The C55A Single Nucleotide Polymorphism in CTLA-4 Gene, a New Possible Biomarker in Thyroid Autoimmune Pathology Such as Hashimoto's Thyroiditis.

Hashimoto's thyroiditis (HT) is a chronic autoimmune disorder characterized by the production of autoantibodies against the thyroid gland. Different studies have shown that several genes may be associated with HT, which explains why patients often have family members with thyroiditis or other autoimmune diseases. The aim of this case-control study was to evaluate the correlation between polymorphisms at the level of exon 1 from the CTLA-4 gene and the susceptibility to developing HT. In this study, we found that there is no statistically significant association between the polymorphism rs231775 (A22G in exon 1) of the CTLA-4 gene and a genetic predisposition to HT. In contrast, a strong association was discovered for the first time between C55A in exon 1 of the CTLA-4 gene and HT. Our findings suggest that there is a genetic relationship between the CTLA-4 (+55A/C) genotype and the seropositivity against thyroid autoantigens, such as anti-thyroid peroxidase (ATPO) and anti-thyroglobulin antibodies (ATG).

Stress-induced immunosuppression affecting immune response to Newcastle disease virus vaccine through "miR-155-CTLA-4" pathway in chickens.

MiR-155 and CTLA-4 are important factors involved in the regulation of immune function. However, there is no report about their involvement in function regulation of stress-induced immunosuppression affecting immune response. In this study, the chicken model of stress-induced immunosuppression affecting immune response (simulation with dexamethasone and immunization with Newcastle disease virus (NDV) attenuated vaccine) was established, then the expression characteristics of miR-155 and CTLA-4 gene were analyzed at several key time points during the processes of stress-induced immunosuppression affecting NDV vaccine immune response at serum and tissue levels. The results showed that miR-155 and CTLA-4 were the key factors involved in stress-induced immunosuppression and NDV immune response, whose functions involved in the regulation of immune function were different in different tissues and time points, and 2 day post immunization (dpi), 5dpi and 21dpi were the possible key regulatory time points. CTLA-4, the target gene of miR-155, had significant game regulation relationships between them in various tissues, such as bursa of Fabricius, thymus and liver, indicating that miR-155-CTLA-4 pathway was one of the main mechanisms of their involvement in the regulations of stress-induced immunosuppression affecting NDV immune response. This study can lay the foundation for in-depth exploration of miR-155-CTLA-4 pathway involved in the regulation of immune function.

Association of cytotoxic T-lymphocyte-associated protein 4 polymorphisms with recurrent pregnancy loss: A case-control study.

Background: A large proportion of cases of recurrent pregnancy loss (RPL) are associated with immunological factors. Objective: This study investigated the association between single nucleotide polymorphisms of cytotoxic T-lymphocyte-associated protein (CTLA)-4 gene in women with a history of RPL compared to healthy women. Materials and Methods: A case-control study was performed on 2 groups consisting of 120 healthy women with no history of abortion and at least one delivery (control) and 120 women with a history of 2 or more primary RPLs (case). In addition, 5 mL of peripheral blood sample was taken from all subjects. The frequencies of CTLA-4 rs3087243 and rs231775 polymorphisms were assayed by restriction fragment length polymorphism polymerase chain reaction and rs5742909 using the high-resolution melting real-time polymerase chain reaction method. Results: The mean age of the women in the control and RPL groups were 30.03 ± 4.23 (range 21-37), and 28.64 ± 3.61 yr (range 20-35), respectively. Pregnancy loss numbers ranged between 2-6 in women with a history of RPL, and between 1 and 4 in the successful pregnancy group. Statistical analysis showed a significant difference between the genotypes of GG and AG in the 2 groups in rs3087243 polymorphism (OR 1.00 for GG genotype and OR 2.87 for AG genotype, p = 0.0043). No significant difference was observed in the genotype frequencies of rs231775 and rs5742909 polymorphisms, of the 2 groups (p = 0.37, and p = 0.095), respectively. Conclusion: Our findings indicated that CTLA-4 polymorphism, rs3087243, might be associated with a risk of RPL in Iranian women.

