Replication of the TNFSF4 (OX40L) promoter region association with systemic lupus erythematosus

Blockade of OX40/OX40L signaling using anti-OX40L alleviates murine lupus nephritis

Genetic variants of the OX40 ligand (OX40L) locus are associated with the risk of systemic lupus erythematosus (SLE), it is unclear how the OX40L blockade delays the lupus phenotype. Therefore, we examined the effects of an anti-OX40L antibody in MRL/Lpr mice. Next, we investigated the effect of anti-OX40L on immunosuppression in keyhole limpet hemocyanin-immunized C57BL/6J mice. In vitro treatment of anti-OX40L in CD4+ T and B220+ B cells was used to explore the role of OX40L in the pathogenesis of SLE. Anti-OX40L alleviated murine lupus nephritis, accompanied by decreased production of anti-dsDNA and proteinuria, as well as lower frequencies of splenic T helper (Th) 1 and T-follicular helper cells (Tfh). In keyhole limpet hemocyanin-immunized mice, decreased levels of immunoglobulins and plasmablasts were observed in the anti-OX40L group. Anti-OX40L reduced the number and area of germinal centers. Compared with the control IgG group, anti-OX40L downregulated CD4+ T-cell differentiation into Th1 and Tfh cells and upregulated CD4+ T-cell differentiation into regulatory T cells in vitro. Furthermore, anti-OX40L inhibited toll-like receptor 7-mediated differentiation of antibody-secreting cells and antibody production through the regulation of the SPIB-BLIMP1-XBP1 axis in B cells. These results suggest that OX40L is a promising therapeutic target for SLE.

PRDX6AS1 gene polymorphisms and SLE susceptibility in Chinese populations

Background

Systemic lupus erythematosus (SLE) is a complex, multisystem autoimmune disease that is characterized by the production of autoantibodies. Although accumulated evidence suggests that the dysregulation of long non-coding RNAs (lncRNAs) is involved in the pathogenesis of SLE, the genetic contributions of lncRNA coding genes to SLE susceptibility remain largely unknown. Here, we aimed to provide more evidence for the role of lncRNA coding genes to SLE susceptibility.

Methods

The genetic association analysis was first adopted from the previous genome-wide association studies (GWAS) and was then validated in an independent cohort. PRDX6-AS1 is located at chr1:173204199-173446294. It spans a region of approximately 240 kb, and 297 single nucleotide polymorphisms (SNPs) were covered by the previous GWAS. Differential expression at the mRNA level was analyzed based on the ArrayExpress Archive database.

Results

A total of 33 SNPs were associated with SLE susceptibility, with a P<1.68×10^-4. The strongest association signal was detected at rs844649 (P=2.12×10^-6), according to the previous GWAS. Combining the results from the GWAS Chinese cohort and our replication cohort, we pursued a meta-analysis approach and found a pronounced genetic association between PRDX6-AS1 rs844649 and SLE susceptibility (p_meta=1.24×10^-13, OR 1.50, 95% CI: 1.34–1.67). The mRNA expression of PRDX6 was elevated in peripheral blood cells, peripheral blood mononuclear cells (PBMCs), and multiple cell subpopulations, such as B cells, CD4⁺ T cells, CD3⁺ cells, and monocytes in patients with SLE. The PRDX6 protein expression level was also increased in patients with SLE compared with healthy donors.

Conclusion

Our study provides new evidence that variants located in lncRNA coding genes are associated with SLE susceptibility.

Association of TNFSF4 polymorphisms with systemic lupus erythematosus: a meta-analysis

OBJECTIVE

To more precisely estimate the association between the tumor necrosis factor ligand superfamily member 4 (TNFSF4) gene polymorphisms and systemic lupus erythematosus (SLE) susceptibility, we performed a meta-analysis on the association of the following single nucleotide polymorphisms (SNPs) of TNFSF4 with SLE: rs1234315, rs844648, rs2205960, rs704840, rs844644, rs10489265.

METHODS

A literature-based search was conducted using PubMed, MEDLINE, Embase, Web of Science databases, and Cochrane Library databases to identify all relevant studies. And the association of TNFSF4 gene polymorphisms and SLE susceptibility was evaluated by pooled odds ratio (OR) with 95% confidence interval (CI).

RESULTS

The meta-analysis produced overall OR of 1.42 (95% CI 1.36-1.49, P < 0.00001), 1.41 (95% CI 1.36-1.46, P < 0.00001) and 1.34 (95% CI 1.26-1.42, P < 0.00001) for the rs2205960, rs1234315 and rs704840 polymorphisms respectively, confirming these three SNPs confer a significant risk for the development of SLE. On the other hand, the meta-analysis produced overall OR of 0.92 (95% CI 0.70-1.21, P = 0.54) for the rs844644 polymorphism, suggesting no significant association. And no association was also found between either rs844648 1.11 (OR 1.11, 95% CI 0.86-1.43, P = 0.41) or rs10489265 (OR 1.17, 95% CI 0.94-1.47, P = 0.17) polymorphism with SLE susceptibility, respectively.

