Lack of association between an exon 1 CTLA-4 gene polymorphism A(49)G and multiple sclerosis in a Polish population of the Lower Silesia region

Multiple sclerosis (MS) a chronic inflammatory demyelinating disease of the central nervous system is believed to have a T cell-mediated autoimmune etiology. The cytotoxic T lymphocyte antigen 4 (CTLA-4) gene is a strong candidate for the involvement in autoimmune diseases because CTLA-4 plays an important role in the downregulation of the early and late stages of T cell activation and the maintenance of peripheral T cell tolerance. To examine the genetic association of the CTLA-4 gene locus with MS, we analyzed an exon 1 CTLA-4 gene polymorphism A(49)G in 102 unrelated Polish MS patients in the Lower Silesia region and 101 age- and sex-matched healthy subjects. The distribution of CTLA-4 exon 1 A(49)G genotype, phenotype and allele frequencies did not differ between patients with MS and healthy subjects.     

PTPN22基因多态性与自身免疫甲状腺病的相关性

目的:检测PTPN22基因的单核苷酸多态性(SNP)及其与中国人自身免疫甲状腺病(AITD)的相关性, 并研究CTLA- 4基因SNP与PTPN22 SNP的相互关系.方法:采用PCR-RFLP技术分析231例AITD患者, 其中Graves'病(GD)149例, 桥本甲状腺炎(HT)82例和131例健康对照者PTPN22基因 1858 C>T及CTLA- 4基因49A>G位点的基因型.采用SASP-PCR技术分析PTPN22基因启动子-1123G>C的基因型.结果:(1)PTPN22基因的 1858C>T位点不存在多态性;(2)PTPN22基因-1123G>C SNP的等位基因和基因型分布频率在GD组与正常对照组间的差异有统计学意义(P值分别为0.040和0.013, OR值分别为1.44和2.33);(3) CTLA- 4基因 49A>G位点的等位基因和基因型分布频率在AITD组与正常组间有明显差异;(4)与携带PTPN22的G等位基因及CTLA- 4的AA基因型者相比, 携带PTPN22CC基因型与CTLA- 4 AG或GG基因型者发生GD的OR值=3.31(95%CI: 2.69-8.89).结论:PTPN22基因启动子-1123G>C SNP与GD的发生相关, 其CC基因型与CTLA- 4基因的G 等位基因对GD的发生起协同作用.     

Association of the A/G polymorphism at position 49 in exon 1 of CTLA-4 with the susceptibility to unexplained recurrent spontaneous abortion in the Chinese population

PROBLEM: To investigate whether the A/G polymorphism at position 49 in exon 1 of cytotoxic T lymphocyte antigen-4 (CTLA-4) gene, which delivers a negative signal to T-cell activation, confers the susceptibility to unexplained recurrent spontaneous abortion in the Chinese population. METHOD OF STUDY: A total of 168 patients with unexplained recurrent spontaneous abortion (RSA), who were treated in the Renji Hospital affiliated to the Shanghai Second Medical University, were matched against 117 women with normal pregnancy history. Case-control study to compare the frequency of G/A alleles, AA/AG/GG genotypes and A + (AA + AG) /G+ (GG + AG) phenotypes of CTLA-4 between RSA patients and controls were performed. After amplification of CTLA-4 exon-1 region by polymerase chain reaction (PCR), restriction fragment-length polymorphism (RFLP) was used to detect the polymorphism at position 49 in exon-1 of CTLA-4 gene. Statistical significance was tested by SPSS software. RESULTS: There were dissimilar distributions of G/A alleles, AA/AG/GG genotypes and A+/G+ phenotypes of CTLA-4 between RSA patients and controls. The frequencies of G allele (P = 0.032) and GG genotype (P = 0.011) in RSA patients were significantly higher than those in controls, while the frequencies of AG genotype (P = 0.039) and A + (AA + AG) phenotype in RSA patients were decreased significantly (P = 0.011). CONCLUSIONS: Our findings suggest that A/G polymorphism in exon-1 of CTLA-4 is associated with the immunopathogenesis of RSA, and it confers susceptibility to RSA in Chinese population.     