Association between the CTLA4 +49A/G (rs231775) and CT60 (rs3087243) gene variants with vitiligo: study on a Mexican population

Abstract Background: Vitiligo is characterized by an autoimmune response targeting melanocytes, thus resulting in skin depigmentation. There are several genetic components involved in the development of vitiligo, of which various gene polymorphisms are currently considered as risk factors. For example, the CTLA4 (T-lymphocyte antigen 4) +49A/G (rs231775) and CT60 (rs3087243) gene variants have been associated with a predisposition for autoimmune diseases in different populations; however, their involvement in the development of vitiligo remains controversial. Objective: We evaluated the association between vitiligo and the CTLA4 +49A/G (rs231775) and CT60 (rs3087243) gene variants in a Mexican population. Methods: A total of 116 vitiligo patients and 117 control subjects from northeast Mexico were included in the study and analyzed through PCR-RFLP to determine whether there is an association between vitiligo and CTLA4 +49A/G (rs231775) and CT60 (rs3087243) gene variants. Results: No statistical difference was observed for both gene polymorphisms between vitiligo patients and controls (p > 0.05). Otherwise, vitiligo activity, family history of vitiligo, personal history of autoimmune diseases, or sex did not show any difference (p > 0.05). Conclusion: As suggested by the analysis of a northeastern Mexican population, the CTLA4 +49A/G (rs231775) and CT60 (rs3087243) gene variants do not constitute a risk factor in the development of vitiligo.

Association between the CTLA4 +49A/G (rs231775) and CT60 (rs3087243) gene variants with vitiligo: study on a Mexican population.

BACKGROUND: Vitiligo is characterized by an autoimmune response targeting melanocytes, thus resulting in skin depigmentation. There are several genetic components involved in the development of vitiligo, of which various gene polymorphisms are currently considered as risk factors. For example, the CTLA4 (T-lymphocyte antigen 4) +49A/G (rs231775) and CT60 (rs3087243) gene variants have been associated with a predisposition for autoimmune diseases in different populations; however, their involvement in the development of vitiligo remains controversial. OBJECTIVE: We evaluated the association between vitiligo and the CTLA4 +49A/G (rs231775) and CT60 (rs3087243) gene variants in a Mexican population. METHODS: A total of 116 vitiligo patients and 117 control subjects from northeast Mexico were included in the study and analyzed through PCR-RFLP to determine whether there is an association between vitiligo and CTLA4 +49A/G (rs231775) and CT60 (rs3087243) gene variants. RESULTS: No statistical difference was observed for both gene polymorphisms between vitiligo patients and controls (p > 0.05). Otherwise, vitiligo activity, family history of vitiligo, personal history of autoimmune diseases, or sex did not show any difference (p > 0.05). CONCLUSION: As suggested by the analysis of a northeastern Mexican population, the CTLA4 +49A/G (rs231775) and CT60 (rs3087243) gene variants do not constitute a risk factor in the development of vitiligo.

Influence of cytotoxic T lymphocyte antigen 4 genetic variants on acute rejection in kidney transplant patients: precision medicine perspective.

Background: The most effective and common treatment for end-stage renal disease is kidney transplantation.The personalized approach to kidney transplantation, which utilizes precision medicine principles, determines distinctive genomics characteristics of candidates/recipients that must be taken into account. Cytotoxic T lymphocyte associated protein 4 (CTLA4) may be a suitable candidate gene for studying allograft rejection. The aim of this study was to understand whether we can consider two common variants of the CTLA4 gene as a risk factor of transplant rejection in a group of Iranian population. Methods: Totally, 169 kidney transplant recipients, including acute rejections (N=39) and non-rejection (N=130) groups who underwent transplantation were included in this study. The genotyping of rs5742909 (-318C/T) and rs231775 (+49A/G) variants of the CTLA4 gene were performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Results: The AG genotype frequency of rs231775 variant was the same in both patients with and without a history of rejection while, none of those groups had homozygote genotype. In rs5742909, both CT and TT frequencies of patients with rejected transplant were lower than patients with a normal outcome. Conclusions: The results of the presented study suggest that rs231775 and rs5742909 of CTLA4 genetic variants are not linked to acute rejection who underwent kidney transplantation. So, these variants cannot be considered as risk factors of acute allograft rejection in a group of Iranian renal transplantation recipients. However, the transplantation precision medicine may be an important area for the improvement of patients outcome as the precision medicine has already entered clinical practice in kidney transplantation.