CONCLUSIONS

Our meta-analysis demonstrated that the TNFSF4 rs2205960, rs1234315 and rs844840 SNPs was significantly associated with an increased risk of SLE.

Machine learning integration of scleroderma histology and gene expression identifies fibroblast polarisation as a hallmark of clinical severity and improvement

OBJECTIVE

We sought to determine histologic and gene expression features of clinical improvement in early diffuse cutaneous systemic sclerosis (dcSSc; scleroderma).

METHODS

Fifty-eight forearm biopsies were evaluated from 26 individuals with dcSSc in two clinical trials. Histologic/immunophenotypic assessments of global severity, alpha-smooth muscle actin (aSMA), CD34, collagen, inflammatory infiltrate, follicles and thickness were compared with gene expression and clinical data. Support vector machine learning was performed using scleroderma gene expression subset (normal-like, fibroproliferative, inflammatory) as classifiers and histology scores as inputs. Comparison of w-vector mean absolute weights was used to identify histologic features most predictive of gene expression subset. We then tested for differential gene expression according to histologic severity and compared those with clinical improvement (according to the Combined Response Index in Systemic Sclerosis).

RESULTS

aSMA was highest and CD34 lowest in samples with highest local Modified Rodnan Skin Score. CD34 and aSMA changed significantly from baseline to 52 weeks in clinical improvers. CD34 and aSMA were the strongest predictors of gene expression subset, with highest CD34 staining in the normal-like subset (p<0.001) and highest aSMA staining in the inflammatory subset (p=0.016). Analysis of gene expression according to CD34 and aSMA binarised scores identified a 47-gene fibroblast polarisation signature that decreases over time only in improvers (vs non-improvers). Pathway analysis of these genes identified gene expression signatures of inflammatory fibroblasts.

CONCLUSION

CD34 and aSMA stains describe distinct fibroblast polarisation states, are associated with gene expression subsets and clinical assessments, and may be useful biomarkers of clinical severity and improvement in dcSSc.

TNFSF4 is a risk factor to systemic lupus erythematosus in a Latin American population

OBJECTIVE

The aim of this study was to examine the association of three TNFSF4 single nucleotide variants (SNVs) with systemic lupus erythematosus (SLE) susceptibility in Mexican patients.

METHODS

Genotypes of the TNFSF4 rs1234315T/C, rs2205960G/T, and rs704840T/G SNVs were determined using a TaqMan assay. In our study, we included 395 patients with SLE and 500 controls.

RESULTS

Our information shows a significant difference in the allelic and genotypic frequency of the three TNFSF4 SNVs between cases and controls. Thus, our data showed an association between TNFSF4 rs1234315T/C (T vs. C, OR 1.40, p = 0.00087), rs2205960G/T (G vs. T, OR 1.32, p = 0.0037), and rs704840T/G (T vs. G, OR 1.41, p = 0.0003) and SLE susceptibility in Mexican subjects. Besides, we conducted a meta-analysis to determine the role of TNFSF4 rs2205960G/T and SLE susceptibility; our results showed that this variant is a risk factor for SLE in Latin Americans and Asians.

CONCLUSION

Our results show that TNFSF4 rs1234315T/C, rs2205960G/T, and rs704840T/G are risk factors to SLE in Mexicans. This is the first study to document an association between TNFSF4 rs704840T/G and SLE in a Latin American population. In addition, our meta-analysis showed that TNFSF4 rs2205960G/T is a risk factor for Asians and Latin Americans. Key Point • The TNFSF4 rs1234315T/C, rs2205960G/T, and rs704849T/G SNVs are risk factors to SLE in patients from Mexico.

Associations between TNFSF4 gene polymorphisms (rs2205960 G > A, rs704840 T > G and rs844648 G > A) and susceptibility to autoimmune diseases in Asians: a meta-analysis

BACKGROUND

Tumor necrosis factor superfamily member 4 (TNFSF4) has significant role in modulating autoimmune diseases (ADs) and single nucleotide polymorphism (SNP) is also related with the susceptibility to some diseases. So a meta-analysis aimed at systematically assessing the associations between TNFSF4 polymorphisms (rs2205960 G > A, rs704840 T > G and rs844648 G > A) and ADs risk was performed in Asians.

METHODS

Total 14 eligible articles published before March 2019 involving 35 studies, of which 21 studies (16,109 cases and 26,378 controls) for rs2205960 G > A, 8 studies (2,424 cases and 3,692 controls) for rs704840 T > G, and 6 studies (3,839 cases and 5,867 controls) for rs844648 G > A were included. Effects of the three respective polymorphisms on the susceptibility to ADs were estimated by pooling the odds ratios (ORs) with their corresponding 95% confidence interval (95% CI) in allelic, dominant, recessive, heterozygous and homozygous models.

