Cytotoxic T-lymphocyte Antigen-4 Gene Polymorphisms Research Articles

Graves’ Disease in Brazilian Children and Adults: Lack of Genetic Association with CTLA-4 +49A>G Polymorphism

Background/Aim: In several populations, major histocompatibility complex and CTLA-4 (cytotoxic T lymphocyte antigen-4) gene polymorphisms are related to adult subjects with Graves’ disease (GD). Our aim was to study the association of +49A>G polymorphism of the CTLA-4 gene in Brazilian children and adults with GD and its correlation with clinical and laboratory markers of disease severity. Methods: CTLA-4 +49A>G polymorphism was established by polymerase chain reaction-restriction fragment length polymorphism analysis in 44 children and 72 adults with GD and compared to a stringent control group consisting of octogenarians with no history of thyroid disease; free T₄ and T₃ levels and T₃/T₄ ratio, antithyroid antibodies, and Graves’ ophthalmopathy were also evaluated according to genotype. Results: No significant difference was found in the frequency of CTLA-4 +49A>G polymorphism among children and adults with GD compared to controls and within groups. There was no significant correlation between the presence of G allele and Graves’ ophthalmopathy, gender, age at diagnosis, and biochemical markers of disease severity. Conclusion: The frequency of CTLA-4 +49A>G polymorphism is not different in children and adults with GD compared to the normal control population and does not seem to contribute independently to the severity of the clinical presentation of GD.

Association studies of CTLA-4, CD28, and ICOS gene polymorphisms with B-cell chronic lymphocytic leukemia in the Polish population

Abnormal expression of the costimulatory molecules cytotoxic T-lymphocyte antigen 4 (CTLA-4), CD28, and inducible co-stimulator (ICOS) leads to disturbances of immune response and an increased risk of cancer. An extended study was undertaken to evaluate the association among the polymorphisms CTLA-4c.49A>G, CTLA-4g.319C>T, CTLA-4g.*642AT(8_33), CD28c.17+3T>C, and ICOSc.1554+4GT(8_15) and susceptibility to B-cell chronic lymphocytic leukemia (B-CLL) in the Polish population. The study revealed increased frequency of the CTLA-4g.319C>T [T] allele and the CTLA-4g.319C>T [T] phenotype in B-CLL patients compared with healthy controls (p = 0.003, odds ratio [OR] = 1.73; and p = 0.009, OR = 1.74, respectively). The presence of the CD28c.17+3T>C [C] allele and the CD28c.17+3T>C [C] phenotype increased the OR of B-CLL to 1.59 (p = 0.007) and 1.74 (p = 0.007), respectively. Either CTLA-4g.319C>T or CD28c.17+3T>C was associated with time to Rai stage progression. The distributions of the alleles and genotypes of the ICOS gene significantly differed between patients and controls (p = 0.0009 and p = 0.006, respectively). Individuals possessing short alleles were 2.02 times more prone to B-CLL than others (p = 0.001), whereas carriers of long alleles were protected from B-CLL (p = 0.02, OR = 0.62). The haplotype association study and multivariate analysis confirmed the association of CTLA-4g.319C>T and ICOSc.1554+4GT(8_15) gene polymorphisms with B-CLL. The polymorphic sites CTLA-4c.49A>G and CTLA-4g.*642AT(8_33) did not correlate with B-CLL. Our results are the first in the literature to report that gene polymorphism of the costimulatory molecules CTLA-4, CD28, and ICOS contributes to susceptibility to B-CLL.

