Mannose binding lectin: a biomarker of systemic lupus erythematosus disease activity

The roles of collectins in renal diseases and transplantation

The collectins are soluble C-type lectins and a group of proteins characterized with common structural features: a collagen-like domain and a carbohydrate-binding domain. These proteins are essential components of the innate immune system, pivotal for recognizing and eliminating pathogens to protect against infections. Over recent decades, research has significantly advanced our understanding of collectins. Beyond their fundamental role in host defense, collectins have been emerged as multifunctional proteins involved in modulating inflammatory and immune responses, facilitating the clearance of cellular debris, and even stimulating cell proliferation. These diverse roles are critical for maintaining physiological balance and hold substantial implications in various disease processes, particularly in renal diseases and transplantation. Here, we review the roles of collectins in renal diseases and transplantation focusing on four prominent members of the collectin family: mannose-binding lectin (MBL), surfactant proteins (SP-A and SP-D), and collectin-11 (CL-11). These proteins have gained considerable attention in current research due to their roles in renal diseases and transplantation, shedding light on their impact beyond traditional immune defense mechanisms. Understanding their involvement in these contexts is crucial for exploring potential therapeutic avenues and interventions aimed at mitigating renal pathology and improving outcomes in transplantation settings.

High frequency of anti-Saccharomyces cerevisiae antibodies in chronic hepatitis C

BACKGROUND AND STUDY AIM

Chronic hepatitis C (CHC) is a liver disease caused by the hepatitis C virus. Anti-Saccharomyces cerevisiae (S. cerevisiae) antibodies (ASCA) are frequently reported in autoimmune diseases but rarely in viral infections. We aimed to determine the frequency of ASCA in adult patients with CHC.

PATIENTS AND METHODS

Eighty-eight patients with CHC and 160 healthy blood donors were included in this study. ASCA-IgG and IgA levels were determined using enzyme linked immunosorbent assay. For statistical analysis, we used open EPI version 3 as software. Correlations were determined by Spearman's test using IBM® SPSS® Statistics.

RESULTS

ASCA (IgG or IgA) were present in 31.8 % of patients and in 3.7 % of controls (p < 10-6). ASCA-IgG and ASCA-IgA were more frequent in patients with CHC than in healthy subjects (23.9 % vs. 3.1 %; p < 10-5 and 9.1 % vs. 0.6 %; p = 0.002, respectively). In patients, mean levels of ASCA-IgG and IgA were significantly higher than in controls (9.95 ± 11.78 U/mL vs. 2.28 ± 2.86 U/mL, p < 10-6 and 5.96 ± 7.69 U/mL vs. 0.56 ± 0.12 U/mL, p < 10-6; respectively). In patients with CHC, the mean level of ASCA-IgG was significantly higher than that of ASCA-IgA (9.95 ± 11.78 U/mL vs. 5.96 ± 7.69 U/mL, p = 0.008).

CONCLUSION

The frequency of ASCA was significantly higher in patients with CHC than in healthy controls.

Soybean Agglutinin Alters the Gut Microbiota and Promotes Inflammation in Lupus-Prone MRL/lpr Mice

BACKGROUND

Certain foods can trigger flares in patients with systemic lupus erythematosus. Lectins in edible plants have been reported to increase inflammation.

OBJECTIVE

This study aimed to determine the effects of 1-time intake of soybean agglutinin (SBA) on the gut microbiota and immune response in lupus-prone MRL/MpJ (MRL)/lpr mice.

METHODS

MRL/MpJ-Faslpr/J (MRL/lpr) and MRL mice were randomly assigned into 4 groups (8 mice/group): MRL mice + phosphate-buffered saline (PBS) (CON), MRL mice + SBA (CS), MRL/lpr mice + PBS (LPR), and MRL/lpr + SBA (LS). PBS and SBA were orally administered at 16 wk of age, and all mice were killed 24 h after oral challenge. The disease phenotype, levels of proinflammatory cytokines, and composition of the intestinal microbiota were determined.

RESULTS

Interferon-gamma (IFN-γ) in the serum was significantly higher, whereas the level of serum IL-10 was significantly lower in LS mice than in LPR mice [fold change (FC) = 1.31 and FC = 0.36, respectively]. The expression levels of IL-6 and TNF-α in the spleen of LS mice were significantly higher than those in LPR mice (FC = 1.66 and FC = 1.96, respectively). The expression levels of IL-6, TNF-α, and IL-1β in the kidney were also significantly higher in LS mice than in LPR mice (FC = 2.89, FC = 3.78, and FC = 2.02, respectively). The relative abundances of Erysipelotrichaceae and Turicibacter in LS mice were significantly higher than those in LPR mice (FC = 1.73 and FC = 1.74, respectively). The percentage of Breg cells in the mesenteric lymph nodes was significantly lower in LS mice than in LPR mice (FC = 0.53) (P < 0.05). No change was found between SBA treatment or not in the control (MRL) mice.

CONCLUSIONS

One-time intake of SBA can promote the secretion of proinflammatory cytokines, downregulate Breg cells, and alter the intestinal flora in MRL/lpr mice within 24 h of oral challenge, which may contribute to exacerbation of lupus.

The Lectin Pathway of the Complement System-Activation, Regulation, Disease Connections and Interplay with Other (Proteolytic) Systems

The complement system is the other major proteolytic cascade in the blood of vertebrates besides the coagulation-fibrinolytic system. Among the three main activation routes of complement, the lectin pathway (LP) has been discovered the latest, and it is still the subject of intense research. Mannose-binding lectin (MBL), other collectins, and ficolins are collectively termed as the pattern recognition molecules (PRMs) of the LP, and they are responsible for targeting LP activation to molecular patterns, e.g., on bacteria. MBL-associated serine proteases (MASPs) are the effectors, while MBL-associated proteins (MAps) have regulatory functions. Two serine protease components, MASP-1 and MASP-2, trigger the LP activation, while the third component, MASP-3, is involved in the function of the alternative pathway (AP) of complement. Besides their functions within the complement system, certain LP components have secondary ("moonlighting") functions, e.g., in embryonic development. They also contribute to blood coagulation, and some might have tumor suppressing roles. Uncontrolled complement activation can contribute to the progression of many diseases (e.g., stroke, kidney diseases, thrombotic complications, and COVID-19). In most cases, the lectin pathway has also been implicated. In this review, we summarize the history of the lectin pathway, introduce their components, describe its activation and regulation, its roles within the complement cascade, its connections to blood coagulation, and its direct cellular effects. Special emphasis is placed on disease connections and the non-canonical functions of LP components.