自身免疫性甲状腺病CTLA—4基因外显子1A／G^49多态性研究

目的　探讨细胞毒性T淋巴细胞相关抗原4（CTLA-4）基因外显子1的49位点A／G多态性与自身免疫性甲状腺病（AITDs）的相关性。方法　采用多聚酶链反应限制性片段长度多态性（PCR-RFLP）技术分析122例自身免疫甲状腺病患者,其中Graves’病（GD）87例,桥本甲状腺炎（HT）35例,84例健康对照的CTLA-4基因外显子1的49位点基因型。采用ELISA技术检测AITDs患者甲状腺功能,间接免疫荧光法检测甲状腺球蛋白抗体（TGAb）和甲状腺抗过氧化物酶抗体（TPOAb）。结果　AITDs患者CTLA-4／G     

CTLA-4 gene polymorphisms and their influence on predisposition to autoimmune thyroid diseases (Graves’ disease and Hashimoto's thyroiditis)

Introduction

Autoimmune thyroid disease (AITD) is associated with both genetic and environmental factors which lead to the overactivity of immune system. Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4) gene polymorphisms belong to the main genetic factors determining the susceptibility to AITD (Hashimoto''s thyroiditis, HT and Graves'' disease, GD) development. The aim of the study was to evaluate the relationship between CTLA-4 polymorphisms (A49G, 1822 C/T and CT60 A/G) and HT and/or GD in Polish patients.

Material and methods

Molecular analysis involved AITD group, consisting of HT (n=28) and GD (n=14) patients, and a control group of healthy persons (n=20). Genomic DNA was isolated from peripheral blood and CTLA-4 polymorphisms were assessed by polymerase chain reaction-restriction fragment length polymorphism method, using three restriction enzymes: Fnu4HI (A49G), BsmAI (1822 C/T) and BsaAI (CT60 A/G).

Results

Statistical analysis (χ² test) confirmed significant differences between the studied groups concerning CTLA-4 A49G genotypes. CTLA-4 A/G genotype was significantly more frequent in AITD group and OR analysis suggested that it might increase the susceptibility to HT. In GD patients, OR analysis revealed statistically significant relationship with the presence of G allele. In controls, CTLA-4 A/A genotype frequency was significantly increased suggesting a protective effect. There were no statistically significant differences regarding frequencies of other genotypes and polymorphic alleles of the CTLA-4 gene (1822 C/T and CT60 A/G) between the studied groups.

Conclusions

CTLA-4 A49G polymorphism seems to be an important genetic determinant of the risk of HT and GD in Polish patients.     

CT60 single nucleotide polymorphism of the CTLA-4 gene is associated with susceptibility to Graves' disease in the Taiwanese population

Graves' disease (GD) is an autoimmune disease but the underlying etiology has not been completely elucidated. Genetic susceptibility has been believed to play a major role. Recent studies showed that the CT60 single nucleotide polymorphism (SNP), which is in the 3'-noncoding region of the CTLA-4 gene, is strongly associated with some immune-mediated diseases. The aim of this study was to test for association between GD susceptibility and polymorphisms of CTLA-4 (ie, the CT60 SNP and the exon 1 +49 SNP) in the Taiwanese population. Our results demonstrate significant differences in the frequencies of the genotypes and alleles between 107 GD patients and 101 control subjects in the CT60 and exon 1 +49 SNPs (p <0.05). Significant differences in phenotypes were only found for CT60 SNP (78.4% vs 67.8% between patients and controls; chi2 = 3.93, p = 0.047). Furthermore, we found that the G/G genotype of both CT60 and exon 1 +49 was associated with increased risk for GD (p = 0.022, OR = 1.97). Significant linkage disequilibrium was found between the CT60 SNP and the exon 1 +49 SNP in both GD patients and control subjects (D' = 1.00). Because of tight linkage disequilibrium, a combination of these SNPs enhanced the role of the CTLA-4 gene in GD. The frequency of the disease-susceptible G allele of CT60 was comparable to that in Japanese and higher than in Caucasians. In conclusion, we provide evidence that CT60 SNP is associated with susceptibility to GD in the Taiwanese population.     