RESULTS

The overall analysis revealed that all the rs2205960 G > A, rs704840 T > G and rs844648 G > A polymorphisms could increase the risk of ADs in allelic, dominant, recessive, heterozygous and homozygous models. Furthermore, subgroup analysis showed that both rs2205960 G > A and rs704840 T > G were significantly associated with the susceptibility to systemic lupus erythematosus (SLE). What's more, statistically significant association between rs2205960 G > A polymorphism and primary Sjögren's syndrome (pSS) susceptibility was also observed in allelic, dominant and heterozygous models.

CONCLUSIONS

This current meta-analysis suggested that all of the three TNFSF4 polymorphisms may be associated with ADs susceptibility in Asians.

Whole Exome Sequencing of Patients from Multicase Families with Systemic Lupus Erythematosus Identifies Multiple Rare Variants

In an effort to identify rare alleles associated with SLE, we have performed whole exome sequencing of the most distantly related affected individuals from two large Icelandic multicase SLE families followed by Ta targeted genotyping of additional relatives. We identified multiple rare likely pathogenic variants in nineteen genes co-segregating with the disease through multiple generations. Gene co-expression and protein-protein interaction analysis identified a network of highly connected genes comprising several loci previously implicated in autoimmune diseases. These genes were significantly enriched for immune system development, lymphocyte activation, DNA repair, and V(D)J gene recombination GO-categories. Furthermore, we found evidence of aggregate association and enrichment of rare variants at the FAM71E1/EMC10 locus in an independent set of 4,254 European SLE-cases and 4,349 controls. Our study presents evidence supporting that multiple rare likely pathogenic variants, in newly identified genes involved in known disease pathogenic pathways, segregate with SLE at the familial and population level.

Association between TNFSF4 and BLK gene polymorphisms and susceptibility to allergic rhinitis

Allergic rhinitis (AR) is a common inflammatory disease of the upper airway. Recent evidence suggests that gene‑gene interactions between tumor necrosis factor receptor superfamily 4 (TNFSF4) and B cell lymphocyte kinase (BLK) may have a synergistic effect on T and B cells in determining immunologic aberration, via the nuclear factor‑κB pathway. The present study was performed to evaluate the potential association between specific single nucleotide polymorphisms (SNPs) in the TNFSF4 and BKL genes with susceptibility to AR in Chinese subjects. A population‑based case‑control study was performed in 600 Chinese AR patients and 700 controls. Blood was drawn for DNA extraction, and 9 SNPs (6 in TNFSF4 and 3 in BKL genes) were selected and genotyped. The TNFSF4 SNPs rs1234314 and rs1234315, and the BLK SNPs rs13277113 and rs1600249 were observed to occur in different frequencies between the AR patients and the controls. The CC (rs1234314, rs1234315) and AA (rs1600249, rs13277113) genotypes provided protective effects against AR, whereas the AG (rs13277113) genotype presented a risk factor for AR. The haplotypes ACC in the rs1234313‑rs1234314‑rs1234315 block and GA in the rs2254546‑rs13277113 block significantly decreased the risk of AR, whereas the GGT and AG haplotypes served protective roles. SNP interaction analysis further indicated that there may be synergistic effects among the selected sets of polymorphisms. The present study suggests a novel association between specific TNFSF4 and BLK gene polymorphisms and AR risk, highlighting their potential utility as genetic biomarkers for AR susceptibility in a Chinese Han population.

Association of TNFSF4 Polymorphisms with Vogt-Koyanagi-Harada and Behcet's Disease in Han Chinese

To investigate whether single nucleotide polymorphisms (SNPs) of the Tumor Necrosis Factor Superfamily 4 (TNFSF4) gene are associated with Vogt–Koyanagi–Harada (VKH) and Behcet’s disease (BD) in a Chinese Han population. A two-stage case control study was carried out in 1331 VKH, 938 BD and 1752 healthy controls. Ten TNFSF4 SNPs, including rs1234314, rs1234315, rs2205960, rs704840, rs2795288, rs844654, rs12039904, rs10912580, rs844665, and rs844644, were genotyped using the PCR-restriction fragment length polymorphism method. Genotype and allele frequencies were analyzed between cases and healthy controls using the X² or Fisher’s exact test and p values were corrected for multiple comparisons. We observed a significantly increased frequency of the TT genotype of rs1234315 in BD patients (Pc = 1.44 × 10⁻⁵, OR = 1.734, 95% CI = 1.398–2.151). The frequency of the TT genotype of rs12039904 was significantly higher in patients with VKH disease as compared to controls (Pc = 4.62 × 10⁻⁵, OR = 1.959, 95% CI = 1.483–2.588). Analysis of clinical manifestations in VKH disease and BD did not show an association with the TNFSF4 gene polymorphisms. The study suggests that the TNFSF4 gene may be involved in the susceptibility to VKH disease and BD in Han Chinese.

