TRAF1/C5, eNOS, C1q, but not STAT4 and PTPN22 gene polymorphisms are associated with genetic susceptibility to systemic lupus erythematosus in Turkey

Interactions between TNFAIP3, PTPN22, and TRAF1-C5 gene polymorphisms in patients with primary Sjögren's syndrome

Objectives

The aim of our study was to investigate whether TNFAIP3, PTPN22, and TRAF1-5 single nucleotide polymorphisms (SNPs) are associated with susceptibility, severity, or serological markers in primary Sjögren's syndrome (pSS).

Patients and methods

The cases and controls study was conducted between December 2021 and June 2022. TNFAIP3 rs10499194C/T, rs6920220G/A, and rs2230926T/G, PTPN22 rs2476601C/T and rs33996649G/A, and TRAF1-C5 rs10818488G/A polymorphisms were genotyped in 154 female pSS patients (mean age: 45.2±6.8 years) and 313 female control subjects (mean age: 50.3±7.5 years) using the TaqMan® SNP genotyping assay. An association analysis between TNFAIP3, PTPN22, and TRAF1-C5 SNPs and susceptibility, clinical characteristics, and serological markers of pSS was performed. Interactions between TNFAIP3, PTPN22, and TRAF1-C5 SNPs were also evaluated in patients and controls.

Results

The genotype and allele frequencies showed no association with susceptibility, severity, or serological markers of pSS. Nevertheless, several interactions between TNFAIP3 and TRAF1-C5 or TNFAIP3, PTPN22, and TRAF1-C5 genotypes were associated with susceptibility to pSS (p<0.01).

Conclusion

Individual TNFAIP3, PTPN22, and TRAF1-C5 SNPs are not associated with susceptibility, severity, or serological markers of pSS. However, genetic interactions between TRAF1-C5 and TNFAIP3 or TNFAIP3, PTPN22, and TRAF1-C5 SNPs are risk factors for pSS.

Gene polymorphisms within regions of complement component C1q in HIV associated preeclampsia

OBJECTIVE

This study investigates the association of C1q gene (rs292001 and rs294183) polymorphisms in HIV infected and uninfected preeclamptic women of African ancestry.

MATERIALS AND METHODS

The study population consisted of 325 pregnant women of African ancestry grouped into 145 normotensive pregnant women (72 HIV uninfected normotensive, 73 HIV infected normotensive) and 180 preeclamptic pregnant women (103 HIV uninfected preeclamptics, 77 HIV infected preeclamptics). Preeclamptic pregnant women were further sub-grouped into 79 early-onset preeclampsia (EOPE) (40 HIV uninfected EOPE, 39 HIV infected EOPE) and 101 late-onset preeclampsia (LOPE) (63 HIV uninfected LOPE, 38 HIV infected LOPE). Genotyping of complement C1q gene polymorphisms (rs292001 and rs294183) was detected using a TaqMan® SNP Genotyping assay from purified DNA.

RESULTS

No significant differences in allelic and genotype frequencies of rs292001 and rs294183 between preeclamptic and normotensive women were observed. Likewise, there were no significant differences in allelic and genotype frequencies between HIV infected normotensive vs HIV infected preeclampsia and HIV uninfected normotensive vs HIV uninfected preeclampsia for both SNPs. However, the odds ratio of preeclamptic women having the GA genotype was 1:2.

CONCLUSION

We demonstrate that SNPs of the C1q gene (rs292001 and rs294183) are not associated with the pathogenesis of PE development in women of African ancestry. The role ofC1qrs292001 heterozygous GA is highlighted (with and without HIV infection) may affect susceptibility to PE development. Notably, this dysregulation may affect C1q translation and protein output thus influencing the downstream role of the complement system and functional immunology in HIV infection comorbid with PE.

Association of C1q gene cluster variants with rheumatoid arthritis: a pilot study

Single-nucleotide polymorphisms (SNPs) in C1q gene cluster were previously linked to autoimmunity and SLE, but data are scarce for their association with RA. In the present study, we evaluated associations of five SNPs (rs665691, rs682658, rs172378, rs292001 and rs294179) in the C1q genetic region with RA and some of its clinical and immunologic characteristics. Fifty-eight RA patients and 67 age- and gender-matched healthy controls, all Caucasian, participated in the study. They were genotyped for the five SNPs using TaqMan allelic discrimination assay, and their C1q levels were estimated by ELISA. Rheumatoid factor and anti-citrullinated peptide antibodies were measured (using latex agglutination and ELISA resp.) in the RA patients' group and relevant clinical information was collected. RA patients and healthy controls had similar frequencies of alleles and genotypes of rs665691, rs682658 and rs294179. Minor G-allele and GG genotype of rs172378 were associated with RA (OR = 2.80; 95% CI 1.62-4.81; p = 0.0002 and OR = 5.01; 95% CI 1.55-16.24; p = 0.007, resp.), as well as AA genotype of rs292001 (OR = 3.23; 95% CI 1.15-9.08; p = 0.026). C1q levels were significantly lower (still normal) in RA patients' group compared to healthy volunteers: 89 µg/ml (68-121) vs 114 µg/ml (60-169), p < 0.0001. Significant association was established between rs172378 and rs292001 and RA, in contrast to rs665691, rs682658 and rs294179. RA patients had lower C1q levels than healthy controls. Our findings correspond to the scientific knowledge so far and add additional clarity from a Bulgarian cohort.