Cytotoxic T lymphocyte-associated antigen-4 polymorphism in patients with rheumatic heart disease

Acute rheumatic fever (ARF) is a systemic inflammatory disease occurring as a consequence of an exaggerated immune response to group A, beta haemolytic streptococcal pharyngitis. The molecular mimicry between human target organs/tissues and specific components of the infectious organism leads to the development of autoimmune reactions and cardiac tissue damage in rheumatic heart disease (RHD). Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) is a negative regulator of T cell activation and proliferation during the immune response. CTLA-4 gene polymorphism has been shown to affect the inhibitory function of CTLA-4. We aimed to analyze the association of CTLA-4 gene locus at position 49 of exon 1 with susceptibility to ARF/RHD. This study included a total of 98 patients with RHD as a sequela of ARF, who fulfilled the revised classification criteria of Jones and 154 healthy unrelated controls. CTLA-4 +49 A/G polymorphism was genotyped by using PCR-RLFP technique. Data was analyzed by binary logistic regression models. The frequencies of GG, GA and AA genotypes were found to be 14%, 47% and 39%, respectively, in patients and 6%, 45% and 49%, respectively, in controls. The GG genotype was found to be significantly different between patients and controls (OR: 3.11; P = 0.016). GA and AA genotypes did not statistically differ between patients and controls. Our data showed a significant association of +49G /G polymorphism in a small patient group with RHD.     

CTLA4 polymorphisms and ophthalmopathy in Graves' disease patients: association study and meta-analysis

Studies in the past have clearly established that cytotoxic T-lymphocyte antigen-4 (CTLA4) is a susceptible gene for Graves' disease (GD). However, association studies between the CTLA4 exon-1 +49A/G polymorphism and the risk of developing Graves' ophthalmopathy (GO) in GD patients have revealed conflicting results. In this study, associations of two CTLA4 polymorphisms (+49A/G and CT60) with GD risk and GO susceptibility in GD patients were investigated in a Chinese population. In addition, a meta-analysis was performed to better assess the purported association between the +49A/G polymorphism and GO susceptibility in GD patients. Our results demonstrated that both the +49A/G and CT60 polymorphisms were associated with GD susceptibility in the Chinese population. No significant association with GO susceptibility in GD patients was confirmed regardless of which polymorphism was tested individually. Similarly, the meta-analysis results provided minimal evidence about the role of the +49A/G polymorphism and GO risk in GD patients. Interestingly, haplotypic analysis demonstrated different scenarios concerning the role of CTLA4 in GO susceptibility in the Chinese GD patients. We found that the +49A-CT60G haplotype was marginally statistically associated with the increased risk of GO in GD patients (OR = 1.63, 95%CI 1.00-2.64, p = 0.05). In conclusion, our results suggested that CTLA4 might be involved in the susceptibility to GD in the Chinese population. Although neither +49A/G nor CT60 polymorphism was associated with the risk of GO in GD patients, the haplotypic analysis provided some evidence about its role in GO susceptibility in the Chinese GD patients. We suggest that more association studies recruiting haplotypic analysis should be performed to investigate the role of CTLA4 gene in GO susceptibility in patients from different nations.     

Thyroid autoantibody production is influenced by exon 1 and promoter CTLA-4 polymorphisms in patients with Hashimoto's thyroiditis

