Etiopathogenesis of systemic lupus erythematosus

Interplay between the Chaperone System and Gut Microbiota Dysbiosis in Systemic Lupus Erythematosus Pathogenesis: Is Molecular Mimicry the Missing Link between Those Two Factors?

Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease characterized by self-immune tolerance breakdown and the production of autoantibodies, causing the deposition of immune complexes and triggering inflammation and immune-mediated damage. SLE pathogenesis involves genetic predisposition and a combination of environmental factors. Clinical manifestations are variable, making an early diagnosis challenging. Heat shock proteins (Hsps), belonging to the chaperone system, interact with the immune system, acting as pro-inflammatory factors, autoantigens, as well as immune tolerance promoters. Increased levels of some Hsps and the production of autoantibodies against them are correlated with SLE onset and progression. The production of these autoantibodies has been attributed to molecular mimicry, occurring upon viral and bacterial infections, since they are evolutionary highly conserved. Gut microbiota dysbiosis has been associated with the occurrence and severity of SLE. Numerous findings suggest that proteins and metabolites of commensal bacteria can mimic autoantigens, inducing autoimmunity, because of molecular mimicry. Here, we propose that shared epitopes between human Hsps and those of gut commensal bacteria cause the production of anti-Hsp autoantibodies that cross-react with human molecules, contributing to SLE pathogenesis. Thus, the involvement of the chaperone system, gut microbiota dysbiosis, and molecular mimicry in SLE ought to be coordinately studied.

A clinical population pharmacokinetic/pharmacodynamic model for BIIB059, a monoclonal antibody for the treatment of systemic and cutaneous lupus erythematosus

A population pharmacokinetic/pharmacodynamic (popPK/PD) model for BIIB059 (anti-blood dendritic cell antigen 2 [anti-BDCA2]), a humanized immunoglobulin G1 monoclonal antibody currently under development for the treatment of SLE and CLE, is presented. BIIB059 binds BDCA2, a plasmacytoid dendritic cell (pDC)-specific receptor that inhibits the production of IFN-I and other inflammatory mediators when ligated. Phase 1 PK and PD data of healthy adult volunteers (HV, n = 87) and SLE subjects (n = 22) were utilized for the development of the popPK/PD model. The data included single and multiple dosing of intravenous and subcutaneous BIIB059. BDCA2 internalization (PD marker) was measured for all subjects by monitoring reduction of BDCA2 on pDC cell surface and used for development of the popPD model. A two-compartment popPK model with linear plus non-linear elimination was found to best describe BIIB059 PK. BDCA2 levels were best captured using an indirect response model with stimulation of the elimination of BDCA2. Clearance in SLE subjects was 25% higher compared to HV (6.87 vs 5.52 mL/h). Bodyweight was identified as only other covariate on clearance and central volume. The estimates of EC₅₀ and E_max were 0.35 μg/mL and 8.92, respectively. No difference in EC₅₀ and E_max was observed between SLE and HV. The popPK/PD model described the data accurately, as evaluated by pcVPCs and bootstrap. The presented popPK/PD model for BIIB059 provides valuable insight into the dynamics and dose-response relationship of BIIB059 for the treatment of SLE and CLE and was used to guide dose selection for the Phase 2 clinical study (NCT02847598).

Temporomandibular Disorders and Oral Features in Systemic Lupus Erythematosus Patients: An Observational Study of Symptoms and Signs

Aims: Systemic Lupus Erythematosus (SLE) is a connective tissue disease characterized by a wide range of pleomorphic pictures, including mucocutaneous, renal, musculoskeletal and neurological symptoms. It involves oral tissues, with hyposalivation, tooth decay, gingivitis, angular cheilitis, ulcers and glossitis. Temporomandibular disorders represent a heterogeneous group of inflammatory or degenerative diseases of the stomatognatic system, with algic and/or dysfunctional clinical features involving temporomandibular joint (TMJ) and related masticatory muscles. The aim of this study was to investigate the prevalence of oral manifestations and temporomandibular disorders (TMD) in SLE patients (Lp) compared with a control group. Methods: Fifty-five patients (9 men and 46 women) with diagnosed Lupus were recruited in the study group. A randomly selected group of 55 patients, matched by sex and age, served as control group. The examination for TMD symptoms and signs was based on the standardized Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) through a questionnaire and clinical examination. Results: Lupus patients complained more frequently (95.8%) of oral and TMJ symptoms (dysgeusia, stomatodynia, masticatory muscle pain during function, neck and shoulder muscles pain and presence of tinnitus) but only xerostomia (χ2=4,1548 p=0,0415), temple headache (χ2=4,4542 p=0,035) and the sensation of a stuck jaw (Mid-p-test p=0,043) were significant. About signs, cheilitis (p=0,0284) oral ulcers (χ2=4,0104 p=0,045) and fissured tongue are significantly more frequent in study group. The salivary flow was significantly decreased in the study group respect to the control one (p<0.0001). As regard to the oral kinematics, restricted movements (RM) in protrusion and left lateral movement were significantly different between study group and controls. In particular, 85,2% of Lp showed limited protrusion versus 56,4% of controls (χ2= 10,91 p<0,001); 59,3% of Lp had also a limitation during left lateral movement versus 47,3% of controls (T=2,225 p=0,0282). About bruxism, only the indentations on the lateral edges of the tongue were found in Lp group (72,7%), with a significant difference respect to controls (χ2=7,37 p=0,007). Conclusions: While masticatory muscles have an overlapping behavior in both groups, the findings collected show a more severe TMJ kinematic impairment in Lp than in controls, with protrusion and left lateral movements significantly different. In addition, a remarkable reduction of salivary flow has been detected in Lp compared to controls. In conclusion, this autoimmune disease seems to play a role in oral manifestations and TMJ disorders, causing an increase in orofacial pain and an altered chewing function.

Performance of cytokine models in predicting SLE activity

Background

Identification of universal biomarkers to predict systemic lupus erythematosus (SLE) flares is challenging due to the heterogeneity of the disease. Several biomarkers have been reported. However, the data of validated biomarkers to use as a predictor for lupus flares show variation. This study aimed to identify the biomarkers that are sensitive and specific to predict lupus flares.

Methods

One hundred and twenty-four SLE patients enrolled in this study and were prospectively followed up. The evaluation of disease activity achieved by the SLE disease activity index (SLEDAI-2K) and clinical SLEDAI (modified SLEDAI). Patients with active SLE were categorized into renal or non-renal flares. Serum cytokines were measured by multiplex bead-based flow cytometry. The correlation and logistic regression analysis were performed.

Results

Levels of IFN-α, MCP-1, IL-6, IL-8, and IL-18 significantly increased in active SLE and correlated with clinical SLEDAI. Complement C3 showed a weakly negative relationship with IFN-α and IL-18. IL-18 showed the highest positive likelihood ratios for active SLE. Multiple logistic regression analysis showed that IL-6, IL-8, and IL-18 significantly increased odds ratio (OR) for active SLE at baseline while complement C3 and IL-18 increased OR for active SLE at 12 weeks. IL-18 and IL-6 yielded higher sensitivity and specificity than anti-dsDNA and C3 to predict active renal and active non-renal, respectively.