Investigation of Association of Complement 5 Genetic Polymorphisms with Sepsis and Sepsis-Induced Inflammatory Responses

Background

Complement 5 (C5) and C5a production play a pivotal role in the pathophysiology of sepsis. Strong evidence demonstrates an association of C5 gene polymorphisms with various inflammatory diseases. However, no current studies have explored the clinical relevance of C5 polymorphisms in sepsis.

Methods

Two C5 gene polymorphisms, rs17611 and rs2269067, were identified by genotyping in 636 sepsis patients and 753 controls in a Han Chinese population. C5 gene expression was detected via quantitative real-time PCR. C5a and proinflammatory cytokine production was measured by enzyme-linked immunosorbent assay. An Annexin V apoptosis assay was performed to assess cell apoptosis.

Results

Our results showed significantly lower frequencies of rs2269067 GC/CC genotypes or C allele in sepsis patients than healthy controls. The frequencies of rs17611 CC/CT genotypes or C allele were significantly overrepresented in both the septic shock and non-survivor subgroups. Patients with this sepsis-associated high-risk rs17611 C allele exhibited a significant increase in C5a, TNF-α and IL-6 production. However, no significant difference in C5a and downstream proinflammatory cytokine production was observed among patients with different rs2269067 genotypes. In addition, in vitro experiments showed an effect of recombinant C5a on enhancing LPS-stimulated IL-1β, IL-6 and TNF-α production and cell apoptosis in THP-1 monocytes.

Conclusion

The rs2269067 polymorphism conferred protection against sepsis susceptibility. The rs17611 polymorphism was associated with increased C5a production, which ultimately potentiated the secretion of downstream proinflammatory cytokines and conferred susceptibility to sepsis progression and poor prognosis.

Association between complement gene polymorphisms and systemic lupus erythematosus: a systematic review and meta-analysis

Complement dysfunction results in impaired ability in clearing apoptotic cell debris that may stimulate autoantibody production in systemic lupus erythematosus (SLE). Herein, we provided a comprehensive search to find and meta-analyze any complement gene polymorphisms associated with SLE. The ITGAM, C1q, and MBL gene polymorphisms were included in this meta-analysis to reveal the exact association with SLE risk. Electronic databases, including Scopus, PubMed, and Google Scholar, were searched to find studies investigating the ITGAM, C1q, and MBL gene polymorphisms and SLE risk in different populations. The pooled odds ratio (OR) and its corresponding 95% confidence interval (CI) were used to analyze the association between ITGAM, C1q, and MBL gene polymorphisms and susceptibility to SLE. According to inclusion criteria, a total of 24 studies, comprising 4 studies for C1QA rs292001, 5 studies for C1QA rs172378, 9 studies for ITGAM rs1143679, 8 studies for MBL rs1800450, 3 studies for MBL2 rs1800451, and 3 studies for MBL2 rs5030737, were included in the final meta-analysis. A significant positive association was found between rs1143679 and SLE risk, while rs1800451 significantly associated with decreased SLE susceptibility. In summary, ITGAM gene rs1143679 SNP and MBL gene rs1800451 SNP were positively and negatively associated with SLE risk, respectively.

Genetic Polymorphisms in Genes Involved in the Type I Interferon System (IFIH1/MDA-5, TNFAIP3/A20, and STAT4): Association with SLE Risk in Egyptian Children and Adolescents

Purpose

Systemic lupus erythematosus (SLE) is a multifactorial autoimmune inflammatory disease that is influenced by both genetic and environmental factors and associated with dysregulation of type I interferon (INF) response. This study aimed to investigate the effects of single nucleotide polymorphisms (SNPs) of the IFIH1, TNFAIP3, and STAT4 genes in the type I INF system on SLE risk in Egyptian children and adolescents.

Patients and Methods

We recruited 94 SLE individuals and 94 healthy subjects. SNPs of IFIH1 rs3747517 C/T, TNFAIP3 rs610604 G/T, and STAT4 rs7574865 G/T were evaluated using TaqMan™ SNP genotyping assay.

Results

Individuals with the TT, CT+TT genotypes, and T allele of rs3747517 in the IFIH1 gene were protective for SLE patients (OR = 0.429, 95% CI = 0.191-0.962, P = 0.040), (OR = 0.685, 95% CI = 0.477-0.984, P = 0.041), and (OR = 0.705, 95% CI = 0.527-0.944, P = 0.019), respectively. Also, individuals with the TT, GT+TT genotypes, and T allele of rs7574865 in the STAT4 gene were associated with SLE risk (OR = 3.945, 95% CI = 1.303-11.947, P = 0.015), (OR = 1.536, 95% CI = 1.058-2.231, P = 0.024), and (OR = 1.522, 95% CI = 1.113-2.082, P = 0.009), respectively. In the case of TNFAIP3 rs610604, no significant association of genotypes or alleles with SLE were detected, while the three SNPs did not show any significant association with the SLE clinical or laboratory features.

Conclusion

Our findings indicated that rs3747517 in IFIH1 was protective for SLE in Egyptian children and adolescents. Moreover, rs7574865 in STAT4 not rs610604 in TNFAIP3 was associated with SLE risk.

Cq1 Exon Polymorphisms in Caucasian and African American Systemic Lupus Erythematosus patients

BACKGROUND

C1q protein is composed of three protein chains (A, B and C) that are the products of separate genes. Genetic deficiencies in C1Q genes are important factors influencing the risk of systemic lupus erythematosus (SLE). Therefore, this study aimed to investigate the possible association of single nucleotide polymorphisms (SNPs) in the coding region of the C1Q genes with SLE.