Long-term remission following antithyroid drug withdrawal in patients with Graves' hyperthyroidism: parameters with prognostic value.

OBJECTIVE: To assess the predictive value of some clinical and biochemical parameters, and of the +49 A/G polymorphism of the CTLA-4 gene, for long-term remission following the withdrawal of antithyroid drugs before starting antithyroid drug therapy. STUDY DESIGN: Observational, prospective and longitudinal study. METHODS: Seventy-two patients (11 of whom were men) with newly diagnosed Graves' hyperthyroidism who had been attended consecutively at a University Clinic in a population with sufficient iodine intake were included in the study. EXCLUSION CRITERIA: patients under the age of 18, pregnant women and non-Caucasian patients. All subjects were treated following a well-defined protocol. Long-term remission was calculated at 12 and 36 months following withdrawal of the antithyroid drug. RESULTS: Thirty-six of the 72 study subjects experienced a remission of at least 12 months following withdrawal of methimazole, with no differences according to their age or sex. A comparison made between the remission rates seen in both groups yielded significant differences regarding the presence of Graves' orbitopathy, the duration of the treatment with methimazole and the absence of the CTLA-4 G/G genotype. In the univariate and multivariate analyses performed, only lower frequencies of Graves' orbitopathy and an absence of the CTLA-4 G/G genotype were considered independent predictors of long-term remission. CONCLUSIONS: The absence of Graves' orbitopathy and of the CTLA-4 G/G genotype are independent predictors of long-term remission following a first course of antithyroid drugs.

Identification of porcine CTLA4 gene polymorphism and their association with piglet diarrhea and performance traits.

The objective of this study was to evaluate the association between the cytotoxic T-lymphocyte-associated antigen 4 (CTLA4) gene and piglet diarrhea. In this study, the mRNA expression of the CTLA4 gene increased significantly in IPEC-J2 cells after Escherichia coli K88 infection. Single nucleotide polymorphisms (SNPs) located in the 5' flanking region (SNPs g.107281989C>T) and 3'-untranslated region (3'-UTR; SNPs g.107288753C>A) were identified, and they were in linkage disequilibrium in both Min pigs and the Landrace population. Association analysis showed that Landrace piglets with a TT or AA genotype had a lower diarrhea index, and AA animals had higher average daily gain when compared to CC pigs, respectively (p < 0.05). However, the relationship between SNPs and diarrhea and performance traits in the Min population was not significant. Haplotype analysis indicated that the TC haplotype had the lowest diarrhea index. The 5' flanking deletion assay suggested that SNP g.107281989C>T was a molecular marker instead of the functional marker. This research demonstrated that genetic variances in the CTLA4 gene had significant effects on Landrace piglet diarrhea resistance.

Cytotoxic T lymphocyte antigen-4 gene polymorphisms and susceptibility to type 1 autoimmune hepatitis in the Tunisian population.

Genetic factors and gene polymorphisms leading to the onset of autoimmune response in autoimmune hepatitis (AIH) are still not full elucidated. Since the CTLA-4 molecule is a key modulator of the lymphocytes responses we hypothezied that deficiencies or mutations in the gene encoding CTLA4 protein may be involved in AIH susceptibility and trigger the autoimmune response. We investigated 3 distinct polymorphic sites (+49A > G, CT60 G > A and -318C > T) of the CTLA4 gene in 50 AIH patients and 100 healthy controls using the KASP genotyping technology. A significant positive association with AIH susceptibility was found for the GG genotype in +49 position of the CTLA4 gene which was significantly higher in AIH patients compared to controls (28% vs 9%, p = 0.003, OR = 3.93 [1.56-9.88]). The CTLA4 A/A genotype in position CT60 was more significantly frequent in controls comparing to AIH patients and could be considered as a protective genotype for the tunisian patients. CTLA4 genotyping in position -318 did not show any statistically significant difference in genotype or allele distribution. The CTLA4 gene polymorphism in position +49 is associated to AIH susceptibility in the Tunisian population. Mutation in the CTLA4 gene may lead to a modification of the CTLA4 protein structure that could have functional relevance in AIH pathogenesis and onset.