The role and application of three IFN-related reactions in psoriasis

The pathophysiology of psoriasis is a highly complicated one. Due to the disease's specificity, it not only affects the patient's skin negatively but also manifests systemic pathological changes. These clinical symptoms seriously harm the patient's physical and mental health. IFN, a common immunomodulatory factor, has been increasingly demonstrated to have a significant role in the development of psoriatic skin disease. Psoriasis is connected with a variety of immunological responses. New targets for the therapy of autoimmune skin diseases may emerge from further research on the mechanics of the associated IFN upstream and downstream pathways. Different forms of IFNs do not behave in the same manner in psoriasis, and understanding how different types of IFNs are involved in psoriasis may provide a better notion for future research. This review focuses on the involvement of three types of IFNs in psoriasis and related therapeutic investigations, briefly describing the three IFNs' production and signaling, as well as the dual effects of IFNs on the skin. It is intended that it would serve as a model for future research.

Management of Lupus Nephritis: New Treatments and Updated Guidelines

Management of lupus nephritis has evolved considerably over the past years. Here, we provide a comprehensive review of clinical trials that form the basis for the Kidney Disease: Improving Global Outcomes and EULAR/ERA-EDTA updated guidelines and present day trials that will change the landscape of lupus nephritis therapy in years to come. In addition, we highlight the issues related to cost of therapy, resistant disease, and downstream adverse effects of specific therapies.

Critical role of lectin pathway mediated by MBL-associated serine proteases in complement activation for the pathogenesis in systemic lupus erythematosus

In complement activation system, although the classical pathway has shown to play a critical role for the pathogenesis of SLE, the role of lectin pathway has remained unknown in the pathogenesis of SLE. As Mannose-binding lectin-associated serine proteases (MASPs) are associated with activation of the lectin pathway, we conducted this study to clarify MASPs associations in the pathogenesis of SLE. We evaluated the serum level of MASPs (MASP-1 and MASP-2) in total 68 SLE patients consisting of 15 patients with biopsy-confirmed membranous lupus nephritis (M-LN), 35 patients with biopsy-confirmed proliferative lupus nephritis (P-LN), and 18 SLE patients without LN (non-LN). Our data showed that the serum levels of MASPs were reduced in both P-LN and non-LN although those of M-LN were not reduced. Our data show that the lectin pathway mediated by MASPs plays a critical role for the pathogenesis of SLE except for M-LN.

The role of MBL, PCT, CRP, neutrophil-lymphocyte ratio, and platelet lymphocyte ratio in differentiating infections from flares in lupus

BACKGROUND

The distinction between infection and flare in systemic lupus erythematosus (SLE) has always been a dilemma for clinicians as the clinical and biochemical profiles overlap. The present study evaluated affordable biomarkers to distinguish infection from flare in an SLE cohort in a tertiary care center in eastern India.

METHODS

One hundred and fifty-two SLE patients were clinically evaluated and enrolled in the present study. Hematological, immunological, and biochemical profiles and various biomarkers such as C reactive protein (CRP), procalcitonin (PCT), and Mannose-binding lectin (MBL) were quantified.

RESULTS

One hundred and fifty-two patients (152) were enrolled in the present study and all had SLEDAI scores of more than 4. From which 70 had infection, and the common infections were urinary tract infection (34.28%) followed by pneumonia (27.14%). Neutrophil-lymphocyte ratio (NLR) and C-reactive protein (CRP) were significantly elevated in SLE with infections (NLR: 5.84 ± 2.47; CRP: 30.56 ± 41.63) than those with flare (NLR: 3.87 ± 2.62; CRP: 8.73 ± 9.53). The receiver operating characteristic curve (ROC) analysis revealed CRP, PLR, and NLR as important markers for predicting infections (CRP: AUC = 0.682, p = 0.0001; PLR: AUC = 0.668, p = 0.0008; NLR: AUC = 0.742, p < 0.0001). The MBL and PCT levels were comparable among SLE flare and those with infections.

CONCLUSIONS

NLR and CRP levels are affordable biomarkers to distinguish infections from flares in SLE. MBL and PCT could not differentiate flare from an infection. Key Points • Biomarkers for the differentiation of infection and flare in SLE are limited. • NLR, PLR, and CRP are promising biomarkers to enable differentiation. • PCT and MBL are not ideal biomarkers to differentiate infection from flare.

TMT-based quantitative proteomics analysis and potential serum protein biomarkers for systemic lupus erythematosus

Systemic lupus erythematosus (SLE) was not only a typical systemic autoimmune disease, but also one of the most challenging heterogeneous diseases for physicians. Currently, the pathogenesis of SLE was unclear, and there were no accurate, universal or easy-to-use diagnostic criteria for assessing SLE activity and predicting SLE severity. Proteins were direct effectors of biological mechanisms, and were closer to clinical phenotypes than the other discovered biomarkers. Moreover, proteins were widely used as biomarkers for clinical diagnosis and mechanism research of many diseases. Herein, we compared the proteins profiles of healthy individuals (HCs) and SLE patients to reveal the pathogenesis and provide evidence for diagnosis and management of persons with SLE. Serum samples were collected from 28 SLE patients and 30 HCs. Tandem mass tag (TMT)-based quantitative proteomics method was used to identify, screen and detect differentially expressed proteins (DEPs) in the collected serum samples. A total of 744 proteins were identified, and 84 of them were considered as DEPs with 71 upregulated and 13 downregulated. Bioinformatics analysis suggested that these DEPs were mainly involved in many biological processes, including immune response, signal transduction, inflammatory response, proteolysis, innate immune response and apoptosis, which were closely related to the pathogenesis of SLE. After comprehensive analysis, serum amyloid A1 (SAA1) and endothelin (CD248) were identified as specific biomarkers for the diagnosis of SLE, and were confirmed by subsequent enzyme-linked immunosorbent assays (ELISA), indicating a high reliability of TMT-based quantitative proteomics results. Areas under the ROC curve (AUC) results confirmed that SAA1 and CD248 combination as early immune diagnosis biomarkers of SLE presented excellent sensitivity and specificity.

Intertwined pathways of complement activation command the pathogenesis of lupus nephritis

The complement system is involved in the origin of autoimmunity and systemic lupus erythematosus. Both genetic deficiency of complement components and excessive activation are involved in primary and secondary renal diseases, including lupus nephritis. Among the pathways, the classical pathway has long been accepted as the main pathway of complement activation in systemic lupus erythematosus. However, more recent studies have shown the contribution of factors B and D which implies the involvement of the alternative pathway. While there is evidence on the role of the lectin pathway in systemic lupus erythematosus, it is yet to be demonstrated whether this pathway is protective or harmful in lupus nephritis. Complement is being explored for the development of disease biomarkers and therapeutic targeting. In the current review we discuss the involvement of complement in lupus nephritis.