METHODS

To search for potential SNPs in the encoding regions of C1q A, B and C chains, Cq1 exons were initially amplified and directly sequenced from leukocyte DNA from a subset of Caucasian and African American SLE patients and healthy controls. The sequences were analyzed by the Phrap and Phred software analysis system and the SNPs were identified by visual inspection. To test if any of these SNPs were linked to susceptibility to SLE, they were measured in 210 SLE patients ((59 African Americans and 151 Caucasians) and 129 matched healthy controls (55 African Americans and 74 Caucasians) by restriction fragment length polymorphism analysis.

RESULTS

The sequencing phase of the study identified three synonymous SNPs: Nucleotide 276G>A in C1QA, 66C>A in C1QB and 129G>A in C1QC. Statistically, no differences were found in genotype or allele frequencies between patients and controls for the 276G>A or 66C>A SNP. However, in Caucasians, the frequencies of the 129G>A genotypes were significantly different between SLE patients and controls (P = 0.005), specifically with the GG genotype being over represented in the controls (P = 0.004).

CONCLUSION

The results show that the homozygous 129GG genotype is associated with protection against SLE onset. This protection is race dependent, being observed in Caucasians but not African Americans. The mechanism of this association is currently unclear.

Common and rare genetic variants of complement components in human disease

Genetic variability in the complement system and its association with disease has been known for more than 50 years, but only during the last decade have we begun to understand how this complement genetic variability contributes to the development of diseases. A number of reports have described important genotype-phenotype correlations that associate particular diseases with genetic variants altering specific aspects of the activation and regulation of the complement system. The detailed functional characterization of some of these genetic variants provided key insights into the pathogenic mechanisms underlying these pathologies, which is facilitating the design of specific anti-complement therapies. Importantly, these analyses have sometimes revealed unknown features of the complement proteins. As a whole, these advances have delineated the functional implications of genetic variability in the complement system, which supports the implementation of a precision medicine approach based on the complement genetic makeup of the patients. Here we provide an overview of rare complement variants and common polymorphisms associated with disease and discuss what we have learned from them.

The role of gene polymorphisms in endometriosis

Endometriosis is a benign gynecologic disorder, affecting up to 10% of women, characterized by the presence of functional endometrial tissue at ectopic positions generally within the peritoneum. It is a heritable condition influenced by multiple genetic and environmental factors, with an overall heritability estimated at approximately 50%. In this study, we investigated whether single nucleotide polymorphisms (SNPs) rs7521902, rs10859871 and rs11031006, mapping to WNT4, VEZT and FSHB genetic loci, respectively, are associated with risk for endometriosis in a Greek population. This study included 166 women with histologically confirmed endometriosis diagnosed through surgery and 150 normal controls. Genotyping of the rs7521902, rs10859871 and rs11031006 SNPs was performed with Taqman primer/probe sets. A significant association was detected with the AC genotype of rs7521902 (WNT4) in patients with stage III and IV disease only. Evidence for association with endometriosis was also found for the AC genotype of the rs10859871 of VEZT. Notably, a significant difference in the distribution of the AG genotype and the minor allele A of FSHB rs11031006 SNP was found between the endometriosis patients and controls. We found a genetic association between rs11031006 (FSHB) SNP and endometriosis. WNT4 and VEZT genes constitute the most consistently associated genes with endometriosis. In the present study, an association of rs7521902 (WNT4) and rs10859871 (VEZT) was confirmed in women with endometriosis at the genotypic but not the allelic level.

PTPN22 1858C > T polymorphism and susceptibility to systemic lupus erythematosus: a meta-analysis update

Studies performed in the past years showed PTNP22 1858 C > T (rs2476601) polymorphism as associated with systemic lupus erythematosus susceptibility, although conflicting findings are still found. In this context, a powerful statistical study, such as meta-analysis, is necessary to establish a consensus. The aim of this study was to evaluate association studies between the PTPN22 1858 C > T polymorphism and SLE by a meta-analysis update, including three recently published studies in the last three years. A total of 3868 SLE patients and 7458 healthy individuals were considered herein, enclosing 19 studies from Asian, American, European and Latin ethnic groups. Odds ratio (OR) was performed for allelic, dominant and recessive genetic models. Statistically significant association was found between the PTPN22 1858 C > T polymorphism and susceptibility to SLE in all inheritance models. Allelic genetic model data (OR = 1.54, 95% confidence interval (CI) = 1.38-1.72, p value=.000) shows that T allele confers increased SLE susceptibility. As well as recessive genetic model (OR = 2.04, 95% CI = 1.09-3.82, p value = .030) for T/T genotype. Instead, dominant genetic model shows that C/C genotype confers lower susceptibility for SLE development (OR = 0.62, 95% CI = 0.54-0.72, p value = .000). In addition, we provided an ethnicity-derived meta-analysis. The results showed association in Caucasian (OR = 1.47, p value = .000) and Latin (OR = 2.41, p value = .000) ethnic groups. However, rs2476601 polymorphism is not associated nor in Asian (OR= 1.31; p value = .54) and African (OR = 2.04; p value=.22) populations. In conclusion, present meta-analysis update confirms that T allele and T/T genotype in PTPN22 1858 C > T polymorphism confers SLE susceptibility, particular in Caucasian and Latin groups, suggesting PTPN22 1858 C > T as a potential genetic marker in SLE susceptibility.