Increased frequency of the CTLA‐4 49 A/G polymorphism in patients with acquired haemophilia A compared to healthy controls

Acquired haemophilia (AH) is an autoimmune disorder characterized by autoantibodies against endogenous factor VIII (FVIII). Half of the patients present with an underlying disease known to cause the FVIII autoantibodies whereas in the other half the disease is of idiopathic nature. Recently, it has been shown that variants of the polymorphic cytotoxic T lymphocyte antigen-4 (CTLA-4) gene are associated with autoimmune diseases and also represent a risk factor for inhibitor formation in inherited haemophilia A. In the present study, we investigated whether CTLA-4 variants also play a role in the pathogenesis of AH. Therefore, we analyzed three single nucleotide polymorphisms (SNPs) of the CTLA-4 gene (-318 C/T, +49 A/G and CT60 A/G) in 57 AH patients and 98 controls. The CTLA-4 + 49 G allele occurred with a significantly higher frequency in patients with AH compared with controls [odds ratio (OR) = 2.17, 95% confidence interval (CI): 1.36-3.48, P = 0.001]. This effect was mainly caused by a higher frequency of the 49 G allele in female patients (OR = 5.1, 95% CI: 1.76-15.02, P = 0.002), whereas in males the frequencies were not significantly different (OR = 1.4, P = 0.5). A higher frequency of the G allele was also observed in the subcohort with AH and underlying autoimmune disease (OR = 3.1, P = 0.04). Our observations of a higher frequency of the CTLA-4 + 49 A/G SNP in AH patients are in concordance with findings in other autoimmune disorders. In conclusion, on the background of the CTLA-4 gene polymorphism, further genetic and/or environmental factors might contribute to and finally trigger the clinical manifestation of AH.

Association of CTLA-4 gene polymorphisms with sporadic breast cancer in Chinese Han population

BackgroundThe host immunogenetic background plays an important role in the development of breast cancer. Cytotoxic T-lymphocyte antigen-4 (CTLA-4) is a molecule expressed predominantly on activated T cells and is important during the down-regulation of T-cell activation. To evaluate the potential influences of CTLA-4 gene polymorphisms on breast cancer risk, a case-control study was conducted in Han women of Northeast China.MethodsWe genotyped CTLA-4 variants (-1661 G/A, -658 T/C, -318 T/C, +49 G/A and CT60 G/A) to tag all common haplotypes (≥ 1% frequency) in 117 Chinese breast cancer cases and 148 age/sex matched healthy individuals. Genotypes were determined by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Data was analyzed using the Chi-square test and Haploview software.ResultsThe frequency of CTLA-4 -1661G allele, -318T allele and CT60G allele carriers was significantly higher in patients than in controls (P = 0.0057, OR 1.91, 95% CI 1.21–3.02; P = 0.0031, OR 2.39, 95% CI 1.34–4.27; P = 0.023, OR 1.52, 95% CI 1.06–2.17, respectively). The -658T allele carrier frequency was significantly lower than in controls (P = 0.0000082, OR 0.17, 95% CI 0.08–0.37), whereas the +49A allele was significantly associated with tumor size in patients (P = 0.0033). Two common CTLA-4 haplotypes, ATCGA and ATCAG, were higher in healthy controls than patients (P = 0.0026, OR 0.17, 95% CI 0.05–0.54; P = 0.034, OR 0.12, 95% CI 0.02–0.92, respectively). A strong association was observed between tumor size and the ACCAA, ACCAG and ACCGA haplotypes (P = 0.0032, P = 0.0000031 and P = 0.017).ConclusionThese results suggest that polymorphisms of the CTLA-4 gene may modify individual susceptibility to and progression of breast cancer in Chinese Han women.

POSSIBLE ASSOCIATION OF CYTOTOXIC T LYMPHOCYTE ANTIGEN-4 GENETIC POLYMORPHISM WITH LIVER DAMAGE OF PRIMARY BILIARY CIRRHOSIS IN JAPAN

Cytotoxic T lymphocyte antigen-4 (CTLA-4) is an important inhibitor of T-lymphocyte response. Polymorphisms in the CTLA-4 gene have been reported to be associated with numerous autoimmune diseases. The aim of this study was to determine whether polymorphisms of CTLA-4 exon 1 (+49) genes are associated with susceptibility and clinicolaboratory findings of primary biliary cirrhosis (PBC) in the Japanease population. Blood samples were obtained from 45 patients (6 men and 39 women, aged 23-56 years) with PBC and 73 healthy controls (48 men and 25 women, aged 22-72 years). CTLA-4 exon 1 (+49) polymorphism was defined using a polymerase chain reaction-restriction fragment length polymorphism with Bst71I restriction enzyme. The genotype frequencies of A/A, A/G, and G/G in 45 patients with PBC were 11% (5 patients), 44% (20 patients), and 44% (20 patients), respectively. There was no significant difference between frequencies in PBC patients and healthy controls. PBC patients with G/G genotype had significantly higher serum levels of ALT, GGT, and IgM than those in patients with A/A or A/G genotype. In conclusion, CTLA-4 gene polymorphisms are not associated with susceptibility of PBC in Japan; however, G/G genotype may be associated with liver damage.