Determination of mir-155 and mir-146a expression rates and its association with expression level of TNF-α and CTLA4 genes in patients with Behcet's disease.

INTRODUCTION: MicroRNAs (miRNAs) are involved in the pathogenesis of inflammatory diseases. MiR-146 and miR-155 emerged as key regulators of the immune response. This study designed to analyze the miR-146a and miR-155 expression in patients with Behcet's disease (BD) and investigated their association with the expression of tumor necrosis factor-alpha (TNF-α) and cytotoxic T lymphocyte associated antigen-4 (CTLA-4) genes. METHODOLOGY: In a case-control study, 47 Iranian Azeri BD patients and 61 age- and sex matched healthy controls recruited to the study. Peripheral blood mononuclear cells (PBMCs) were isolated from EDTA blood tubes by Ficoll density-gradient centrifugation. Genomic DNA samples of BD and healthy controls were extracted using the rapid genomic DNA extraction method from the peripheral blood collected in tubes containing EDTA. Total RNA was extracted from the PBMCs according to the TRIzol protocol. MiR-146a, miR-155, TNF-α and CTLA-4 expression were studied using real-time PCR. RESULTS: MiR-155 and TNF-α expression was significantly increased, whilst CTLA-4 expression was significantly decreased in the PBMCs of BD patients. There was no significant difference in the miR-146a expression rate between BD patients and controls. A positive correlation between miR-155 and TNF-α expression and negative correlation between miR-155 and CTLA-4 expression were observed. No significant association was observed between the expression of miR-155, miR-146a, TNF-α and CTLA-4 genes with BD activity. MiR-155 and miR-146a expression rate were significantly higher in patients with uveitis and phlebitis, respectively. DISCUSSION AND CONCLUSION: The expression of miR-155 increased in BD and associated with upregulation of TNF-α and downregulation of CTLA-4 genes.

CTLA-4 (+49A/G) and NOD2/CARD15 (N852S) polymorphisms with inflammatory bowel disease in Turkish patients.

Crohn's disease (CD) and ulcerative colitis (UC) are the major types of inflammatory bowel disease (IBD) and exhibit similar clinical features and epidemiology. The main objective of this study was to analyze the correlation between the CTLA-4 gene +49A/G polymorphism and the NOD2/CARD15 gene N852S polymorphism in Turkish patients with IBD using polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis. In this study, we evaluated the frequency of the CTLA-4 (+49A/G) and NOD2/CARD15 (N852S) polymorphisms in 62 patients with CD, 76 patients with UC, and 152 healthy individuals. The CTLA-4 and NOD2/CARD15 variants, rs231775 and rs104895467, were genotyped by PCR followed by RFLP. The results for the patients and the control group were statistically analyzed. According to our results, the CTLA-4 gene +49A/G polymorphism AA genotype was prevalent in CD patients and controls (29% vs 40%); the AG (56% vs 51%) and GG (15% vs 9%) genotypes were also observed. The prevalence of the of AA, AG and GG genotypes for the +49A/G polymorphism was 56%, 32% and 12%, respectively, in the UC patients, and 40%, 51% and 9%, respectively, in the healthy controls. In all subjects, just one band of 151 bp, corresponding to wild-type N852S, was found, and no other N852S mutant bands (151+129+22 and 129+22 bp) were detected using PCR-RFLP fragment electrophoresis.The CTLA-4 gene +49 A/G polymorphism and the NOD2/CARD15 gene N852S polymorphism were not associated with CD or UC in a Turkish population.

CTLA-4 Gene Haplotypes and the Risk of Chronic Hepatitis C Infection; a Case Control Study.

