CTLA-4 gene polymorphism of exon 1(+49 A/G) in Turkish systemic lupus erythematosus patients

Cytotoxic T-lymphocyte associated protein 4 (CTLA4) polymorphisms are linked to systemic lupus erythematosus: an updated meta-analysis

Cytotoxic T-lymphocyte associated protein 4 (CTLA-4) molecule controls T cell immune response. Functional single nucleotide polymorphisms (SNPs) in the CTLA-4 gene have been associated with several autoimmune diseases, including systemic lupus erythematosus (SLE).  However, the genetic association of the CTLA-4 variants with vulnerability to SLE remained contradictory. We have conducted a current meta-analysis by combining the findings of prior published articles in order to make a conclusive statement. Various literature databases were screened with appropriate keywords to obtain relevant articles, and eligible reports were obtained using well-defined inclusion and exclusion criteria. Meta-analysis was performed by Comprehensive Meta-analysis V 3.3, and various statistical parameters such as odds ratio, 95% confidence interval, and probability values were computed. A total of 3847 SLE patients and 5278 healthy controls were considered in the present meta-analysis from 26 individual reports. A significant association of CTLA-4 +49 A/G (G vs. A: p=0.03, OR=1.47) and -1722 T/C (p=0.02, OR=0.87) polymorphisms were observed with susceptibility and resistance against the development of SLE, respectively. However, the other two SNPs in the CTLA-4 gene (-318 C/T and -1661 A/G) failed to establish a connection. Interestingly, subgroup analysis revealed an association of CTLA-4 +49 A/G with a predisposition to SLE only in the Asian population (G vs. A: p=0.04, OR=1.26, GG vs. AA: p=0.02, OR=1.84, AG vs AA: p=0.01, OR=1.44, GG+AG vs AA: p=0.01, OR=1.52) and not in Caucasians. The current meta-analysis suggests a significant CTLA-4 +49 A/G variant association with susceptibility to SLE development in overall and Asian populations. In contrast, the other variant, -1722 T/C, is linked with protection against SLE. However, further case-control studies in diverse ethnic populations are requisite.

Association of CTLA-4 (+49 A/G) polymorphism with susceptibility to autoimmune diseases: A meta-analysis with trial sequential analysis

OBJECTIVES

In recent years, more and more studies have been focusing on the association between Cytotoxic T lymphocyte antigen-4 (CTLA-4) (+49 A/G) gene polymorphism and autoimmune diseases. However, the results of previous studies are still controversial. The meta-analysis is aiming at determining the association in CTLA-4 (+49 A/G) gene rs231775 polymorphism and ankylosing spondylitis (AS), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE).

METHODS

We searched PubMed, Web of Science, Chinese National Knowledge Infrastructure (CNKI) and Chinese Biomedical Database (CBM) up to November 2020, use random or fixed-effect models to perform meta-analysis to compare alleles and other genetic models, including homozygous, heterozygous, recessive and dominant models. The odds ratio (OR) with a 95% confidence interval (95% CI) was used to assess the correlation between CTLA-4 (+49 A/G) gene polymorphism and the genetic affectability of AS, RA, and SLE. Meanwhile, we used sequential trial analysis (TSA) to analyze the reliability of the results. Finally, we searched the relevant data of genome-wide association studies (GWAS) to further verify the accuracy of the experimental results.

RESULTS

47 studies with 11,893 cases and 12,032 healthy controls were included. The rs231775 G allele was relevant to high risk of autoimmune disease over all people (P < 0.05). The G allele of rs231775 was significantly related to RA susceptibility (P < 0.05), but not with AS or SLE. Subgroup analysis by ethnicity indicated that rs231775 G allele was closely related to RA in Caucasian populations and Mongolian populations (P < 0.05). A strong connection within rs231775 G allele and AS affectability was uncovered in Caucasian populations (P < 0.05). The analysis of the TSA shows that the meta-analysis can draw the conclusion.

CONCLUSION

CTLA-4 (+49 A/G) gene rs231775 G allele increases the risk of autoimmune diseases in Caucasian populations. And it also increases the risk of RA in Caucasian and Mongolian populations. More sample size and more elaborately designed studies are needed to elucidate the relationship in CTLA-4 (+49 A/G) gene rs231775 G allele and autoimmune diseases, especially AS, SLE.