Conclusion

The heterogeneity of SLE pathogenesis leads to different signaling mechanisms and mediates through several cytokines. The monitoring of cytokines increases the sensitivity and specificity to determine SLE disease activity. IL-18 predicts the risk of active renal SLE while IL-6 and IL-8 predict the risk of active non-renal. The sensitivity and specificity of these cytokines are higher than the anti-dsDNA or C3. We propose to use the serum level of IL-18, IL-6, and IL-8 to monitor SLE disease activity in clinical practice.

Impacts of GFP-FoxP3+ regulatory T cells on lupus hallmarks differ by genetic background and type of GFP knock-in

FoxP3 reporter mice expressing green fluorescence protein (GFP) have been used as a very convenient tool to investigate the impact of regulatory T (Treg) cells on pathogenesis in autoimmune diseases. Here, we found that GFP-FoxP3⁺ knock-in (KI) mice showed alterations in the production of anti-nuclear autoantibodies (ANAs) and nephritis with different extent, depending on the presence or absence of lupus susceptibility gene locus 1 (Sle1) and KI method: contrasting with B6.Sle1.fGFP-FoxP3 mice, expressing GFP via N-terminal insertion, B6.Sle1.iGFP-FoxP3, expressing GFP via bicistronic internal ribosome entry site-driven promotion, exhibited significantly lower penetrance of serum ANA, comparing to control B6.Sle1 mice. Moreover, B6.Sle1.GFP-FoxP3⁺ mice reduced the Sle1-induced splenomegaly and B-cell expansion independently of the KI method employed, mainly by reducing the numbers of transitional 1 (T1) B cells and CD21^-CD23^- B cells, including plasmablasts and plasma cells. The absolute numbers of both splenic CD4⁺ T cells and Treg cells from B6.Sle1.GFP-FoxP3 KI mice were significantly reduced but their proportion was not changed, compared to B6.Sle1 mice. Although the glomerular basement membranes were thickened in both B6.Sle1 and B6.Sle1.iGFP-FoxP3 mice, they were thinner in B6.Sle1.fGFP-FoxP3 mice. The latter mice expressed more nephrophilic autoantibodies and deposited more complement component 3 in glomeruli compared to B6.iGFP-FoxP3 mice. FoxP3⁺ Treg cells may modulate B-cell tolerance in lupus-prone B6.Sle1 mice, presumably by modulating pathogenic, nephrophilic autoantibody production and nephritis.

Serum and urine interleukin-17A levels as biomarkers of disease activity in systemic lupus erythematosus

OBJECTIVES

This study examined the correlations of both serum and urine interleukin-17A (IL-17A) levels with disease activity in systemic lupus erythematosus (SLE). This study was also aimed at determining their sensitivity and specificity as biomarkers of disease activity in SLE.

METHODS

A cross-sectional study was performed involving SLE patients (n = 120 patients) from Universiti Kebangsaan Malaysia Medical Centre (UKMMC). Serum and urinary IL-17A levels were determined by immunoassay while disease activity was assessed using Systemic Lupus Erythematosus Disease Activity Index-2000 (SLEDAI-2K) and British Isles Lupus Assessment Group's 2004 index (BILAG 2004) scores. The correlations between serum and urinary IL-17A levels with total SLEDAI-2K and BILAG 2004 scores were determined using bivariate correlation analyses. Receiver operating characteristic curves were calculated to determine their sensitivity and specificity as disease activity biomarkers.

RESULTS

Both serum and urinary IL-17A levels correlated with total scores of BILAG 2004, BILAG renal, BILAG mucocutaneous, and SLEDAI-2K (P < 0.05). Urine IL-17A levels correlated positively with urine protein : creatinine index while serum IL-17 level correlated with the BILAG hematology score (all P < 0.05). The area under curve of serum IL-17A and urine IL-17A with BILAG and SLEDAI scores were low (<0.75).

CONCLUSION

Despite positive correlations between serum and urine IL-17A with SLE disease activity, both were neither sensitive nor specific as biomarkers to predict active disease. Hence, IL-17 measurement has no role in SLE disease activity assessments and future studies are needed to search for other reliable activity biomarkers.

ATP signaling and NTPDase in Systemic Lupus Erythematosus (SLE)

Systemic lupus erythematosus (SLE) is an autoimmune and inflammatory disease with periods of exacerbation and remission. SLE is characterized by the irreversible breakdown of immunological self-tolerance, where there is deregulation of multiple aspects of the immune system. SLE immune dysfunction is characterized by activation of autoreactive T lymphocytes, and hyperactivity of B lymphocytes with consequent production of several autoantibodies. ATP is a purinergic mediator released into the extracellular space in response to cell and tissue damage which operates as a danger signal to modulate immune and inflammatory responses. ATP binds to P2 receptors and its levels are regulated by NTPDase (CD39). SLE patients exhibit increased levels of ATP which binds to P2X receptors resulting in activation of the inflammasome and consequent release of IL-1β and IL-18, cytokines associated with disease pathogenesis. CD39 is upregulated in SLE representing an important immunoregulatory mechanism by controlling inflammation and favoring the production of adenosine. The aim of this review is to clarify the effects of ATP on the modulation of the inflammatory process and immune responses via P2 receptors as well as the role of NTPDase in the immunopathogenesis of SLE.

The model of circulating immune complexes and interleukin-6 improves the prediction of disease activity in systemic lupus erythematosus

Systemic Lupus Erythematosus (SLE) is an autoimmune disease resulting in autoantibody production, immune complex deposition, and complement activation. The standard biomarkers such as anti-dsDNA and complements (C3 and C4) do not always correlate with active clinical SLE. The heterogeneity of SLE patients may require additional biomarkers to designate disease activity. Ninety SLE patients participated in this study. Evaluation of disease activity was achieved with the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) and modified SLEDAI-2K. The measured serum biomarkers were anti-dsDNA, C3, C4, ESR, interleukin-6 (IL-6), and circulating immune complexes (CIC). IL-6, ESR and CIC significantly increased in active clinical SLE. Complement, anti-dsDNA, ESR and CIC correlated with SLEDAI-2K while only anti-dsDNA, CIC, ESR and IL-6 correlated with modified SLEDAI-2K. A combination of biomarkers gave a higher odds ratio (OR) than any single biomarker. A combination of IL-6 or CIC exhibited the highest OR (OR = 7.27, 95%CI (1.99-26.63), p = 0.003) while either complement or anti-dsDNA showed a moderate odds ratio (OR = 3.14, 95%CI (1.16-8.48), p = 0.024) of predicting clinical active SLE. The combination of CIC and IL-6 strongly predicts active clinical SLE. CIC and IL-6 can be used in addition to standard biomarkers to determine SLE activity.

Elevated levels of CCR6+ T helper 22 cells correlate with skin and renal impairment in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease with a variety of pathological features. Our study investigated the potential role of CCR6+ T cells in organ impairment of SLE patients. We analyzed CCR6+/- T cell subset populations and compared the concentrations of IL-22, IFN-γ, TNF-α, and IL-17A cytokines in 67 patients with newly diagnosed SLE and 26 healthy controls. We found that SLE patients had elevated percentages of CCR6+ T, CCR6+ Th22, Th17, Th17.1, and CCR6- Th2 cell subsets, along with increased concentrations of IL-22, IFN-γ, TNF-α, and IL-17 cytokines. Higher levels of CCR6+ T and CCR6+ Th22 cells, along with plasma IL-22 were observed in SLE patients with sole skin and/or renal impairment. The percentage of Th22 cells also correlated with Revised Cutaneous Lupus Erythematosus Disease Area and Severity Index (RCLASI) and IgG levels, and inversely correlated with C3 levels in SLE patients with sole skin impairment. SLE patients with sole renal impairment showed a correlation between the percentage of Th22 cells and ESR levels. Our data indicated that CCR6+ Th22 cells may contribute to the pathogenesis of new onset SLE patients with skin or renal impairment, and CCR6 may, thus, be a possible therapeutic target for SLE treatment.