Cytotoxic T-lymphocyte antigen 4 gene polymorphisms and susceptibility to chronic hepatitis B

To assess the three polymorphism regions within cytotoxic T-lymphocyte antigen 4 (CTLA-4) gene, a C/T base exchange in the promoter region -318 (CTLA-4 -318C/T), an A/G substitution in the exon 1 position 49 (CTLA-4 49A/G), a T/C substitution in 1172 (CTLA-4 -1172T/C) in patients with chronic hepatitis B. Fifty-one patients with chronic hepatitis B virus infection and 150 healthy subjects were recruited sequentially as they presented to the hepatic clinic. Classification of chronic hepatitis B virus (HBV)-infected patients was as asymptomatic carrier state (26 patients) and chronic hepatitis B (25 patients). Genomic DNA was isolated from anti-coagulated peripheral blood Buffy coat using Milleros salting-out method. The presence of the CTLA-4 gene polymorphisms was determined using polymerase chain reaction amplification refractory mutation system (ARMS). We observed a significant association between -318 genotypes frequency (T+C-, T+C+, T-C+) and susceptibility to chronic hepatitis B (P=0.012, OR=0.49, 95%CI: 0.206-1.162). However, we did not observe a significant association for +49 genotype frequency (T+C+, T+C- T-C+) and -1172 genotype frequency (C+T+, T+C- C+T-) and state of disease. Our results suggest that CTLA-4 gene polymorphisms may partially be involved in the susceptibility to chronic hepatitis B.

Association of HLA-DR, -DQ Genotype and CTLA-4 Gene Polymorphism with Graves’ Disease in Japanese Children

Objective: Childhood onset Graves’ disease (GD) has been documented to be clinically distinct from adult onset GD, and an association with the genes encoding HLA and CTLA-4 (cytotoxic T lymphocyte antigen-4) has been reported in both Caucasian and Japanese adult GD patients. The aim of this study was to determine whether HLA-DR, -DQ and CTLA-4 are associated with childhood onset GD in Japanese individuals. Methods: We investigated the genotype of HLA class II (DRB1, DQB1) and the A/G transition polymorphism of CTLA-4 exon 1 position 49 in 43 GD patients and in healthy controls for comparison. The CTLA-4 alleles were identified by the polymerase chain reaction (PCR) of genomic DNA and restriction fragment-length polymorphism analysis (PCR-RFLP) with Ita1. Results: The frequency of both HLA-DRB1*0405 and DQB1*0401 was increased in the patient group (DRB1*0405: 26.7%, p < 0.001; DQB1*0401: 25.6%, p < 0.005) compared with the controls. Patients with GD had a significantly lower frequency of the AA genotype of CTLA-4 than the controls, but there was no difference in allele frequency between the G and A allele. Conclusions: the association of HLA-DRB1 and DQB1 genotype with susceptibility to childhood onset GD differs from that in adult onset GD, whereas the association between CTLA-4 gene polymorphism and childhood onset GD is similar to that in adult onset GD in Japanese individuals, but the association is weak.

Progression of multiple sclerosis is associated with exon 1 CTLA-4 gene polymorphism.

Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system which is widely believed to have a T-cell-mediated etiology. The cytotoxic T-lymphocyte antigen-4 (CTLA-4) antigen molecule plays a key role in the downregulation of T-cell responses. To examine the genetic association of the CTLA-4 gene locus with MS, we analyzed an exon 1 (A49G) transition. One hundred and fifty-two MS patients and 154 controls were examined. The A/G transition was genotyped by a polymerase chain reaction followed by labeling with a SNaPshot kit and detection using a capillary genetic analyzer. The genotype, allele and phenotype frequencies did not differ significantly between MS patients and controls. Those MS patients with AA and AG genotypes had 4.36 times greater risk of progressing from the relapsing-remitting to the secondary progressive form of the disease than those with the GG genotype. The results of our study indicate that CTLA-4 (A49G) exon 1 polymorphism is associated with MS progression.

No evidence for an association of the CTLA4 gene with bipolar I disorder.

The purpose of the present paper was to investigate the relationship between the first exon at position +49 (A/G) polymorphism of the cytotoxic T lymphocyte antigen 4 (CTLA4) gene and bipolar disorder. Among the Korean patients diagnosed with bipolar disorder according to Diagnostic and Statistical Manual of Mental Disorders (4th edn; DSM-IV), 90 patients without serious medical illness, neurologic illness, hormonal disorder, or concomitant mental illness were selected. The normal control group consisted of 149 age- and sex-matched subjects without current or past history of autoimmune diseases or mental disorder. DNA was extracted from peripheral blood using proteinase K; and the exon 1 region of the CTLA4 gene was amplified by polymerase chain reaction. Gene typing was performed using single strand conformation polymorphism. There were no significant differences in genotype frequencies of CTLA4*G/G, CTLA4*G/A, and CTLA4*A/A between the patients with bipolar disorder and the control group (48.9% vs 46.3%, 44.4% vs 39.6%, and 6.7% vs 14.1%, respectively). There were no significant differences in allelic frequencies of CTLA4*G and CTLA4*A between the patients with bipolar disorder and the control group (71.1% vs 66.1%; 28.9% vs 33.9%, respectively). In the present study an association was not found of exon 1 (+49) polymorphism of CTLA4 gene with bipolar disorder in the Korean population.

Cytotoxic T lymphocyte antigen–4 gene polymorphisms do not confer susceptibility to autoimmune hepatitis types 1 and 2 in Brazil

Objectives Susceptibility to autoimmune hepatitis (AIH) has been linked to different HLA-DR antigens in distinct populations. Recently, an A–G polymorphism in exon 1 of the cytotoxic T lymphocyte antigen-4 (CTLA-4) gene was associated with predisposition to AIH type 1 (AIH-1) in white individuals in North America. This polymorphism has been associated with several other autoimmune diseases, presumably because of its effect in the expression of CTLA-4, an adhesion molecule that downregulates peripheral T cell responses. The aims of this study were to assess the frequency of CTLA-4 genotypes in Brazilian patients with AIH-1 and AIH type 2 (AIH-1), as well as to investigate the influence of these genotypes in disease expression. Methods Determination of CTLA-4 genotypes was carried out in 106 patients with AIH-1, 26 subjects with AIH-2, and 67 healthy control subjects by polymerase chain reaction (PCR)–based techniques. Results No difference in the distribution of CTLA-4 genotypes was observed in subjects with AIH-1 and AIH-2 as compared to healthy controls. Patients with AIH-1 and AIH-2 with the GG genotype exhibited lower γ-globulin and ALT levels, respectively. Conclusions Susceptibility to AIH-1 and AIH-2 in Brazilian patients is not influenced by exon 1 CTLA-4 gene polymorphisms at position 49.

Cytotoxic T lymphocyte antigen-4 gene polymorphisms do not confer susceptibility to autoimmune hepatitis types 1 and 2 in Brazil.