Association of AIRE (rs2075876), but not CTLA4 (rs231775) polymorphisms with systemic lupus erythematosus

BACKGROUND

The AIRE (rs2075876) and CTLA4 (rs231775) variants have a crucial function in controlling the negative selection and suppression of T lymphocytes. Numerous reports studied the association of AIRE and CTLA4 variants with different autoimmune disorders, but with inconclusive conclusions. The main purpose of this work is to evaluate the association of these two variants with SLE susceptibility among Egyptian patients.

SUBJECTS AND METHODS

A total of 247 participants (100 SLE patients and 147 healthy controls) were enrolled in this case-controlled study. The genomic DNA of these dual variants was genotyped using the TaqMan genotyping method.

RESULTS

The AIRE (rs2075876) variant conferred protection against developing SLE disease under allelic [A allele vs. G allele; OR = 0.16, 95%CI = 0.09-0.28], and dominant [GA + AA vs. GG; OR = 0.14, 95%CI = 0.05-0.34] models. Moreover, patients with AIRE rs2075876 (A/A) genotype revealed a statistically significant with lower levels of complement 3 (p-value = 0.007). Nonetheless, the CTLA4 (rs231775) variant was not associated with increased risk of SLE under all genetic association models (p-value > 0.05). However, CTLA4 rs231775 (G/G) genotype observed significant difference with recurrent infection and hematuria.

CONCLUSIONS

Our findings indicated that the AIRE (rs2075876) variant conferred protection against developing SLE disease, but not the CTLA4 (rs231775) variant.

The potential for immune checkpoint modulators in cerebrovascular injury and inflammation

Introduction: Neuroinflammation has been linked to poor neurologic and functional outcomes in many cerebrovascular disorders. Immune checkpoints are upregulated in the setting of traumatic brain injury, intracerebral hemorrhage, ischemic stroke, central nervous systems vasculitis, and post-hemorrhagic vasospasm, and are potential mediators of pathologic inflammation. Burgeoning evidence suggests that immune checkpoint modulation is a promising treatment strategy to decrease immune cell recruitment, cytokine secretion, brain edema, and neurodegeneration.Areas covered: This review discusses the role of immune checkpoints in neuroinflammation, and the potential for therapeutic immune checkpoint modulation in inflammatory cerebrovascular disorders. A search of Pubmed and clinicaltrials.gov was performed to find relevant literature published within the last 50 years.Expert opinion: The clinical success of immune-activating checkpoint modulators in human cancers has shown the immense clinical potential of checkpoint-based immunotherapy. Given that checkpoint blockade can also precipitate a pathologic pro-inflammatory or autoimmune response, it is plausible that these pathways may also be targeted to quell aberrant inflammation. A limited but growing number of studies suggest that immune checkpoints play a critical role in regulating the immune response in the central nervous system in a variety of contexts, and that immune-deactivating checkpoint modulators may be a promising treatment strategy for acute and chronic neuroinflammation in cerebrovascular disorders.

Role of CTLA4 A49G polymorphism in systemic lupus erythematosus and its geographical distribution

CTLA-4 (cytotoxic T-lymphocyte-associated protein-4) or CD152 is an inhibitory receptor expressed constitutively on CD4+ CD25+ T regulatory lymphocytes and transiently on activated CD4+ and CD8+ T lymphocytes. Its inhibitory function promotes long-lived anergy in immune cells and prevents autoimmunity. Therefore, it plays a crucial role in T cell-mediated autoimmunity, and thus in susceptibility to autoimmune diseases, including systemic lupus erythematosus (SLE). It is encoded by CTLA4 gene in humans. AtoG polymorphism at position +49 of CTLA4 gene is the only polymorphism which changes amino acid sequence from alanine to threonine in the leader sequence, which may affect the function of CTLA-4. Association of CTLA4 polymorphisms with SLE has been investigated in several reports in different ethnic populations from different countries, which have shown highly inconsistent findings. In this review, we have compiled previous studies which have reported the association of CTLA4 A49G polymorphism in SLE and its geographical distribution.