BACKGROUND: The prevalence of hepatitis C virus (HCV) infection is increasing worldwide. Cytotoxic Tlymphocyte-associated protein 4 (CTLA-4) may play a role in the intensity of the disease. The aim of this study was to evaluate the association between genetic variants of the CTLA-4 and HCV infection. METHODS: Restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) was performed as the genotyping assay at four different positions (+49 A>G, -318 C>T, -1722 T>C, and - 1661 A>G). Haplotypes were analyzed using PHASE software. Sixty-five HCV patients and 65 healthy individuals as controls who were referred to the hepatitis clinic in Mashhad, Iran, were recruited. Genomic DNA was extracted from whole blood of participants. RESULTS: In a dominant analysis model of the -1661 position (GG vs. AA+AG), the AA genotype was more common in controls than in patients (adjusted P = 0.0003; OR = 0.15, 95% CI = 0.051 -0.42). The GCAT haplotype was also more prevalent in controls than in patients (adjusted P = 0.01; OR = 0.40, 95% CI = 0.20-0.81). Furthermore, the ACGT/ACGT diplotype was more common in controls than in patients (P = 0.0037; OR = 0.15, 95% CI = 0.04-0.54). In addition, the ACGT/ACAT diplotype was more frequent in patients than controls (adjusted P =0.003; OR = 2.48, 95% CI = 1.37- 4.50). CONCLUSION: Our results indicated that polymorphisms in CTLA-4 and certain haplotypes may affect the risk of HCV infection in our population, although a larger sample size may be required to confirm this association.

The Role of Cytotoxic T-lymphocyte-associated Protein 4 (CTLA-4) Gene, Thyroid Stimulating Hormone Receptor (TSHR) Gene and Regulatory T-cells as Risk Factors for Relapse in Patients with Graves Disease.

BACKGROUND: graves' disease (GD) is the most common condition of thyrotoxicosis. The management of GD is initiated with the administration of antithyroid drugs; however, it requires a long time to achieve remission. In reality more than 50% of patients who had remission may be at risk for relapse after the drug is stopped. This study aimed to evaluate the role of clinical factors such as smoking habit, degree of ophtalmopathy, degree of thyroid enlargement; genetic factors such as CTLA-4 gene on nucleotide 49 at codon 17 of exon 1, CTLA-4 gene of promotor -318, TSHR gene polymorphism rs2268458 of intron 1; and immunological factors such as regulatory T cells (Treg) and thyroid receptor antibody (TRAb); that affecting the relapse of patients with Graves' disease in Indonesia. METHODS: this was a case-control study, that compared 72 subjects who had relapse and 72 subjects without relapse at 12 months after cessation of antithyroid treatment, who met the inclusion criteria. Genetic polymorphism examination was performed using PCR-RFLP. The number of regulatory T cells was counted using flow cytometry analysis and ELISA was used to measure TRAb. The logistic regression was used since the dependent variables were categorical variables. RESULTS: the analysis of this study demonstrated that there was a correlation between relapse of disease and family factors (p=0.008), age at diagnosis (p=0.021), 2nd degree of Graves' ophthalmopathy (p=0.001), enlarged thyroid gland, which exceeded the lateral edge of the sternocleidomastoid muscles (p=0.040), duration of remission period (p=0.029), GG genotype of CTLA-4 gene on the nucleotide 49 at codon 17 of exon 1 (p=0.016), CC genotype of TSHR gene on the rs2268458 of intron 1 (p=0.003), the number of regulatory T cells (p=0.001) and TRAb levels (p=0.002). CONCLUSION: genetic polymorphisms of CTLA-4 gene on the nucleotide 49 at codon 17 of exon 1, TSHR gene SNP rs2268458 of intron 1, number of regulatory T cells and TRAb levels play a role as risk factors for relapse in patients with Graves' disease.

CTLA-4 gene polymorphisms associate with efficacy of postoperative radioiodine-131 for differentiated thyroid carcinoma.

AIM: To investigate the association of CTLA-4 polymorphisms with efficacy of postoperative radioiodine-131 (I-131) treatment for differentiated thyroid carcinoma (DTC). METHODS: A total of 324 DTC patients and 350 healthy individuals were enrolled in our study. Patients received I-131 remnant ablation following surgical resection. Based on the treatment efficacy, patients were divided into the effective (n = 183) and ineffective groups (n = 141). CTLA-4 polymorphisms (+49A>G, CT60A>G and -318C>T) were genotyped by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: AG + AA genotype distribution and A allele frequency of +49A>G and CT60A>G polymorphisms were higher in the effective group than the ineffective group. CONCLUSION: +49A>G and CT60A>G polymorphisms were associated with the efficacy of postoperative I-131 treatment for DTC; and they might be bioindicators related to the prognosis of I-131 treatment.