Τhe genetics of juvenile idiopathic arthritis: Searching for new susceptibility loci

Juvenile idiopathic arthritis (JIA) is an autoimmune disease that is characterized by persistent chronic arthritis and affected by genetic and environmental factors. Different genetic variations have been reported as risk factors for JIA. However, given that many results could not be replicated in individuals of different ancestral origin, it was assumed that heterogeneous genetic factors are involved in this disease. In the present study, we analyzed three single nucleotide polymorphisms (SNPs), namely PTPRC (rs10919563), TYK2 (rs34536443) and PRKCQ (rs4750316), which were found to be associated with JIA in previous studies. We also investigated whether the intron-4 located 27-bp VNTR of endothelial nitric oxide synthase (eNOS), is associated with risk for JIA in Greece. In total, 125 JIA patients and 221 healthy controls from northern Greece were included in the study as a sample set. Samples were then analyzed, and genotyped for the three SNPs with TaqMan primer-probe sets, using a Real-Time PCR platform (ViiA™ 7 Real-Time PCR system), while eNOS VNTR polymorphism was genotyped by PCR. Statistical analysis was performed using a GraphPad Prism statistical program. The χ² test was used to examine differences of genotype and allele frequencies between patients and controls. Statistical significance was defined by using the two-tailed P<0.05 test. Bioinformatics analysis was conducted by using BlastP, Pymol, Maestro and Desmond. In the case-control association study performed, eNOS only was found to be associated with JIA. Genotype a/a and allele ‘a’ were found in a higher frequency in JIA patients than in controls [p<0.0001, odds ratio (OR)=0.15, 95% confidence intervals (CI): 0.065–0.37; and p<0.0001, OR=0.34, 95% CI: 0.23–0.49, respectively]. No associations with JIA were detected for TYK2, PTPRC or PRKCQ. Aiming to investigate the structural consequences and the structure/function relationships accompanying the Pro1104 to Ala (rs34536443) mutation on TYK2 protein, bioinformatics analysis was performed. Combining three-dimensional (3D)-modeling and molecular dynamics simulations we identified changes in structural flexibility, affecting the functionality of the kinase domain of TYK2. To the best of our knowledge, this is the first time that eNOS VNTR polymorphism is associated with susceptibility to JIA, suggesting a differential role of allele ‘a’ in various complex diseases. The current data emphasize the importance of comparative studies in populations of a different ancestral background towards the clarification of the role of specific alleles in the development of JIA.

Application of Various Statistical Models to Explore Gene-Gene Interactions in Folate, Xenobiotic, Toll-Like Receptor and STAT4 Pathways that Modulate Susceptibility to Systemic Lupus Erythematosus

INTRODUCTION

In view of our previous studies showing an independent association of genetic polymorphisms in folate, xenobiotic, and toll-like receptor (TLR) pathways with the risk for systemic lupus erythematosus (SLE), we have developed three statistical models to delineate complex gene-gene interactions between folate, xenobiotic, TLR, and signal transducer and activator of transcription 4 (STAT4) signaling pathways in association with the molecular pathophysiology of SLE.

METHODS

We developed additive, multifactor dimensionality reduction (MDR), and artificial neural network (ANN) models.

RESULTS

The additive model, although the simplest, suggested a moderate predictability of 30 polymorphisms of these four pathways (area under the curve [AUC] 0.66). MDR analysis revealed significant gene-gene interactions among glutathione-S-transferase (GST)T1 and STAT4 (rs3821236 and rs7574865) polymorphisms, which account for moderate predictability of SLE. The MDR model for specific auto-antibodies revealed the importance of gene-gene interactions among cytochrome P450, family1, subfamily A, polypeptide 1 (CYP1A1) m1, catechol-O-methyltransferase (COMT) H108L, solute carrier family 19 (folate transporter), member 1 (SLC19A1) G80A, estrogen receptor 1 (ESR1), TLR5, 5-methyltetrahydrofolate-homocysteine methyltransferase reductase (MTRR), thymidylate synthase (TYMS). and STAT4 polymorphisms. The ANN model for disease prediction showed reasonably good predictability of SLE risk with 30 polymorphisms (AUC 0.76). These polymorphisms contribute towards the production of SSB and anti-dsDNA antibodies to the extent of 48 and 40%, respectively, while their contribution for the production of antiRNP, SSA, and anti-cardiolipin antibodies varies between 20 and 30%.

CONCLUSION

The current study highlighted the importance of genetic polymorphisms in folate, xenobiotic, TLR, and STAT4 signaling pathways as moderate predictors of SLE risk and delineates the molecular pathophysiology associated with these single nucleotide polymorphisms (SNPs) by demonstrating their association with specific auto-antibody production.

Association of the polymorphisms of TRAF1 (rs10818488) and TNFAIP3 (rs2230926) with rheumatoid arthritis and systemic lupus erythematosus and their relationship to disease activity among Egyptian patients

Aim of the study

Recent studies demonstrated the association of tumor necrosis factor α-induced protein 3 (TNFAIP3) (rs2230926) and tumor necrosis factor receptor associated factor 1 (TRAF1) (rs10818488) with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) in different populations. We aimed at determining whether they confer susceptibility to SLE and RA in Egyptian population and if there is any relation to disease activity and auto-antibodies profile.

Material and methods

A case-control study involving 105 individuals with RA, 90 with SLE and 75 healthy controls was performed using TaqMan genotyping assay for two SNPs that showed the best evidence of association in the previous Caucasian studies.

Results

We detected significant differences in G allele frequency of TNFAIP3 (rs2230926) with SLE (p = 0.017^*) and RA (OR = 2.333; 95% CI: 1.103-4.935, p = 0.023^*) and association with RA disease activity (< 0.001). The A allele of TRAF1 was significantly increased in RA compared to controls(p = 0.049) and with RA activity (p = 0.001), while TRAF1 polymorphism did not exhibit any significant difference in the frequencies of genotypes or alleles in SLE and control (p = 0.280).