Chloroquine treatment reduces the number of cutaneous HLA-DR+ and CD1a+ cells in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that can be exacerbated by exposure to ultraviolet radiation (UVR). The number and phenotype of antigen presenting cells in the skin play a role in cutaneous immune response generation. Although antimalarials are widely used in SLE treatment, their mode of action is not completely elucidated. The aim of our study was to determine the effect of chloroquine treatment on HLA-DR+ and CD1a+ cell number in locally irradiated (three minimal erythema doses of UVB) and normal appearing skin in SLE patients and healthy subjects. A significantly higher number of HLA-DR+ and CD1a+ cells were found in both locations in SLE patients compared with controls. Following three months of daily chloroquine treatment (250 mg), the HLA-DR+ and CD1a+ cell counts were significantly reduced in both irradiated and unirradiated sites of SLE patients, although still higher than in controls. Chloroquine treatment reduces the number of antigen presenting cells in the skin of SLE patients, and this effect may explain the antimalarials beneficial immunoregulatory and anti-inflammatory properties.

Impaired phagocytosis of apoptotic cell material in serologically active clinically quiescent patients with systemic lupus erythematosis

AIM

Serologically active clinically quiescent (SACQ) patients with systemic lupus erythematosus (SLE) account for 8-12% of all patients with SLE, but there is disagreement about whether such patients are indeed clinically stable. Patients with clinically active SLE have decreased macrophage function, although the status of SACQ patients with SLE is unclear.

METHOD

This study compared 18 patients who met the diagnostic criteria for SACQ SLE with 18 healthy volunteers with regard to the capability of macrophages to clear apoptotic bodies by use of a modified serum-free phagocytosis test. Macrophages that naturally differentiated from monocytes were used to engulf apoptotic cells developed from polymorphonuclear neutrophils.

RESULTS

The results showed that macrophages from SACQ patients with SLE had less phagocytotic capability than those from healthy controls.

CONCLUSION

The significant reduction of macrophage phagocytotic capability in these patients suggests the potential for disease recurrence. The use of a serum-free method confirmed the presence of intrinsic factors that modulate the decrease of macrophage function in SLE.

HMGB1 Promotes Systemic Lupus Erythematosus by Enhancing Macrophage Inflammatory Response

Background/Purpose. HMGB1, which may act as a proinflammatory mediator, has been proposed to contribute to the pathogenesis of multiple chronic inflammatory and autoimmune diseases including systemic lupus erythematosus (SLE); however, the precise mechanism of HMGB1 in the pathogenic process of SLE remains obscure. Method. The expression of HMGB1 was measured by ELISA and western blot. The ELISA was also applied to detect proinflammatory cytokines levels. Furthermore, nephritic pathology was evaluated by H&E staining of renal tissues. Results. In this study, we found that HMGB1 levels were significantly increased and correlated with SLE disease activity in both clinical patients and murine model. Furthermore, gain- and loss-of-function analysis showed that HMGB1 exacerbated the severity of SLE. Of note, the HMGB1 levels were found to be associated with the levels of proinflammatory cytokines such as TNF-α and IL-6 in SLE patients. Further study demonstrated that increased HMGB1 expression deteriorated the severity of SLE via enhancing macrophage inflammatory response. Moreover, we found that receptor of advanced glycation end products played a critical role in HMGB1-mediated macrophage inflammatory response. Conclusion. These findings suggested that HMGB1 might be a risk factor for SLE, and manipulation of HMGB1 signaling might provide a therapeutic strategy for SLE.

Interleukin-2 treatment reverses effects of cAMP-responsive element modulator α-over-expressing T cells in autoimmune-prone mice

Systemic autoimmune diseases, such as systemic lupus erythematosus (SLE), are often characterized by a failure of self-tolerance and result in an uncontrolled activation of B cells and effector T cells. Interleukin (IL)-2 critically maintains homeostasis of regulatory T cells (T(reg)) and effector T cells in the periphery. Previously, we identified the cAMP-responsive element modulator α (CREMα) as a major factor responsible for decreased IL-2 production in T cells from SLE patients. Additionally, using a transgenic mouse that specifically over-expresses CREMα in T cells (CD2CREMαtg), we provided in-vivo evidence that CREMα indeed suppresses IL-2 production. To analyse the effects of CREMα in an autoimmune prone mouse model we introduced a Fas mutation in the CD2CREMαtg mice (FVB/Fas(-/-) CD2CREMαtg). Overexpression of CREMα strongly accelerated the lymphadenopathy and splenomegaly in the FVB/Fas(-/-) mice. This was accompanied by a massive expansion of double-negative (DN) T cells, enhanced numbers of interferon (IFN)-γ-producing T cells and reduced percentages of T(regs). Treatment of FVB/Fas(-/-) CD2CREMαtg mice with IL-2 restored the percentage of T(regs) and reversed increased IFN-γ production, but did not affect the number of DNTs. Our data indicate that CREMα contributes to the failure of tolerance in SLE by favouring effector T cells and decreasing regulatory T cells, partially mediated by repression of IL-2 in vivo.

Decreased interleukin 35 and CD4+EBI3+ T cells in patients with active systemic lupus erythematosus

BACKGROUND

Interleukin 35 (IL-35) is likely to contribute to the development of autoimmune diseases, as the Epstein-Barr virus-induced gene protein 3 (EBI3) is the specificity subunit of IL-35. Nevertheless, until recently, no studies have evaluated its role in systemic lupus erythematosus (SLE) in humans. The objective of this study was to investigate the serum IL-35 level and the percentage of CD4EBI3 T cells in the peripheral blood of patients with SLE and explore the roles of double-positive T cells and IL-35 in the pathogenesis of SLE and the effects of glucocorticoid on these roles.

METHODS

Fifty-five hospitalized patients with SLE were recruited, and 20 volunteers were enrolled as healthy controls. Serum IL-35 levels were measured by enzyme-linked immunosorbent assay, and the percentage of CD4EBI3 T cells was analyzed by flow cytometry.

RESULTS

The serum IL-35 level and the percentage of CD4EBI3 T cells were significantly decreased in patients with active SLE compared with healthy controls and patients with inactive SLE. The serum IL-35 level and the percentage of CD4EBI3 T cells were negatively correlated with the SLE disease activity index. The percentages of CD4EBI3 T cells and serum IL-35 levels in 10 untreated patients with active SLE were increased at days l, 3, and 7 after the treatment with methylprednisolone (0.8 mg·kg·d) compared with the percentages before the treatment.

CONCLUSIONS

These results demonstrate that abnormalities in IL-35 and CD4EBI3 T cells may play important roles in the pathogenesis of SLE; the percentage of double-positive T cells and the level of IL-35 are parameters for the evaluation of SLE activity and severity.

