves as an Inflammatory Activity Marker and Predicts Steroid Response in Autoimmune Hepatitis

BACKGROUND AND AIM

Adipocytokines, especially leptin is involved in a wide spectrum of proinflammatory functions, in various tissues. This study was carried out to assess the role of serum leptin in autoimmune hepatitis.

METHODS

Serum leptin was analyzed in treatment naïve autoimmune hepatitis (AIH, n = 48) patients and compared with the primary biliary cholangitis (PBC, n = 16), chronic hepatitis C (CHC, n = 16) and healthy controls (n = 15). Serum leptin correlation was assessed on liver function tests, disease activity, T regulatory cells (Tregs), and Th17 cells in the liver biopsies and on steroid treatment response in AIH.

RESULTS

Serum leptin was higher in AIH than in PBC, CHC, and HC {AIH: 335 (106.2-580), PBC: 126 (52-381.2), CH: 67 (3.7-133.5) and HC: 66 (40-157.5) ng/ml; P = 0.001}. In AIH cases; serum leptin correlated with hepatic activity index (r = 0.896; P < 0.001); serum transaminases (aspartate aminotransferases (AST) = 0.615, P < 0.001, alanine aminotransferases (ALT) = 0.551, P < 0.001). It had inverse correlation with Treg cells (P = -0.711, P < 0.001) and positively correlated with Th17 cells (r = 0.650, P < 0.001) in the liver biopsy tissue. High serum leptin was found to be associated with steroid partial or nonresponsiveness at 4 weeks (P = 0.002).

CONCLUSION

Serum leptin is indicative of higher AIH activity and a reduced number of Tregs cells in liver biopsy tissue. Leptin negative cases have more chances of steroid responsiveness and could help in the selection of AIH cases for appropriate therapy.

Evaluation of the serum β2 Microglobulin level in patients with systemic lupus erythematosus and its correlation with disease activity

BACKGROUND

Designation of disease activity is serious for the management of systemic lupus erythematosus (SLE). Serum level of β2 microglobulin (β2M) may be associated with illness activity in SLE disease. Since the role of β2M for assessing of illness activity in SLE is not completely clear, the current study aimed to discern evaluation of β2M in patients with SLE and its correlation with sickness activity.

MATERIALS AND METHODS

In this case-control study, 50 patients with SLE disease and 25 healthy individuals were selected in Imam Khomeini Hospital in central of Urmia. Blood samples were collected safely from patients, serum was removed, and β2M measured using an ELISA method. The results for other parameters including C reactive protein, C3, C4, anti dsDNA and erythrocyte sedimentation rate were obtained from patients' medical record. Data analyzed using appropriate statistical tests including Mann-Whitney U test, Independent f-test, Kruskal-Wallis, and Spearman used for analysis of data.

RESULTS

In the current study, a significant difference was seen between two groups in terms of β2M (p < 0.001). Remarkable correlation was seen between the level of β2M with disease activity (p < 0.001). Furthermore, there are significant relevancy between the level of β2M with 24-hour urine protein, ESR, disease activity score, and CRP (p < 0.05).

CONCLUSION

The results revealed that serum amount of β2M in SLE patients is higher compared to healthy ones, which is significantly correlated to score of illness activity, CRP, and ESR in patients with SLE disease. Hence β2M might be an excellent serological marker helping the prediction of sickness activity and inflammation in SLE patients.

Role of CTLA4 A49G polymorphism in systemic lupus erythematosus and its geographical distribution

CTLA-4 (cytotoxic T-lymphocyte-associated protein-4) or CD152 is an inhibitory receptor expressed constitutively on CD4+ CD25+ T regulatory lymphocytes and transiently on activated CD4+ and CD8+ T lymphocytes. Its inhibitory function promotes long-lived anergy in immune cells and prevents autoimmunity. Therefore, it plays a crucial role in T cell-mediated autoimmunity, and thus in susceptibility to autoimmune diseases, including systemic lupus erythematosus (SLE). It is encoded by CTLA4 gene in humans. AtoG polymorphism at position +49 of CTLA4 gene is the only polymorphism which changes amino acid sequence from alanine to threonine in the leader sequence, which may affect the function of CTLA-4. Association of CTLA4 polymorphisms with SLE has been investigated in several reports in different ethnic populations from different countries, which have shown highly inconsistent findings. In this review, we have compiled previous studies which have reported the association of CTLA4 A49G polymorphism in SLE and its geographical distribution.