Mannan-binding lectin exacerbates the severity of psoriasis by promoting plasmacytoid dendritic cell differentiation via the signal transducer and activator of transcription 3-interferon regulatory factor 8 axis

Psoriasis is a chronic inflammatory skin disease mediated by host immune responses. Plasmacytoid dendritic cells (pDC) and interferon (IFN)-α secreted by pDC are involved in the initiation of psoriasis. Mannan-binding lectin (MBL), a vital component of the complement pathway, plays a critical role in innate immune defense and the inflammatory response. Our previous study found that MBL could exacerbate skin inflammation in psoriatic mice, but the effect of MBL on pDC remains unstudied. Herein, we revealed that the circulating level of MBL was elevated in patients with psoriasis compared with the healthy controls. Moreover, the MBL level was positively correlated with disease severity, relative inflammatory cytokine levels, and peripheral blood (PB) pDC frequency in psoriasis. An in vitro study determined that the MBL protein could promote the differentiation of human pDC and upregulate the production of relative inflammatory cytokines and chemokines. Additionally, MBL-deficient (MBL^-/- ) mice exhibited decreased accumulation of pDC in lymph nodes, spleens, and skin lesions with reduced secretion of pDC-related cytokines compared with wild-type (WT) mice in the preliminary stage of psoriasis induced by imiquimod. Notably, the differentiation of pDC from bone marrow (BM) cells derived from MBL^-/- mice was weakened compared with that from WT mice upon Fms-like tyrosine kinase 3 ligand (Flt3L) incubation. Mechanistic research indicated that the signal transducer and activator of transcription 3 (STAT3)-interferon regulatory factor 8 (IRF8) axis was responsible for MBL-modulated pDC differentiation. In summary, these results suggest that MBL exacerbates the severity of psoriasis by enhancing pDC differentiation and pDC-related cytokine secretion via the STAT3-IRF8 axis, thus providing a new target for psoriasis treatment.

A Plausible Role for Collectins in Skin Immune Homeostasis

The skin is a complex organ that faces the external environment and participates in the innate immune system. Skin immune homeostasis is necessary to defend against external microorganisms and to recover from stress to the skin. This homeostasis depends on interactions among a variety of cells, cytokines, and the complement system. Collectins belong to the lectin pathway of the complement system, and have various roles in innate immune responses. Mannose-binding lectin (MBL), collectin kidney 1, and liver (CL-K1, CL-L1) activate the lectin pathway, while all have multiple functions, including recognition of pathogens, opsonization of phagocytosis, and modulation of cytokine-mediated inflammatory responses. Certain collectins are localized in the skin, and their expressions change during skin diseases. In this review, we summarize important advances in our understanding of how MBL, surfactant proteins A and D, CL-L1, and CL-K1 function in skin immune homeostasis. Based on the potential roles of collectins in skin diseases, we suggest therapeutic strategies for skin diseases through the targeting of collectins and relevant regulators.

Common and Novel Markers for Measuring Inflammation and Oxidative Stress Ex Vivo in Research and Clinical Practice-Which to Use Regarding Disease Outcomes?

Many chronic conditions such as cancer, chronic obstructive pulmonary disease, type-2 diabetes, obesity, peripheral/coronary artery disease and auto-immune diseases are associated with low-grade inflammation. Closely related to inflammation is oxidative stress (OS), which can be either causal or secondary to inflammation. While a low level of OS is physiological, chronically increased OS is deleterious. Therefore, valid biomarkers of these signalling pathways may enable detection and following progression of OS/inflammation as well as to evaluate treatment efficacy. Such biomarkers should be stable and obtainable through non-invasive methods and their determination should be affordable and easy. The most frequently used inflammatory markers include acute-phase proteins, essentially CRP, serum amyloid A, fibrinogen and procalcitonin, and cytokines, predominantly TNFα, interleukins 1β, 6, 8, 10 and 12 and their receptors and IFNγ. Some cytokines appear to be disease-specific. Conversely, OS-being ubiquitous-and its biomarkers appear less disease or tissue-specific. These include lipid peroxidation products, e.g., F2-isoprostanes and malondialdehyde, DNA breakdown products (e.g., 8-OH-dG), protein adducts (e.g., carbonylated proteins), or antioxidant status. More novel markers include also -omics related ones, as well as non-invasive, questionnaire-based measures, such as the dietary inflammatory-index (DII), but their link to biological responses may be variable. Nevertheless, many of these markers have been clearly related to a number of diseases. However, their use in clinical practice is often limited, due to lacking analytical or clinical validation, or technical challenges. In this review, we strive to highlight frequently employed and useful markers of inflammation-related OS, including novel promising markers.

Role of biomarkers in the diagnosis and prognosis of patients with cutaneous lupus erythematosus

Cutaneous lupus erythematosus (CLE) is a connective tissue disease with varying presentations, and clinical sequelae including itching, dyspigmentation, and scarring. CLE can occur as its own entity or in conjunction with systemic disease, known as systemic lupus erythematosus (SLE). Because CLE is clinically diverse, identification of a biomarker may help not only facilitate early diagnosis and management but also identify individuals at risk for poor prognosis and development of SLE. While potential biomarkers in SLE have been extensively studied, few biomarkers for CLE have been identified and incorporated into clinical practice. Anti-SS-A antibody is a commonly used biomarker for diagnosis of subacute CLE patients. Type I interferon-related proteins such as MxA and guanylate binding protein‐1 (GBP-1) and chemokines such as CXCR3, CXCL9, and CXCL10 have been identified as biomarkers that may support diagnosis and track disease activity. First-line oral treatment for CLE currently consists of anti-malarials such as hydroxychloroquine (HCQ), chloroquine (CQ), and quinacrine (QC). Studies have found that an increased myeloid dendritic cell population with higher TNF-α expression may be predictive of poor treatment response to HCQ in CLE patients. Autoantibodies against nuclear antigens (e.g., anti-double-stranded DNA and anti-Smith antibodies) and elevated erythrocyte sedimentation rate have been more commonly found in CLE patients progressing to SLE than those who have not. This review aims to summarize previous and emerging biomarkers for CLE patients.

Expanding the Role of Complement Therapies: The Case for Lupus Nephritis

The complement system is an innate immune surveillance network that provides defense against microorganisms and clearance of immune complexes and cellular debris and bridges innate and adaptive immunity. In the context of autoimmune disease, activation and dysregulation of complement can lead to uncontrolled inflammation and organ damage, especially to the kidney. Systemic lupus erythematosus (SLE) is characterized by loss of tolerance, autoantibody production, and immune complex deposition in tissues including the kidney, with inflammatory consequences. Effective clearance of immune complexes and cellular waste by early complement components protects against the development of lupus nephritis, while uncontrolled activation of complement, especially the alternative pathway, promotes kidney damage in SLE. Therefore, complement plays a dual role in the pathogenesis of lupus nephritis. Improved understanding of the contribution of the various complement pathways to the development of kidney disease in SLE has created an opportunity to target the complement system with novel therapies to improve outcomes in lupus nephritis. In this review, we explore the interactions between complement and the kidney in SLE and their implications for the treatment of lupus nephritis.

CD14 (C-159T) polymorphism is associated with increased susceptibility to SLE, and plasma levels of soluble CD14 is a novel biomarker of disease activity: A hospital-based case-control study

BACKGROUND

Cluster of differentiation 14 (CD14) plays a crucial role in the innate immune response of the host in protection against various pathogens. The importance of soluble CD14 in autoimmune disorders has been described in different populations. However, the role of sCD14 in systemic lupus erythematosus (SLE) is poorly understood. Further, the association of functional variants at the promoter region of the CD14 gene (-159 C > T) with susceptibility to SLE or disease severity needs to be defined.