TNFSF4 polymorphisms are associated with systemic lupus erythematosus in the Malaysian population

Tumour necrosis factor superfamily 4 (TNFSF4) gene has been reported to be associated with systemic lupus erythematosus (SLE) susceptibility due to its encoding for OX40L protein that can increase autoantibody production and cause imbalance of T-cell proliferation. The purpose of this study was to investigate the association of TNFSF4 rs2205960, rs1234315, rs8446748 and rs704840 with SLE in the Malaysian population. A total of 476 patients with SLE and 509 healthy controls were recruited. Real-time polymerase chain reaction (PCR) was applied to genotype the selected single nucleotide polymorphisms (SNPs). Allelic and genotypic frequencies of each SNP were calculated for each ethnic group, and association test was performed using logistic regression. The overall association of each SNP in Malaysian patients with SLE was determined with meta-analysis. The frequency of minor T allele of TNFSF4 rs2205960 was significant in Chinese and Indian patients with SLE, with P values of 0.05 (OR = 1.27, 95% CI: 1.00-1.61) and 0.004 (OR = 3.16, 95% CI: 1.41-7.05), respectively. Significant association of minor G allele of rs704840 with SLE was also observed in Chinese (P = 0.03, OR = 1.26, 95% CI: 1.02-1.56). However, after Bonferroni correction, only T allele of rs2205960 remained significantly associated with Indian cohort. Overall, minor G allele of rs704840 showed significant association with SLE in the Malaysian population with P values of 0.05 (OR = 1.20, 95% CI: 1.00-1.43). We suggested TNFSF4 rs704840 could be the potential SLE risk factors in the Malaysian population.

The genetic basis of systemic lupus erythematosus: What are the risk factors and what have we learned

The genome-wide association study is a free-hypothesis approach based on screening of thousands or even millions of genetic variants distributed throughout the whole human genome in relation to a phenotype. The relevant role of the genome-wide association studies in the last decade is undisputed because it has permitted to elucidate multiple risk genetic factors associated with the susceptibility to several human complex diseases. Regarding systemic lupus erythematosus (SLE) this approach has allowed to identify more than 60 risk loci for SLE susceptibility across populations to date, increasing our understanding on the pathogenesis of this disease. We present the latest findings in the genetic of SLE across populations using genome-wide approaches. These studies revealed that most of the genetic risk is shared across borders and ethnicities. Finally, we focus on describing the most important risk loci for SLE attempting to cover the genetic findings in relation to functional polymorphisms, such as missense single nucleotide polymorphisms (SNPs) or regulatory variants involved in the development of the disease. The functional studies try to identify the causality of some GWAS-associated variants, many of which fall in non-coding regions of the genome, suggesting a regulatory role. Many loci show an environmental interaction, another aspect revealed by the studies of epigenetic modifications and those associated with genetic variants. Finally, new-generation sequencing technologies can open other paths in the research on SLE genetics, the role of rare variants and the detailed identification of causal regulatory variation. The clinical relevance of the genetic factors will be shown when we are able to use them or in combination with other molecular measurements to re-classify a heterogeneous disease such as SLE.

OX40 Ligand Contributes to Human Lupus Pathogenesis by Promoting T Follicular Helper Response

Increased activity of T follicular helper (Tfh) cells plays a major pathogenic role in systemic lupus erythematosus (SLE). However, the mechanisms that cause aberrant Tfh cell responses in SLE remain elusive. Here we showed the OX40 ligand (OX40L)-OX40 axis contributes to the aberrant Tfh response in SLE. OX40L was expressed by myeloid antigen-presenting cells (APCs), but not B cells, in blood and in inflamed tissues in adult and pediatric SLE patients. The frequency of circulating OX40L-expressing myeloid APCs positively correlated with disease activity and the frequency of ICOS(+) blood Tfh cells in SLE. OX40 signals promoted naive and memory CD4(+) T cells to express multiple Tfh cell molecules and were sufficient to induce them to become functional B cell helpers. Immune complexes containing RNA induced OX40L expression on myeloid APCs via TLR7 activation. Our study provides a rationale to target the OX40L-OX40 axis as a therapeutic modality for SLE.

Genes associated with SLE are targets of recent positive selection

The reasons for the ethnic disparities in the prevalence of systemic lupus erythematosus (SLE) and the relative high frequency of SLE risk alleles in the population are not fully understood. Population genetic factors such as natural selection alter allele frequencies over generations and may help explain the persistence of such common risk variants in the population and the differential risk of SLE. In order to better understand the genetic basis of SLE that might be due to natural selection, a total of 74 genomic regions with compelling evidence for association with SLE were tested for evidence of recent positive selection in the HapMap and HGDP populations, using population differentiation, allele frequency, and haplotype-based tests. Consistent signs of positive selection across different studies and statistical methods were observed at several SLE-associated loci, including PTPN22, TNFSF4, TET3-DGUOK, TNIP1, UHRF1BP1, BLK, and ITGAM genes. This study is the first to evaluate and report that several SLE-associated regions show signs of positive natural selection. These results provide corroborating evidence in support of recent positive selection as one mechanism underlying the elevated population frequency of SLE risk loci and supports future research that integrates signals of natural selection to help identify functional SLE risk alleles.