Conclusions

TNFAIP3 is a susceptibility gene to SLE and RA in the Egyptian population and is correlated to disease activity and the presence of autoantibodies while TRAF1 polymorphisms increase the risk of RA but not to SLE in Egyptian populations.

Association of juvenile idiopathic arthritis with PTPN22 rs2476601 is specific to females in a Greek population

BACKGROUND

Juvenile idiopathic arthritis (JIA) is an autoimmune disease characterized by persistent chronic arthritis. Disease risk is believed to be influenced by both genetic and environmental factors. It is well established that the PTPN22 single nucleotide polymorphism (SNP) rs2476601 is associated with JIA susceptibility. It was recently reported in an Australian study that this association is restricted to females and is not observed in males. A significant source of inconsistency amongst the literature on autoimmune disease susceptibility genes stems from an inability to replicate genetic findings across different racial or ethnic groups. We therefore attempted to generate further evidence of the female-specific association of rs2476601 in a homogeneous Greek population.

FINDINGS

We genotyped rs2476601 in 128 Caucasian JIA patients (70.3 % female) and 221 healthy controls (28.1 % female) from Northern Greece. Overall, PTPN22 was associated with increased risk of JIA in this Greek sample (OR = 2.3, 95 % CI 1.1 - 5.1, p = 0.038). Sex-stratified analyses showed that, once again, the risk association was restricted to females (Female: OR = 19.9, 95 % CI 1.2 - 342, p = 0.0016; Male: OR = 1.1, 95 % CI 0.3 - 3.1, p = 0.94) supporting the prior findings.

CONCLUSIONS

Our data demonstrates that this sex-specific pattern of association is broadly applicable to different populations, and provides further impetus to undertake mechanistic studies to understand the impact of sex on PTPN22 in JIA.

C1q rs292001 polymorphism and C1q antibodies in juvenile lupus and their relation to lupus nephritis

C1q deficiency is related strongly to systemic lupus erythematosus (SLE), but very few and inconsistent studies explored the single nucleotide polymorphisms of the C1q gene in relation to juvenile SLE (jSLE) and lupus nephritis (LN). The objective of this study was to analyse whether C1q rs 292001 polymorphism is associated with SLE and disease phenotype, especially nephritis, and to investigate the relation between this polymorphism and clinical data, treatment outcome, serum level of C1q protein and antibodies. Typing of C1q rs292001 polymorphism using restriction fragment length polymorphism and measuring serum levels of C1q protein and antibodies by enzyme-linked immunosorbent assay (ELISA) were performed for 130 children with SLE and 208 healthy controls. The A allele of C1q rs292001 was associated with jSLE and LN (P = 0·005 and 0·013, respectively) and the AA genotype was associated with jSLE (P = 0·036). Low serum levels of C1q protein were found in jSLE and LN (P < 0·001 and 0·009, respectively), and these levels were increased after treatment in patients with LN (P = 0·009) and active renal disease (P = 0·027). Higher titres of C1q antibodies were found in patients with LN (P = 0·015) and correlated negatively with C1q protein level (P < 0·001) and patient age (P = 0·04). The A allele and AA genotype of C1q rs292001 can be considered a susceptibility risk factor and the GG genotype could be considered protective for jSLE and LN in the studied cohort of Egyptian children. Decreased serum levels of C1q protein and increased titres of C1q antibodies may be involved in the pathogenesis of jSLE, especially LN.

C1q, antibodies and anti-C1q autoantibodies

The complement system has long been known for its role in combating infections. More recently the complement system is becoming increasingly appreciated for its role in processes that range from waste transport, immune tolerance and shaping of the adaptive immune response. Antibodies represent the humoral part of the adaptive immune response and the complement system interacts with antibodies in several ways. Activated complement fragments impact on the production of antibodies, the complement system gets activated by antibodies and complement proteins can be the target of (auto)antibodies. In this review, written to celebrate the contributions of Prof. Dr. M.R. Daha to the field of immunology and especially complement, we will focus on C1q and its various interactions with antibodies. We will specifically focus on the mechanisms by which C1q will interact with monomeric IgG versus polymerized IgG and fluid-phase IgM versus solid-phase IgM. In addition in this review we will discuss in detail how C1q itself is targeted by autoantibodies and how these autoantibodies are currently considered to play a role in human disease.

TRAF1/C5 rs10818488 polymorphism is not a genetic risk factor for acquired aplastic anemia in a Chinese population

The tumor necrosis factor receptor-associated factor 1/complement C5 (TRAF1/C5) genes have been suggested as two candidate genes for conferring susceptibility to autoimmunity and inflammation. The aim of the present study was to investigate the association of single nucleotide polymorphisms (SNP) of TRAF1/C5 genes with the risk for aplastic anemia (AA). In this case-control study, the genotyping of TRAF1/C5 rs10818488 polymorphism was detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The frequencies of AA, AG and GG genotypes, and A and G alleles were 21.9%, 52.4%, 25.7%, 48.1% and 51.9%, respectively, in AA patients. There was no significant differences in terms of genotype and allele distributions between AA patients and healthy controls (P=0.687 and 0.955, respectively). Similar results were found between the two groups when stratified by the disease severity including very severe AA (vSAA), SAA and non-SAA (NSAA). Our results indicated that TRAF1/C5 rs10818488 polymorphism might not contribute to susceptibility to AA in a Chinese population.