Angiotensin-Converting Enzyme Gene I/D Polymorphism Is Associated With Systemic Lupus Erythematosus Susceptibility: An Updated Meta-Analysis and Trial Sequential Analysis

Angiotensin-converting enzyme (ACE) gene is indispensable for endothelial control and vascular tone regulatory systems, usually affected in Systemic Lupus Erythematosus (SLE). ACE insertion/deletion (I/D) polymorphism may influence the progress of SLE. Earlier studies have investigated this association without any consistency in results. We performed this meta-analysis to evaluate the precise association between ACE I/D polymorphism and SLE susceptibility. The relevant studies were searched until December, 2017 using Medline (PubMed), Google-Scholar and EMBASE search engines. Twenty-five published studies involving 3,308 cases and 4,235 controls were included in this meta-analysis. Statistically significant increased risk was found for allelic (D vs. I: p = 0.007; OR = 1.202, 95% CI = 1.052–1.374), homozygous (DD vs. II: p = 0.025; OR = 1.347, 95% CI = 1.038–1.748), dominant (DD+ID vs. II: p = 0.002; OR = 1.195, 95% CI = 1.070–1.334), and recessive (DD vs. ID+II: p = 0.023; OR = 1.338, 95% CI = 1.042–1.718) genetic models. Subgroup analysis stratified by Asian ethnicity revealed significant risk of SLE in allelic (D vs. I: p = 0.045; OR = 1.238, 95% CI = 1.005–1.525) and marginal risk in dominant (DD+ID vs. II: p = 0.056; OR = 1.192, 95% CI = 0.995–1.428) models; whereas, no association was observed for Caucasian and African population. Publication bias was absent. In conclusion, ACE I/D polymorphism has significant role in overall SLE risk and it can be exploited as a prognostic marker for early SLE predisposition.

Polymorphism of keratin 1 associates with systemic lupus erythematosus and systemic sclerosis in a south Chinese population

Both systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) diseases are related to the genetic and environmental factors, causing damage to the skin. The mutations of keratin 1 gene (KRT1) were reported to associate with skin diseases. The single-nucleotide polymorphism (SNP, rs14024) and the indel polymorphism (cds-indel, rs267607656), consisting mostly of the common haplotypes and could be used for genotyping of KRT1. We used the PCR with sequence specific primers (PCR-SSP) to determine the genotype of KRT1 in 164 SLE, 99 SSc patients, and 418 healthy controls. The results showed that the mutant with G at SNP rs14024 was associated with the high risk to SLE (p = 6.48×10-5) and SSc (p = 8.75×10-5), while the deletion allele at rs267607656 was associated with the low risk to SSc (p = 4.89×10-4) comparing to the normal controls. Haplogenotype, Del-/MU+ was associated with high susceptibility to SLE (OR = 1.87, p = 0.001) and SSc (OR = 2.29, p = 2.34×10-4). In contrast, the Haplogenotype Del+/MU- was associated with resistance to SLE (OR = 0.35, p = 6.24×10-5) and SSc (OR = 0.34, p = 0.001). This study demonstrates that the variations in KRT1 and the specific polymorphism of KRT1 in this Chinese Han population are associated with autoimmune diseases SLE and SSc. Typing KRT1 might be helpful to identify SLE and SSc patients.

Leptin promotes systemic lupus erythematosus by increasing autoantibody production and inhibiting immune regulation

Leptin is an adipocytokine that plays a key role in the modulation of immune responses and the development and maintenance of inflammation. Circulating levels of leptin are elevated in systemic lupus erythematosus (SLE) patients, but it is not clear whether this association can reflect a direct influence of leptin on the propathogenic events that lead to SLE. To investigate this possibility, we compared the extent of susceptibility to SLE and lupus manifestations between leptin-deficient (ob/ob) and H2-matched leptin-sufficient (wild-type, WT) mice that had been treated with the lupus-inducing agent pristane. Leptin deficiency protected ob/ob mice from the development of autoantibodies and renal disease and increased the frequency of immunoregulatory T cells (Tregs) compared with leptin-sufficient WT mice. The role of leptin in the development of SLE was confirmed in the New Zealand Black (NZB) × New Zealand White (NZW)F1 (NZB/W) mouse model of spontaneous SLE, where elevated leptin levels correlated with disease manifestations and the administration of leptin accelerated development of autoantibodies and renal disease. Conversely, leptin antagonism delayed disease progression and increased survival of severely nephritic NZB/W mice. At the cellular level, leptin promoted effector T-cell responses and facilitated the presentation of self-antigens to T cells, whereas it inhibited the activity of regulatory CD4 T cells. The understanding of the role of leptin in modulating autoimmune responses in SLE can open possibilities of leptin-targeted therapeutic intervention in the disease.