METHODS

Two hundred female SLE patients diagnosed on systemic lupus international collaborating clinics (SLICC) classification criteria and age, sex, matched healthy controls were enrolled in the present study. Polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) method was used to genotype CD14 (C-159 T) polymorphism. Plasma levels of IFN-α, TNF-α, and sCD14 were quantified by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Prevalence of mutant genotypes (CT and TT) and minor allele (T) of CD14 (C-159T) polymorphism was significantly higher in SLE cases compared to healthy controls (CT: P < 0.0001; OR = 3.26, TT:P < 0.0001; OR = 3.39; T:P = 0.0009, OR = 1.62). Further, lupus nephritis patients had a higher prevalence of homozygous mutants (TT) and mutant allele (T)(TT: P = 0.0002, OR = 8.07; T: P = 0.001, OR = 1.32). SLE patients displayed significantly increased plasma sCD14, TNF-α, and IFN-α levels in comparison to healthy controls. These cytokines were significantly elevated in patients of lupus nephritis compared to those without kidney involvement. Interestingly, sCD14 levels correlated positively with SLE disease activity index-2K (SLEDAI-2K) scores and 24 hours proteinuria.

CONCLUSION

CD14 (C-159T) polymorphism is associated with an increased predisposition to the development of SLE and lupus nephritis: sCD14 is a promising novel biomarker for assessing disease activity and lupus nephritis.

Association of MBL-2 gene polymorphisms with systemic lupus erythematosus: an updated meta-analysis and trial sequential analysis

OBJECTIVES

Mannose-binding lectin (MBL), an essential innate immune molecule, enhances the opsonization process and activates the complement system. Genetic variations at the promoter and coding region of the MBL-2 gene have been associated with susceptibility to systemic lupus erythematosus (SLE); however, reports remained inconsistent. The present study performs a meta-analysis of published peer-reviewed articles to draw a definitive conclusion.

MATERIALS AND METHODS

Published peer-reviewed articles on the association of MBL-2 gene polymorphisms and SLE were screened on various databases such as PubMed (Medline), ScienceDirect, and Google Scholar. A total of 23 eligible articles were included in the present study, comprising 3074 SLE patients and 3985 controls. Genotype and/or allele data for MBL-2 polymorphisms (A > B, A > C, A > D, A > O, Y > X and H > L) were extracted and analyzed by Comprehensive Meta-Analysis software (CMA V3.1).

RESULTS

The overall analysis revealed a significant association of MBL-2 (A > O) polymorphism with a predisposition to SLE in allele contrast (p = 0.000; OR = 1.261), homozygous (p = 0.005; OR = 1.482), heterozygous (p = 0.004; OR = 1.247), dominant (p = 0.000; OR = 1.303) and recessive (p = 0.025; OR = 1.356) genetic comparison model. Similar results were also observed in the comparison of allele and the dominant genetic model of MBL-2 (A > B) polymorphism in overall (allele: p = 0.000, OR = 1.46, dominant: p = 0.001, OR = 1.31) and in the Asian cohorts (allele: p = 0.007, OR = 1.43, dominant: p = 0.008, OR = 1.32). Interestingly, MBL-2 (Y-221X) polymorphism exhibited protection against the development of SLE in heterozygous (p = 0.005, OR = 0.619) and dominant genetic comparison (p = 0.01, OR = 0.672) models.

CONCLUSIONS

MBL-2 variants (A > O and A > B) are associated with predisposition to SLE. Conversely, promoter polymorphism (Y-221X) offers protection against SLE development.

Precision medicine in lupus nephritis: can biomarkers get us there?

Patients with systemic lupus erythematosus frequently develop lupus nephritis (LN), a condition that can lead to end-stage kidney disease. Multiple serum and urine biomarkers for LN have been proposed in recent years, yet none have become incorporated into clinical use. The majority of studies have been single center with significant variability in cohorts, assays, and sample storage, leading to inconclusive results. It has become clear that no single biomarker is likely to be sufficient to diagnose LN, identify flares, and define the response to therapy and prognosis. A more likely scenario is a panel of urine, serum, tissue, and genetic biomarkers. In this review, we summarize traditional and novel biomarkers and discuss how they may be utilized in order to bring precision medicine to clinical practice in LN.

Mannose Binding Lectin and Pentraxin 3 in Patients with Diabetic Retinopathy

BACKGROUND

Mannose binding lectin (MBL) is a protein of the complement system and pentraxin-3 (PTX3) is an acute phase protein both with an important role in inflammatory diseases, such as diabetic retinopathy (DR).

AIM OF THE STUDY

To evaluate whether plasma MBL and PTX3 levels are associated with the development of DR and if patients with and without DR can be distinguished.

METHODS

The patients were divided into three groups: diabetic without DR; with mild/moderate DR, and with severe/proliferative DR. PTX3 and MBL levels were measured with enzyme-linked immunosorbent assay kits.

RESULTS

A total of 74 patients were included. A significant association was observed between high levels of MBL and severe DR; 47% of patients with severe/proliferative DR had high levels of MBL, whereas 12% of the patients with diabetes but no DR had high levels of MBL (p = 0.008; odds ratio [OR]: 6.06; 95% confidence interval [CI]: 1.4-25.0). High levels of MBL were more frequent in patients with severe/proliferative disease (47%) when compared to those with mild/moderate DR (20%), p = 0.04 (OR: 3.46; 95% CI: 1.0-11.8). PTX3 levels were similar among the groups and were not related to the development or severity of DR.

CONCLUSION

We found a significant association between high plasma MBL levels and DR development as well as with severe/proliferative DR. We observed no relationship between plasma PTX3 levels and the development or severity of DR.

Mannose-binding lectin serum levels in patients with systemic lupus erythematosus: association with thrombocytopaenia and seizure

The complement system contributes to the pathogenesis of systemic lupus erythematosus (SLE). Mannose-binding lectin (MBL) is a key molecule of the lectin pathway of complement and seems to be related to the clinical manifestations of this disease. We evaluated the serum levels of MBL and its relationship with disease onset and clinical findings in SLE patients. Serum samples were analysed in 195 patients and 145 healthy controls from southern Brazil. Patients with high MBL levels (above 2000 ng/ml) showed a significant increase in the frequency of thrombocytopaenia ( p = 0.007; OR = 2.71; 95% CI = 1.32-5.55); and seizures ( p = 0.034; OR = 2.61; 95% CI = 1.07-6.37). A positive correlation between disease activity and MBL levels (>2000 ng/ml; p = 0.031, rho = 0.279) as well as of MBL concentration with accumulated organ damage ( p = 0.021; rho = 0.232) was observed. Our results suggest a role for MBL in the development of clinical manifestations such as thrombocytopaenia and seizures in SLE patients. These findings corroborate the participation of the lectin pathway of complement in the pathophysiologic mechanisms underlying clinical manifestations of SLE.

