Association of tumor necrosis factor receptor 2 (TNFR2) polymorphism with susceptibility to systemic lupus erythematosus

Lupus nephritis: Biomarkers

Lupus nephritis (LN) or renal involvement of systemic lupus erythematosus (SLE), is a common manifestation occurring in at least 50 % of SLE patients. LN remains a significant source of morbidity, often leading to progressive renal dysfunction and is a major cause of death in SLE. Despite these challenges, advances in the understanding of the pathogenesis and genetic underpinnings of LN have led to a commendable expansion in available treatments over the past decade. This chapter provides a foundation for the understanding LN pathogenesis, diagnosis, and epidemiology, and guides the reader through recent advances in biomarkers, genetic susceptibility of this intricate condition.

TNF-α signals through ITK-Akt-mTOR to drive CD4+ T cell metabolic reprogramming, which is dysregulated in rheumatoid arthritis

Upon activation, T cells undergo metabolic reprogramming to meet the bioenergetic demands of clonal expansion and effector function. Because dysregulated T cell cytokine production and metabolic phenotypes coexist in chronic inflammatory disease, including rheumatoid arthritis (RA), we investigated whether inflammatory cytokines released by differentiating T cells amplified their metabolic changes. We found that tumor necrosis factor-α (TNF-α) released by human naïve CD4+ T cells upon activation stimulated the expression of a metabolic transcriptome and increased glycolysis, amino acid uptake, mitochondrial oxidation of glutamine, and mitochondrial biogenesis. The effects of TNF-α were mediated by activation of Akt-mTOR signaling by the kinase ITK and did not require the NF-κB pathway. TNF-α stimulated the differentiation of naïve cells into proinflammatory T helper 1 (TH1) and TH17 cells, but not that of regulatory T cells. CD4+ T cells from patients with RA showed increased TNF-α production and consequent Akt phosphorylation upon activation. These cells also exhibited increased mitochondrial mass, particularly within proinflammatory T cell subsets implicated in disease. Together, these findings suggest that T cell-derived TNF-α drives their metabolic reprogramming by promoting signaling through ITK, Akt, and mTOR, which is dysregulated in autoinflammatory disease.

Cytokines in Systemic Lupus Erythematosus-Focus on TNF-α and IL-17

Systemic lupus erythematosus (SLE) is an autoimmune disorder known for its complex pathogenesis, in which cytokines play an essential role. It seems that the modulation of these cytokines may impact disease progression, being considered potential biomarkers. Thus, TNF (tumor necrosis factor)-α and IL (interleukin)-17 are molecules of great interest in SLE. TNF-α plays a dual role in SLE, with both immunosuppressive and proinflammatory functions. The role of IL-17 is clearly described in the pathogenesis of SLE, having a close association with IL-23 in stimulating the inflammatory response and consecutive tissue destruction. It appears that patients with elevated levels of these cytokines are associated with high disease activity expressed by the SLE disease activity index (SLEDAI) score, although some studies do not confirm this association. However, TNF-α and IL-17 are found in increased titers in lupus patients compared to the general population. Whether inhibition of these cytokines would lead to effective treatment is under discussion. In the case of anti-TNF-α therapies in SLE, the possibility of ATIL (anti-TNF-induced lupus) is a serious concern that limits their use. The use of anti-IL-17 therapies in SLE is a promising option, but not yet approved. Future studies of these cytokines in large cohorts will provide valuable information for the management of SLE.

TNFR2 Costimulation Differentially Impacts Regulatory and Conventional CD4+ T-Cell Metabolism

CD4+ conventional T cells (Tconvs) mediate adaptive immune responses, whereas regulatory T cells (Tregs) suppress those responses to safeguard the body from autoimmunity and inflammatory diseases. The opposing activities of Tconvs and Tregs depend on the stage of the immune response and their environment, with an orchestrating role for cytokine- and costimulatory receptors. Nutrient availability also impacts T-cell functionality via metabolic and biosynthetic processes that are largely unexplored. Many data argue that costimulation by Tumor Necrosis Factor Receptor 2 (TNFR2) favors support of Treg over Tconv responses and therefore TNFR2 is a key clinical target. Here, we review the pertinent literature on this topic and highlight the newly identified role of TNFR2 as a metabolic regulator for thymus-derived (t)Tregs. We present novel transcriptomic and metabolomic data that show the differential impact of TNFR2 on Tconv and tTreg gene expression and reveal distinct metabolic impact on both cell types.

Tumor necrosis factor‑α in systemic lupus erythematosus: Structure, function and therapeutic implications (Review)

Tumor necrosis factor‑α (TNF‑α) is a pleiotropic pro‑inflammatory cytokine that contributes to the pathophysiology of several autoimmune diseases, such as multiple sclerosis, inflammatory bowel disease, rheumatoid arthritis, psoriatic arthritis and systemic lupus erythematosus (SLE). The specific role of TNF‑α in autoimmunity is not yet fully understood however, partially, in a complex disease such as SLE. Through the engagement of the TNF receptor 1 (TNFR1) and TNF receptor 2 (TNFR2), both the two variants, soluble and transmembrane TNF‑α, can exert multiple biological effects according to different settings. They can either function as immune regulators, impacting B‑, T‑ and dendritic cell activity, modulating the autoimmune response, or as pro‑inflammatory mediators, regulating the induction and maintenance of inflammatory processes in SLE. The present study reviews the dual role of TNF‑α, focusing on the different effects that TNF‑α may have on the pathogenesis of SLE. In addition, the efficacy and safety of anti‑TNF‑α therapies in preclinical and clinical trials SLE are discussed.

Tumor necrosis factor receptor II and PTPN22 genes polymorphisms and the risk of systemic lupus erythematosus in Egyptian children

BACKGROUND

Many genes have been implicated in the pathogenesis of systemic lupus erythematosus (SLE). Tumor necrosis factor (TNF) is a potent cytokine stimulator acting through 2 cell surface receptors (TNFR I and II). TNFRII gene which controls expression of these receptors has been linked to SLE susceptibility through promoting apoptosis. Also; Protein tyrosine phosphatase non receptor 22 (PTPN22) gene enhances intrinsic phosphatase activity of T lymphocytes leading to their dysregulation and stimulates autoimmune process of lupus and its rs2476601 has been linked to susceptibility to thyroiditis in SLE patients in few studies.

OBJECTIVES

(i) to investigate the correlation between 2 SNPs of TNFR II and PTPN22 genes and SLE susceptibility in a cohort of Egyptian children compared to controls (ii) and to investigate their possible association with different clinical presentations of the disease in children.

SUBJECTS AND METHODS

Typing of TNFR II rs1061622 and PTPN22 rs2476601 SNPs were done using polymerase chain reaction-restriction fragment length polymorphism for 74 children with SLE and 100 matched healthy controls.

RESULTS

Children with SLE had more frequent G allele and GG genotype of TNFR II rs1061622 (p < 0.001) and more T allele and TT genotype of PTPN22 rs2476601 (p = 0.012 and <0.001, respectively) compared to controls. Only 6 patients (8%) had thyroiditis (hypothyroidism) with T allele and TT genotype of PTPN22 1858 T more prevalent in those patients versus those without thyroiditis (p ≤ 0.001). Apart from, thyroiditis, no significant association was found between genotypes and alleles frequencies of the 2 studied SNPs and other clinical manifestations of the disease.