A T cell gene expression panel for the diagnosis and monitoring of disease activity in patients with systemic lupus erythematosus

Systemic Lupus Erythematosus (SLE) remains a challenging disease to diagnose and follow, as no reliable biomarkers are known to date. We designed a gene expression panel with 40 genes known to play a role in SLE pathogenesis. We found that the combined expression of these genes in SLE T cells can accurately differentiate SLE from healthy individuals and patients with other autoimmune diseases. The accuracy of the test increased further (83%) when only three out of the initial genes (OAS2, CD70 and IL10) were used. A T cell score, calculated from the combined expression levels of these genes, correlated positively with various SLE activity markers in a cross-sectional cohort and in a few patients that were followed prospectively. These data showcase the usefulness of measuring mRNA levels of key molecules in diagnosing and following patients with SLE.

Increased serum β2-microglobulin is associated with clinical and immunological markers of disease activity in systemic lupus erythematosus patients

The objective of this study was to explore the relationship between serum levels of β2-microglobulin (β2MG), which some studies suggest reflect disease activity in systemic lupus erythematosus (SLE), and various clinical and immunological markers of disease activity in SLE. Twenty-six SLE patients and 10 healthy controls were included. Disease activity was assessed by: SLEDAI, 24 hr-proteinuria, circulating levels of complement C3, anti-double-stranded DNA (anti-dsDNA), β2MG and various pro-inflammatory and anti-inflammatory cytokines (IL-6, IL-8, IL-10, IL-18) measured with a multiplex assay, IFN-α assessed with a reporter gene assay, and a combined expression score of 12 IFN-α inducible genes in peripheral blood mononuclear cells.

Median serum levels of β2MG were significantly higher in SLE patients vs controls (2.8 mg/L, range: 1.1–21.6 and 1.2 mg/L, range: 0.9–1.7, respectively, p < 0.001). β2MG was correlated with SLEDAI score ( R = 0.68, p < 0.001), 24 hr-proteinuria ( R = 0.64, p < 0.001), and complement C3 ( R = −0.52, p = 0.007). The cytokines were significantly correlated with β2MG: IL-6 ( R = 0.45, p = 0.02), IL-8 ( R = 0.75, p < 0.001), IL-10 ( R = 0.67, p < 0.001) and IL-18 ( R = 0.71, p < 0.001) as were serum IFN-α ( R = 0.45, p = 0.02) and the IFN-α inducible gene-score ( R = 0.51, p = 0.01). The results support that β2MG may serve as a marker of disease activity in SLE. The correlations with the measured cytokines indicate that increased β2MG in SLE reflects immunological activity.

Comparison of neuropsychological impairment and vocational outcomes in systemic lupus erythematosus and multiple sclerosis patients

Systemic lupus erythematosus (SLE) and multiple sclerosis (MS) are chronic immunologic diseases that can cause cognitive dysfunction. MS is a central nervous system (CNS) disease characterized by demyelination and progressive brain atrophy. SLE is an autoimmune disease capable of damaging multiple organ systems, including the CNS. Cognitive disturbances are seen in both SLE and MS. The present study is concerned with understanding the similarities and differences between the cognitive profiles of SLE and MS as well as the relationship between cognitive impairment and vocational disability in these patients. We examined 47 SLE patients, 47 MS patients, and 44 healthy controls. The groups were well matched on demographics and the patient groups were also matched on disease duration and severity. Group comparisons revealed that generative verbal fluency and visual-spatial memory are more profoundly affected in MS than SLE; whereas depression, fatigue, and working memory deficits are similarly involved in both diseases. Logistic regression analysis revealed that executive function, in particular, was predictive of vocational outcomes in SLE and MS patients.