Strong genetic susceptibility to thyroid autoantibody (TAb) diathesis has been shown and one of the major genes involved is probably CTLA-4 gene. Our recent study of patients with Graves' disease has demonstrated that exon 1 CTLA-4 gene polymorphism influences higher TAb production. Here, we evaluated the influence of exon 1 and promoter CTLA-4 polymorphisms on TAb production in 109 newly diagnosed patients with Hashimoto's thyroiditis (HT). Serum TSH, thyroid peroxidase antibodies (TPOAb) and thyroglobulin antibodies (TgAb) were measured. 49 A/G and -318 C/T polymorphisms were detected using polymerase chain reaction amplification of genomic DNA and restriction fragment length polymorphism analysis. Patients with AG and GG genotype had significantly higher TPOAb median values compared to patients with AA genotype (P < 0.003). Similarly, TgAb median value was significantly higher in AG patients and in the entire G-allele carrying group (P < 0.02). Compared to both T-allele carrying genotypes, CC genotype presented with significantly higher TPOAb median value (P < 0.02), whereas TgAb median values did not differ significantly between various genotypes. In conclusion, our results indicate that G allele influences higher TPOAb and TgAb production, whereas C allele affects especially TPOAb production in patients with HT. Therefore, our findings provide further evidence that CTLA-4 is a major TAb susceptibility gene.     

中国人自身免疫性肝病相关性 CTLA-4基因多态性研究

目的　探讨细胞毒性 T细胞相关抗原 - 4 (cytotoxic T lymphocyte- associated antigen- 4 ,CTL A- 4 )基因启动子 - 318和第 1外显子区第 4 9位基因多态性与中国人自身免疫性肝炎 (autoimmunehepatitis,AIH)、原发性胆汁性肝硬化 (primary biliary cirrhosis,PBC)发病的相关性。方法　应用限制性片段长度多态性方法分析 6 2例 AIH和 77例 PBC患者外周血单核细胞基因组 DNA CTL A- 4启动子 -318T/ C、第 1外显子区第 4 9位基因 A/ G多态性 ,并与 16 0名正常对照比较。结果　 AIH组 CTL A- 4启动子 - 318位 T/ C基因型分布与对照组比较差异无显著性 ,但 C等位基因频率明显高于正常对照组 (P=0 .0 2 ,OR=2 .4 3)。 PBC患者 CTL A- 4第 1外显子区第 4 9等位基因分布与正常对照组比较差异非常显著(P=0 .0 0 6 ) ,PBC患者 G等位基因频率明显高于正常组 (P=0 .0 0 4 6 ,OR=1.8)。联合分析 CTL A- 4启动子与第 1外显子的基因多态性分布 ,虽然 AIH组和 PBC组 GG- CC型携带率均比正常人高 (AIH组 :32 .3% ,PBC组 :37.7% ,对照组 :2 2 .5 % ) ,但是统计学分析结果均显示两组患者与正常人差异无显著性。结论　 CTL A- 4启动子 - 318和第 1外显子区第 4 9位基因多态性可能与中国人 AIH、PBC易感性相关。     

Functional polymorphism of cytotoxic T-lymphocyte antigen 4 and nasopharyngeal carcinoma susceptibility in a Chinese population

Cytotoxic T-lymphocyte antigen 4 (CTLA-4; CD152) is a secondary receptor of B7 (CD80 and CD86) and shares homology with the CD28 receptor. Although the structures of CTLA-4 and CD28 are very similar, they deliver different costimulatory signals. A functional polymorphism in CTLA-4 exon 1 position +49 that can affect the T-cell response has been reported by several groups. Previous case–control studies also revealed this polymorphism contribute to the risk of autoimmune diseases and common cancers. However, the relationship between CTLA-4 functional polymorphism and nasopharyngeal carcinoma (NPC) susceptibility has not yet been explored. In this study, we performed a case–control study in a Chinese population. Our result showed that the CTLA-4 +49 A>G polymorphism is associated with NPC susceptibility. The subjects carrying the CTLA-4 +49 AA genotype have a ∼1.8-fold increased risk of NPC (adjust OR 1.83; 95% CI, 1.16–2.93) when compared with the GG genotype.     