Sex Differences in monocytes and TLR4 associated immune responses; implications for systemic lupus erythematosus (SLE)

It has been shown that TLR7 and TLR9 signaling play a role in SLE pathogenesis. Our recent study revealed that estrogen receptor α knockout mice have impaired inflammatory responses to TLR3, TLR4, TLR7 and TLR9 ligand stimulation in DCs, B cells and whole spleen cells. These findings indicate that estrogen receptor mediated signaling may impact universal TLR responsiveness. Whether estrogen has a direct or indirect effect on TLR responsiveness by immune cells is not clear. There is evidence of a role of TLR4 in SLE disease pathogenesis, such as the kidney damage, the induction of CD40 and autoantibodies, the suppression of regulatory T cells, and the role of pro-inflammatory cytokines (e.g., IL-6, IL-1β, TNF-α) in SLE pathogenesis that can be induced by TLR4-mediated monocyte activation, suggesting that TLR4 and TLR4 responsiveness are also important for SLE disease. This review will focus on TLR4 responses and monocytes, which are understudied in systemic autoimmune diseases such as SLE.

Trans-ancestral studies fine map the SLE-susceptibility locus TNFSF4

We previously established an 80 kb haplotype upstream of TNFSF4 as a susceptibility locus in the autoimmune disease SLE. SLE-associated alleles at this locus are associated with inflammatory disorders, including atherosclerosis and ischaemic stroke. In Europeans, the TNFSF4 causal variants have remained elusive due to strong linkage disequilibrium exhibited by alleles spanning the region. Using a trans-ancestral approach to fine-map the locus, utilising 17,900 SLE and control subjects including Amerindian/Hispanics (1348 cases, 717 controls), African-Americans (AA) (1529, 2048) and better powered cohorts of Europeans and East Asians, we find strong association of risk alleles in all ethnicities; the AA association replicates in African-American Gullah (152,122). The best evidence of association comes from two adjacent markers: rs2205960-T (P=1.71 × 10(-34) , OR=1.43[1.26-1.60]) and rs1234317-T (P=1.16 × 10(-28) , OR=1.38[1.24-1.54]). Inference of fine-scale recombination rates for all populations tested finds the 80 kb risk and non-risk haplotypes in all except African-Americans. In this population the decay of recombination equates to an 11 kb risk haplotype, anchored in the 5' region proximal to TNFSF4 and tagged by rs2205960-T after 1000 Genomes phase 1 (v3) imputation. Conditional regression analyses delineate the 5' risk signal to rs2205960-T and the independent non-risk signal to rs1234314-C. Our case-only and SLE-control cohorts demonstrate robust association of rs2205960-T with autoantibody production. The rs2205960-T is predicted to form part of a decameric motif which binds NF-κBp65 with increased affinity compared to rs2205960-G. ChIP-seq data also indicate NF-κB interaction with the DNA sequence at this position in LCL cells. Our research suggests association of rs2205960-T with SLE across multiple groups and an independent non-risk signal at rs1234314-C. rs2205960-T is associated with autoantibody production and lymphopenia. Our data confirm a global signal at TNFSF4 and a role for the expressed product at multiple stages of lymphocyte dysregulation during SLE pathogenesis. We confirm the validity of trans-ancestral mapping in a complex trait.

Association of OX40L polymorphisms with sporadic breast cancer in northeast Chinese Han population

OX40L is an important costimulatory molecule that plays a crucial role in the regulation of T-cell-mediated immunity. The interaction of OX40-OX40L is involved in the pathogenesis of multiple autoimmune and inflammatory diseases such as systemic lupus erythematosus (SLE), carotid artery disease and cancer. The genetic variants of OX40L can increase the risk of SLE, atherosclerosis, systemic sclerosis and show gender-specific effects in some studies. Accordingly, we performed a case-control study including 557 breast cancer patients and 580 age- and sex-matched healthy controls to investigate whether single nucleotide polymorphisms (SNPs) in the OX40L gene are associated with sporadic breast cancer susceptibility and progression in Chinese Han women. Seven SNPs of OX40L (rs6661173, rs1234313, rs3850641, rs1234315, rs12039904, rs844648 and rs10912580) were genotyped with the method of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The results indicated that rs3850641G allele could increase the susceptibility to breast cancer (P = 0.009662), even in the validation study (P = 0.0001515). A significant association between rs3850641 and breast cancer risk was observed under the additive model and dominant model (P = 0.01042 and 0.01942, respectively). The haplotype analysis showed that haplotype A(rs844648)A(rs10912580) was significantly associated with breast cancer, even after 10,000 permutations for haplotypes in block only (P = 0.0003). In clinicopathologic features analysis, the association between rs1234315 and C-erbB2 status was significant (P = 0.02541). Our data primarily indicates that rs3850641 of OX40L gene contributes to sporadic breast carcinogenesis in a northeast Chinese Han population.