Biomarkers for systemic lupus erythematosus

The urgent need for lupus biomarkers was demonstrated in September 2011 during a Workshop sponsored by the Food and Drug Administration: Potential Biomarkers Predictive of Disease Flare. After 2 days of discussion and more than 2 dozen presentations from thought leaders in both industry and academia, it became apparent that highly sought biomarkers to predict lupus flare have not yet been identified. Even short of the elusive biomarker of flare, few biomarkers for systemic lupus erythematosus (SLE) diagnosis, monitoring, and stratification have been validated and employed for making clinical decisions. This lack of reliable, specific biomarkers for SLE hampers proper clinical management of patients with SLE and impedes development of new lupus therapeutics. As such, the intensity of investigation to identify lupus biomarkers is climbing a steep trajectory, lending cautious optimism that a validated panel of biomarkers for lupus diagnosis, monitoring, stratification, and prediction of flare may soon be in hand.

Different effects of bortezomib on the expressions of various protein kinase C isoenzymes in T cells of patients with systemic lupus erythematosus and in Jurkat cells

The effects of proteosome inhibitor Bortezomib (BZ) were studied in vitro for 24 h on the protein kinase C (PKC) profiles, rates of proliferation and apoptosis in Jurkat cells and lymphocytes of 10 patients with systemic lupus erythematosus (SLE) and nine healthy subjects. The expressions of PKC proteins, the rates of proliferation and apoptosis were determined. The effects of BZ were different in the Jurkat and lupus T cells. Whereas BZ elevated the expression of PKC θ, δ and ξ isoenzymes in the Jurkat cells, it was unable to do that in the lupus T cells. BZ induced a dose-dependent increase in the apoptosis of Jurkat cells, while decreased the proliferation. The same effect of BZ was observed on the apoptosis of lymphocytes both in SLE and healthy subjects at concentrations higher than the therapeutic dose. We conclude that BZ treatment in vitro was not able to restore the SLE-specific defect (decrease) in the expression of PKC isoenzymes in the T cells as it was expected. This can be a limiting factor in the positive clinical effects of BZ in lupus.

CTLA-4 gene polymorphism and the risk of systemic lupus erythematosus in the Chinese population

Several variants of CTLA-4 have been reported to be associated with susceptibility systemic lupus erythematosus (SLE); however, findings have been inconsistent across different populations. Using a case-control study design, we have investigated the role of CTLA-4 polymorphism at positions −1661 and −1722 on SLE susceptibility in our Chinese SLE population in central China's Hubei province. Samples were collected from 148 SLE patients and 170 healthy controls. Polymerase chain reaction restriction fragments length polymorphism (PCR-RFLP) was used to analyze the genotypes of the two sites. Statistically significant difference was observed in genotypes for −1722, but not for −1661. The frequency of the T allele on the −1722 SNP was significantly increased in SLE patients: 57.8% versus 40.6% in controls (P < 0.001, OR = 2.002). While the detected C allele frequency in the controls was significantly elevated in comparison to that in the SLE patients (59.4% versus 42.2%). On the contrary, no association was found between SLE and CTLA-4 polymorphism at position −1661.

Beta 2-microglobulin can be a disease activity marker in systemic lupus erythematosus

BACKGROUND

To investigate the clinical significance of beta2-microglobulin in Korean patients with systemic lupus erythematosus (SLE).

METHODS

Blood samples were collected from patients with SLE (n = 100) and normal healthy controls (n = 50). The level of beta2-microglobulin was investigated by enzyme-linked immunosorbent assay. Serial samples from SLE patients were collected at 4.2 +/- 2.6 months after first sampling.

RESULTS

The beta2-microglobulin levels of the SLE patients (2.64 +/- 0.11 microg/mL) were higher than the normal controls (2.14 +/- 0.04 microg/mL, P < 0.001). The patients with SLE with serositis, oral ulcer, or lupus nephritis had significantly higher beta2-microglobulin levels than those without, respectively. A significant correlation was found between the beta2-microglobulin level and each of anti-dsDNA antibody, hemoglobin, complement, and SLE Disease Activity Index. In sequential sampling of patients with SLE, a positive correlation was found between the change of the SLE Disease Activity Index and the change of the beta2-microglobulin levels.