Association of rs172378 C1q gene cluster polymorphism with lupus nephritis in Bulgarian patients

Introduction

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease that can affect substantially any organ in the body. One of its most severe manifestations is lupus nephritis. Hereditary C1q deficiency is strongly related to SLE but there are very few and inconsistent studies exploring the single nucleotide polymorphisms (SNPs) of the C1q gene cluster in relation to the pathogenesis of SLE. In the present study we evaluated the possible association of gene variants in complement C1q gene cluster with susceptibility to lupus nephritis in a Bulgarian population, focusing on five previously associated with SLE SNPs in other populations.

Materials and methods

Thirty-eight patients with lupus nephritis and 185 healthy controls, all from Bulgaria, were genotyped for the five C1q SNPs, rs587585, rs292001, rs172378, rs294179 and rs631090, by quantitive real-time PCR methods. We also determined C1q serum levels of C1q and haemolytic activity of C1q in relation to C1q genotypes.

Results

Lupus nephritis patients and healthy controls had statistically similar frequencies of genotypes and alleles of rs587585, rs292001, rs294179 and rs631090 SNPs. Nevertheless, minor G allele in rs172378 was significantly overrepresented in lupus nephritis patients when compared with healthy controls (36% vs. 23%, odds ratio = 1.80, 95% confidence interval = 1.06–3.06, p = 0.029). The SNP rs292001 showed a trend towards lower serum C1q levels in healthy controls. Two SNPs – rs294179 and rs292001 – were in a linkage disequilibrium in patients and healthy controls with different power (healthy controls: r2 = 0.6526, D′ = 0.842; lupus nephritis patients: r2 = 0.491, D′ = 0.686). The haplotype C-A-A-T-T in the patient group was associated with lupus nephritis: 7.7% vs. 0.8%, odds ratio = 10.81, 95% confidence interval = 1.45–80.57, p = 0.002.

Conclusions

These results support the implication of the G allele in rs172378 as a risk factor for lupus nephritis in a homozygous status, at least for a Bulgarian population.

Role of interferon alpha in endothelial dysfunction: insights into endothelial nitric oxide synthase-related mechanisms

Systemic lupus erythematosus (SLE) is an autoimmune disease that is characterized by the production of autoantibodies against nuclear antigens such as double-stranded DNA. Lupus predominantly affects women (ratio, 9:1). Moreover, premenopausal women with SLE are 50 times more likely to have a myocardial infarction. Although specific risk factors for advanced cardiovascular complications have not been identified in this patient population, endothelial dysfunction is highly prevalent. Recent studies show that the type I interferon signature gene expression coincides with impaired brachial artery flow-mediated dilation and diminished endothelial progenitor cell circulation, both markers of impaired endothelial function. Although many factors promote the development of vascular endothelial dysfunction, all pathways converge on the diminished activity of endothelial nitric oxide synthase (eNOS) and loss of nitric oxide (NO) bioavailability. Studies examining the effects of type I interferons on eNOS and NO in SLE are missing. This literature review examines the current literature regarding the role of type I interferons in cardiovascular disease and its known effects on regulators of eNOS and NO bioavailability that are important for proper endothelial cell function.

Association of STAT4 rs7574865 with susceptibility to systemic lupus erythematosus in Iranian population

Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease with complex genetic inheritance that affecting different organs and systems. STAT4 has been newly identified as a susceptible gene in the development of SLE. According to recent studies, STAT4 has been associated with SLE in various populations. We investigated whether STAT4 single nucleotide polymorphisms (SNPs) were associated with susceptibility and clinical features of SLE in Iranian patients. The study group comprised 280 patients with SLE and 281 sex-, age-, and ethnicity-matched healthy controls of Iranian ancestry. Two SNPs (rs7574865 and rs7601754) were genotyped using the TaqMan MGB Allelic Discrimination method. Our results showed a significant association between rs7574865 T allele (odds ratio (OR) = 1.50, 95 % CI = 1.18-1.92, P = 0.002) and susceptibility to SLE. The rs7574865TT genotype (P = 0.02, OR = 1.94, 95 % CI = 1.74-3.19) and GT genotype (P = 0.008, OR = 1.71, 95 % CI = 1.19-2.45) showed a significant association with the risk of SLE in the Iranian population. We concluded that STAT4 rs7574865 is associated with SLE susceptibility in the Iranian population and this SNP might be a factor in the pathogenesis of SLE. However, further studies are required to investigate the mechanism by which polymorphisms in this gene lead to SLE.

Sequence polymorphism and expression variability of Crassostrea gigas immune related genes discriminate two oyster lines contrasted in term of resistance to summer mortalities

Summer mortalities of Crassostreagigas are a major concern in oyster aquaculture. They are the result of a complex interaction between the host, pathogens and environmental factors. Oyster genetics have been identified as an essential determinant of oyster susceptibility to summer mortalities. As the capability of oysters to circumvent diseases depends in part on their immune defenses, we aimed to analyze the gene expression and sequence polymorphism of 42 immune related genes in two oyster lines selected for their “High” (H) and “Low” (L) survival to summer mortalities. Results showed that the variability of gene expression and the sequence polymorphism acting on particular genes could enable the discrimination between H and L oyster lines. Besides, a higher sequence polymorphism was observed on the L line affecting 11 of the 42 analyzed genes. By analyzing gene expression, sequence polymorphism and gene copy number of two antimicrobial peptide families (Cg-Defs and Cg-Prp), and an antimicrobial protein (Cg-BPI) on individual oysters, we showed that gene expression and/or sequence polymorphism could also discriminate H and L oyster lines. Finally, we observed a positive correlation between the gene expression and the gene copy number of antimicrobials and that sequence polymorphism could be encoded in the genome. Overall, this study gives new insights in the relationship between oyster immunity and divergent phenotypes, and discusses the potential implication of antimicrobial diversity in oyster survival to summer mortalities.