Association of G-174C polymorphism of the interleukin-6 gene promoter with Graves' ophthalmopathy

Interleukin-6 (IL-6) may play an important role in the pathogenesis of Graves' ophthalmopathy (GO). The aim of this study was to analyze the association of IL-6 gene promoter polymorphism, at position - 174 (G --> C, termed as G-174C), which may affect IL-6 production, with the development of GO. The G-174C polymorphism was determined in 279 Polish-Caucasian patients with Graves' disease (GD), of which 108 had clinically evident ophthalmopathy (NOSPECS class III or higher) and 186 healthy Polish adults. In patients with GD, the frequencies of the C allele (45 vs 42%; P = 0.35) and C/C genotype (20 vs 15%; P = 0.13) were not significantly different compared to controls. Subdividing patients with GD for the presence of eye disease revealed that the C allele (44 vs 45%; P = 0.76) and C/C genotype (20 vs 20%; P = 0.92) were equally distributed in patients with or without ophthalmopathy. There was also no association between the G-174C polymorphism and the severity of eye changes. Finally, IL-6 genotypes were not associated with laboratory findings (thyroid volume, serum IL-6 and thyroid autoantibodies levels) in patients with GD at diagnosis. Our results suggest that G-174C polymorphism of the IL-6 gene does not contribute to the development and severity of GO.     

CTLA-4 Gene Exon-1 +49 A/G Polymorphism: Lack of Association with Autoimmune Disease in Patients with Common Variable Immune Deficiency

The presence of the G allele of exon-1 +49 A/G polymorphisms of the cytotoxic T lymphocyte antigen 4 (CTLA-4) gene has been described as a risk factor associated with the development of autoimmune diseases. Since Common Variable Immune Deficiency (CVID) is associated with autoimmune manifestations in approximately 25% of patients, we sought to examine the association of the CTLA-4 single nucleotide polymorphism with autoimmunity and other inflammatory complications. Sixteen of 47 CVID (34%) patients had a history of autoimmunity, and 15 (32%) had known granulomatous disease with or without lymphoid hyperplasia. CTLA-4 genotype frequencies were AA 40% (19), AG 45% (21), and GG 15% (7). Allele frequencies were A 63% and G 37%, similar to control populations. There were no significant associations between CTLA-4 exon-1 +49 A/G polymorphism and autoimmune or lymphoid hyperplasia and granulomatous disease in this mostly Caucasian CVID patient population.     

High incidence of CTLA-4 AA (CT60) polymorphism in renal cell cancer

Polymorphism in genes encoding T-cell regulatory proteins and cytokines may influence inflammation and cancer development via regulation of antitumor immune response. In the current study we analyzed genotypic frequencies of cytotoxic T-lymphocyte antigen-4 (CTLA-4)/CT60, CTLA-4/A49G, interleukin (IL)-4, and IL-10 polymorphisms in 117 renal cell carcinoma patients, 96 patients with colorectal cancer, and 196 healthy controls to test for an association between polymorphism in these genes and the risk of renal and colon cancer in a Spanish group of patients. In the case-control study, DNA samples from cancer patients and controls were analyzed using a TaqMan single nucleotide polymorphism genotyping assay. The distribution of IL-4 and IL-10 polymorphisms was similar between renal cancer patients and controls. However, a higher incidence of CTLA-4/CT60-AA genotype (p = 0.005; odds ratio (OR)= 2.12 with 95% confidence interval (CI): 1.28-3.50) and CTLA-4/A49G-AA (p = 0.022; OR = 1.76 with 95% CI: 1.11-2.80) genotype was observed in renal cancer patients than in controls. In addition, we observed a positive correlation between the AA genotype in both CTLA-4 polymorphisms and RCC grade, suggesting a role for the CTLA4 gene in tumor development. Therefore, our data suggest the CTLA-4 gene may be a candidate as a renal adenocarcinoma susceptibility gene, but does not play an important role in colon cancer.     