CONCLUSION

The G allele and GG genotype of TNFR II rs1061622 and T allele and TT genotype of PTPN22 rs2476601 genes polymorphism can be considered as risk factors for the development of SLE. The presence of the T allele of PTPN22 rs2476601 may increase the risk of concomitant thyroiditis in Egyptian children with SLE but further studies are required to confirm this finding as thyroiditis was reported only in few cases in this study.

Macrophage-derived cytokines in pneumonia: Linking cellular immunology and genetics

Macrophages represent the first line of anti-pathogen defense - they encounter invading pathogens to perform the phagocytic activity, to deliver the plethora of pro- and anti-inflammatory cytokines, and to shape the tissue microenvironment. Throughout pneumonia course, alveolar macrophages and infiltrated blood monocytes produce increasing cytokine amounts, which activates the antiviral/antibacterial immunity but can also provoke the risk of the so-called cytokine "storm" and normal tissue damage. Subsequently, the question of how the cytokine spectrum is shaped and balanced in the pneumonia context remains a hot topic in medical immunology, particularly in the COVID19 pandemic era. The diversity in cytokine profiles, involved in pneumonia pathogenesis, is determined by the variations in cytokine-receptor interactions, which may lead to severe cytokine storm and functional decline of particular tissues and organs, for example, cardiovascular and respiratory systems. Cytokines and their receptors form unique profiles in individual patients, depending on the (a) microenvironmental context (comorbidities and associated treatment), (b) lung monocyte heterogeneity, and (c) genetic variations. These multidisciplinary strategies can be proactively considered beforehand and during the pneumonia course and potentially allow the new age of personalized immunotherapy.

Selective inhibition of Tumor necrosis factor receptor-1 (TNFR1) for the treatment of autoimmune diseases

Anti-TNF biologics have achieved great success in the treatment of autoimmune diseases and have been the most selling biologics on market. However, the anti-TNF biologics have shown some disadvantages such as poor efficacy to some patients and high risk of infection and malignancies during clinical application. Current anti-TNF biologics are antibodies or antibody fragments that bind to TNF-α and subsequently block both TNF-TNFR1 and TNF-TNFR2 signaling. Transgenic animal studies indicate that TNFR1 signaling is responsible for chronic inflammation and cell apoptosis whereas TNFR2 signaling regulates tissue regeneration and inflammation. Recent studies propose to selectively inhibit TNFR1 to enhance efficacy and avoid side effects. In this review, we introduce the biology of TNF-TNFR1 and TNF-TNFR2 signaling, the advantages of selective inhibition of TNF-TNFR1 signaling and research updates on the development of selective inhibitors for TNF-TNFR1 signaling. Antibodies, small molecules and aptamers that selectively inhibit TNFR1 have showed therapeutic potential and less side effects in preclinical studies. Development of selective inhibitors for TNFR1 is a good strategy to enhance the efficacy and reduce the side effects of anti-TNF inhibitors and will be a trend for next-generation of anti-TNF inhibitors.

Treg cell-based therapies: challenges and perspectives

Cellular therapies using regulatory T (Treg) cells are currently undergoing clinical trials for the treatment of autoimmune diseases, transplant rejection and graft-versus-host disease. In this Review, we discuss the biology of Treg cells and describe new efforts in Treg cell engineering to enhance specificity, stability, functional activity and delivery. Finally, we envision that the success of Treg cell therapy in autoimmunity and transplantation will encourage the clinical use of adoptive Treg cell therapy for non-immune diseases, such as neurological disorders and tissue repair.

Association of the TNF-α-308, TNF-α-238 gene polymorphisms with risk of bone-joint and spinal tuberculosis: a meta-analysis

The aim of the present study was to investigate the association of TNF-α-308 and TNF-α-238 gene polymorphisms with the risk of bone-joint and spinal tuberculosis (TB) by meta-analysis. By searching PubMed, Web of Science, Wanfang databases, CNKI, Medline, and Cochrane Library, the published articles about studies of the association of the TNF-α-308, TNF-α-238 gene polymorphisms with risk of bone-joint and spinal tuberculosis were collected by two reviewers. Begg’s and Egger’s tests were performed to assess publication bias. Stata 12.0 software was used for data analysis. The symmetry of the funnel plot indicated no significant publication bias in the Begg’s test (A: P=1.00, B: P=0.764), and the results of the Egger’s test showed no evidence of publication bias (A: P=0.954, B: P=0.626). Seven studies assessed the relationship between TNF-α-308 gene polymorphisms and risk of bone-joint and spinal tuberculosis risk. The heterogeneity (I²) of GG vs. AA or AG was 0% and there was no heterogeneity (χ² = 0.06 and P=0.944) in a fixed-effects model. There was also a lack of association between TNF-α-308 polymorphism and bone-joint and spinal tuberculosis risk under the recessive model. The remaining models of the TNF-α-308 genotype and further studies of TNF-α-238 did not show a noteworthy association. Overall, there was no significant association between TNF-α-308, TNF-α-238 gene polymorphisms and bone-joint and spinal tuberculosis risk. Our study suggests that tumor necrosis factor α (TNF-α) gene polymorphisms may not contribute to bone-joint and spinal tuberculosis based on the current evidence.

Role of TNF-TNF Receptor 2 Signal in Regulatory T Cells and Its Therapeutic Implications

Tumor necrosis factor α (TNFα) is a pleiotropic cytokine which signals through TNF receptor 1 (TNFR1) and TNF receptor 2 (TNFR2). Emerging evidence has demonstrated that TNFR1 is ubiquitously expressed on almost all cells, while TNFR2 exhibits a limited expression, predominantly on regulatory T cells (Tregs). In addition, the signaling pathway by sTNF via TNFR1 mainly triggers pro-inflammatory pathways, and mTNF binding to TNFR2 usually initiates immune modulation and tissue regeneration. TNFα plays a critical role in upregulation or downregulation of Treg activity. Deficiency in TNFR2 signaling is significant in various autoimmune diseases. An ideal therapeutic strategy for autoimmune diseases would be to selectively block the sTNF/TNFR1 signal through the administration of sTNF inhibitors, or using TNFR1 antagonists while keeping the TNFR2 signaling pathway intact. Another promising strategy would be to rely on TNFR2 agonists which could drive the expansion of Tregs and promote tissue regeneration. Design of these therapeutic strategies targeting the TNFR1 or TNFR2 signaling pathways holds promise for the treatment of diverse inflammatory and degenerative diseases.