The lupus susceptibility locus Sle1 facilitates the peripheral development and selection of anti-DNA B cells through impaired receptor editing

Systemic lupus erythematosus is characterized by the spontaneous production of IgG autoantibodies in patients and lupus-prone mice. In this study, we investigated the effect of the Sle1 lupus susceptibility locus on the peripheral development of 56R(+) anti-DNA transgenic B cells by tracking 56R(+) B cells in mice without (B6.56R) or with (B6.Sle1.56R) the Sle1 locus. Compared with B6.56R mice, B6.Sle1.56R mice exhibited increased class-switched IgG2a anti-DNA Abs in their serum, encoded by the transgene. Interestingly, within the spleen, Sle1 facilitated the development of these cells into clusters of IgG2a class-switched B cells juxtaposed to CD4(+) T cells within extrafollicular sites. Through sequence analysis of B cell hybridomas, we also found that B cells from B6.Sle1.56R mice are inefficient at Ig H and L chain editing. Thus, the Ig H chains in Sle1.56R(+) B cells are partnered more often with cationic L chains that facilitate DNA binding. Taken together, these findings indicate that the Sle1 lupus-susceptibility locus may facilitate the emergence of anti-DNA B cells by subduing BCR revision and possibly by shaping the extrafollicular development of effector B cells, although the precise molecular mechanisms await further study.

MicroRNAs in the pathogenesis of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease, characterized by the production of autoantibodies against multiple organs. MicroRNAs (miRNAs) are non-coding, single-stranded small RNAs that post-transcriptionally regulate gene expression. Evidence is accumulating that miRNAs play a pivotal role in the pathogenesis of SLE. This article reviews the pertinent publications (searched from the PubMed database) involving the mechanisms of actions of miRNA associated with the pathogenesis of SLE. The search of related literature was extended as far back as 1979. In this mini-review we first introduce the miRNAs briefly and later discuss their regulatory roles in the DNA methylation pathway, type I interferon pathway, estrogen and regulatory T-cells in the pathogenesis of SLE.

Epigenetic modulation of RFC1, MHC2TA and HLA-DR in systemic lupus erythematosus: association with serological markers and six functional polymorphisms of one-carbon metabolic pathway

The current study was conducted to elucidate the effect of genetic variations in one-carbon metabolism on the epigenetic regulation of major histocompatibility complex II transactivator (MHC2TA), reduced folate carrier 1 (RFC1/SLC19A1) and human leukocyte antigen (HLA)-DR in systemic lupus erythematosus (SLE). PCR-RFLP/AFLP, bisulfite-sequencing and real-time PCR approaches were used for genetic, epigenetic and expression analysis respectively. SLE cases exhibited elevated plasma homocysteine levels compared to healthy controls (24.93 ± 1.3 vs. 11.67 ± 0.48 μmol/l), while plasma folate levels showed no association (7.10 ± 2.49 vs. 7.64 ± 2.09 ng/ml). The RFC1 80G>A polymorphism showed 1.32-fold risk (95% CI: 1.02-1.72) for SLE, while glutamate carboxypeptidase II (GCPII) 1561C>T showed reduced risk (OR: 0.47, 95% CI: 0.24-0.90). The expression of RFC1 (0.37 ± 0.09 vs. 0.60 ± 0.17) and HLA-DR (0.68 ± 0.17 vs. 0.98 ± 0.02) was down regulated in the SLE cases. The hypermethylation of RFC1 as observed in the current study may contribute for its down regulation. Plasma folate and thymidylate synthase (TYMS) 5'-UTR 28 bp tandem repeat showed an inverse association with methylation of RFC1 and MHC2TA. SLE cases with hypocomplementemia showed hypermethylation of RFC1, hypomethylation/up regulation of MHC2TA and down regulation of HLA-DR. The hypermethylation of MHC2TA and down regulation of RFC1, MHC2TA and HLA-DR were observed in anti-cardiolipin antibody positive SLE cases. The up regulation of RFC1 and HLA-DR was observed in anti-dsDNA antibody positive SLE cases. The hypomethylation/upregulation of RFC1 and MHC2TA was observed in anti-RNP antibody positive cases. To conclude, one-carbon genetic variants influence epigenetic of MHC2TA and RFC1, thus contributing to phenotypic heterogeneity of SLE.

Interferon-α abrogates the suppressive effect of apoptotic cells on dendritic cells in an in vitro model of systemic lupus erythematosus pathogenesis

OBJECTIVE

An increased incidence of apoptotic cells and an increased activation of dendritic cells (DC) may be involved in the pathogenesis of systemic lupus erythematosus (SLE). We investigated the characteristics of apoptotic neutrophils and monocyte-derived DC of patients with SLE, their interaction, and the influence of autoantibodies and inflammatory cytokines on this interaction.

METHODS

Kinetics of neutrophil apoptosis and DC activation were studied by flow cytometry. To analyze the interaction of apoptotic cells with phagocytes, crossover coculture experiments were performed with DC from patients with SLE and apoptotic Jurkat T cells as well as with apoptotic neutrophils from patients with SLE and the monocytic cell line U937. SLE serum and cytokines were added to this coculture, and activation and suppression of DC were quantified by levels of inflammatory cytokine secretion.

RESULTS

Apoptotic neutrophils and DC from patients with SLE showed no inherent defects compared to healthy controls, and the suppressive nature of their interaction was not affected. Autoantibodies as well as the inflammatory cytokines interleukin 17 (IL-17) and IL-1β had no influence on the interaction in this setup. Interferon (IFN)-α, however, substantially reduced the suppressive effect of apoptotic cells on DC.

CONCLUSION

The data suggest that aberrant immune reactivity in SLE is not generally due to an intrinsic defect in apoptotic cells, their processing, or their interaction with DC, but likely arises from the milieu in which this interaction takes place. Our study highlights the importance of IFN-α during early stages of SLE and its potential as a therapeutic target.

High occurrence of in vitro apoptosis of lymphocytes induced by serum from systemic lupus erythematosus patients is associated with increased serum levels of anti-C1q autoantibodies

BACKGROUND

The ethiopathogenesis of increased apoptosis of lymphocytes in systemic lupus erythematosus (SLE) is still incompletely understood but anti-C1q autoantibodies have been shown to induce apoptosis in lymphocytes from healthy donors and certain cell lines.

AIM

This study was undertaken to investigate the relationship between peripheral lymphocyte apoptosis and serum levels of anti-C1q autoantibodies in SLE patients.

METHODS

The sera of 124 patients with SLE involving 62 active SLE and 62 inactive SLE, fulfilling America College of Rheumatology (ACR) classification criteria for SLE (1997) were incubated with peripheral blood lymphocytes of healthy donors. The results were compared with 124 sex- and age-matched normal controls. Apoptotic lymphocytes (AL) were detected by flow cytometry using annexin V and propidium iodide binding. Anti-C1q autoantibodies were detected by an enzyme-linked immunoassay kit for all SLE patients.

RESULTS

Results demonstrated that the percentage of AL in the peripheral blood of active SLE patients was significantly higher (n = 62, 34.95 ± 12.78%) than that of the inactive SLE patients (n = 62, 30.69 ± 10.13%, P = 0.042, 95%CI = 0.16-8.36) and normal controls (n = 124, 27.92 ± 10.22%, P = 0.001, 95%CI = 3.33-10.73). The percentage of AL significantly correlated with serum levels of anti-C1q autoantibodies in the active SLE patients (r = 0.263, P = 0.039) but not in the inactive SLE patients (r = 0.170, P = 0.185).

CONCLUSION

The results of this study suggest that increased serum levels of anti-C1q autoantibodies are responsible for apoptosis and may play a pathogenic role in SLE patients, especially in active disease.