Association of CTLA4 exon-1 polymorphism with the tumor necrosis factor-α in the risk of systemic lupus erythematosus among South Indians

Cytotoxic T lymphocyte associated-antigen (CTLA4) is a potential negative regulatory molecule of T-cells and associated with several autoimmune diseases. Several reports from different ethnic groups showed that the polymorphisms of the CTLA4 gene have been associated with autoimmune diseases including SLE. Therefore, we aimed to investigate the +49 A/G polymorphism in South Indian SLE patients and its association with disease aetiology and serological markers. A total of 534 samples were genotyped for the +49 A/G polymorphism in exon 1 of the CTLA-4 gene through PCR-RFLP method. We found significant association of genotype and allele frequencies with +49 A/G polymorphism in SLE patients. The frequency of the +49 A/G polymorphism rs231775 'GG' genotype was significantly higher in patients with SLE (12.32%) than those in healthy control subjects (4.6%) (OR: 1.797; 95% CI 1.264-2.554; p=0.001). The frequency of mutant allele 'G' also found to be significantly higher in cases (36.01%) than controls (24.92%) (OR: 1.695, 95% CI: 1.298-2.214, p<0.001). We observed significant increase in serum TNF-α, interferon-α, IL-10 and IL-12 in SLE cases compared to controls. We also found a significant association of serum TNF-α, interferon-α, IL-10 and IL-12 with SLE phenotypes. In addition there was a significant increase in serum TNF-α level in "GG" genotype SLE subjects suggesting that it might play a major role in the advancement of SLE disease.

The CTLA4 +49 A/G (rs231775) polymorphism influences susceptibility to SLE in South Indian Tamils

Systemic lupus erythematosus (SLE) is a prototype autoimmune disease with complex etiology. Loss of immune tolerance and synthesis of autoantibodies against nuclear antigens contributes to the disease. Genetic aberrations disrupting the functions of immune regulatory receptors may facilitate the development of autoimmune diseases. Cytotoxic T-lymphocyte antigen 4 (CTLA4) is an inhibitory receptor for T cells and this study was carried out to analyze the influence of CTLA4 +49A/G (rs231775) polymorphism on susceptibility to SLE in ethnic Tamils. Three hundred SLE patients and 460 age and sex similar, ethnicity-matched controls were screened for the +49 A/G polymorphism by real time polymerase chain reaction (PCR). The wild allele (A) frequency in controls and cases was 63% and 47%, respectively. The presence of heterozygous (AG) and homozygous mutant (GG) genotype was associated with a significant risk to develop SLE (P = 0.0001, OR-2.29, 95% confidence interval (CI), 1.6-3.3) and (P = 0.0001, OR-4.3, 95% CI, 2.8-6.99). The frequency of mutant allele (G) in patients was also significantly associated with SLE (P = 0.0001, OR-1.9, 95% CI, 1.5-2.4). However, this polymorphism did not influence the clinical or serological phenotypes in our study. Therefore the CTLA4 +49 A/G polymorphism is a potential genetic risk factor for lupus susceptibility in South Indian Tamils, but does not appear to influence either the clinical or serological phenotype.

Systemic Lupus Erythematosus: Old and New Susceptibility Genes versus Clinical Manifestations

Systemic Lupus Erythematosus (SLE) is one of the most relevant world-wide autoimmune disorders. The formation of autoantibodies and the deposition of antibody-containing immune complexes in blood vessels throughout the body is the main pathogenic mechanism of SLE leading to heterogeneous clinical manifestations and target tissue damage. The complexity of etiology and pathogenesis in SLE, enclosing genetic and environmental factors, apparently is one of the greatest challenges for both researchers and clinicians. Strong indications for a genetic background in SLE come from studies in families as well as in monozygotic and dizygotic twins, discovering several SLE-associated loci and genes (e.g. IRF5, PTPN22, CTLA4, STAT4 and BANK1). As SLE has a complex genetic background, none of these genes is likely to be entirely responsible for triggering autoimmune response in SLE even if they disclosure a potentially novel molecular mechanisms in the pathogenesis' disease. The clinical manifestations and disease severity varies greatly among patients, thus several studies try to associate clinical heterogeneity and prognosis with specific genetic polymorphisms in SLE associated genes. The continue effort to describe new predisposing or modulating genes in SLE is justified by the limited knowledge about the pathogenesis, assorted clinical manifestation and the possible prevention strategies. In this review we describe newly discovered, as well as the most studied genes associated to SLE susceptibility, and relate them to clinical manifestations of the disease.

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.

CTLA-4 polymorphisms and systemic lupus erythematosus: a comprehensive meta-analysis

OBJECTIVE

The aim of this study was to determine whether the SNPs +49A/G and CT60A/G of the CTLA-4 gene are associated with susceptibility to systemic lupus erythematosus (SLE).