CONCLUSIONS

These data suggest that the measurement of beta2-microglobulin seem to be a useful addition to the laboratory tests that can help in assessment of disease activity of SLE.

Association of GSTT1, GSTM1 and CYP1A1 polymorphisms with susceptibility to systemic lupus erythematosus in the Chinese population

BACKGROUND

GSTT1, GSTM1, CYP1A1 are enzymes responsible for the detoxification of the toxicant which may be involved in the development of systemic lupus erythematosus (SLE). We examined the relationship between the risk of SLE and the polymorphisms of these genes in the Chinese population.

METHODS

Samples from 298 SLE patients and 284 healthy controls were collected. Polymerase chain reaction-restriction fragments length polymorphism (PCR-RFLP) was used to analyze the genotypes of CYP1A1 m2 and m4, while multiplex PCR was used to analyze the genotypes of GSTT1 and GSTM1.

RESULTS

Statistically significant difference was observed in genotypes for GSTM1 (p=0.003, OR 1.66 [95% CI 1.19-2.32]), but not for GSTT1 (p=0.119, OR 0.77 [95% CI 0.56-1.07]), in the SLE patients as compared with the controls. Combinational analysis for double-null deletion of both GSTT1 and GSTM1 showed no significant difference (p=0.863, OR 1.03 [95% CI 0.70-1.52]). Significant difference was observed in the genotype frequencies (p=0.013), but not in the allele frequencies (p=0.444, OR 0.90 [95% CI 0.70-1.17]), of CYP1A1 m2. All candidates have a wild-type genotype for CYP1A1 m4.

CONCLUSIONS

Polymorphisms of GSTM1 are associated with SLE in the Chinese population.

Pathogenic mechanisms in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic inflammatory disease characterized by the dysfunction of T cells, B cells, and dendritic cells and by the production of antinuclear autoantibodies. This editorial provides a synopsis of newly discovered genetic factors and signaling pathways in lupus pathogenesis that are documented in 11 state-of-the-art reviews and original articles. Mitochondrial hyperpolarization underlies mitochondrial dysfunction, depletion of ATP, oxidative stress, abnormal activation, and death signal processing in lupus T cells. The mammalian target of rapamycin, which is a sensor of the mitochondrial transmembrane potential, has been successfully targeted for treatment of SLE with rapamycin or sirolimus in both patients and animal models. Inhibition of oxidative stress, nitric oxide production, expression of endogenous retroviral and repetitive elements such as HRES-1, the long interspersed nuclear elements 1, Trex1, interferon alpha (IFN-alpha), toll-like receptors 7 and 9 (TLR-7/9), high-mobility group B1 protein, extracellular signal-regulated kinase, DNA methyl transferase 1, histone deacetylase, spleen tyrosine kinase, proteasome function, lysosome function, endosome recycling, actin cytoskeleton formation, the nuclear factor kappa B pathway, and activation of cytotoxic T cells showed efficacy in animal models of lupus. Although B cell depletion and blockade of anti-DNA antibodies and T-B cell interaction have shown success in animal models, human studies are currently ongoing to establish the value of several target molecules for treatment of patients with lupus. Ongoing oxidative stress and inflammation lead to accelerated atherosclerosis that emerged as a significant cause of mortality in SLE.

Systems biology of lupus: mapping the impact of genomic and environmental factors on gene expression signatures, cellular signaling, metabolic pathways, hormonal and cytokine imbalance, and selecting targets for treatment

Systemic lupus erythematosus (SLE) is characterized by the dysfunction of T cells, B cells, and dendritic cells, the release of pro-inflammatory nuclear materials from necrotic cells, and the formation of antinuclear antibodies (ANA) and immune complexes of ANA with DNA, RNA, and nuclear proteins. Activation of the mammalian target of rapamycin (mTOR) has recently emerged as a key factor in abnormal activation of T and B cells in SLE. In T cells, increased production of nitric oxide and mitochondrial hyperpolarization (MHP) were identified as metabolic checkpoints upstream of mTOR activation. mTOR controls the expression T-cell receptor-associated signaling proteins CD4 and CD3zeta through increased expression of the endosome recycling regulator Rab5 and HRES-1/Rab4 genes, enhances Ca2+ fluxing and skews the expression of tyrosine kinases both in T and B cells, and blocks the expression of Foxp3 and the generation of regulatory T cells. MHP, increased activity of mTOR, Rab GTPases, and Syk kinases, and enhanced Ca2+ flux have emerged as common T and B cell biomarkers and targets for treatment in SLE.