Association of TNFRSF1B Promoter Polymorphisms with Human Disease: Further Studies Examining T-Regulatory Cells Are Required

The TNFR2 receptor is expressed by highly active regulatory T cells, and thus constitutes an important therapeutic target for the treatment of autoimmune disease and cancer. Disease susceptibility as well as the potential response to therapies directed at TNFR2 could be significantly impacted by genetic variation in the promoter of the TNFRSF1B gene that codes for the TNFR2 protein. To date, only a few studies have examined the association of TNFRSF1B promoter variation with disease, and the potential impact on T-regulatory cell (Treg) number and function has not been examined. We propose that copy number variation of a key transcription factor binding site has a significant effect on TNFRSF1B promoter activity, and should be considered in studies of disease susceptibility and especially with regard to variation in the level of TNFR2 expression on Tregs.

Inflammation and Atherosclerosis: The Role of TNF and TNF Receptors Polymorphisms in Coronary Artery Disease

Inflammation plays an important role in the pathogenesis of atherosclerosis and coronary syndromes; moreover, various lines of evidence suggest that genetic factors contribute significantly to the risk of coronary artery disease (CAD). Through its effects on endothelial function, coagulation, insulin resistance and lipid metabolism, the proinflammatory cytokine TNF could be involved in cardiovascular pathophysiology. The aim of our study is to analyze whether TNF gene promoter (-308 G/A; −857 G/A) and TNF receptor polymorphisms (TNFR1 MspA1 I exon 1 and TNFR2 Nla III exon 6) show involvement in CAD predisposition in a group of Italian patients compared with healthy controls. Genotyping was performed by PCR-RFLP. Consecutive Italian patients with angiographically proven CAD (n= 248) were compared with controls (n=241), matched for age, sex and geographical origins. CAD patients showed a higher frequency of the TNF −308 A allele than healthy controls (p=0.046). After stratification according to risk factors for CAD, our analysis revealed that CAD patients with diabetes (p=0.042) and CAD patients without hypertension (p=0.0495) displayed a higher frequency of the TNF −308 AA genotype compared with healthy controls. Our data stress the inflammatory nature of CAD and show a possible involvement of TNF −308G/A promoter polymorphisms in the predisposition to the development of this disease. The less frequent A allele seems to be a predisposing factor for development of CAD in particular pathological settings associated with the disease itself, such as diabetes.

TNF-308 G/A polymorphism and risk of systemic lupus erythematosus in the Polish population

OBJECTIVES

Numerous studies have been performed with TNF-α-308 G/A (rs1800629) single nuclear polymorphism (SNP) to evaluate the risk of SLE in various ethnicities. However, the significance of TNF-α-308 G/A in both clinical and laboratory studies of the disease remains unclear.

METHODS

Using a high-resolution melting curve analysis, we assessed the prevalence of TNF-α-308 G/A SNP in SLE patients (n = 262) and controls (n = 528) in a Polish population. We also assessed the contribution of this SNP to various clinical symptoms and the presence of autoantibodies in SLE patients.

RESULTS

The p-value obtained using a χ(2) test for the trend of TNF-α-308 G/A was statistically significant (ptrend = 0.0297). However, using logistic regression analysis for the presence of the HLA-DRB1*03:01 haplotype, we observed that the TNF-α-308 G/A SNP may be the DRB1*03:01-dependent risk factor of SLE in the Polish population. There was a significant contribution of TNF-α-308 A/A and A/G genotypes to arthritis OR = [2.692 (1.503-4.822, p = 0.0007, pcorr = 0.0119)] as well as renal SLE manifestation OR = [2.632 (1.575-4.397, p = 0.0002, pcorr = 0.0034)]. There was a significant association between TNF-α-308 A/A and A/G genotypes and the presence of anti-Ro antibodies (Ab) OR = 3.375(1.711-6.658, p = 0.0003, pcorr = 0.0051). However, the logistic regression analysis revealed that only renal manifestations and the presence of anti-anti-Ro antibodies remained significant after adjustment to the presence of the HLA-DRB1*03:01 haplotype.

CONCLUSION

Our studies indicate that the TNF-α-308 G/A polymorphism may be a DRB1*03:01 haplotype-dependent genetic risk factor for SLE. However, this SNP was independently associated with renal manifestations and production of anti-Ro Ab.

Role of tumor necrosis factor alpha in the pathogenesis of atrial fibrillation: A novel potential therapeutic target?

Atrial fibrillation (AF) is the most common sustained arrhythmia in clinical practice and a major cause of morbidity and mortality. Although the fundamental mechanisms underlying AF remain incompletely understood, atrial remodeling, including structural, electrical, contractile, and autonomic remodeling, has been demonstrated to contribute to the substrate for AF maintenance. Accumulating evidence shows that tumor necrosis factor alpha (TNF-α) plays exceedingly important roles in atrial remodeling. This article reviews recent advances in the roles of TNF-α in the pathogenesis of AF, elucidates the related mechanisms, and exploits its potential usefulness as a novel therapeutic target.

CXCL13, CCL4, and sTNFR as circulating inflammatory cytokine markers in primary and SLE-related autoimmune hemolytic anemia

Background

A considerable proportion of autoimmune hemolytic anemia (AIHA) are secondary to underlying autoimmune disorders, especially syetemic lupus erythematosus (SLE), and the clinical and laboratory index for early discrimination between primary and SLE-related AIHA has yet to be defined. In the present study, we proposed novel cytokine patterns in the pathogenesis of AIHA as well as parameters for the timely identification of SLE-related patients.

Methods

AIHA patients confirmed by immunohematology techniques from September 2010 to December 2012 in our facility were consecutively included and categorized into primary (n = 19) and SLE-related (n = 18) groups. Plasma cytokine profiles were measured in a single procedure by Quantibody Human Inflammatory Array 1 (RayBiotech, Norcross, GA).

Results

SLE-related AIHA patients demonstrated younger age (39 ± 20 vs.57 ± 16 years, p = 0.004), poorer reticulocyte compensation (6.8 ± 7.1 vs.12.2 ± 8.6%, p = 0.045), lower levels of lactate dehydrogenase [361 (265-498) vs. 622 (387-1154) U/L, p = 0.004], and higher occurrence of anticardiolipin antibody [9/18 (50%) vs. 2/19 (10.9%), p = 0.009]. MCP-1/CCL2, MIP-1β/CCL4, BLC/CXCL13, IL-8/CXCL8, sTNFRI, and sTNFRII were significantly up-regulated in both groups, while sTNFRII was remarkably higher in SLE-related patients. Among both groups, hemoglobin level was negatively correlated with CXCL13 (r = -0.332, p = 0.044), while reticulocyte count was positively correlated with CCL4 (r = 0.456, p = 0.005).

Conclusion

CXCL13 and CCL4 could act as circulating biomarkers in AIHA, and indicated disease severity and erythroid compensation, respectively. Higher plasma sTNFRII might favor the diagnosis of SLE-related instead of primary AIHA.

TNF receptors: signaling pathways and contribution to renal dysfunction

Tumor necrosis factor (TNF), initially reported to induce tumor cell apoptosis and cachexia, is now considered a central mediator of a broad range of biological activities from cell proliferation, cell death and differentiation to induction of inflammation and immune modulation. TNF exerts its biological responses via interaction with two cell surface receptors: TNFR1 and TNFR2. (TNFRs). These receptors trigger shared and distinct signaling pathways upon TNF binding, which in turn result in cellular outputs that may promote tissue injury on one hand but may also induce protective, beneficial responses. Yet the role of TNF and its receptors specifically in renal disease is still not well understood. This review describes the expression of the TNFRs, the signaling pathways induced by them and the biological responses of TNF and its receptors in various animal models of renal diseases, and discusses the current outcomes from use of TNF biologics and TNF biomarkers in renal disorders.