METHODS

The comprehensive meta-analysis for +49A/G included 1753 cases and 2279 controls, and for CT60A/G included 676 cases and 576 controls. Allelic and genotypic comparisons between cases and controls were evaluated. For +49A/G, we also subdivided it by population.

RESULTS

For +49A/G, statistically significant differences were not noted (fixed: odds ratio [OR]: 1.033, 95% confidence interval [95% CI]: 0.937-1.139; random: OR: 1.038, 95% CI: 0.907-1.188). When subdivided into Asia and Europe subgroups, it showed that this polymorphism is still not significantly associated with SLE [for Asia: (fixed: OR: 1.069, 95% CI: 0.932-1.227; random: OR: 1.055, 95% CI: 0.846-1.316); for Europe: (fixed: OR: 0.988, 95% CI: 0.842-1.161; random: OR: 1.015, 95% CI: 0.805-1.281)]. And CT60A/G also did not demonstrate significant differences with SLE (fixed: OR: 1.099, 95% CI: 0.922-1.31; random: OR: 0.918, 95% CI: 0.581-1.448).

CONCLUSION

The results suggest that the CLTA-4 gene was not associated with SLE. Further investigations are required to identify whether other at-risk polymorphisms within CTLA-4 confer a risk of SLE and to clarify the role of the CTLA-4 gene.

Association of CTLA4 gene polymorphisms with susceptibility and pathology correlation to pulmonary tuberculosis in Southern Han Chinese

The cytotoxic T lymphocyte antigen-4 (CTLA4) gene is a key negative regulator of the T lymphocyte immune response. It has been found that CTLA4 +49A>G (rs231775), +6230G>A (rs3087243), and 11430G>A (rs11571319) polymorphisms are associated with susceptibility to many autoimmune diseases, and can down-regulate the inhibition of cellular immune response of CTLA4. Three SNPs in CTLA4 were genotyped by using the PCR and DNA sequencing methods in order to reveal the susceptibility and pathology correlation to pulmonary tuberculosis in Southern Han Chinese. We found that the frequency of CTLA4 +49AG genotype in the pulmonary tuberculosis patients (38.42%) was significantly lower than that of the healthy controls (49.77%), (P(cor)=0.038, OR 0.653, 95% CI 0.436-0.978). But, no associations were found between the other 2 SNPs (+6230G>A, 11430G>A) and tuberculosis (P>0.05). Haplotype analysis showed that the frequency of haplotype AGG in the healthy controls group (6.9%) was significantly higher than the pulmonary tuberculosis patients group (1.4%), (global P=0.005, P(cor)=0.0002, OR 0.183, 95% CI 0.072-0.468). In addition, haplotype GGA was found to be significantly related to tuberculosis with double lung lesion rather than single lung lesion (P(cor)=0.042). This study is the first to report that genetic variants in the CTLA4 gene can be associated with pulmonary tuberculosis in Southern Han Chinese, and CTLA4 +49AG genotype as well as haplotype AGG may reduce the risk of being infected with pulmonary tuberculosis. The GGA haplotype was related to tuberculosis with double lung lesion, which provides a new experimental basis to clarify the pathogenesis of pulmonary tuberculosis.

CTLA-4 gene polymorphism and the risk of systemic lupus erythematosus in the Chinese population

Several variants of CTLA-4 have been reported to be associated with susceptibility systemic lupus erythematosus (SLE); however, findings have been inconsistent across different populations. Using a case-control study design, we have investigated the role of CTLA-4 polymorphism at positions −1661 and −1722 on SLE susceptibility in our Chinese SLE population in central China's Hubei province. Samples were collected from 148 SLE patients and 170 healthy controls. Polymerase chain reaction restriction fragments length polymorphism (PCR-RFLP) was used to analyze the genotypes of the two sites. Statistically significant difference was observed in genotypes for −1722, but not for −1661. The frequency of the T allele on the −1722 SNP was significantly increased in SLE patients: 57.8% versus 40.6% in controls (P < 0.001, OR = 2.002). While the detected C allele frequency in the controls was significantly elevated in comparison to that in the SLE patients (59.4% versus 42.2%). On the contrary, no association was found between SLE and CTLA-4 polymorphism at position −1661.