Increased numbers of NK cells, NKT-like cells, and NK inhibitory receptors in peripheral blood of patients with chronic obstructive pulmonary disease

T cells and B cells participate in the pathogenesis of COPD. Currently, NK cells and NKT cells have gained increasing attention. In the present study, 19 COPD patients and 12 healthy nonsmokers (HNS) were recruited, and their pulmonary function was assessed. The frequencies of CD3⁺ T, CD4⁺ T, CD8⁺ T, B, NK, and NKT-like cells were determined using flow cytometry. The frequencies of spontaneous and inducible IFN-γ⁺ or CD107a⁺ NK and NKT-like cells as well as activating or inhibitory receptors were also detected. The potential association of lymphocyte subsets with disease severity was further analyzed. Significantly decreased numbers of CD3⁺ and CD4⁺ T cells, and the CD4⁺/CD8⁺ ratio, but increased numbers of CD3⁻CD56⁺ NK and CD3⁺CD56⁺ NKT-like cells were observed in COPD patients compared to HNS. The frequencies of inducible IFN-γ-secreting NK and NKT-like cells were less in COPD patients. The frequencies of CD158a and CD158b on NK cells and CD158b on NKT-like cells were greater. The frequency of CD158b⁺ NK cells was negatively correlated with FEV₁% prediction and FEV₁/FVC. Our data indicate that COPD patients have immune dysfunction, and higher frequencies of inhibitory NK cells and NKT-like cells may participate in the pathogenesis of COPD.

Glucocorticoid downregulates expression of IL-12 family cytokines in systemic lupus erythematosus patients

OBJECTIVE

This study aims to investigate expression of interleukin 12 (IL-12) family cytokines IL-12, IL-23, IL-27 and IL-35 in systemic lupus erythematosus (SLE) patients and the effect of glucocorticoid (GC) treatment on their expression.

METHODS

Plasma concentration of IL-12, IL-23, IL-27, IL-35, IL-6 and anti-double-stranded DNA (dsDNA) antibodies in 30 newly diagnosed severe SLE patients and 30 matched healthy subjects was measured by enzyme-linked immunosorbent assay. The correlation between the levels of IL-12 family cytokines and the levels of IL-6 or anti-dsDNA antibodies was analyzed by Spearman rank correlation.

RESULTS

Significantly higher levels of plasma IL-12, IL-23, IL-27, IL-35, IL-6 and anti-dsDNA antibodies were observed in SLE patients compared with healthy controls (p < 0.05), and after prednisone treatment, the serum levels of IL-12 family cytokines decreased significantly. Moreover, serum levels of IL-12, IL-23, IL-27 and IL-35 were correlated with serum levels of IL-6 and anti-dsDNA antibodies in pre-treatment as well as post-treatment SLE patients.

CONCLUSIONS

SLE patients have increased plasma levels of IL-12 family cytokines and GCs can downregulate the expression of them in SLE patients. Therefore, members of the IL-12 family may be involved in the pathophysiological process of SLE.

Expression level of the growth factor progranulin is related with development of systemic lupus erythematosus

Background

This study is to investigate the expression of progranulin (PGRN) in systemic lupus erythematosus (SLE) patients and the effect of glucocorticoid (GC) treatment on its expression.

Methods

Thirty newly diagnosed severe SLE patients and 30 healthy subjects were enrolled in this study. The serum levels of PGRN and the inflammatory factors of SLE were detected by ELISA and the mRNA expression of these proteins were detected by real-time PCR.

Results

The serum levels of PGRN, IL-6, PR3, TNFR, TNF-α and anti-dsDNA antibody in SLE patients were increased significantly compared with healthy controls (P < 0.05). The relative expression of PGRN mRNA was increased by 4.88-fold in pre-treatment SLE patients compared with controls (P < 0.05). After prednisone treatment, the serum levels of PGRN decreased significantly, and the relative expression of PGRN mRNA was decreased by 1.34-fold compared with the untreated controls (P < 0.01). Moreover, Serum concentration of PGRN was correlated with serum levels of IL-6, TNF-α, TNFR and anti-dsDNA antibody in both pre-treatment and post-treatment SLE patients.

Conclusions

PGRN is up-regulated in the SLE patients and is correlated with pro-inflammatory cytokines and anti-dsDNA antibody. Glucocorticoids can down-regulate the expression of PGRN in SLE patients.

Virtual slides

http://www.diagnosticpathology.diagnomx.eu/vs/1562484036905973

Increased interleukin‑9 and CD4+IL-9+ T cells in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease of unknown origin affecting all the organ systems. Apart from genetic and environmental factors, autoantibody and immune complex deposition as well as cytokine imbalances contribute to immune dysfunction. Interleukin‑9 (IL-9) is a T cell-derived factor preferentially expressed by CD4+ T cells and it has been characterized in human and murine systems. IL-9 targets cells of the lymphoid, myeloid and mast cell lineages, and is likely to contribute to the development of allergic and autoimmune diseases such as asthma, arthritis, multiple sclerosis and experimental autoimmune encephalomyelitis (EAE). Nevertheless, until recently there have been no studies on its role in SLE in humans. In the present study, the mRNA and serum IL-9 levels in the peripheral blood of SLE patients and healthy controls were assessed using real-time PCR and enzyme-linked immunosorbent assay (ELISA), respectively. Flow cytometry was used to analyze the percentages of CD4+IL-9+ T cells in SLE patients. Moreover, differences between the groups and the effect of glucocorticoids were analyzed. The results showed that the plasma concentration and mRNA levels of IL-9 were significantly elevated in SLE patients compared with the healthy controls. The percentages of CD4+IL-9+ T cells were also increased in SLE patients. In addition, serum IL-9 levels and the percentages of CD4+IL-9+ T cells were correlated with the SLE disease activity index (SLEDAI). Additionally, the percentages of CD4+IL-9+ T cells and serum IL-9 levels in 8 untreated active SLE patients were decreased at 1, 2 and 3 weeks after treatment with methylprednisolone. In conclusion, we provide evidence that IL-9 is increased in SLE patients. Moreover, it is described for the first time that high expression of IL-9 levels and the percentages of CD4+IL-9+ T cells correlate with disease activity and severity. This suggests an important role of IL-9 in the pathogenesis of SLE.

IL-7Rαlow memory CD8+ T cells are significantly elevated in patients with systemic lupus erythematosus

OBJECTIVE

Human effector memory (EM) CD8(+) T cells include IL-7Rα(high) and IL-7Rα(low) cells with distinct cellular characteristics, including the expression of cytotoxic molecules. Both NK cells and the NK cell-associated molecule 2B4 that is expressed on CD8(+) T cells promote cytotoxicity. Here we analysed the expression of 2B4 on IL-7Rα(high) and IL-7Rα(low) EM CD8(+) T cells and its contribution to cytotoxicity. We also analysed the frequency of IL-7Rα(high) and IL-7Rα(low) EM CD8(+) T cells in patients with SLE or lupus and in healthy individuals given the potential role of cytotoxic CD8(+) T cells in the pathogenesis of lupus.

METHODS

We used flow cytometry to measure the expression of 2B4 on IL-7Rα(high) and IL-7Rα(low) EM CD8(+) T cells as well as the frequency of these cell populations in the peripheral blood of healthy individuals and patients with SLE. Also, 2B4-mediated cytotoxicity was quantitated in IL-7Rα(high) and IL-7Rα(low) EM CD8(+) T cells using target cells with CD48 antigen.