Distinguishing infections vs flares in patients with systemic lupus erythematosus

SLE is a chronic autoimmune disease involving multiple systems. Patients with SLE are highly susceptible to infections due to the combined effects of their immunosuppressive therapy and the abnormalities of the immune system that the disease itself causes, which can increase mortality in these patients. The differentiation of SLE activity and infection in a febrile patient with SLE is extremely difficult. Activity indexes are useful to identify patients with lupus flares but some clinical and biological abnormalities may, however, make it difficult to differentiate flares from infection. Several biological markers are now recognized as potential tools to establish the difference between SLE activity and infection, including CRP and procalcitonin. It is possible, however, that the use of only one biomarker is not sufficient to confirm or discard infection. This means that new scores, which include different biomarkers, might represent a better solution for differentiating these two clinical pictures. This review article describes several markers that are currently used, or have the potential, to differentiate infection from SLE flares.

Genetic variants in FH are associated with renal histopathologic subtypes of lupus nephritis: a large cohort study from China

Objective Genetic variants in FH (complement factor H) were reported to associate with susceptibility to systemic lupus erythematosus (SLE). This study proposed that the genetic defects of FH in the susceptibility and in the development of lupus nephritis might be different. Methods This study enrolled 334 lupus nephritis patients, 269 SLE patients without clinical renal involvement and 350 controls. Two-step genotyping was performed. First, all the exons of the FH gene were fully sequenced in 100 lupus nephritis patients and 100 healthy controls. Second, genotyping of three common variants reported to be functional, rs1061170, rs800292 and rs6677604, was conducted in all the recruited individuals. Further, analysis of their associations with SLE/lupus nephritis susceptibility and the clinico-pathological parameters in the lupus nephritis group was performed. Results No significant differences were observed in allele and genotype frequencies of the three single nucleotide polymorphisms between lupus patients and controls. There was a significantly higher ratio of CC/CT genotypes of rs1061170 in lupus nephritis patients with class III than in the other two classes (class III vs. class IV vs. class V: 21.0% vs. 9.7% vs. 9.4%; P = .044). The rs6677604-GG genotype was observed to be associated with the absence of anti-ds DNA antibody ( P = .021), and the rs800292-TT genotype was associated with a higher level of circulating C3 ( P = 0.20) in lupus nephritis. Conclusion In an independent cohort, this is the first genetic association analysis focusing on FH genetic variants in Chinese lupus nephritis patients. It was found that the variants in the FH gene might affect the histopathologic subtypes and some clinical features of the disease.

Organ-specific biomarkers in lupus

Systemic lupus erythematosus (SLE) is a complex and highly heterogeneous disease, which affects multiple organs, including joints, skin, kidneys, heart, hematopoietic system, and nerve system. While the etiopathogenesis of SLE still remains unclear, genetic susceptibilities and aberrant epigenetic modifications are believed to be involved. For precision therapy, it is necessary to assess accurately and objectively organ involvements and disease activity, which is difficult by current clinical laboratory tests. Biomarkers, which are a biologic, genetic, epigenetic or a chemical characteristic and conveniently detectable, serve as measures of disease diagnosis, activity, prognosis, and manifestation prediction, thereby providing instruction for individualized therapy. In addition, biomarkers differ according to different manifestations, since the disease activity index and treatments vary significantly. For example, unlike other non-renal SLE, lupus nephritis requires significant immunosuppressive drugs. Over the past decades, the research on biomarkers in lupus has been strengthened and numerous promising biomarkers have been identified at levels of genomics, transcriptomics and proteomics. In this review, we summarize the conventional and novel biomarkers in the tissue-specific manner, and discuss their roles in specific organ diagnosis, future manifestation prediction, disease activity assessment and their correlation with histology results. By doing so, it aims to shed a light on individualized treatment.

Complement in autoimmune diseases

The complement system is an ancient and evolutionary conserved element of the innate immune mechanism. It comprises of more than 20 serum proteins most of which are synthesized in the liver. These proteins are synthesized as inactive precursor proteins which are activated by appropriate stimuli. The activated forms of these proteins act as proteases and cleave other components successively in amplification pathways leading to exponential generation of final effectors. Three major pathways of complement pathways have been described, namely the classical, alternative and lectin pathways which are activated by different stimuli. However, all the 3 pathways converge on Complement C3. Cleavage of C3 and C5 successively leads to the production of the membrane attack complex which is final common effector. Excessive and uncontrolled activation of the complement has been implicated in the host of autoimmune diseases. But the complement has also been bemusedly described as the proverbial "double edged sword". On one hand, complement is the final effector of tissue injury in autoimmune diseases and on the other, deficiencies of some components of the complement can result in autoimmune diseases. Currently available tools such as enzyme based immunoassays for functional assessment of complement pathways, flow cytometry, next generation sequencing and proteomics-based approaches provide an exciting opportunity to study this ancient yet mysterious element of innate immunity.

Highly Expression of CD11b and CD32 on Peripheral Blood Mononuclear Cells from Patients with Adult-Onset Still's Disease

BACKGROUND

We investigated the potential role of several pattern-recognition receptors (PRRs; CD11b, CD11c, CD32, CD206, CD209, and dectin-1) in adult-onset Still's disease (AOSD).

METHODS

The study included 13 untreated AOSD patients, 19 rheumatoid arthritis (RA) patients (as a disease control), and 19 healthy controls (HCs). The PRRs were quantified in peripheral blood using flow cytometry. The serum levels of interleukin-17 (IL-17), IL-18, and IL-23 were measured by enzyme-linked immunosorbent assay.

RESULTS

Significantly higher mean frequencies of cells presenting CD11b and CD32 from whole blood were observed in patients with AOSD than in patients with RA or HC. The levels of IL-17, IL-18, and IL-23 were elevated in AOSD patients compared to HCs. CD11b frequencies from whole cells correlated with systemic scores, lactate dehydrogenase (LDH) levels, aspartate transaminase levels, interleukin-23 (IL-23) levels, and IL-18. Frequencies of CD209 from granulocytes were significantly correlated with systemic scores, and the erythrocyte sedimentation rate and levels of C-reactive protein, ferritin, LDH, IL-23, and interleukin-18 (IL-18).

CONCLUSIONS

Elevated frequencies of circulating CD11b-positive cells and positive correlations with disease activity markers suggest that circulating CD11b-positive cells contribute to the pathogenesis of AOSD.

Plant Lectins Activate the NLRP3 Inflammasome To Promote Inflammatory Disorders

Plant-derived dietary lectins have been reported to be involved in the pathogenesis of several inflammatory diseases, including inflammatory bowel disease, diabetes, rheumatoid arthritis, and celiac disease, but little is known about the molecular mechanisms underlying lectin-induced inflammation. In this study, we showed that plant lectins can induce caspase-1 activation and IL-1β secretion via the NLRP3 inflammasome. Lectins were internalized and subsequently escaped from the lysosome and then translocated to the endoplasmic reticulum. Endoplasmic reticulum-loaded plant lectins then triggered Ca²⁺ release and mitochondrial damage, and inhibition of Ca²⁺ release and mitochondrial reactive oxygen species by chemical inhibitors significantly suppressed NLRP3 inflammasome activation. In vivo, plant lectin-induced inflammation and tissue damage also depended on the NLRP3 inflammasome. Our findings indicate that plant lectins can act as an exogenous "danger signal" that can activate the NLRP3 inflammasome and suggest that dietary lectins might promote inflammatory diseases via the NLRP3 inflammasome.