The methionine 196 arginine polymorphism of the TNF receptor 2 gene (TNFRSF1B) is not associated with worse outcomes in heart failure

Tumor necrosis factor α (TNFα) may contribute to the pathologic process of congestive heart failure (CHF). TNFα signaling occurs through two receptors; TNFR1 (TNFRSF1A) and TNFRII (TNFRSF1B). In humans a single nucleotide polymorphism (rs1061622 in TNFRSF1B exon 6; T587G) encodes two different amino acids (M196R) in the transmembrane region. The 587G allele is associated with greater severity and/or prevalence of some inflammatory diseases, but its role in CHF in unknown. This study sought to test the hypothesis that the 587G allele is associated with a worse outcome or more severe phenotype in CHF. Peripheral blood DNA was isolated and genotyped from 379 heart failure patients enrolled in a genetic outcome study (GRACE); (44.7% ischemic, 70.4% male, 8.5% black race, age 55.6 ± 11.7 yr (SD), LVEF 24.5 ± 8.3%, NYHA 2.53 ± 0.64). Genotyping was performed by PCR-RFLP. Cardiac function was assessed from medical records at study entry. The distribution of genotypes in this population was 54% T/T, 38.4% G/T and 7.7% G/G. Mean LV ejection fraction (T/T 24.4 ± 8.2, T/G 25.0 ± 8.4, G/G 23.3 ± 8.6, n=352, p=ns) and LV end-diastolic dimensions (T/T 6.57 ± 0.93, T/G 6.53 ± 1.0, G/G 6.57 ± 0.78, n=211, p=ns) were comparable in all groups. Transplant-free survival (median 23 months (range 1-62 months) did not vary by genotype (p=0.95). A lack of effect (p=0.74) on transplant-free survival was also observed in a subset of patients with ischemic heart failure (n=169). The TNFRSF1B 587G allele is not associated with the severity of heart failure phenotype or clinical outcomes in patients with chronic CHF.

Innate immune system gene polymorphisms in maternal and child genotype and risk of preterm delivery

OBJECTIVE

There is little information about the combination of genetic variability in pregnant women and their children in relation to the risk of preterm delivery (PTD). In a sub-cohort of 487 non-Hispanic white and 288 African-American mother/child pairs, the Pregnancy Outcomes and Community Health Study assessed 10 functional polymorphisms in 9 genes involved in innate immune function.

METHODS

Race-stratified weighted logistic regression models were used to calculate odds ratios for genotype and PTD/PTD subtypes. Polymorphisms significantly associated with PTD/PTD subtypes were tested for mother/child genotype interactions.

RESULTS

Three maternal polymorphisms (IL-1 receptor antagonist intron two repeat (IL-1RN), matrix metalloproteinase- -C1562T, and TNF receptor two M196R (TNFR2)) and three child polymorphisms (IL1-RN, tumor necrosis factor-alpha -G308A, and TNFR2) were associated with PTD, but associations varied by PTD subtype and race. Two interactions were detected for maternal and child genotype. Among non-Hispanic white women, the odds of PTD was higher when both mother and child carried the IL-1RN allele two (additive interaction p < 0.05). Among African-American women, the odds of PTD were higher when both mother and child carried the TNFR2 R allele (multiplicative interaction p < 0.05).

CONCLUSION

These results highlight the importance of assessing both maternal and child genotype in relation to PTD risk.

Signal transduction by tumor necrosis factor receptors

Tumor necrosis factor (TNF) is a key mediator in the inflammatory response which is implicated in the onset of a number of diseases. Research on TNF led to the characterization of the largest family of cytokines known until now, the TNF superfamily, which exert their biological effects through the interaction with transmembrane receptors of the TNFR superfamily. TNF itself exerts its biological effects interacting with two different receptors: TNFR1 and TNFR2. TNFR1 presents a death domain on its intracellular region. In contrast to TNFR1, TNFR2 does not have a death domain. Activation of TNFR1 implies the consecutive formation of two different TNF receptor signalling complexes. Complex I controls the expression of antiapoptotic proteins that prevent the triggering of cell death processes, whereas Complex II triggers cell death processes. TNFR2 only signals for antiapoptotic reactions. However, recent evidence indicates that TNFR2 also signals to induce TRAF2 degradation. TRAF2 is a key mediator in signal transduction of both TNFR1 and TNFR2. Thus, this novel signalling pathway has two important implications: on one hand, it represents an auto regulatory loop for TNFR2; on the other hand, when this signal is triggered TNFR1 activity is modified so that antiapoptotic pathways are inhibited and apoptotic reactions are enhanced.

Lack of association between tumour necrosis factor receptor types 1 and 2 gene polymorphism and severe acute alcoholic hepatitis

BACKGROUND/AIMS

Tumour necrosis factor-alpha (TNF-alpha) is involved in the physiopathology of severe acute alcoholic hepatitis (AAH) binding with TNF receptor types TNFR1 and TNFR2, whose serum concentrations are elevated. We studied the role of TNFR1 and TNFR2 gene polymorphism in AAH patients.

METHODS

One hundred and ninety-two patients (58 AAH with Maddrey score >or=32, 44 non-AAH cirrhoses, 90 healthy individuals) were genotyped for A36G TNFR1 and T676G TNFR2 using polymerase chain reaction-restriction fragment length polymorphism technique. Serum sTNFR1 and sTNFR2 were assayed.

RESULTS

The AAH and two control groups did not differ for genotype distribution. In three groups, A (36 TNFR1) and T (676 TNFR2) allelic frequencies were similar, at 0.47, 0.47, 0.44 and 0.78, 0.81, 0.80, respectively. The 36 TNFR1, 676 TFNR2 genotypes did not influence on prognostic scores (Maddrey, Child-Pugh), nor in response to corticosteroids or 6-month survival. sTNFR1 levels were higher in AAH than healthy group (3.07+/-1.14 vs. 1.17+/-0.27 ng/ml, P<0.001) and sTNFR2 levels were higher in AAH than cirrhosis (3.6+/-1.02 vs. 3.1+/-1.03, P<0.05) and healthy groups (3.6+/-1.02 vs. 1.91+/-0.54, P<0.001). However, sTNFR1 and sTNFR2 levels did not vary significantly according to genotypes.

CONCLUSION

These results did not support an association between 36 TNFR1, 676 TNFR2 gene polymorphisms and AAH.

TNF receptor 2 pathway: drug target for autoimmune diseases

Although drug development has advanced for autoimmune diseases, many current therapies are hampered by adverse effects and the frequent destruction or inactivation of healthy cells in addition to pathological cells. Targeted autoimmune therapies capable of eradicating the rare autoreactive immune cells that are responsible for the attack on the body's own cells are yet to be identified. This Review presents a new emerging approach aimed at selectively destroying autoreactive immune cells by specific activation of tumour necrosis factor receptor 2 (TNFR2), which is found on autoreactive and normal T lymphocytes, with the potential of avoiding or reducing the toxicity observed with existing therapies.