Association of TNFSF4 polymorphisms with systemic lupus erythematosus: a meta-analysis

INTRODUCTION

To more precisely estimate the association between the tumor necrosis factor ligand superfamily member 4 (TNFSF4) gene polymorphisms and systemic lupus erythematosus (SLE) risk, we surveyed studies on the association of the TNFSF4 rs2205960, rs1234315, rs844644, and rs844648 polymorphisms with SLE.

METHODS

A literature-based search was conducted to identify all relevant studies. A total of eight independent studies were identified and subsequently reviewed in the meta-analysis.

RESULTS

The meta-analysis showed an association between the TNFSF4 rs2205960 polymorphism and SLE in all subjects [ odds ratio (OR) 1.327, 95% confidence interval (CI) 1.227-1.436, P < 0.001]. In a subgroup analysis by ethnicity, a significantly increased risk for SLE was associated with TNFSF4 rs2205960 T allele among patients of European (OR 1.254, 95% CI 1.185-1.328, P < 0.001) and Asian ethnicity (OR 1.425, 95% CI 1.352-1.501, P < 0.001). The meta-analysis of the rs1234315 polymorphism revealed no association between SLE and the rs1234315 T allele in all subjects (OR 1.167, 95% CI 0.874-1.558, P = 0.296), but the results of the subgroup analysis revealed significant association in subjects of Asian ethnicity (OR 1.386, 95% CI 1.318-1.458, P < 0.001). No association was found between the rs844644 and rs844648 polymorphisms and SLE.

CONCLUSION

The results of our meta-analysis suggest that the TNFSF4 rs2205960 polymorphism may confer susceptibility to SLE in different populations and that the TNFSF4 rs1234315 polymorphism is associated with susceptibility to SLE in Asians.

Independent replication and meta analysis of association studies establish TNFSF4 as a susceptibility gene preferentially associated with the subset of anticentromere-positive patients with systemic sclerosis

OBJECTIVE

Independent replication with large cohorts and metaanalysis of genetic associations are necessary to validate genetic susceptibility factors. The known tumor necrosis factor (ligand) superfamily, member 4 gene (TNFSF4) systemic lupus erythematosus (SLE) risk locus has been found to be associated with systemic sclerosis (SSc) in 2 studies, but with discrepancies between them for genotype-phenotype correlation. Our objective was to validate TNFSF4 association with SSc and determine the subset with the higher risk.

METHODS

Known SLE and SSc TNFSF4 susceptibility variants (rs2205960, rs1234317, rs12039904, rs10912580, and rs844648) were genotyped in 1031 patients with SSc and 1014 controls of French white ancestry. Genotype-phenotype association analysis and meta analysis of available data were performed, providing a population study of 4989 patients with SSc and 4661 controls, all of European white ancestry.

RESULTS

Allelic and genotypic associations were observed for the 5 single-nucleotide polymorphisms (SNP) with the subset of patients with SSc who are positive for anticentromere antibodies (ACA) and only a trend for association with SSc and limited cutaneous SSc. Rs2205960 exhibited the strongest allelic association in ACA+ patients with SSc [p = 0.0015; OR 1.37 (1.12-1.66)], with significant intra-cohort association when compared to patients with SSc positive for ACA. Metaanalysis confirmed overall association with SSc but also raised preferential association with the ACA+ subset and strongest effect with rs2205960 [T allele p = 0.00013; OR 1.33 (1.15-1.54) and TT genotype p = 0.00046; OR 2.02 (1.36-2.98)].

CONCLUSION

We confirm TNFSF4 as an SSc susceptibility gene and rs2205960 as a putative causal variant with preferential association in the ACA+ SSc subphenotype.

TNF superfamily in inflammatory disease: translating basic insights

The tumor necrosis factor (TNF) and TNF receptor superfamilies (TNFSF and TNFRSF) consist of approximately 50 membrane and soluble proteins that can modulate cellular function. Most of these molecules are expressed by or can target cells of the immune system, and they have a wide range of actions including promoting cellular differentiation, survival, and production of inflammatory cytokines and chemokines. Emerging data show that TNFSF ligand-receptor signaling pathways are active in inflammatory and autoimmune disease. Furthermore, several genetic polymorphisms in TNFSF and TNFRSF associate with susceptibility to developing disease. Here, we examine recent data regarding the potential of these molecules as targets for therapy of autoimmune and inflammatory disease.

A replication study confirms the association of TNFSF4 (OX40L) polymorphisms with systemic sclerosis in a large European cohort

OBJECTIVES

The aim of this study was to confirm the influence of TNFSF4 polymorphisms on systemic sclerosis (SSc) susceptibility and phenotypic features.