RESULTS

We found that IL-7Rα(high) EM CD8(+) T cells had higher levels of 2B4 expression compared with IL-7Rα(low) EM CD8(+) T cells. Triggering 2B4 enhanced the cytotoxic function of IL-7Rα(low) EM CD8(+) T cells against target cells. We also noticed that patients with SLE had an increased frequency of IL-7Rα(low) EM CD8(+) T cells that correlated with disease manifestation.

CONCLUSION

Our findings show that SLE patients have increased IL-7Rα(low) EM CD8(+) T cells, possibly contributing to tissue damage through 2B4-mediated cytotoxicity.

Changes in immune cell frequencies after cyclophosphamide or mycophenolate mofetil treatments in patients with systemic lupus erythematosus

This study was designed to explore the profile of immune cell subsets, including T, B, natural killer (NK), and NKT cells, in systemic lupus erythematosus (SLE) patients, and to determine their relationships with the clinical index and the effects of cyclophosphamide (CYC) and mycophenolate mofetil (MMF) treatment. SLE patients (n = 28) and age/sex-matched healthy controls (n = 28) were evaluated. The patients were equally divided into two treatment groups: intravenous drip (IVD) with CYC and prednisolone, and oral MMF and IVD with prednisolone. SLE peripheral blood samples were taken immediately prior to treatment and after 4 weeks of drug treatment. T, B, NK, and NKT cell subsets were measured by flow cytometry. Double-stranded DNA antibody and Sm antibody were detected by indirect immunofluorescence. Serum C3, C4, and C-reactive protein were determined by scatter turbidimetry. The percentages of CD3+CD4+ T, CD3-CD16CD56+ NK, and CD3+CD16CD56+ NKT cells and the CD4+/CD8+ ratio were significantly lower in SLE patients, while CD3+CD8+ T and CD3-CD19+ B cells were higher than the controls. The lymphocyte subsets were significantly correlated with the SLE disease activity index (SLEDAI) and complement factors (C3, C4). Four weeks of CYC or MMF treatment led to a significant increase in CD3+CD4+ T cells (P < 0.05). In addition, both CYC and MMF treatments led to increases in CD3+ T and CD3-CD16CD56+NKT cells and decreases in CD3-CD16CD56+ NK and CD3+CD8+ T cells, but these changes were not obvious. The significant correlation that exists between lymphocytes subsets and SLEDAI activity scores suggests that the lymphocyte subsets may reflect SLE severity. Our results indicate that both the traditional cyclophosphamide agent and the new mycophenolate mofetil agent can regulate the lymphocyte subsets and consequent abnormal immunity, suggesting that MMF, which is known to produce less side-effects than CYC, may be used as an effective treatment of SLE.

Inflammatory cytokines in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease of unknown origin affecting virtually all organ systems. Beyond genetic and environmental factors, cytokine imbalances contribute to immune dysfunction, trigger inflammation, and induce organ damage. The key cytokine that is involved in SLE pathogenesis is interferon alpha. Interferon secretion is induced by immune complexes and leads to upregulation of several inflammatory proteins, which account for the so-called IFN signature that can be found in the majority of SLE PBMCs. Additionally IL-6 and IFN-y as well as T-cell-derived cytokines like IL-17, IL-21, and IL-2 are dysregulated in SLE. The latter induce a T-cell phenotype that is characterized by enhanced B-cell help and enhanced secretion of proinflammatory cytokines but reduced induction of suppressive T cells and activation-induced cell death. This paper will focus on these cytokines and highlights pathophysiological approaches and therapeutic potential.

The pathway of estradiol-induced apoptosis in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a disease with unknown etiology. The pathologic role of sex hormones and apoptosis in SLE has often been discussed. We studied the effects of estradiol in the pathway of induced apoptosis in Iranian SLE patients. T lymphocytes from 35 SLE patients and 20 age-matched controls were isolated and cultured in the presence of 10(-8) M 17-β estradiol. The expression levels of Fas, Fas ligand (FasL), Bcl-2, caspase-8, and caspase-9 mRNAs were determined semiquantitatively in comparison to the expression level of beta actin RNA. Estradiol exposure did not have any significant effects on the expression levels of Fas, Bcl-2, and caspase-9 in SLE patients and controls. However, the expression levels of FasL and caspase-8 were significantly increased in SLE patients, but not in controls. This suggests the probable involvement of extrinsic apoptosis pathway in estradiol-induced apoptosis in SLE.

The detrimental effects of IFN-α on vasculogenesis in lupus are mediated by repression of IL-1 pathways: potential role in atherogenesis and renal vascular rarefaction

Systemic lupus erythematosus (SLE) is characterized by increased vascular risk due to premature atherosclerosis independent of traditional risk factors. We previously proposed that IFN-α plays a crucial role in premature vascular damage in SLE. IFN-α alters the balance between endothelial cell apoptosis and vascular repair mediated by endothelial progenitor cells (EPCs) and myeloid circulating angiogenic cells (CACs). In this study, we demonstrate that IFN-α promotes an antiangiogenic signature in SLE and control EPCs/CACs, characterized by transcriptional repression of IL-1α and β, IL-1R1, and vascular endothelial growth factor A, and upregulation of IL-1R antagonist and the decoy receptor IL-1R2. IL-1β promotes significant improvement in the functional capacity of lupus EPCs/CACs, therefore abrogating the deleterious effects of IFN-α. The beneficial effects from IL-1 are mediated, at least in part, by increases in EPC/CAC proliferation, by decreases in EPC/CAC apoptosis, and by preventing the skewing of CACs toward nonangiogenic pathways. IFN-α induces STAT2 and 6 phosphorylation in EPCs/CACs, and JAK inhibition abrogates the transcriptional antiangiogenic changes induced by IFN-α in these cells. Immunohistochemistry of renal biopsies from patients with lupus nephritis, but not anti-neutrophil cytoplasmic Ab-positive vasculitis, showed this pathway to be operational in vivo, with increased IL-1R antagonist, downregulation of vascular endothelial growth factor A, and glomerular and blood vessel decreased capillary density, compared with controls. Our study introduces a novel putative pathway by which type I IFNs may interfere with vascular repair in SLE through repression of IL-1-dependent pathways. This could promote atherosclerosis and loss of renal function in this disease.

The uptake by blood-borne phagocytes of monosodium urate is dependent on heat-labile serum factor(s) and divalent cations

Accumulation in tissues of post-apoptotic cells is a feature frequently observed in patients with systemic lupus erythematosus and in murine models of systemic autoimmune diseases. One of the endogenous danger molecules released by secondarily necrotic cells is monosodium urate (MSU), which is already established to be the causative agent of gout. Here, we show that MSU is taken up by eosinophils, neutrophils and monocytes in a process involving (a) heat-labile serum factor(s) and divalent cations. The uptake induces the release of the pro-inflammatory cytokines IL-1beta/IL-18/TNFalpha and IL-6/IL-8 by monocytes and PMN, respectively.