Transmembrane TNF-alpha: structure, function and interaction with anti-TNF agents

Transmembrane TNF-α, a precursor of the soluble form of TNF-α, is expressed on activated macrophages and lymphocytes as well as other cell types. After processing by TNF-α-converting enzyme (TACE), the soluble form of TNF-α is cleaved from transmembrane TNF-α and mediates its biological activities through binding to Types 1 and 2 TNF receptors (TNF-R1 and -R2) of remote tissues. Accumulating evidence suggests that not only soluble TNF-α, but also transmembrane TNF-α is involved in the inflammatory response. Transmembrane TNF-α acts as a bipolar molecule that transmits signals both as a ligand and as a receptor in a cell-to-cell contact fashion. Transmembrane TNF-α on TNF-α-producing cells binds to TNF-R1 and -R2, and transmits signals to the target cells as a ligand, whereas transmembrane TNF-α also acts as a receptor that transmits outside-to-inside (reverse) signals back to the cells after binding to its native receptors. Anti-TNF agents infliximab, adalimumab and etanercept bind to and neutralize soluble TNF-α, but exert different effects on transmembrane TNF-α-expressing cells (TNF-α-producing cells). In the clinical settings, these three anti-TNF agents are equally effective for RA, but etanercept is not effective for granulomatous diseases. Moreover, infliximab induces granulomatous infections more frequently than etanercept. Considering the important role of transmembrane TNF-α in granulomatous inflammation, reviewing the biology of transmembrane TNF-α and its interaction with anti-TNF agents will contribute to understanding the bases of differential clinical efficacy of these promising treatment modalities.

A functional haplotype in the 3'untranslated region of TNFRSF1B is associated with tuberculosis in two African populations

RATIONALE

Susceptibility to tuberculosis is not only determined by Mycobacterium tuberculosis infection, but also by the genetic component of the host. The pleiotropic cytokine tumor necrosis factor-alpha is essential to control tuberculosis infection, and various tumor necrosis factor family members and their respective receptors may contribute to tuberculosis risk.

OBJECTIVES

To investigate four functionally relevant polymorphisms in the tumor necrosis factor receptor 2-encoding gene, tumor necrosis factor receptor superfamily member 1B, for association with tuberculosis susceptibility.

METHODS

Genotyping of four polymorphisms was performed in independent populations from South Africa (429 cases and 482 control subjects) and Ghana (640 cases and 1,158 control subjects), and the association of the variants with tuberculosis was tested using two case-control association studies.

MEASUREMENTS AND MAIN RESULTS

Single-point and haplotype analysis in South Africans revealed an association in the 3'untranslated region of the investigated gene. The T allele of rs3397 alone and/or the 3' untranslated region haplotype GTT may confer protection against tuberculosis insofar as both allele and haplotype frequencies were significantly lower in case subjects than in controls. The GTT genotype had previously been shown to increase the decay of tumor necrosis factor receptor 2 messenger ribonucleic acid, and messenger ribonucleic acid destabilization may represent a key molecular mechanism for disease susceptibility. Interestingly, the association signal appeared to be restricted to women. The genetic finding was validated in female participants from Ghana. The combined P value in the haplotype analysis was P = 0.00011.

CONCLUSIONS

Our finding emphasizes the importance of tumor necrosis factor/tumor necrosis factor receptor-mediated immune responses in the pathogenesis of tuberculosis.

Cigarette Smoking,STAT4andTNFRSF1BPolymorphisms, and Systemic Lupus Erythematosus in a Japanese Population

Objective.

Recent studies have identified signal transducer and activator of transcription 4 (STAT4) as a susceptibility gene for systemic lupus erythematosus (SLE) in different populations. Similarly, tumor necrosis factor receptor superfamily, member 1B (TNFRSF1B) has been reported to be associated with SLE risk in Japanese populations. Along with environmental factors such as smoking, both polymorphisms may modulate an individual’s susceptibility to SLE. We investigated these relationships in a case-control study to evaluate risk factors for SLE among Japanese women.

Methods.

We investigated the relationship of theSTAT4rs7574865 andTNFRSF1Brs1061622 polymorphisms to SLE risk with special reference to their combination and interaction with cigarette smoking among 152 SLE cases and 427 controls.

Results.

The TT genotype ofSTAT4rs7574865 was significantly associated with increased risk of SLE (OR 2.21, 95% CI 1.10–4.68). Subjects with at least one G allele ofTNFRSF1Brs1061622 had an increased risk of SLE (OR 1.56, 95% CI 0.99–2.47). The attributable proportion due to the interaction between theTNFRSF1Brs1061622 genotypes and smoking was estimated to be 0.49 (95% CI 0.07–0.92), indicating that 49% of the excess risk for SLE in smokers with at least one G allele was due to an additive interaction. A lack of significant associations ofSTAT4with smoking was observed. No significant gene-gene interactions were found among polymorphisms ofSTAT4andTNFRSF1B.

Conclusion.

Our findings suggest that the association between cigarette smoking and SLE could be differentiated by theTNFRSF1Brs1061622 T allele among female Japanese subjects. This preliminary exploratory result should be confirmed in a larger study.

TNF receptor I polymorphism is associated with persistent palindromic rheumatism

OBJECTIVES

To investigate the association between tumour necrosis factor-alpha (TNFalpha), TNF receptor superfamily member 1A (TNFRSF1A, also known as TNFRI), TNFRSF1B (TNFRII), and interleukin-1beta (IL-1beta) single nucleotide polymorphisms (SNPs) and the susceptibility to persistent palindromic rheumatism (PR).

METHODS

Fifty-six unrelated patients with persistent PR and 100 unrelated healthy controls were genotyped for TNFalpha -308G/A, -238G/A, and +488G/A, TNFRSF1A -609G/T and +36A/G, TNFRSF1B +676T/G and +1663G/A, and IL-1beta -511C/T, -31T/C, and +3954C/T using real-time polymerase chain reaction (RT-PCR).

RESULTS

The TNFRSF1A +36G allele [odds ratio (OR) = 3.94, p = 0.003, corrected p (p(c)) = 0.03] and the TNFRSF1A +36AG genotype (OR = 4.81, p = 0.002, p(c) = 0.04) were significantly associated with persistent PR. The frequency of TNFRSF1B +676T/+1663A was increased in PR patients (OR = 2.12, p = 0.01), but failed to reach statistical significance after Bonferroni correction. No correlation was observed between persistent PR and TNFalpha, TNFRSF1A -609G/T, or IL-1beta SNPs.

CONCLUSIONS

The results of this study provide evidence of an association between persistent PR and SNPs within the TNFRSF1A gene, and suggest that TNFRI is involved in the aetiopathogenesis of PR.