Mannose-Binding Lectin Deficiency in Brazilian Patients with Spondyloarthritis

BACKGROUND

Infections are usually involved in the pathogenesis of spondyloarthritis (SpA). Mannose-binding lectin (MBL) is a component of the innate immune system with an important role in microbial defense.

OBJECTIVE

To study the prevalence of MBL deficiency in SpA patients as well as its influence in the clinical profile of these diseases.

METHODS

We studied 89 SpA patients and 89 healthy individuals, paired for age and gender. MBL serum levels were measured by ELISA test. Individuals with levels ≤100 ng/mL were considered deficient. SpA patients had determination of Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Ankylosing Spondylitis Disease Activity Score (ASDAS)-CRP, Bath Ankylosing Spondylitis Functional Index (BASFI), C reactive protein (CRP), erythrocyte sedimentation rate (ESR), and review of their clinical profile.

RESULTS

SpA patients had MBL levels ranging from 100 to 4100 ng/mL (median = 375 ng/mL); controls levels ranged from 100 to 4703 ng/mL (median = 1204 ng/mL; p < 0.0001). The prevalence of MBL deficiency was 27/89 (30.3%) in SpA patients and 12/89 (13.5%) in controls, with p = 0.01; OR = 2.5 (95% IC = 1.2-5.3). No association/correlation was found between MBL levels with BASDAI, BASFI, age at disease onset, ASDAS-CRP, ESR, CRP, presence of uveitis, HLAB27, peripheral arthritis, or SpA subtype (all p = NS).

CONCLUSION

MBL levels may be linked with the occurrence of SpA but do not influence its phenotype.

Association between the Presence of Autoantibodies Targeting Ficolin-3 and Active Nephritis in Patients with Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the production of multiple autoantibodies. Antibodies against Ficolin-3 were previously identified in the sera of some SLE patients, but their prevalence and significance have not been yet investigated. The aims of this study were to determine the prevalence of anti-ficolin-3 antibodies among SLE patients and to investigate their potential as diagnostic and/or prognostic biomarkers in SLE. In this retrospective study, sera from SLE patients (n = 165) were selected from a preexisting declared biological collection. Samples from healthy controls (n = 48) were matched with SLE sera. Disease activity was determined according to the SLEDAI score. Anti-ficolin-3, anti-dsDNA and anti-C1q antibodies levels were measured in sera by ELISA. First, a highly significant difference was found in the anti-ficolin-3 levels between SLE patients and healthy subjects. Anti-ficolin-3 antibodies were detected as positive in 56 of 165 (34%) SLE patients. The titer of anti-ficolin-3 antibodies was correlated with the SLEDAI score (r = 0.38, p<0.0001). The presence of anti-ficolin-3 antibodies was associated with anti-C1q and anti-dsDNA antibodies. Regarding associations with clinical manifestations, the presence of active lupus nephritis was significantly associated with the presence of anti-ficolin-3 antibodies (p≤0.001). This association with renal involvement was higher with anti-ficolin-3 or anti-C1q antibodies than with other auto-antibodies. Interestingly, the combination of anti-ficolin-3 and anti-C1q antibodies demonstrated higher specificity than any other serological biomarker. These results suggest that anti-ficolin-3 antibodies could be useful for the diagnosis of active nephritis in SLE patients.

Mannose binding lectin polymorphisms in systemic lupus erythematosus in Spain

Low mannose binding lectin (MBL) producer genotypes have been considered as a systemic lupus erythematosus (SLE) risk factor. The aim of this study was to explore whether polymorphisms in the MBL gene are associated with susceptibility to SLE and disease-specific clinical manifestations or with disease severity in SLE patients in Son Llàtzer Hospital. MBL2 exon 1 and promoter polymorphisms were genotyped and MBL plasma levels were quantified by ELISA in 39 SLE cases and in 96 healthy controls. High MBL producer genotypes HYPA and LXPA were the most frequent haplotypes (65 and 62 participants, respectively). LYQC/HYPD, LXPA/LYQC and LYPB/HYPD were only found in SLE, and all of them were related to severe MBL deficiency. SLE patients showed a trend towards more severe MBL deficiency (MBL <100 ng/mL) compared to controls (10 [25.6%] and 11 [11.46%] respectively, P = 0.07). The wild-type genotype was more frequent in controls compared to SLE. The trend towards more severe MBL deficiency in SLE and the fact that some of the low-MBL producer genotypes were only found in SLE patients, suggest that low MBL levels or MBL2 variant could be a risk factor for the development of SLE.

The dysfunctions of complement factor H in lupus nephritis

OBJECTIVE

Our previous study showed that plasma levels of factor H (FH) were significantly decreased in patients with lupus nephritis and reflected lupus nephritis activity. The aim of this study was to further investigate in vitro biofunctions of plasma FH in patients with lupus nephritis.

METHODS

FH was purified from the first run of plasma exchange in four active lupus nephritis patients and two non-renal involvement systemic lupus erythematosus (SLE) patients, and plasma from two healthy controls. Then, the biofunctions of the purified FH were analyzed. In addition, FH exons sequencing analysis was performed.

RESULTS

Homogeneous FH was purified from the plasma fractions and the purity of the purified FH was comparable to the commercial FH. The abilities of FH binding with C3b and mCRP, and its protecting abilities from the lysis of sheep erythrocytes, from No. 3 and No. 4 lupus nephritis patients, decreased significantly compared with those in normal controls. The purified FH from lupus nephritis patients Nos. 2-4 could not induce the phagocytosis of late apoptotic cells significantly compared with normal controls. All four lupus nephritis patients had the known SNP rs1061147 (SCR5, A307A), rs1061170 (SCR7, Y402H), CM050194 (SCR20, S1191W) and CM010322 (SCR20, V1197A), which might be associated with the above dysfunctions.

CONCLUSIONS

Dysfunctions of FH, including the regulations of complement alternative pathway and the clearance of apoptotic cells, were found in some active lupus nephritis patients, which were associated with their clinical phenotypes. The FH SNPs might contribute to the dysfunctions of FH in patients with lupus nephritis.