The common -318C/T polymorphism in the promoter region of CTLA4 gene is associated with reduced risk of ophthalmopathy in Chinese Graves' patients

Studies in the past have clearly established that CTLA4 is a susceptible gene for Graves' disease (GD). However, association studies between CTLA4 and the risk of developing Graves' ophthalmopathy (GO) in GD patients have shown conflicting results. In this study, associations of five CTLA4 single nucleotide polymorphisms (-1722A/G, -1661A/G, -318C/T, +49G/A, CT60) with GD risk and GO susceptibility in GD patients were investigated in a Chinese population. Our results showed that either +49A/G or CT60 polymorphism was associated with GD susceptibility in the Chinese population. Significant differences in the distribution of the genotypes or alleles evaluated between GD patients with and without clinically evident GO were only found for -318C/T polymorphism (P = 0.03). Multiple logistic regressions revealed that the -318T allele was negatively associated with GO under both additive and dominant genetic models (adjusted OR = 0.56, 95%CI 0.35-0.89, P = 0.014; adjusted OR = 0.51, 95%CI 0.30-0.84, P = 0.009, respectively). Stratification analysis according to gender demonstrated different scenarios concerning the role of the -318T allele in GO risk: a significant protective role for GO was only confirmed in male but not in female GD patients. Haplotype analyses showed that only the haplotypes containing the -318T allele played a protective role in GO. In conclusion, results from this study suggested that the -318T allele might play a protective role in GO susceptibility for GD patients at least in the Chinese population. However, extended analyses with larger sample size should be carried out in patients from different ethnic origins to further verify this association.     

CTLA-4 Gene Polymorphisms in Tunisian Patients with Graves' Disease

Graves' disease (GD) is an organ-specific autoimmune disorder of multifactorial etiology with a polygenic mode of inheritance. A recent report has demonstrated that there is a linkage and an association between the genetic markers of the CTLA-4 gene on chromosome 2q33 and GD. In order to confirm this association in a Tunisian population, three polymorphisms of the CTLA-4 gene were analyzed: the first is at the -318 position from the ATG start codon consisting of a C/T change; the second is in position 49 of exon 1, which lies in the A/G transition; and the third is in the 3' untranslated region with variant lengths of the dinucleotide (AT)n repeat. The genomic DNA from 144 patients with GD and 205 healthy individuals was genotyped after specific polymerase chain reaction amplification. Comparative analysis using a chi(2) test showed a weak yet significant difference in allele frequencies of the A/G dimorphic marker between patients and controls (P < 0.05), and a significant increase of A/A homozygous individuals among patients (21.53 vs 12.7%, P = 0.02, odds ratio (OR) = 1.89) was found. Analyses of CTLA-4 A/G polymorphism with respect to sex showed a significant difference in A/A genotypes between female patients and controls (OR = 2.14; 95%, 1.13 < OR < 4.04, P < 0.05). The distribution of CTLA-4 (AT)n allele frequencies differed between patients and controls (chi(2) = 38.18, 20 degrees of freedom, P = 0.0084) and the highest OR was found with the CTLA-4 (AT)-224-bp allele (OR = 6.43, 1.7 < OR < 28.64; P = 0.001). In conclusion, these results show that the CTLA-4 gene, or one closely associated with it, confers susceptibility to GD in a Tunisian population.     

Association of CTLA-4 (+49A/G) Gene Polymorphism with Type 1 Diabetes Mellitus in Egyptian Children

Objective: To investigate the distribution of cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) (+49 A/G) gene variants and the association of these variants with the clinical and laboratory findings in Egyptian children with Type-1 Diabetes (T1D). Methods: A case control study was done for 104 Egyptian children with T1D and 78 age and sex matched healthy control. CTLA-4 (+49 A/G) gene polymorphism typing was done by PCR amplification followed by restriction fragment length polymorphism (RFLP) method. Results: CTLA-4 G allele and GG homozygous genotype were significantly increased in T1D patients than in control group (P = 0.047, P = 0.048 respectively). There is no statistical difference between patient with optimal diabetic control (HbA1c < 8.5) and poor control (HbA1c ≥ 8.5) as regarding the CTLA-4 gene variant. The CTLA-4 GG genotype was statistically associated with younger age of patients (P = 0.027) and younger age of presentation (P = 0.036). Insignificant association was found between CTLA-4 alleles / genotypes and diabetic complications. Conclusion: The CTLA-4 +49 GG homozygous genotype is associated with T1D in Egyptian children especially with younger age of onset and in younger patients, and not associated with grades of diabetic control or diabetic complication.     