A novel approach to investigation of the pathogenesis of pterygium based on assessment of promoter hyper-methylation and expression profile of CTLA4 gene: A credible report of CTLA4 gene expression in human eye tissue.

BACKGROUND: Pterygium is the human eye lesion whose prevalence in the general population is estimated about 2%. The disease, in extreme phase, can lead to visual disturbance and eventually causes complete loss of vision due to the lesion growth over the papillary axis. Pterygium invasive tissue is a tumor-like tissue that is initially identified and then is attacked by cytotoxic T cells. Cytotoxic T lymphocyte associated antigen 4 (CTLA4), as a modulator molecule of the adaptive immune system, plays a critical role in maintaining peripheral T cell tolerance by diminishing its responsiveness and increasing its activation threshold. The aim of this study is to investigate the association between some epigenetic changes of the CTLA4 gene, such as promoter methylation and gene expression, and pathogenesis of pterygia. MATERIALS AND METHODS: Genomic DNA was extracted from 75 formalin-fixed, paraffin-embedded tissues of pterygia and 70 specimens of normal conjunctiva from eyes without pterygium as the control group, collected from Sistan and Baluchestan population. CTLA4 gene promoter methylation was carried out by methylation-specific PCR technique. The gene expression analysis was done on extracted total RNA from 20 healthy and 23 pterygium tissue samples using Real-Time PCR technique. RESULTS: Promoter methylation changes of CTLA4 gene were not statistically different in patients with pterygium in comparison with healthy controls (OR=1.614; 95% CI=0.57-4.75; P value=0.37). However, gene expression level of CTLA4 was remarkably different in patients and healthy controls (Mean±SD: 1.343±0.133 and 2.027±0.219, respectively; P value=0.009). CONCLUSION: This is a credible evidence of CTLA4 gene expression in human eye tissue. This first hand attempt of investigating the association of epigenetic changes of the CTLA4 gene and pathogenesis of pterygia, indicated a significant intensification of the gene expression of CTLA4 in patients with pterygia. We suggest that increasing CTLA4 gene expression can be a trigger which promotes pterygium enlargement. However, further studies on more populations with larger sample sizes need to be done to verify this hypothesis in the future.

Correlation between CTLA-4 gene rs221775A>G single nucleotide polymorphism and multiple sclerosis susceptibility. A meta-analysis.

OBJECTIVE: The aim of this meta-analysis was to undertake a meta-analysis to evaluate the correlation between cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) gene rs221775 A>G single nucleotide polymorphism and the susceptibility of multiple sclerosis (MS) susceptibility. METHOD: Published manuscripts about CTLA-4 gene rs221775A>G single nucleotide polymorphism and multiple sclerosis susceptibility were searched in the computerized bibliographic searches of Pubmed Embase and China National Knowledge Infrastructure (CNKI). Potential studies were screened and data for 5025 MS patients and 4706 controls from 20 publications were included. The association between CTLA-4 gene rs221775A>G single nucleotide polymorphism and multiple sclerosis susceptibility were demonstrated by odds ratio (OR) and 95% confidence interval (95%CI). RESULTS: The pooled results showed no significant association between CTLA-4 gene rs221775A>G single nucleotide polymorphism and multiple sclerosis susceptibility for dominant genetic model [OR=1.02, 95%CI:0.90~1.05, (P=0.80)], homozygous genetic model [OR=0.85,95%CI:0.71 ~1.03,(P=0.10)] and recessive genetic model [OR=0.99,95% CI:0.89~1.10,(P=0.90)]. CONCLUSION: With current evidence, CTLA-4 gene rs221775A>G single nucleotide polymorphism had no association with the susceptibility of multiple sclerosis.

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.