Tumor necrosis factor receptor superfamily, member 1B haplotypes increase or decrease the risk of inflammatory bowel diseases in a New Zealand caucasian population

Inflammatory bowel diseases (IBDs) comprising Crohn disease (CD) and ulcerative colitis (UC) are chronic inflammatory conditions with polygenic susceptibility. Interactions between TNF-alpha and TNF-alpha receptor play a fundamental role in inflammatory response. This study investigates the role that selected single nucleotide polymorphisms (SNPs) and haplotypes in the TNF-alpha receptor (TNSFRSF1B) gene play in the risk of IBD in a New Zealand Caucasian population. DNA samples from 388 CD, 405 UC, 27 indeterminate colitis patients, and 293 randomly selected controls, from Canterbury, New Zealand were screened for 3 common SNPs in TNSFRSF1B: rs1061622 (c.676T > C), rs1061624 (c.*1663A > G), and rs3397 (c.*1690T > C), using TaqMan technologies. Carrying the rs1061624 variant decreased the risk of UC in the left colon (OR 0.73, 95% CI = 0.54–1.00) and of being a smoker at diagnosis (OR 0.62; 95% CI = 0.40–0.96). Carrying the rs3397 variant decreased the risk of penetrating CD (OR 0.62, 95% CI = 0.40–0.95). Three marker haplotype analyses revealed highly significant differences between CD patients and control subjects (χ² = 29.9, df = 7, P = .0001) and UC cases and controls (χ² = 46.3, df = 7, P < .0001). We conclude that carrying a 3-marker haplotype in the TNSFRSF1B gene may increase (e.g., haplotype of GGC was 2.9-fold more in the CD or UCpatients) or decrease (e.g., TGT was 0.47-fold less in UC patients) the risk of IBD in a New Zealand Caucasian population.

Does the simultaneous tumor necrosis factor receptor 2, tumor necrosis factor promoter gene polymorphism represent a higher risk for alcoholic liver disease?

BACKGROUND AND AIM

Tumor necrosis factor alpha (TNF-alpha) is a proinflammatory cytokine that seems to play a crucial role in the pathogenesis of alcoholic liver disease (ALD). TNF-alpha exerts its effects by binding to specific receptors (TNFR); the polymorphism of TNFRII T587G has been associated with increased TNF apoptotic response and its presence may increase the risk to develop liver disease. The aim of this study was to evaluate the prevalence of the TNF-alpha G238A promoter and TNFRII polymorphisms, individually or simultaneously, in ALD.

METHODS

TNF-alpha G238A and TNFRII T587G polymorphisms were studied in 103 unrelated patients with ALD (biopsy confirmed or clinical evidence) and in 76 heavy drinkers without liver disease (NLD). Single nucleotide polymorphism gene was detected by a polymerase chain reaction-restriction fragment length polymorphisms method. All patients had, at least, a 5 year history of alcohol consumption greater than 80 g/day.

RESULTS

TNF-alpha G238A allele frequency was similar in both groups. TNFRII T587G allele frequency was slightly higher in the ALD group than in the NLD group (21 vs. 18%, P=NS). TNF-alpha G238A and TNFRII T587G were simultaneously present in six ALD patients and in none of NLD patients (P=0.04).

CONCLUSION

Although individually there was no association between TNFRII T587G or TNF-alpha G238A polymorphisms and ALD, this study suggests that the presence of both polymorphisms may enhance the susceptibility for ALD. TNF-alpha G238A may increase TNF-alpha production, which when associated with TNFRII T587G, can further exacerbate TNF-alpha response leading to a greater risk of ALD.

A potential role of TNFR gene polymorphisms in autoimmune thyroid diseases in the Tunisian population

Autoimmune thyroid diseases (AITDs) including Graves disease (GD) and autoimmune hypothyroidism (AH) are associated with TNF genes polymorphisms. TNF molecules bind to TNFRI and TNFRII. No genetic association was reported between TNFR and AITDs. In this study, we have analysed two polymorphisms in TNFRI gene (TNFRI+36A/G SNP and a microsatellite (GT)(17) (GA)(n)) and one polymorphism in TNFRII gene (TNFRII +676 T/G). All these polymorphisms were studied in a large Tunisian family with high prevalence of AITDs, and on a case-control sample of 91 GD patients and 165 controls. The present study was undertaken to investigate the genetic association of these polymorphisms with AITDs development. We reported the implication of TNFRIA3 allele in AITDs pathogenesis in familial and case control studies, respectively (chi(2)=4.13, p=0.042; chi(2)=9.26, p(c)=0.005). In addition, Case-control study has revealed for the first time that TNFRII+676G allele was associated with GD (chi(2)=11.53; p=0.0007). Two TNFRI haplotypes were found to be associated with GD: TNFRI+36G-A8, TNFRI+36A-A3 (chi(2)=88.07; p=6.32x10(-21), chi(2)=16.78; p=4.2x10(-5), respectively). Our data showed that TNFRI polymorphisms have an important role in AITDs pathogenesis in both familial and case-control samples and that TNFRII was rather implicated in GD development in the Tunisian population.

GvHD-associated cytokine polymorphisms do not associate with Omenn syndrome rather than T-B- SCID in patients with defects in RAG genes

Recombinase activating genes 1/2 (RAG1/2) deficiency, critical to initiate gene rearrangement encoding lymphocyte receptors, causes T-B- severe combined immunodeficiency (SCID) and Omenn syndrome (OS), characterised by erythroderma, hepatosplenomegaly, lymphadenopathy, activated, clonal T cell expansions with restricted TCRVbeta family usage, and opportunistic infection. Many features of OS resemble graft-versus-host disease (GvHD). Frequency of GvHD-associated cytokine gene polymorphisms (CGPs) with OS was investigated to explain phenotypic differences between T-B- SCID and OS. Allele frequencies of IFNgamma T874A, IFNgamma-R1, TNFalphad microsatellites, IL-10 promoter region C592A and A1082G, IL-4 C-590T, IL-6 G-174C, IL-4R Q+576R, IFNgamma-R1 T-56C, TNFalphaRII 196 M/R single-nucleotide polymorphisms and IL-1Ra intron 1 VNTR were examined in 33 OS and 23 SCID patients. No significant differences in allele frequencies were found between the groups, and no trends identified. The mechanisms determining the OS or T-B-NK+ SCID phenotype remain to be determined.

A functional M196R polymorphism of tumour necrosis factor receptor type 2 is associated with systemic lupus erythematosus: a case-control study and a meta-analysis

OBJECTIVES

To perform a case-control study of a functional M196R polymorphism of tumour necrosis factor receptor type 2 (TNF-RII) in a Japanese population and a meta-analysis of all published reports on the polymorphism to investigate the association of the M196R polymorphism of TNF-RII with systemic lupus erythematosus (SLE).

METHODS

The functional M196R polymorphism of TNF-RII was genotyped by using polymerase chain reaction combined with the subsequent single-strand conformation polymorphism (PCR-SSCP) analysis for screening, followed by nucleotide sequencing for confirmation. A total of 331 patients and 359 controls were subjected to a case-control study. A meta-analysis of the available case-control studies including all published data as well as our own data was performed to investigate the association of the functional M196R polymorphism of TNF-RII with SLE.