The search for lupus biomarkers

Few biomarkers for systemic lupus erythematosus (SLE) have been validated and employed for making clinical decisions. The lack of reliable, specific biomarkers for SLE hampers the proper clinical management of patients with SLE and impedes the development of new lupus therapeutics. This void has led to renewed enthusiasm for identifying biomarkers that precisely and specifically reflect the pathophysiological and clinical changes of SLE. Several laboratory markers have shown early promise as biomarkers for lupus susceptibility, diagnosis and monitoring. These include polymorphisms and copy-number variations of complement C4 and Fcgamma receptor genes (disease susceptibility), cell-bound complement C4d (diagnosis and/or disease activity), CD27(high) plasma cells (disease activity), 'interferon signature' (disease activity) and anti-C1q and anti-NMDA (disease activity and organ involvement). Although these and other promising candidate biomarkers have been identified, they still need to be validated through rigorous, large-scale multicentre studies. This article briefly reviews the historical aspects of lupus biomarkers and summarises current efforts to advance the field.

Estradiol targets T cell signaling pathways in human systemic lupus

The major risk factor for developing systemic lupus erythematosus (SLE) is being female. The present study utilized gene profiles of activated T cells from females with SLE and healthy controls to identify signaling pathways uniquely regulated by estradiol that could contribute to SLE pathogenesis. Selected downstream pathway genes (+/- estradiol) were measured by real time polymerase chain amplification. Estradiol uniquely upregulated six pathways in SLE T cells that control T cell function including interferon-alpha signaling. Measurement of interferon-alpha pathway target gene expression revealed significant differences (p= 0.043) in DRIP150 (+/- estradiol) in SLE T cell samples while IFIT1 expression was bimodal and correlated moderately (r= 0.55) with disease activity. The results indicate that estradiol alters signaling pathways in activated SLE T cells that control T cell function. Differential expression of transcriptional coactivators could influence estrogen-dependent gene regulation in T cell signaling and contribute to SLE onset and disease pathogenesis.

T-cell and B-cell signaling biomarkers and treatment targets in lupus

PURPOSE OF REVIEW

Systemic lupus erythematosus is characterized by the production of antinuclear autoantibodies and dysfunction of T-cells, B-cells, and dendritic cells. Here, we review newly recognized genetic factors and mechanisms that underlie abnormal intracellular signal processing and intercellular communication within the immune system in systemic lupus erythematosus.

RECENT FINDINGS

Activation of the mammalian target of rapamycin plays a pivotal role in abnormal activation of T and B-cells in systemic lupus erythematosus. In T-cells, increased production of nitric oxide and mitochondrial hyperpolarization were identified as metabolic checkpoints upstream of mammalian target of rapamycin activation. Mammalian target of rapamycin controls the expression T-cell receptor-associated signaling proteins CD4 and CD3zeta through increased expression of the endosome recycling regulator HRES-1/Rab4 gene, mediates enhanced Ca2+ fluxing and skews the expression of tyrosine kinases both in T and B-cells, and blocks the expression of Foxp3 and the expansion of regulatory T-cells. Mitochondrial hyperpolarization and the resultant ATP depletion predispose T-cells to necrosis, thus promoting the dendritic cell activation, antinuclear autoantibody production, and inflammation.

SUMMARY

Mitochondrial hyperpolarization, increased activity of mammalian target of rapamycin and Syk kinases, enhanced receptor recycling and Ca2+ flux have emerged as common T and B-cell biomarkers and targets for treatment in systemic lupus erythematosus.

Emerging new pathways of pathogenesis and targets for treatment in systemic lupus erythematosus and Sjogren's syndrome

PURPOSE OF REVIEW

Systemic lupus erythematosus (SLE) and Sjogren's syndrome are chronic inflammatory diseases characterized by the dysfunction of T cells, B cells, and dendritic cells and the production of antinuclear autoantibodies. Here, we evaluate newly discovered molecular and cellular targets for the treatment of SLE and Sjogren's syndrome.