Family Analysis of Linkage and Association of HLA-DRB1, CTLA4, TGFB1, IL4, CCR5, RANTES, MMP9 and TIMP1 Gene Polymorphisms with Multiple Sclerosis.

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system (CNS). Proteins of the immune system, as well as proteins that are involved in the infiltration of activated immune cells in the CNS, play an important role in the pathogenesis of MS. We investigated the association and linkage with MS of the following immune-system genes polymorphisms: HLA-DRB1,CTLA4,TGFB1,IL4,CCR5 andRANTES, as well as of the matrix metalloproteinase 9 (MMP9) and tissue inhibitor of metalloproteinase  1 (TIMP1) genes polymorphisms. For this purpose we used the transmission disequilibrium test (TDT). The group investigated was comprised of 100 nuclear families of Russian ethnicity, each consisting of an affected offspring and his nonaffected parents. It was found that HLA-DRB1*15alleleandMMP9*-1562C allele were transmitted from healthy heterozygous parents to affected children more frequently than alternative alleles (p  =  0.02 andp  =  0.04, respectively). Another family-based method, AFBAC (affected family-based control), showed MS association with HLA-DRB1*15, but not with theMMP9*-1562C allele.

A Study on the Level of T(3), T(4), TSH and the Association of A/G Polymorphism with CTLA-4 Gene in Graves' Hyperthyroidism among South Indian Population.

Graves' disease (GD) is an organ-specific heterogenous autoimmune disorder associated with T-lymphocyte abnormality affecting the thyroid, eyes and skin. GD is a multifactorial disease that develops as a result of complex interaction between genetic susceptibility genes and environmental factors. It has been suggested that the Cytotoxic T lymphocytes associated molecule-4 (CTLA-4) is a genetic susceptibility candidate for GD. The present study was focused on A/G polymorphism at position 49 in exon-1 of the CTLA-4 gene in 80 GD patients (GP) and 80 sex and age matched healthy individuals among South Indian (Madurai) population. Serum concentrations of thyroid hormone (T(4), T(3) and TSH) were determined by using automated analyzer. The genomic DNA was isolated from the patient and control groups and genotyping was performed using the polymerase chain reaction followed by restriction enzyme analysis using Bbv1. Significant difference (P < 0.001) was observed in the level of T(3), T(4) and TSH in GD patients and healthy individuals. The results revealed the CTLA-4 gene G/G genotype to be 32 (40%) in patients and 26 (32.50%) in healthy individuals, A/G genotype to be 37 (46.25%) in patients and 25 (31.25%) in healthy individuals and A/A genotype to be 11 (13.75%) in patients and 29 (36.25%) in healthy individuals. The calculated odds ratio (OR) in individuals with mutant genotype (GG/AG) reveal 3.6 fold risk for GD (95% confidence interval = 1.6-7.8). The mutant "G" allele frequency was observed to be 0.63 in GD patients and 0.48 in healthy individuals. Thus the present study demonstrates an association between the CTLA-4 gene polymorphism and Graves' disease.

The relationships between CTLA-4 gene exon 1 A/G~(49) polymorphism and type 1diabetes mellitus / 中国糖尿病杂志

Objective To investigate the association of cytotoxic T lymphocyte associated antigen 4(CTLA 4) gene polymorphism with type 1 diabetes in Chinese Han population.Methods The A/G phenotype at position 49 of the CTLA 4 gene exon 1 was determined by polymerase chain reaction restriction fragment length polymorphism(PCR RFLP)method in 33 typical type 1 diabetes patients,57 latent autoimmune diabetes in adults(LADA) patients and 84 healthy control subjects of Chinese Han.Results The frequency of the CTLA 4/G 49 phenotype was significantly higher in type 1 diabetes patients than in control subjects(55.6% vs 36.9%, respectively, P =0.0005),but there was no significant difference between typical type 1 DM and LADA groups. Neither the presence nor the absence of G 49 allele influenced the occurrence of islet autoantibody(ICA) and glutamate decarboxylase antibody(GADAb).Conclusion The polymorphism of CTLA 4 gene exon1 confers susceptibility to type 1 diabetes. This association is independent of ICA and GADAb.