RESULTS

Our case-control study did not show any significant association of a functional M196R polymorphism of TNF-RII with SLE, although there was a trend towards association. A meta-analysis of seven case-control studies in eight different ethnic populations including our own showed that 196M/R and 196R/R genotypes combined was significantly associated with an increased risk of SLE (odds ratio (OR) 1.29, 95% confidence interval (CI) 1.04 to 1.60; p = 0.02). Stratification by ethnicity showed a more significant association in Asians, including Japanese, Korean and Vietnamese (OR 1.40, 95% CI 1.10 to 1.78; p = 0.006). The effect of the 196R allele on SLE was not clear in Caucasians.

CONCLUSIONS

The 196R allele of the functional M196R polymorphism of TNF-RII is a risk factor for SLE, especially in the Asian population.

Variable Number of Tandem Repeats of TNF Receptor Type 2 Promoter as Genetic Biomarker of Susceptibility to Develop Invasive Pulmonary Aspergillosis

Tumor necrosis factor alpha (TNF-alpha) and lymphotoxin alpha (LT-alpha) are pivotal mediators of inflammatory responses in fungal infection diseases. We hypothesized that polymorphisms in genes of these cytokines or their receptors might increase the susceptibility of hematologic patients to develop invasive pulmonary aspergillosis (IPA). One hundred two hematologic patients and 124 age-matched controls were enrolled in the study, and the following standard single nucleotide polymorphisms were investigated: TNF-alpha -308 and +489, LT-alpha +252 and Tumor Necrosis Factor Receptor 2 (TNFR2) +676. Variable number of tandem repeats (VNTRs) at position -322 of the TNFR2 gene were also studied. Genotypic and allelic frequencies were similar between patients and controls. IPA was diagnosed in 54 of the 102 patients according to consensus criteria published by the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group. TNF-alpha and LT-alpha polymorphisms were not associated with presence of IPA. Susceptibility to IPA was strongly associated with VNTR at position -322 in the promoter region of the TNR2 gene (p = 0.029) but was not associated with the presence of TNFR2 +676 polymorphism. A genetic difference in TNFR2 promoter VNTR may play a major role in susceptibility to IPA infection.

Tumor necrosis factor receptor 2 M196R polymorphism in rheumatoid arthritis and osteoarthritis: relationship with sTNFR2 levels and clinical features

We investigate the clinical association of tumor necrosis factor receptor 2 (TNFR2) M196R polymorphism with rheumatoid arthritis (RA) and knee osteoarthritis (OA). Acute phase reactants, lipid profile, sTNFR2 levels, disease activity-disability indexes, and TNFR2 M196R polymorphism were analyzed in 50 RA, 50 knee OA patients, and 120 healthy subjects (HS). The M/M genotype frequency was 0.74 (RA), 0.80 (OA), and 0.64 (HS). The M/R genotype frequency was RA (0.26), OA (0.20), and HS (0.29). The R/R genotype was observed only in HS (0.07). The M allele was associated with OA (P = 0.0137, OR = 2.43). Total cholesterol, triglyceride levels, apolipoprotein A-I and B showed significant differences (P < 0.05). The highest sTNFR2 levels were observed in RA and OA (P = 0.001), however M/M and M/R carriers do not correlate with sTNFR2 production. Our findings suggest an association of the M allele with knee OA. In addition, high sTNFR2 levels in RA and OA were found.

Haplotype analysis of tumour necrosis factor receptor genes in 1p36: no evidence for association with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease with partially understood aetiology. The 1p36 region has been previously linked with SLE and harbours tumour necrosis factor receptor (TNFR) genes. Functional and genetic data implicate their gene products in SLE and other autoimmune diseases. In all, single-nucleotide polymorphisms (SNPs) across TNFRSF14 (HVEM), and 43 SNPs across the TNFRSF8 (CD30) and TNFRSF1B (CD120B) locus were investigated for linkage disequilibrium (LD) and haplotype analysis in European-Caucasians. Strong LD was observed across HVEM and CD120B, and little LD and recombination across CD30. We also examined the association of SNPs and haplotypes in HVEM, CD30 and CD120B with SLE in European-Caucasians. There was no evidence of association for these genes in 456 European-Caucasian families with SLE from UK. Haplotype tagging SNPs are made known across areas of strong LD, which will facilitate analysis for susceptibility in other diseases.

Role of Fc gamma receptor IIb polymorphism in the genetic background of systemic lupus erythematosus: insights from Asia

FCGR2B codes for an inhibitory receptor expressed in B cells and monocytes. Polymorphisms of Fcgr2b in mice have been shown to be associated with autoimmune diseases including systemic lupus erythematosus (SLE) and targeted disruption of Fcgr2b renders mice susceptible to induced or spontaneous autoimmunity, depending on the genetic background. Polymorphism screening of FCGR2B has been hampered by the complexity and extreme homology among FCGR family members. We established a specific genotyping system, detected a SNP that changes position 232 amino acid in the transmembrane region from Ile to Thr and found a significant association of 232Thr with SLE in the Japanese, Thai and Chinese populations. In contrast, promoter polymorphism of FCGR2B, but not Ile232Thr, was shown to be associated with SLE in Caucasians. Linkage disequilibrium was observed among FCGR2A, 2B, 3A and 3B genes with varying degrees, but in the Asian populations, each of FCGR2B, 3A and 3B genes was suggested to contribute to the susceptibility to SLE. These results indicate that FCGR2B is a susceptibility gene to SLE in the context of a genetic background, both in humans and mice.

Polymorphism in the tumour necrosis factor receptor II gene is associated with circulating levels of soluble tumour necrosis factor receptors in rheumatoid arthritis

Levels of soluble tumour necrosis factor receptors (sTNFRs) are elevated in the circulation of patients with rheumatoid arthritis (RA). Although these receptors can act as natural inhibitors of tumour necrosis factor-alpha, levels of sTNFRs in RA appear to be insufficient to prevent tumour necrosis factor-alpha induced inflammation. The factors that regulate circulating levels of sTNFRs are unclear, but polymorphisms in the tumour necrosis factor receptor genes may play a role. We investigated the relationship between polymorphisms in the tumour necrosis factor receptor I (TNF-RI) and II (TNF-RII) genes and levels of sTNFRs in two groups of Caucasian RA patients: one with early (disease duration < or = 2 years; n = 103) and one with established disease (disease duration > or = 5 years; n = 151). PCR restriction fragment length polymorphism analysis was used to genotype patients for the A36G polymorphism in the TNF-RI gene and the T676G polymorphism in TNF-RII. Levels of sTNFRs were measured using ELISA. We also isolated T cells from peripheral blood of 58 patients with established RA with known TNF-R genotypes, and release of sTNFRs into the culture medium was measured in cells incubated with or without phytohaemagglutinin. Serum levels of the two sTNFRs (sTNF-RI and sTNF-RII) were positively correlated in both populations, and the level of each sTNFR was significantly higher in the patients with established disease (P < 0.0001). Multiple regression analyses corrected for age, sex and disease duration revealed a significant trend toward decreasing sTNF-RI and sTNF-RII levels across the TNF-RII genotypes (TT > TG > GG) of patients with established disease (P for trend = 0.01 and P for trend = 0.03, respectively). A similar nonsignificant trend was seen for early disease. No relationship with the TNF-RI A36G polymorphism was observed. sTNFRs released by isolated T cells exhibited a similar trend toward decreasing levels according to TNF-RII genotype, although only the association with levels of sTNF-RII was significant. Strong correlations were found between levels of circulating sTNFRs and levels released by T cells in vitro. Our data indicate that the T676G polymorphism in TNF-RII is associated with levels of sTNFRs released from peripheral blood T cells, and with circulating levels of sTNFR in patients with RA.