Association of G-174C Polymorphism of the Interleukin-6 Gene Promoter with Graves' Ophthalmopathy

Interleukin-6 (IL-6) may play an important role in the pathogenesis of Graves' ophthalmopathy (GO). The aim of this study was to analyze the association of IL-6 gene promoter polymorphism, at position -174 (G→C, termed as G-174C), which may affect IL-6 production, with the development of GO. The G-174C polymorphism was determined in 279 Polish-Caucasian patients with Graves' disease (GD), of which 108 had clinically evident ophthalmopathy (NOSPECS class III or higher) and 186 healthy Polish adults. In patients with GD, the frequencies of the C allele (45 vs 42%; P=0.35) and C/C genotype (20 vs 15%; P=0.13) were not significantly different compared to controls. Subdividing patients with GD for the presence of eye disease revealed that the C allele (44 vs 45%; P=0.76) and C/C genotype (20 vs 20%; P=0.92) were equally distributed in patients with or without ophthalmopathy. There was also no association between the G-174C polymorphism and the severity of eye changes. Finally, IL-6 genotypes were not associated with laboratory findings (thyroid volume, serum IL-6 and thyroid autoantibodies levels) in patients with GD at diagnosis. Our results suggest that G-174C polymorphism of the IL-6 gene does not contribute to the development and severity of GO.     

CTLA-4 promoter variants in patients with Graves' disease and Hashimoto's thyroiditis

Abstract: Graves' disease (GD) and Hashimoto's thyroiditis (HT) are T-cell mediated organ-specific autoimmune disorders with a genetic predisposition. The cytotoxic T-lymphocyte antigen 4 (CTLA-4) molecule is the predominant receptor for B7 on activated T cells and represents a negative regulator for T-cell function. Since the CTLA-4-guanine at position 49 of exon 1 is associated with susceptibility to GD as well as to HT and IDDM, we investigated a recently detected cytosine/thymine substitution at position -318 within the CTLA-4 promoter region in patients with GD and HT. 125 patients with GD were significantly more often homozygous for cytosine (86% vs. 73% in controls, P=0.006) and less frequently heterozygous for cytosine and thymine (14% vs. 27%, P=0.008). In 64 patients with HT, the distribution was similar but not significant (81% homozygous for cytosine and 16% heterozygous). When correlating the promoter and the exon 1 polymorphism we found the strongest linkage between thymine (promoter) and adenine (exon 1). In conclusion, a promoter variant of the CTLA-4 gene represents an additional risk marker for GD and HT, but their predisposition is linked to the exon 1 alleles.     

Lack of a strong association of CTLA-4 exon 1 polymorphism with the susceptibility to rheumatoid arthritis and systemic lupus erythematosus in Japanese: an association study using a novel variation screening method

CTLA-4 is considered to be one of the attractive candidates for the susceptibility genes to rheumatic diseases. In the present study, the association of CTLA-4 polymorphism with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) was examined in the Japanese population using the case-control association analysis. Polymerase chain reaction-preferential homoduplex formation assay (PCR-PHFA) was applied for the screening of genetic variations and for the genotyping of a large number of samples. A greater proportion of Japanese patients with RA (44%) and SLE (44%) compared with healthy individuals (37%) had exon 1 49 G/G genotype, but the difference did not reach statistical significance. However, when the patients with RA and healthy individuals were stratified according to HLA-DRB1 alleles, a weakly significant increase of the positivity of CTLA-4 49G allele was observed in HLA-DRB1*0405-positive patients (87%) compared with DRB1*0405-positive healthy individuals (71%) (P = 0.014, odds ratio = 2.77). These results indicate that CTLA-4 exon 1 polymorphism does not contribute greatly to the susceptibility to RA and SLE, at least in Japanese, although the presence of CTLA4 49G allele could be a minor predisposing factor for RA in HLA-DRB1*0405-positive individuals. In addition, PCR-PHFA was shown to be useful for a mass screening of gene variations.