RECENT FINDINGS

The mammalian target of rapamycin in T and B cells has been successfully targeted for treatment of SLE with rapamycin or sirolimus both in patients and animal models. Inhibition of oxidative stress, nitric oxide production, interferon alpha, toll-like receptors 7 and 9, histone deacetylase, spleen tyrosine kinase, proteasome function, lysosome function, endosome recycling, and the nuclear factor kappa B pathway showed efficacy in animal models of lupus. B-cell depletion and blockade of anti-DNA antibodies and T-B cell interaction have shown success in animal models, whereas human studies have so far failed to accomplish clinical endpoints, possibly due to inadequacies in study design.

SUMMARY

Discovery of novel genes and signaling pathways in lupus pathogenesis offers novel biomarker-targeted approaches for treatment of SLE and Sjogren's syndrome.

Immunogenetics of drug-induced skin blistering disorders. Part I: Perspective

The overall immunopathogenesis relevant to a large series of disorders caused by a drug or its associated hyperimmune condition is discussed based upon the examination of the genetics of severe drug-induced bullous skin problems (sporadic idiosyncratic adverse events, including Stevens-Johnson syndrome and toxic epidermal necrolysis). An overarching pharmacogenetic schema is proposed. Immune cognition and early-effector processes are focused upon and a challenging synthesis around systems evolution is explained by a variety of projective analogies. Etiology, human leukocyte antigen-B, immune stability, dysregulation, pharmacomimicry, viruses and an aggressive ethnically differentiated 'karmic' response are discussed.

Immunogenetics of drug-induced skin blistering disorders. Part II: Synthesis

The overall immunopathogenesis relevant to a large series of disorders caused by a drug or its associated hyperimmune condition is discussed based upon examining the genetics of severe drug-induced bullous skin problems (sporadic idiosyncratic adverse events including Stevens–Johnson syndrome and Toxic epidermal necrolysis). New results from an exemplar study on shared precipitating and perpetuating inner causes with other related disease phenotypes including aphtous stomatitis, Behçets, erythema multiforme, Hashimoto’s thyroiditis, pemphigus, periodic fevers, Sweet’s syndrome and drug-induced multisystem hypersensitivity are presented. A call for a collaborative, wider demographic profiling and deeper immunotyping in suggested future work is made.

Activation of mammalian target of rapamycin controls the loss of TCRzeta in lupus T cells through HRES-1/Rab4-regulated lysosomal degradation

Persistent mitochondrial hyperpolarization (MHP) and enhanced calcium fluxing underlie aberrant T cell activation and death pathway selection in systemic lupus erythematosus. Treatment with rapamycin, which effectively controls disease activity, normalizes CD3/CD28-induced calcium fluxing but fails to influence MHP, suggesting that altered calcium fluxing is downstream or independent of mitochondrial dysfunction. In this article, we show that activity of the mammalian target of rapamycin (mTOR), which is a sensor of the mitochondrial transmembrane potential, is increased in lupus T cells. Activation of mTOR was inducible by NO, a key trigger of MHP, which in turn enhanced the expression of HRES-1/Rab4, a small GTPase that regulates recycling of surface receptors through early endosomes. Expression of HRES-1/Rab4 was increased in CD4(+) lupus T cells, and in accordance with its dominant impact on the endocytic recycling of CD4, it was inversely correlated with diminished CD4 expression. HRES-1/Rab4 overexpression was also inversely correlated with diminished TCRzeta protein levels. Pull-down studies revealed a direct interaction of HRES-1/Rab4 with CD4 and TCRzeta. Importantly, the deficiency of the TCRzeta chain and of Lck and the compensatory up-regulation of FcepsilonRIgamma and Syk, which mediate enhanced calcium fluxing in lupus T cells, were reversed in patients treated with rapamcyin in vivo. Knockdown of HRES-1/Rab4 by small interfering RNA and inhibitors of lysosomal function augmented TCRzeta protein levels in vitro. The results suggest that activation of mTOR causes the loss of TCRzeta in lupus T cells through HRES-1/Rab4-dependent lysosomal degradation.