CTLA-4 polymorphisms and systemic lupus erythematosus (SLE): a meta-analysis

The aim of this study was to summarize results on the association of cytotoxic T-lymphocyte antigen-4 (CTLA-4) promoter exon-1 +49 and 1722T/C polymorphism with systemic lupus erythematosus (SLE) susceptibility by using the meta-analysis. We searched all the publications about the association between CTLA-4) promoter exon-1 +49 and 1722T/C polymorphism and SLE from PubMed, Elsevier Science Direct, Chinese Biomedical Literature Database (CBM), Chinese National Knowledge Infrastructure (CNKI), and Wanfang (Chinese). Previous CTLA-4 association studies with SLE, however, have produced inconsistent results. We have performed a meta-analysis to better assess the purported associations. A total of 17 independent studies (to June 2012) testing association between one or more CTLA-4 polymorphisms and SLE were used in this analysis. We have compared allele and genotype frequencies at two polymorphic sites found in exon-1 (at +49) and the promoter region (at -1722). The data demonstrate that the exon-1 +49 polymorphism is associated with SLE susceptibility in Asian population. The overall risk, measured by odds ratio (OR), stratification by ethnicity indicates the exon-1 +49 GG+GA genotype is associated with SLE, at least in Asians (OR = 0.85, 95 % CI = 0.73-0.99, P = 0.04 for GG+GA vs. AA; OR = 0.85, 95 % CI = 0.72-1.00, P = 0.05 for AG vs. AA). Similar trends are found in allele-specific risk estimates and disease association. Overall, there was significant association between the 1722T/C polymorphism and overall SLE risks (OR = 0.78, 95 % CI = 0.63-0.97, P = 0.04 for GG+GA vs. AA, OR = 0.87, 95 % CI = 0.76-0.99, P = 0.04 for G vs. A) in Asian population.In summary, this meta-analysis demonstrates that the CTLA-4 promoter +49A/G and promoter -1722C/T polymorphism may confer susceptibility to SLE, especially in Asian-derived population.

Genetic variants in the region of the C1q genes are associated with rheumatoid arthritis

Rodent models for arthritis implicate a role for complement in disease development and progression. In humans, complement deposition has been observed in inflamed synovia of rheumatoid arthritis (RA) patients. In this study we analysed whether genetic variants of complement component C1q predispose to RA. We genotyped single nucleotide polymorphisms (SNPs) in and around the C1q genes, C1qA, C1qB and C1qC, in a Dutch set of 845 RA cases and 1046 controls. Replication was sought in a sample set from North America (868 cases/1193 controls), and a meta-analysis was performed in a combined samples set of 8000 cases and 23 262 controls of European descent. We determined C1q serum levels in relation to C1q genotypes. In the discovery phase, five of the 13 SNPs tested in the C1q genes showed a significant association with RA. Additional analysis of the genomic area around the C1q genes revealed that the strongest associating SNPs were confined to the C1q locus. Within the C1q locus we observed no additional signal independent of the strongest associating SNP, rs292001 [odds ratio (OR) = 0·72 (0·58-0·88), P = 0·0006]. The variants of this SNP were associated with different C1q serum levels in healthy controls (P = 0·006). Interestingly, this SNP was also associated significantly in genome-wide association studies (GWAS) from the North American Rheumatoid Arthritis Consortium study, confirming the association with RA [OR = 0·83 (0·69-1·00), P = 0·043]. Combined analysis, including integrated data from six GWAS studies, provides support for the genetic association. Genetic variants in C1q are correlated with C1q levels and may be a risk for the development of RA.

Association of genetic polymorphisms in CD40 with susceptibility to SLE in the Korean population

OBJECTIVE

The aim of this study was to examine the association of CD40 polymorphisms with the risk of SLE in the Korean population.

METHODS

A total of 601 Korean SLE patients and 984 healthy controls were enrolled. We selected seven CD40 gene SNPs based on previous results of CD40 gene sequencing in the Korean population. Statistical analysis was carried out by logistic regression, controlling for age and sex as covariates. Odds ratios (ORs) and P-values in co-dominant, dominant and recessive models were also calculated.

RESULTS

SNP rs3765456 showed significant association with risk of SLE (OR = 1.34, P = 0.007, Pcorr = 0.03) in the dominant model. SNPs rs1883832 and rs4810485, and haplotype 2 (GTTCTAA) were also associated with the risk of SLE in the dominant model, but statistical significance disappeared after correction for multiple testing. Haplotype 2 had a protective effect on LN (OR = 0.47, P = 0.01, Pcorr = 0.05) in the recessive model while rs73115010, rs6074028 and haplotype 3 (ACGTCGG) resulted in increased risk of arthritis in the recessive model (OR = 2.87, 2.76 and 2.46, P = 0.002, 0.004 and 0.01, Pcorr = 0.009, 0.02 and 0.05, respectively).

CONCLUSION

CD40 gene polymorphisms are possible risk factors for SLE development, especially rs3765456 in the dominant model. CD40 polymorphisms are also associated with SLE clinical manifestation, mainly nephritis and arthritis. Further replication with larger numbers, and populations of different ethnicities, are needed to confirm our findings.