METHODS

A total of 8 European populations of Caucasian ancestry were included, comprising 3014 patients with SSc and 3125 healthy controls. Four genetic variants of TNFSF4 gene promoter (rs1234314, rs844644, rs844648 and rs12039904) were selected as genetic markers.

RESULTS

A pooled analysis revealed the association of rs1234314 and rs12039904 polymorphisms with SSc (OR 1.15, 95% CI 1.02 to 1.31; OR 1.18, 95% CI 1.08 to 1.29, respectively). Significant association of the four tested variants with patients with limited cutaneous SSc (lcSSc) was revealed (rs1234314 OR 1.22, 95% CI 1.07 to 1.38; rs844644 OR 0.91, 95% CI 0.83 to 0.99; rs844648 OR 1.10, 95% CI 1.01 to 1.20 and rs12039904 OR 1.20, 95% CI 1.09 to 1.33). Association of rs1234314, rs844648 and rs12039904 minor alleles with patients positive for anti-centromere antibodies (ACA) remained significant (OR 1.23, 95% CI 1.10 to 1.37; OR 1.12, 95% CI 1.01 to 1.25; OR 1.22, 95% CI 1.07 to 1.38, respectively). Haplotype analysis confirmed a protective haplotype associated with SSc, lcSSc and ACA positive subgroups (OR 0.88, 95% CI 0.82 to 0.96; OR 0.88, 95% CI 0.80 to 0.96; OR 0.86, 95% CI 0.77 to 0.97, respectively) and revealed a new risk haplotype associated with the same groups of patients (OR 1.14, 95% CI 1.03 to 1.26; OR 1.20, 95% CI 1.08 to 1.35; OR 1.23, 95% CI 1.07 to 1.42, respectively).

CONCLUSIONS

The data confirm the influence of TNFSF4 polymorphisms in SSc genetic susceptibility, especially in subsets of patients positive for lcSSc and ACA.

Genetically determined Amerindian ancestry correlates with increased frequency of risk alleles for systemic lupus erythematosus

OBJECTIVE

To assess whether genetically determined Amerindian ancestry predicts increased presence of risk alleles of known susceptibility genes for systemic lupus erythematosus (SLE).

METHODS

Single-nucleotide polymorphisms (SNPs) within 16 confirmed genetic susceptibility loci for SLE were genotyped in a set of 804 Mestizo lupus patients and 667 Mestizo healthy controls. In addition, 347 admixture informative markers were genotyped. Individual ancestry proportions were determined using STRUCTURE. Association analysis was performed using PLINK, and correlation between ancestry and the presence of risk alleles was analyzed using linear regression.

RESULTS

A meta-analysis of the genetic association of the 16 SNPs across populations showed that TNFSF4, STAT4, ITGAM, and IRF5 were associated with lupus in a Hispanic Mestizo cohort enriched for European and Amerindian ancestry. In addition, 2 SNPs within the major histocompatibility complex region, previously shown to be associated in a genome-wide association study in Europeans, were also associated in Mestizos. Using linear regression, we predicted an average increase of 2.34 risk alleles when comparing an SLE patient with 100% Amerindian ancestry versus an SLE patient with 0% Amerindian ancestry (P < 0.0001). SLE patients with 43% more Amerindian ancestry were predicted to carry 1 additional risk allele.

CONCLUSION

Our results demonstrate that Amerindian ancestry is associated with an increased number of risk alleles for SLE.

Genetic susceptibility to systemic lupus erythematosus in the genomic era

Our understanding of the genetic basis of systemic lupus erythematosus (SLE) has been rapidly advanced using large-scale, case-control, candidate gene studies as well as genome-wide association studies during the past 3 years. These techniques have identified more than 30 robust genetic associations with SLE including genetic variants of HLA and Fcγ receptor genes, IRF5, STAT4, PTPN22, TNFAIP3, BLK, BANK1, TNFSF4 and ITGAM. Most SLE-associated gene products participate in key pathogenic pathways, including Toll-like receptor and type I interferon signaling pathways, immune regulation pathways and those that control the clearance of immune complexes. Disease-associated loci that have not yet been demonstrated to have important functions in the immune system might provide new clues to the underlying molecular mechanisms that contribute to the pathogenesis or progression of SLE. Of note, genetic risk factors that are shared between SLE and other immune-related diseases highlight common pathways in the pathophysiology of these diseases, and might provide innovative molecular targets for therapeutic interventions.

Recent findings on genetics of systemic autoimmune diseases

Association studies of over 1 million SNPs capturing most of the human genome common variation became possible thanks to the information provided by the HapMap International project and the development of high-throughput genotyping technologies at accessible prices. Genome-wide scans analyzing thousands of individuals have now identified most if not all of the major genes involved in susceptibility for several systemic autoimmune diseases. In particular, results for rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and systemic sclerosis (SSc) are reviewed here. While most genes are shared between diseases, few seem to be unique reflecting that we still are long before knowing all genes, their interactions with other genes and the environment and their impact on biological functions.