[The role of incomplete clearance of apoptotic cells in the etiology and pathogenesis of SLE]

Systemic lupus erythematosus (SLE) is a complex prototypic autoimmune disease that is based on genetic factors (complement deficiencies) and is influenced by gender (female), environment (infections and UV irradiation), as well as random events (somatic mutations). The course of the disease is influenced by genes (e.g. FcgammaRIIA) and behaviour (sun-exposure). Inefficient clearance of dying cells and subsequent accumulation of apoptotic cell remnants is an intrinsic defect causing the permanent presence of cellular debris responsible for the initiation of autoimmunity. We favour the hypothesis that post-apoptotic debris accumulates in germinal centres, activates complement, and serves as a survival signal for B-cells that had stochastically become autoreactive in the process of somatic hypermutation (etiology). In the presence of autoantibodies against apoptotic cells or adaptor molecules the accumulation of post-apoptotic remnants (SNEC) causes immune complex formation and their pathological elimination, maintaining auto-inflammation. The SLE-type autoimmunity addresses nucleic acid-containing complex antigens (viromimetica). Autoantibody-protein-nucleic-acid complexes are likely to be mistaken for opsonised viruses. As a consequence, the immune system responds with the production of type-I interferons, a hallmark of SLE (pathogenesis). We conclude that the pathogenicity of autoantibodies is strongly increased if autoantigens are accessible and immune complexes are formed, which may be considered a binary pyrogen formed from less pro-inflammatory components. The accessibility of cognate autoantigens is likely to be related to impaired or delayed clearance of apoptotic cells.

Anti-ribonucleoproteins autoantibodies in patients with systemic autoimmune diseases. Relation with cutaneous photosensitivity

A common feature between patients with a certain group of systemic autoimmune pathologies (SAPs) with rheumatic component, such as lupus erythematosus (LE) in all its forms, is the presence of cutaneous photosensitivity (CP) as well as the existence of autoantibodies (Aabs). These Aabs have also high incidence in other SAPs that do not present CP, like primary Sjögren's syndrome and rheumatoid arthritis. Cutaneous photosensitivity is a condition that consists of an exacerbated skin reaction to solar radiations; its incidence can reach 90% in systemic LE. The mechanisms involved in the development of CP have been extensively studied focusing on different approaches; however, the exact mechanism has not been fully elucidated yet. There are many theories that relate specifically the presence of circulating anti-Ro/SS-A Aabs with the CP phenomenon, though there are several studies which are in disagreement. In this study, we evaluated the Aabs profile (anti-Ro/SS-A 52 kDa, anti-Ro/SS-A 60 kDa, anti-La/SS-B, anti-Sm and ANAs) as well as their titer or reactivity, in a local cohort of 169 patients with SAPs. We related those Aabs profiles and titers with the presence or absence of CP, and we found that there was no significant association between the presence of anti-Ro/SS-A Aabs and the occurrence of CP. On the other hand, a statistically significant positive association was found between CP and high reactivity anti-Sm Aabs, though this fact could be biased by the incidence of both events in SLE patients. To sum up, in the particular population studied, there is no direct relationship between anti-Ro/SS-A Aabs and CP, which is in agreement with some authors and in disagreement with many others, contributing to the endless discussion of this issue.

Dysregulated balance of Th17 and Th1 cells in systemic lupus erythematosus

INTRODUCTION

Interleukin (IL)-17 is a proinflammatory cytokine that is produced largely by a unique CD4(+) T-helper (Th) subset called Th17 cells. The development of Th17 cells is suppressed by interferon (IFN)-gamma produced by Th1 cells, suggesting cross-regulation between Th17 and Th1 cells. Thus, this study analyzed the balance of CD4+ Th17 and Th1 cell responses in peripheral blood from patients with systemic lupus erythematosus (SLE) and healthy subjects.

METHODS

Twenty-five adult patients with SLE and 26 healthy subjects matched for gender and age (+/- 2 years) were recruited. Peripheral blood mononuclear cells (PBMCs) from patients and healthy subjects were stimulated for 4 h ex vivo with phorbol myristate acetate (PMA) and ionomycin. The frequency of CD4(+) T cells producing IL-17 and/or IFN-gamma was measured by using flow cytometry. Expression of Th17-associated chemokine receptors CCR4 and CCR6 on CD4(+) T cells as well as plasma levels of Th17-polarizing cytokines were assessed. Disease activity was evaluated by the SLE disease activity index score (SLEDAI). Unpaired t test and Pearson correlation were used for statistical analyses.

RESULTS

Patients with SLE had an increased frequency of CD4(+)IL-17(+) T cells compared with healthy subjects. However, the frequency of CD4(+)IFN-gamma(+) T cells was similar between the two groups, indicating an altered balance of Th17 and Th1 cell responses in SLE. Patients with SLE also had an increased frequency of CD4(+)CCR4(+)CCR6(+) T cells that are known to produce IL-17. The frequency of CD4(+)IL-17(+) T cells and CD4(+)CCR4(+)CCR6+ T cells correlated with disease activity. In measuring plasma levels of the Th17-polarizing cytokines, levels of IL-6 were higher in patients with SLE than in healthy subjects, although levels of IL-1beta, IL-21, IL-23, and transforming growth factor (TGF)-beta were not different between the two groups.

CONCLUSIONS

We demonstrate an enhanced Th17 cell response that correlates with disease activity in patients with SLE, suggesting a role for IL-17 in the pathogenesis of lupus. Our data indicate that the mechanisms involved in balancing Th1 and Th17 regulation, as well as in producing IL-6, are aberrant in SLE, leading to an increased Th17 response. We suggest that CCR4 and CCR6 expression on CD4(+) T cells should be considered as markers of disease activity, and that IL-17 blocking may offer a therapeutic target in SLE.

Effect of chloroquine phosphate treatment on serum MMP-9 and TIMP-1 levels in patients with systemic lupus erythematosus

Antimalarials are widely used for the treatment of systemic lupus erythematosus. However, their mechanisms of action have not been fully elucidated. Literature data indicate that matrix metalloproteinases may play a role in the immune response and tissue damage that occur in autoimmune skin diseases. The aim of this study was to determine the effect of 3 months of chloroquine treatment on serum levels of MMP-9 and TIMP-1 in patients with systemic lupus erythematosus. The study group consisted of 25 patients with systemic lupus erythematosus and 25 sex- and age-matched healthy volunteers. Before drug administration, serum levels of MMP-9 and TIMP-1 were determined by enzyme-linked immunosorbent assay. The same procedure was performed after chloroquine treatment. We found significantly higher median serum levels of MMP-9 in patients with systemic lupus erythematosus before therapy (57.20 ng/ml) when compared with controls (44.50 ng/ml) (p < 0.001). After chloroquine therapy the median MMP-9 serum level of systemic lupus erythematosus patients decreased significantly (43 ng/ml; p < 0.001). Before treatment the median TIMP-1 serum level in the patients with systemic lupus erythematosus was significantly higher than in the control group (500 vs. 200 ng/ml; p < 0.001), and after therapy it increased significantly (750 ng/ml TIMP-1; p < 0.001). The results suggest that chloroquine treatment may affect the matrix metalloproteinase network, and this effect may contribute to the immunoregulatory and anti-inflammatory properties of antimalarials.