Cytokines and their receptors as biomarkers of systemic lupus erythematosus

Systemic lupus erythematosus is the most clinically diverse autoimmune disease. Owing to its heterogeneous presentation, clinical management of systemic lupus erythematosus remains as one of the greatest challenges. Therefore, there is a great need to assess disease activity accurately. Biomarkers can be objectively measured and evaluated as an indicator of normal biologic processes, pathogenic processes or pharmacologic responses to a therapeutic intervention, and may also predict the risk of the disease, confirm diagnosis, monitor disease activity and provide prognostic information. Cytokines play an important and diverse role in the immune dysregulation in systemic lupus erythematosus. Measuring serum levels of soluble IL-2 receptor, IL-6, IL-10, soluble TNF receptor and IFN-alpha/IFN-induced genes may be promising biomarkers of disease activity in systemic lupus erythematosus.

Neuropsychological impairment in systemic lupus erythematosus: a comparison with multiple sclerosis

In this manuscript, we review literature describing the neuropsychological and brain imaging characteristics of systemic lupus erythematosus (SLE) patients. The findings are compared and contrasted with multiple sclerosis (MS) studies, revealing similarities and differences of interest to clinicians and researchers. While cognitive impairment is somewhat less common in SLE than MS, the diseases share a similar cognitive profile with deficits most prominent on tests emphasizing the speed of information processing, working memory, and visual/spatial learning, and memory. In early or more mildly affected patients, diffuse white matter damage, which may not be apparent on conventional brain imaging, plays a major role in clinical presentation and cognitive testing. The causes of white matter damage are very different, however, and in later stages of the disease MS and SLE appear to give rise to different forms of cerebral pathology. MS may be characterized by increasing brain atrophy affecting especially the cortical and deep gray matter, at least after conversion to secondary progressive course. There is less evidence for neurodegenerative changes in SLE, but patients are increasingly at risk for cerebrovascular disease. We conclude by offering some suggestions for future clinical and imaging research.

Systemic lupus erythaematosus in a multiethnic US cohort (LUMINA) LIII: disease expression and outcome in acute onset lupus

OBJECTIVE

To determine the features associated with acute onset systemic lupus erythaematosus (SLE).

METHODS

A total of 631 SLE patients from LUMINA (for "lupus in minority populations: nature vs nurture"), a multiethnic (Hispanics, African-Americans and Caucasians) cohort, were studied. Acute disease onset was defined as the accrual of > or = 4 American College of Rheumatology (ACR) criteria for the classification of SLE in < or = 4 weeks. Socioeconomic demographic features, clinical manifestations, disease activity, damage accrual, mortality, autoantibodies, HLA class II and FCGR alleles, behavioural/psychological variables were compared between patients with acute and insidious disease onset by univariable (chi(2) and Student t test) and multivariable (stepwise logistic regression) analyses.

RESULTS

A total of 94 (15%) patients had acute disease onset. In the multivariable analysis, patients with acute onset lupus had more renal involvement (odds ratio (OR) = 1.845, 95% CI 1.076-3.162; p = 0.026) and higher disease activity (OR = 1.057, 95% CI 1.005-1.112; p = 0.030). By contrast, age (OR = 0.976, 95% CI 0.956-0.997; p = 0.025), education (OR = 0.901, 95% CI 0.827-0.983, p = 0.019), health insurance (OR = 0.423, 95% CI 0.249-0.718; p = 0.001) and skin involvement (OR = 0.346, 95% CI 0.142-0.843; p = 0.019) were negatively associated with acute onset lupus. No differences were found regarding the serological, genetic and behavioural/psychological features; this was also the case for damage accrual and mortality.

CONCLUSIONS

Patients with acute onset lupus seem to be younger, have a lower socio-economic status and display more severe disease in terms of clinical manifestations and disease activity. However, intermediate (damage) and long-term (mortality) outcomes appear not to be influenced by the type of disease onset in SLE.

The IRF5 polymorphism in type 1 diabetes

The interferon regulatory factor 5 gene (IRF5) has been shown to play a crucial role in harmful immune responses by induction of proinflammatory cytokines. Functional genetic variants associated with increased IRF5 expression of specific isoforms are associated with systemic lupus erythematosus (SLE) and it is possible that they may also predispose to other autoimmune disorders. We tested the association of two IRF5 SNPs, correlated with IRF5 expression and SLE risk, in 947 nuclear family trios type 1 diabetes (T1D) using the transmission disequilibrium test. Our results suggest that the functional IRF5 variations do not confer an obvious risk for T1D.