The lupus family registry and repository

The Lupus Family Registry and Repository (LFRR) was established with the goal of assembling and distributing materials and data from families with one or more living members diagnosed with SLE, in order to address SLE genetics. In the present article, we describe the problems and solutions of the registry design and biometric data gathering; the protocols implemented to guarantee data quality and protection of participant privacy and consent; and the establishment of a local and international network of collaborators. At the same time, we illustrate how the LFRR has enabled progress in lupus genetics research, answering old scientific questions while laying out new challenges in the elucidation of the biologic mechanisms that underlie disease pathogenesis. Trained staff ascertain SLE cases, unaffected family members and population-based controls, proceeding in compliance with the relevant laws and standards; participant consent and privacy are central to the LFRR's effort. Data, DNA, serum, plasma, peripheral blood and transformed B-cell lines are collected and stored, and subject to strict quality control and safety measures. Coded data and materials derived from the registry are available for approved scientific users. The LFRR has contributed to the discovery of most of the 37 genetic associations now known to contribute to lupus through 104 publications. The LFRR contains 2618 lupus cases from 1954 pedigrees that are being studied by 76 approved users and their collaborators. The registry includes difficult to obtain populations, such as multiplex pedigrees, minority patients and affected males, and constitutes the largest collection of lupus pedigrees in the world. The LFRR is a useful resource for the discovery and characterization of genetic associations in SLE.

The genetics of systemic sclerosis

Systemic sclerosis (SSc, scleroderma) is an autoimmune disease clinically characterized by progressive fibrosis in the skin and internal organs. While the pathogenesis of SSc is not completely understood, familial studies and genetic studies suggest that SSc is a complex polygenic disease. In the current review, we will discuss recent studies investigating genetic susceptibility to SSc. Candidate gene studies have identified critical immunoregulatory genes and gene regions including BANK1, FAM167A-BLK, IL23R, IRF5, STAT4, TBX21, and TNFSF4 as susceptibility genes for the development of SSc. More recently a genome-wide association study has been performed and identified CD247 (CD3-zeta) as a novel genetic risk factor for the susceptibility to SSc. Together these genetic association studies have substantially advanced our understanding of SSc pathogenesis and form the foundation for future studies seeking to understand the complexities of SSc.

Genetic factors predisposing to systemic lupus erythematosus and lupus nephritis

Systemic lupus erythematosus (SLE) is a chronic inflammatory disease characterized by a loss of tolerance to self-antigens and the production of high titers of serum autoantibodies. Lupus nephritis can affect up to 74% of SLE patients, particularly those of Hispanic and African ancestries, and remains a major cause of morbidity and mortality. A genetic etiology in SLE is now well substantiated. Thanks to extensive collaborations, extraordinary progress has been made in the past few years and the number of confirmed genes predisposing to SLE has catapulted to approximately 30. Studies of other forms of genetic variation, such as copy number variants and epigenetic alterations, are emerging and promise to revolutionize our knowledge about disease mechanisms. However, to date little progress has been made on the identification of genetic factors specific to lupus nephritis. On the near horizon, two large-scale efforts, a collaborative meta-analysis of lupus nephritis based on all genome-wide association data in Caucasians and parallel scans in four other ethnicities, are poised to make fundamental discoveries in the genetics of lupus nephritis. Collectively, these findings will show that a broad array of pathways underlines the genetic heterogeneity of SLE and lupus nephritis, and provide potential avenues for the development of novel therapies.

OX40-OX40 ligand interaction in T-cell-mediated immunity and immunopathology

T-cell activation is mediated not only by antigen stimulation through T-cell receptors but also by costimulatory signals through costimulatory molecules. Among several costimulatory molecules, the tumor necrosis factor (TNF) receptor family member OX40 plays a key role in the survival and homeostasis of effector and memory T cells. According to the conventional understanding of OX40 costimulation, an interaction between OX40 and OX40 ligand (OX40L) occurs when activated T cells bind to professional antigen-presenting cells (APCs). The T-cell functions, including cytokine production, expansion, and survival, are then enhanced by the OX40 costimulatory signals. Over the last half-decade, evidence has accumulated that OX40 signals are critical for controlling the function and differentiation of Foxp3(+) regulatory T cells, indicating a new aspect of OX40-mediated autoimmunity. Furthermore, the expression of OX40L by mast cells was shown to be important for controlling inflammation through regulatory T-cell function. Besides the essential role played by OX40 signaling in generating memory CD4 T cells, recent reports show that it also has a unique role in generating memory CD8 T cells. In addition, recent genome-wide association studies have identified single-nucleotide polymorphisms of the OX40L and OX40 genes that are related to cardiovascular diseases and SLE, providing direct evidence for the involvement of the OX40-OX40L interaction in human diseases. Here, we review recent progress on how the OX40-OX40L interaction regulates T-cell tolerance, peripheral T-cell homeostasis, and T-cell-mediated inflammatory diseases.