TRAF1 gene polymorphism correlates with the titre of Gp210 antibody in patients with primary biliary cirrhosis

Background. Polymorphisms of TRAF1 (Tumor necrosis factor receptor-associated factor 1) are associated with rheumatoid arthritis (RA). Whether TRAF1 polymorphisms confer increased risk for primary biliary cirrhosis (PBC), an autoimmune liver disease which can co-exist with RA, is unknown. Aim of the Study. To assess the frequency of the RA-conferring susceptibility TRAF1 polymorphisms rs3761847 and rs2900180 in a cohort of PBC patients. The association of TRAF1 polymorphisms with clinical features and autoantibody markers was also analyzed. Methods. We studied 179 PBC patients and 300 controls. Samples were genotyped for TRAF1 gene polymorphisms by real-time PCR. Autoantibodies were tested by ELISA. Results. The frequency of rs3761847 and rs2900180 polymorphisms did not differ between patients and controls. Laboratory or clinical features were not associated with specific polymorphisms. Gp210 autoantibody titres were conspicuously higher among GG homozygotes of rs3761847 as compared with AA homozygotes (P = 0.02). In contrast, antichromatin titers were higher in AA compared to GG rs3761847 homozygotes (P = 0.04). Rheumatoid factor IgG titres were significantly higher in rs2900180 TT homozygotes than CC homozygotes (P = 0.02). Conclusions. TRAF1 polymorphisms occur with the similar frequency in PBC patients and in the general population, but their presence is probably involved in the regulation of specific PBC-related autoantibodies.

Genetics of SLE: functional relevance for monocytes/macrophages in disease

Genetic studies in the last 5 years have greatly facilitated our understanding of how the dysregulation of diverse components of the innate immune system contributes to pathophysiology of SLE. A role for macrophages in the pathogenesis of SLE was first proposed as early as the 1980s following the discovery that SLE macrophages were defective in their ability to clear apoptotic cell debris, thus prolonging exposure of potential autoantigens to the adaptive immune response. More recently, there is an emerging appreciation of the contribution both monocytes and macrophages play in orchestrating immune responses with perturbations in their activation or regulation leading to immune dysregulation. This paper will focus on understanding the relevance of genes identified as being associated with innate immune function of monocytes and macrophages and development of SLE, particularly with respect to their role in (1) immune complex (IC) recognition and clearance, (2) nucleic acid recognition via toll-like receptors (TLRs) and downstream signalling, and (3) interferon signalling. Particular attention will be paid to the functional consequences these genetic associations have for disease susceptibility or pathogenesis.

Associations between TNFSF4 and TRAF1-C5 gene polymorphisms and systemic lupus erythematosus: a meta-analysis

OBJECTIVE

The aim of this study was to determine whether tumor necrosis factor superfamily 4 (TNFSF4) and TNF receptor-associated factor 1-complement 5 (TRAF1-C5) polymorphisms confer susceptibility to systemic lupus erythematosus (SLE).

METHODS

The authors conducted meta-analyses on associations between polymorphisms of the TNFSF4 (rs2205960, rs1234315, rs10489265) and TRAF1-C5 (rs10818488, rs3761847) genes and SLE susceptibility, using fixed and random effects models.

RESULTS

A total of 21 comparative studies were included in this meta-analysis; meta-analysis showed an association between the minor allele of rs2205960 of TNFSF4 and SLE in all study subjects (odds ratio [OR]=1.356, 95% confidence interval [CI]=1.275-1.442, p<1.0×10(-9)). Meta-analysis revealed an association between the minor alleles of rs1234315 and rs10489265 of TNFSF4 and SLE in Asians (OR=1.366, 95% CI=1.295-1.440, p<1.0×10(-9); OR=1.463, 95% CI=1.208-1.771, p=9.7×10(-5)). The minor allele of rs10818488 of TRAF1-C5 was found to be significantly associated with SLE in Europeans (OR=1.210, 95% CI=1.115-1.313, p=5.0×10(-6)). The association p-values remained significant after multiple corrections.

CONCLUSIONS

This meta-analysis confirms that TNFSF4 polymorphisms are associated with susceptibility to SLE in Asians and Europeans. An association was found between the rs10818488 polymorphism of TRAF1-C5 and susceptibility to SLE in Europeans.

Contribution of STAT4 gene single-nucleotide polymorphism to systemic lupus erythematosus in the Polish population

The STAT4 has been found to be a susceptible gene in the development of systemic lupus erythematosus (SLE) in various populations. There are evident population differences in the context of clinical manifestations of SLE, therefore we investigated the prevalence of the STAT4 G > C (rs7582694) polymorphism in patients with SLE (n = 253) and controls (n = 521) in a sample of the Polish population. We found that patients with the STAT4 C/G and CC genotypes exhibited a 1.583-fold increased risk of SLE incidence (95 % CI = 1.168–2.145, p = 0.003), with OR for the C/C versus C/G and G/G genotypes was 1.967 (95 % CI = 1.152–3.358, p = 0.0119). The OR for the STAT4 C allele frequency showed a 1.539-fold increased risk of SLE (95 % CI = 1.209–1.959, p = 0.0004). We also observed an increased frequency of STAT4 C/C and C/G genotypes in SLE patients with renal symptoms OR = 2.259 (1.365–3.738, p = 0.0014), (p_corr = 0.0238) and in SLE patients with neurologic manifestations OR = 2.867 (1.467–5.604, p = 0.0016), (p_corr = 0.0272). Moreover, we found a contribution of STAT4 C/C and C/G genotypes to the presence of the anti-snRNP Ab OR = 3.237 (1.667–6.288, p = 0.0003), (p_corr = 0.0051) and the presence of the anti-Scl-70 Ab OR = 2.665 (1.380–5.147, p = 0.0028), (p_corr = 0.0476). Our studies confirmed an association of the STAT4 C (rs7582694) variant with the development of SLE and occurrence of some clinical manifestations of the disease.