Vaccine-preventable infections in Systemic Lupus Erythematosus

Systemic Lupus Erythematosus (SLE) is characterized by abnormal autoantibody production and clearance. Infections are among the most important causes of morbidity and mortality in SLE patients; they have an increased frequency of severe bacterial and viral infections possibly due to inherited genetic and immunologic defects and to immunosuppressive therapies. In addition, infectious agents can switch on lupus disease expression and activity. Among the strategies to reduce the risk of infection, vaccination can be considered the most reliable option. Most vaccines are effective and safe in SLE patients, although in certain cases immunogenicity may be sub-optimal and vaccination can trigger a flare. Although these issues are currently unresolved, the risk benefit balance is in favor for vaccination to reduce the risk of infection in SLE patients. In the present review we discuss the preventive strategies currently recommended to reduce bacterial and viral infections in SLE.

Insulin-like growth factor binding protein-2 as a novel biomarker for disease activity and renal pathology changes in lupus nephritis

Lupus nephritis (LN) is one of the most serious manifestations of systemic lupus erythematosus. Invasive renal biopsy remains the gold standard for the diagnosis and management of LN. The objective of this study is to validate serum insulin-like growth factor binding protein-2 (IGFBP-2) as a novel biomarker for clinical disease and renal pathology in LN. Eighty-five biopsy-proven lupus nephritis patients, 18 chronic kidney disease (CKD) patients and 20 healthy controls were recruited for enzyme-linked immunosorbent assay (ELISA) testing of serum IGFBP-2 levels. Compared to CKD patients of origins other than lupus or healthy controls, serum IGFBP-2 levels were elevated significantly in LN patients. Serum IGFBP-2 was able to discriminate LN patients from the other two groups of patients [area under the curve (AUC) = 0·65, 95% confidence interval (CI) = 0·52-0·78; P = 0·043 for LN versus CKD; 0·97, 95% CI = 0·93-1·00; P < 0·0001 for LN versus healthy controls]. Serum IGFBP-2 was a potential indicator of both global disease activity and renal disease activity in LN patients, correlated with serum creatinine levels (r = 0·658, P < 0·001, n = 85) and urine protein-to-creatinine levels (r = 0·397, P < 0·001, n = 85). More importantly, in 19 concurrent patient samples, serum IGFBP-2 correlated with the chronicity index of renal pathology (r = 0·576, P = 0·01, n = 19) but not renal pathological classification. In conclusion, serum IGFBP-2 is a promising biomarker for lupus nephritis, reflective of disease activity and chronicity changes in renal pathology.

Primary immunodeficiency association with systemic lupus erythematosus: review of literature and lessons learned by the Rheumatology Division of a tertiary university hospital at São Paulo, Brazil

Primary immunodeficiency disorders (PID) represent a heterogeneous group of diseases resulting from inherited defects in the development, maturation and normal function of immune cells; thus, turning individuals susceptible to recurrent infections, allergy, autoimmunity, and malignancies. In this retrospective study, autoimmune diseases (AIDs), in special systemic lupus erythematosus (SLE) which arose associated to the course of PID, are described. Classically, the literature describes three groups of PID associated with SLE: (1) deficiency of Complement pathway components, (2) defects in immunoglobulin synthesis, and (3) chronic granulomatous disease (CGD). Currently, other PID have been described with clinical manifestation of SLE, such as Wiskott-Aldrich syndrome (WAS), autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED), autoimmune lymphoproliferative syndrome (ALPS) and idiopathic CD4(+) lymphocytopenia. Also we present findings from an adult cohort from the outpatient clinic of the Rheumatology Division of Universidade Federal de São Paulo. The PID manifestations found by our study group were considered mild in terms of severity of infections and mortality in early life. Thus, it is possible that some immunodeficiency states are compatible with survival regarding infectious susceptibility; however these states might represent a strong predisposing factor for the development of immune disorders like those observed in SLE.

Serum ferritin level correlates with SLEDAI scores and renal involvement in SLE

Introduction

Ferritin is an acute-phase reactant that is elevated in various autoimmune disorders. Serum ferritin levels have been positively correlated with disease activity scores of rheumatoid arthritis and systemic lupus erythematosus (SLE). Further, enhanced levels of ferritin have also been reported in lupus nephritis. However, there are no reports from the Indian subcontinent.

Methods

Seventy-six female SLE patients, diagnosed on the basis of revised ACR criteria, and 50 healthy females, age matched from similar geographical areas, were enrolled in the present study. Serum levels of ferritin, IFN-α and IL-6 were quantified by enzyme-linked immunosorbent assay (ELISA). Clinical, biochemical, serological and other markers of disease activity (C3, C4 and anti-dsDNA) were measured by standard laboratory procedure.

Results

Serum ferritin levels were significantly higher in SLE patients compared to healthy controls ( p < 0.0001). Ferritin levels positively correlated with SLE Disease Activity Index (SLEDAI) ( p = 0.001, r = 0.35), anti-dsDNA ( p = 0.001, r = 0.35), IFN-α ( p < 0.0001, r = 0.51) and IL-6 (p < 0.0001, r = 0.65) and negatively correlated with C3 ( p = 0.0006, r = −0.38) and C4 ( p = 0.01, r = −0.28). Interestingly, serum levels of ferritin were positively associated with proteinuria ( p = 0.001, r = 0.36), serum urea ( p = 0.0004, r = 0.39) and serum creatinine ( p = 0.0006, r = 0.38).

Conclusion

Serum ferritin is an excellent marker of disease activity and renal dysfunction in SLE.

Serum mannose-binding lectin and C-reactive protein are potential biomarkers for patients with community-acquired pneumonia

AIM

The aim of this study was to identify whether mannose-binding lectin (MBL) and C-reactive protein (CRP) may be used as clinical biomarkers for predicting outcome of community-acquired pneumonia (CAP) by tracking serum MBL and CRP level changes during a time course.

METHODS

One hundred four patients with CAP and 100 healthy individuals were enrolled in this study. The patients were further divided into Survivor and Death groups based on 30-day mortality. The MBL and CRP levels in these patients at pre- and post-treatments at days 4 and 7 were determined using an immunoturbidimetric assay and an enzyme-linked immunosorbent assay (ELISA).

RESULTS

Compared to the control group, the MBL and CRP levels in the CAP group were significantly higher. CRP levels in the CAP group significantly reduced within 1 week following anti-infection and other supporting therapies including anti-phlegm and liquidation. MBL levels were significantly higher in the Survivor group than in the Death group (p<0.05). On the contrary, CRP levels were significantly higher in the Death group than in the Survivor group (p<0.05). There was a negative correlation between the serum MBL and CRP levels in all patients following the treatments.

CONCLUSION

Both the MBL and CRP can serve as inflammatory markers in predicting the outcome of patients with CAP.

MBL2 gene variants coding for mannose-binding lectin deficiency are associated with increased risk of nephritis in Danish patients with systemic lupus erythematosus

OBJECTIVES

Autoimmunity may in part result from deficiencies in the processing of apoptotic debris. As mannose-binding lectin (MBL) is involved in such processes, we hypothesized that the variants in the MBL2 gene resulting in MBL deficiency confer an increased risk of nephritis in systemic lupus erythematosus (SLE).