IAN5 polymorphisms are associated with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a representative autoimmune disease, which is frequently associated with lymphopenia. Biobreeding (BB) rat is a typical animal model which develops autoimmune diseases with lymphopenia which results from a frame-shift mutation in the immune-associated nucleotide (IAN) 5 gene. IAN5 is involved in the regulation of T-cell activation and survival. To examine the association of IAN5 gene with SLE, we scrutinised the single nucleotide polymorphisms (SNPs) in the IAN5 gene. We conducted a case-control study where 132 SLE patients, 505 rheumatoid arthritis (RA) patients, and 546 controls were genotyped for four SNPs in the IAN5 gene. Two SNPs (+2071C > T and +2677G > A) were associated with susceptibility to SLE (P = 0.040 and 0.045, respectively), and -4432G > A SNP was associated with the development of leukopenia (P = 0.028) and the requirement of steroid pulse therapy (P = 0.040) in SLE patients. Haplotype analyses showed that Ht1(CTCG) was associated with susceptibility to SLE (P = 0.036), and Ht4(ACCG), Ht5(ACTA) and Ht6(GCCG) were associated with the development of nephritis (P = 0.017, 0.019, 0.022, respectively). In conclusion, the IAN5 polymorphisms were associated with susceptibility to SLE and the development of clinical disease manifestations in a strictly Korean population.

The Clinical Application of Ozonetherapy

The reader may be eager to examine in which diseases ozonetherapy can be proficiently used and she/he will be amazed by the versatility of this complementary approach (Table 9 1). The fact that the medical applications are numerous exposes the ozonetherapist to medical derision because superficial observers or sarcastic sceptics consider ozonetherapy as the modern panacea. This seems so because ozone, like oxygen, is a molecule able to act simultaneously on several blood components with different functions but, as we shall discuss, ozonetherapy is not a panacea. The ozone messengers ROS and LOPs can act either locally or systemically in practically all cells of an organism. In contrast to the dogma that “ozone is always toxic”, three decades of clinical experience, although mostly acquired in private clinics in millions of patients, have shown that ozone can act as a disinfectant, an oxygen donor, an immunomodulator, a paradoxical inducer of antioxidant enzymes, a metabolic enhancer, an inducer of endothelial nitric oxide synthase and possibly an activator of stem cells with consequent neovascularization and tissue reconstruction.

Role of Natural Interferon-α Producing Cells (Plasmacytoid Dendritic Cells) in Autoimmunity

The type I interferons (IFNs) have antiviral, cytostatic and prominent immunomodulatory effects, which all are of great importance during viral infections. However, prolonged exposure of the immune system to type I IFN can break tolerance and initiate an autoimmune reaction, eventually leading to autoimmune disease. Recent observations in patients with systemic lupus erythematosus (SLE) have revealed that such individuals have endogenous IFN-alpha inducers, causing an ongoing IFN-alpha production and consequently a continuous stimulation of the immune system. These IFN-alpha inducers consist of small immune complexes (IC) containing DNA or RNA and act on the principal IFN-alpha producing cell, the natural IFN-alpha producing cell (NIPC), also termed the plasmacytoid dendritic cell (PDC). The NIPC/PDC is a key cell in both the innate and adaptive immune response but can also, either directly or via produced IFN-alpha, have a pivotal role in autoimmunity. In this review we summarize recent data concerning NIPC/PDC, including their activation, regulation, function and possible role in autoimmune diseases, especially SLE.

Premature vascular damage in systemic lupus erythematosus: an imbalance of damage and repair?

Systemic lupus erythematosus (SLE) is associated with an increase in the risk of premature cardiovascular complications caused by accelerated atherosclerosis, which significantly contributes to morbidity and mortality. Standard Framingham risk factors seem to be less important predictors of cardiovascular events than the presence of active SLE, and the immune dysregulation characteristic of lupus seems to play a dominant role in atherogenesis. Although both SLE-specific and nonspecific mechanisms have been proposed to play a prominent role in the induction of premature vascular damage in this disease, the exact etiology remains unclear. This review summarizes some of the proposed mechanisms that may promote accelerated vascular damage in lupus and explores potential targets for cardiovascular risk prevention in this patient population.

Raised expression of cytokine receptor gp130 subunit on peripheral lymphocytes of patients with active lupus. A useful tool for monitoring the disease activity?

The glycoprotein gp130 is a signal traducing subunit with a membrane domain of the IL-6 receptor. In addition, gp130 is shared among the receptors for IL-6 superfamily, and it is critically involved in generating signal transduction through these receptors. The aim of the study is to evaluate the expression of the IL-6 superfamily receptor molecule gp130 on TCD4(+) and B cells in patients with systemic lupus erythematosus (SLE). Surface expression of gp130 on TCD4(+) and B lymphocytes was higher in patients with SLE than in healthy controls (2.79 vs 0.36% and 8.36 vs 0.37%, respectively). Patients with active lupus had higher expression of gp130 (relapsed 15.1%, new onset 26.6%) than stable patients (2.83%), in B-cell subset, but not in TCD4 lymphocytes. An important reduction in the gp130 expression on B lymphocytes was observed when the activity of the disease had disappeared after readjusting its immunosuppressive treatment (20.8-3.8%). In addition, there was significant correlation between the activity of the disease, measured like systemic lupus erythematosus disease activity index score, and surface expression of gp130 in lymphocytes B (r(s) = 0.5880, P = 0.0002). According with our results and roc curve analysis, a cut-off in 6.7% of B cells with gp130 expression were defined, who discriminates active/stable SLE with a sensitivity of 0.93 and a specificity of 0.75. In conclusion, there is an altered expression of gp130 in the patients with SLE. The disease activity as well as immunotherapy seems to influence the pattern of expression of gp130 on B-cell subsets in patients with SLE.

Circulating endothelial cells and angiogenic proteins in patients with systemic lupus erythematosus

The aim of our study was to assess absolute counts of different subpopulations of circulating endothelial cells (CEC) in patients with active and inactive systemic lupus erythematosus (SLE). We have also investigated a potential correlation of CEC numbers with serum levels of angiogenic proteins as well as with clinical and laboratory symptoms of the disease. For the first time in SLE, CEC were enumerated directly, by the ‘single platform’ method. Resting (rCEC), activated (aCEC) and progenitor (pCEC) endothelial cells were identified in patients with SLE and healthy volunteers using four-colour flow cytometry. Serum concentrations of angiogenic proteins (vascular endothelial growth factor, placental growth factor (PIGF), soluble vascular cell adhesion molecule and endoglin) were evaluated by ELISA. The SLE activity was scored according to the Systemic Lupus Activity Measure system. We found that total CEC number in patients with SLE was significantly higher (median 14.2/μL) than in the control group (median 3.3/μL) ( P < 0.0001). Absolute counts of aCEC, rCEC and pCEC (medians 4.9/μL, 6.8/μL and 2.3/μL, respectively) were also higher in patients with SLE than in healthy persons (medians 0.9/μL, 1.6/μL and 0.1/μL, respectively), with P < 0.0001 for all comparisons. There was no correlation between CEC or their subpopulations and SLE activity. Strong positive correlations were found between CEC, rCEC and pCEC numbers and serum levels of PIGF. Moreover, aCEC, rCEC and pCEC counts were significantly higher in SLE patients with leukopenia. In conclusion, our results show that absolute CEC counts and angiogenic proteins levels are elevated in patients with SLE as compared with healthy controls. These data may suggest that angiogenic process is involved in the pathogenesis of this disease.

Cytokines in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the production of autoantibodies that can form immune complexes and deposit in tissues, causing inflammation and organ damage. There is evidence that interferons and some interleukins can have an active role in the pathogenesis of SLE and can contribute significantly to the immune imbalance in the disease, whereas the role of some cytokines (such as TNF) is still debated. This review discusses the activity of several cytokines in SLE, their effects on the immune cells in relation to the disease pathogenesis, and the promise and limitations of cytokine-based therapies in clinical trials for lupus patients.