Biomarkers for systemic lupus erythematosus: a review and perspective

PURPOSE OF REVIEW

Despite decades of extensive work in the understanding of the etiopathogenesis of systemic lupus erythematosus, few biomarkers have been validated and widely accepted for this disease. The lack of reliable, specific biomarkers not only hampers clinical management of systemic lupus erythematosus but also impedes development of new therapeutic agents. This paper reviews briefly the historical aspects of systemic lupus erythematosus biomarkers and summarizes recent studies on candidate biomarkers.

RECENT FINDINGS

Recognizing the urgent need for lupus biomarkers, a Lupus Biomarker Working Group has recently been initiated to facilitate collaborative efforts aimed at identifying and validating biomarkers for systemic lupus erythematosus. Based on available data, several laboratory markers have shown promise as biomarkers for susceptibility, diagnosis, and disease activity. These include Fc receptor genes (disease susceptibility), complement C4d-bound erythrocytes (diagnosis or disease activity), CD27 plasma cells (disease activity), 'interferon signature' (disease activity), and anti-C1q antibodies (disease activity and organ involvement).

SUMMARY

There is a longstanding and recently rejuvenated enthusiasm for biomarkers that precisely and specifically reflect the pathophysiologic and clinical changes in systemic lupus erythematosus. Promising candidate biomarkers have been identified but must still be validated through rigorous, large-scale multicenter studies.

Genetics of lupus nephritis

Susceptibility to lupus nephritis is the end-result of complex interactions between polymorphic genetic factors involved in the regulation of immune responses. In humans, genome-wide screens and candidate-gene analyses led to the identification of several loci containing potential targets (FcgammaRIIa, PTPN22, PD-1, IL-10) for physiopathological research and therapeutic interventions. In mice, the generation of congenic mice, bearing in a normal genetic background one single disease-associated locus, greatly improved our understanding of the mechanisms mediating the genetic contribution to the disease. In the future, the identification of disease-associated genes will open new perspectives for the development of more targeted therapies of lupus nephritis.

Tumor necrosis factor receptor gene polymorphisms in Crohn's disease: association with clinical phenotypes

OBJECTIVES

Crohn's disease (CD) is a chronic multifactorial disorder with diverse clinical features that are influenced by a heterogeneous set of genetic factors. TNF-alpha/TNF receptor interactions play a pivotal role in the pathogenesis of the inflammatory response. Our purpose was to determine whether single nucleotide polymorphisms (SNPs) in the TNF receptors confer susceptibility to Crohn's disease and whether they are associated with clinical phenotype.

METHODS

A cohort of 205 consecutively identified and unrelated patients with CD and 106 controls were recruited. Subjects were genotyped for polymorphisms in TNFRSF1A (position +36, -609), TNFRSF1B (+196, +1466), along with the three common CARD15 variants and phenotyped for disease behavior. Genotypic and allelic frequencies were compared between CD and controls and a logistic regression model was constructed to determine independent associations with specific clinical phenotypes.

RESULTS

Only the TNFRSF1A +36 and TNFRSF1B +196 SNPs were associated with CD (p= 0.0019 and 0.034, respectively). The TNFRSF1A +36 mutation was negatively associated with stricturing disease phenotype (OR = 0.384; CI = 0.166-0.887). In contrast, the TNFRSF1B +196 was negatively associated with colitis (OR = 0.410; CI = 0.191-0.880). These associations were independent of CARD15 mutation status. Finally, TNFRSF1B +196 was negatively associated with surgery in CARD15 negative patients.

CONCLUSIONS

These data constitute the first report of an association of TNFRSF1A and TNFRSF1B polymorphisms with CD in a Caucasian population and address the role of TNFR mutations in determining clinical heterogeneity in CD.

TNF and TNFR polymorphisms in severe sepsis and septic shock: a prospective multicentre study

Tumour necrosis factor (TNF) is an important pro-inflammatory cytokine produced in sepsis. Studies examining the association of individual TNF single nucleotide polymorphisms with sepsis have produced conflicting results. This study investigated whether common polymorphisms of the TNF locus and the two receptor genes, TNFRSF1A and TNFRSF1B, influence circulating levels of encoded proteins, and whether individual polymorphisms or extended haplotypes of these genes are associated with susceptibility, severity of illness or outcome in adult patients with severe sepsis or septic shock. A total of 213 Caucasian patients were recruited from eight intensive care units (ICU) in the UK and Australia. Plasma levels of TNF (P = 0.02), sTNFRSF1A (P = 0.005) and sTNFRSF1B (P = 0.01) were significantly higher in those who died on ICU compared to those who survived. There was a positive correlation between increasing soluble receptor levels and organ dysfunction (increasing SOFA score) (sTNFRSF1A R = 0.51, P < 0.001; sTNFRSF1B R = 0.53, P < 0.001), and in particular with the degree of renal dysfunction. In this study, there were no significant associations between the selected candidate TNF or TNF receptor polymorphisms, or their haplotypes, and susceptibility to sepsis, illness severity or outcome. The influence of polymorphisms of the TNF locus on susceptibility to, and outcome from sepsis remains uncertain.

The Met-196 -> Arg variation of human tumor necrosis factor receptor 2 (TNFR2) affects TNF-alpha-induced apoptosis by impaired NF-kappaB signaling and target gene expression

Tumor necrosis factor-alpha (TNF-alpha)-induced signaling is pivotally involved in the pathogenesis of chronic inflammatory diseases. A polymorphism in the TNF receptor 2 (TNFR2) gene resulting in a juxtamembrane inversion from methionine (TNFR2(196MET)) to arginine (TNFR2(196ARG)) has been genetically associated with an increased risk for systemic lupus erythematosus and familial rheumatoid arthritis. Albeit the mutation does not affect the TNF binding kinetics of TNFR2, the present study provides evidence that the mutation results in a significantly lower capability to induce TNFR2-mediated NF-kappaB activation. Pretriggering of TNFR2 with a receptor-specific mutein leads to an enhancement of TNFR1-induced apoptosis, which is further increased in cells carrying the TNFR2(196ARG) variant. A diminished induction of NF-kappaB-dependent target genes conveying either anti-apoptotic or pro-inflammatory functions, such as cIAP1, TRAF1, IL-6, or IL-8 is observed. The mutated form TNFR2(196ARG) shows a reduction of inducible TRAF2 recruitment upon TNF-alpha stimulation. The findings suggest a common molecular mechanism for the involvement of the TNFR2(196ARG) variant in the etiopathogenesis of different chronic inflammatory disorders.