METHODS

A total of 171 SLE patients attending a Danish tertiary rheumatology referral center were included. Common variant alleles in exon 1 of the MBL2 gene (R52C, rs5030737; G54D, rs1800450; G57E, rs1800451) were genotyped. The normal allele and variant alleles are termed A and O, respectively. The follow-up period was defined as the time from fulfillment of the ACR 1987 classification criteria for SLE until the occurrence of an event (nephritis, end-stage renal disease (ESRD), or death) or end of follow-up. Cox regression analyses were controlled for gender, age and race.

RESULTS

During a median follow-up of 5.7 years, nephritis developed in 94 patients, and ESRD developed in 16 of these patients. Twenty-seven patients died. The distribution of the MBL2 genotypes A/A, A/O and O/O was 58%, 35% and 7.0%, respectively. Compared to the rest, O/O patients had 2.6 times (95% CI: 1.2-5.5) higher risk of developing nephritis, and their risk of death after 10 years was 6.0 times increased (95% CI: 1.0-36). MBL serum levels below 100 ng/ml were associated with a 2.0 (95% CI: 1.2-3.4; p = 0.007) increased risk of developing nephritis. ESRD and histological class of nephritis were not associated with MBL deficiency.

CONCLUSIONS

Genetically determined MBL deficiency was associated with development of nephritis in SLE patients, but not with histological class of nephritis or ESRD.

Mannose binding lectin deposition in skin of lupus erythematosus patients: a case series

INTRODUCTION

Mannose binding lectin (MBL) has been linked to predisposition to systemic lupus erythematosus (SLE) and to disease activity. Some studies found deposits of MBL in glomerular tissue of patients with lupus nephritis. There is no research about the deposition of MBL in skin.

MATERIALS AND METHODS

Skin biopsies from lesional and non lesional skin of 4 discoid lupus erythematosus (DLE) and 10 SLE patients were submitted to immunofluorescence staining for IgG, IgA, IgM, C3, C4, C1q, C5b-9 and MBL. Charts were reviewed for demographic, clinical and serological data. Patients with SLE had disease activity measured by SLEDAI.

RESULTS

MBL was found only in SLE lesional skin and its presence showed an association trend towards higher disease activity. Deposition of C5b-9 occurred in vessels only in patients with SLE (70%) and in the two patients with kidney involvement.

CONCLUSIONS

MBL deposition was found in the lesional skin of SLE patients but not in SLE non lesional skin nor in DLE patients, and it seems to be less frequent and less strong than observed in the kidneys biopsies, suggesting that the complement participation in the pathophysiology of SLE process may not be the same in these two clinical manifestations.

Breaking immunological tolerance in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a fairly heterogeneous autoimmune disease of unknown etiology that mainly affects women in the childbearing age. SLE is a prototype type III hypersensitivity reaction in which immune complex depositions cause inflammation and tissue damage in multiple organs. Two distinct cell death pathways, apoptosis and NETosis, gained a great deal of interest among scientists, since both processes seem to be deregulated in SLE. There is growing evidence that histone modifications induced by these cell death pathways exert a central role in the induction of autoimmunity. In the current review, we discuss how abnormalities in apoptosis, NETosis, and histone modifications may lead to a break of immunological tolerance in SLE.

Vitamin D levels in Indian systemic lupus erythematosus patients: association with disease activity index and interferon alpha

INTRODUCTION

Low levels of vitamin D have been associated with several autoimmune disorders including multiple sclerosis, rheumatoid arthritis, type 1 diabetes and systemic lupus erythematosus (SLE). The major source of vitamin D is sunlight but exposure of SLE patients to UV rays has been shown to exacerbate disease pathology. Studies in various populations have shown an association between low vitamin D levels and higher SLE disease activity.

METHODS

We enrolled 129 patients who fulfilled American College of Rheumatology criteria in the study. There were 79 treatment-naïve cases and 50 patients who were under treatment for underlying SLE. There were 100 healthy subjects from similar geographical areas included as controls. Plasma 25-OH vitamin D₃ and interferon (IFN)-α levels were quantified by enzyme-linked immunosorbent assay (ELISA). The gene expression level of IFN-α was determined by quantitative real-time reverse transcriptase polymerase chain reaction (RT-PCR).

RESULTS

Plasma 25-OH vitamin D₃ significantly correlated in an inverse manner with systemic lupus erythematosus disease activity index (SLEDAI) scores (P <0.0001, r = -0.42), anti-dsDNA (P <0.0001, r = -0.39), plasma IFN-α (P <0.0001, r = -0.43) and levels of IFN-α gene expression (P = 0.0009, r = -0.45). Further, plasma levels of IFN-α positively correlated with gene expression of IFN-α (P <0.0001, r = 0.84). Treatment-naïve SLE patients displayed significantly higher plasma levels of IFN-α compared to patients under treatment (P <0.001) and controls (P <0.001).

CONCLUSIONS

These results suggest an important role of vitamin D in regulating disease activity in SLE patients and the need to supplement vitamin D in their treatment.

TLR-9 promoter polymorphisms (T-1237C and T-1486C) are not associated with systemic lupus erythematosus: a case control study and meta-analysis

Toll like receptors (TLRs) are essential molecules implicated in both innate and adaptive immune response. Polymorphisms in TLR gene have been associated with various infectious diseases and autoimmune disorders. Role of TLR9 has been elegantly demonstrated in both human systemic lupus erythematosus (SLE) and mice model of lupus. In the present study we investigated association of TLR-9 promoter polymorphisms (T-1237C and T-1486C) with susceptibility/resistance to SLE in an Eastern Indian state which is endemic to parasitic diseases. 210 Female SLE patients who fulfilled the American College of Rheumatology criteria were enrolled along with matched healthy controls from Odisha, India. TLR-9 polymorphisms (T-1237C and T-1486C) were typed by polymerase chain reaction followed by restriction fragment length polymorphism. For meta-analysis, relevant literatures were searched from PubMed database and comprehensive meta-analysis V2 software was employed for analysis. Allele and genotype frequency of TLR-9 promoter polymorphisms (T-1237C and T-1486C) were comparable among SLE patients and controls. Further, meta-analysis of earlier reports and present study did not reveal a significant association of TLR-9 (T-1237C and T-1486C) polymorphisms with SLE. Data from the present study suggest that TLR-9 promoter polymorphisms are not associated with susceptibility to SLE in an area endemic to parasitic diseases.

Biomarker profiling for lupus nephritis

Lupus nephritis (LN) is one of the most severe manifestations of systemic lupus erythematosus (SLE), which is associated with significant morbidity and mortality of SLE patients. The pathogenesis of LN involves multiple factors, including genetic predisposition, epigenetic regulation and environmental interaction. Over the last decade, omics-based techniques have been extensively utilized for biomarker screening and a wide variety of variations which are associated with SLE and LN have been identified at the levels of genomics, transcriptomics and proteomics. These studies and discoveries have expanded our understanding of the molecular basis of the disease and are important for identification of potential therapeutic targets for disease prediction and early treatment. In this review, we summarize some of the recent studies targeted at the identification of LN-associated biomarkers using genomics and proteomic approaches.