Susceptibility to autoimmune hepatitis (AIH) has been linked to different HLA-DR antigens in distinct populations. Recently, an A-G polymorphism in exon 1 of the cytotoxic T lymphocyte antigen-4 (CTLA-4) gene was associated with predisposition to AIH type 1 (AIH-1) in white individuals in North America. This polymorphism has been associated with several other autoimmune diseases, presumably because of its effect in the expression of CTLA-4, an adhesion molecule that downregulates peripheral T cell responses. The aims of this study were to assess the frequency of CTLA-4 genotypes in Brazilian patients with AIH-1 and AIH type 2 (AIH-1), as well as to investigate the influence of these genotypes in disease expression. Determination of CTLA-4 genotypes was carried out in 106 patients with AIH-1, 26 subjects with AIH-2, and 67 healthy control subjects by polymerase chain reaction (PCR)-based techniques. No difference in the distribution of CTLA-4 genotypes was observed in subjects with AIH-1 and AIH-2 as compared to healthy controls. Patients with AIH-1 and AIH-2 with the GG genotype exhibited lower gamma-globulin and ALT levels, respectively. Susceptibility to AIH-1 and AIH-2 in Brazilian patients is not influenced by exon 1 CTLA-4 gene polymorphisms at position 49.

Cytotoxic T-lymphocyte antigen-4 gene polymorphisms and human T-cell lymphotrophic virus-1 infection: their associations with Hashimoto's thyroiditis in Japanese patients.

Cytotoxic T-lymphocyte antigen-4 (CTLA-4) decreases the immune response of T cells by inactivating the signal that occurs with interaction between CD28 on T cells and B7 on antigen-presenting cells. Gene polymorphisms involving CTLA-4 promoter (-318 C/T), exon 1 (49 A/G), and exon 4 (microsatellite (AT)n) have been linked to Hashimoto's thyroiditis (HT) and other autoimmune diseases. HT also has a reported association with human T-cell lymphotrophic virus-1 (HTLV-1) infection. We investigated the occurrence of CTLA-4 polymorphisms in Japanese patients with HT with and without anti-HTLV-1 antibodies (HTLV-1 Ab). DNA samples from 143 patients with HT and 199 controls were subjected to polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis using the restriction enzymes, Bbv 1, Tse 1, and Mse 1. In the HTLV-1 Ab-positive group the exon 1 G allele was more frequent in patients with HT than in controls (67% vs. 53%, p = 0.0377), and in HTLV-1 Ab-negative group it was also frequent in patients with HT than in controls (68% vs. 53%, p = 0.0041). Frequency of the G allele in HT with HTLV-1 Ab was comparable to those without HTLV-1 Ab. Frequency of polymorphism in the promoter did not differ between patients with HT and controls, nor between controls with and without HTLV-1 Ab. HTLV-1 infection is not associated with CTLA-4 polymorphisms in either HT or controls. HTLV-1 infection is not regulated by genetic factor such as CTLA-4, and may affect occurrence of HT as an independent purely environmental factor.

Association of the CTLA4 3′ untranslated region polymorphism with the susceptibility to rheumatoid arthritis

Cytotoxic T-lymphocyte antigen 4 (CTLA4) gene polymorphism located in the 3′ untranslated region (UTR) was investigated in 141 Spanish patients (38 men and 103 women) with rheumatoid arthritis (RA) and in 194 ethnically-matched healthy controls. Twenty alleles having different numbers of (AT) repeats (from 7 to 32) were found in this population. (AT)7 and (AT)16 were the most frequent alleles, and accounted for almost two-thirds of the allelic frequency in the control population. Consequently, alleles were assigned as L (large: 16 or more AT repeats) or S (short: less than 16 AT repeats). When the L/S distribution in patients and controls were compared, an increase of L alleles was observed among patients (49.9% vs. 39.7%; p = 0.02; pc = 0.04, odds ratio [OR] = 1.46; 95% confidence interval [CI], 1.06–2.01). Hence, the frequency of S alleles was decreased among patients (51.1% vs. 60.3%; p = 0.02; pc = 0.04; OR = 0.69; 95%CI, 0.50–0.95). Moreover, a statistically significant decrease in the frequency of S/S individuals was observed among RA patients (27.7% versus 40.7%; p = 0.01; pc = 0.03; OR = 0.56; 95%CI, 0.34–0.91). These differences were irrespective of the HLA “shared epitope” (SE) status, and were observed similarly among SE+ as well as among SE− patients. After combining these data with other reported previously by us, from studies of CTLA4 49 (A/G) and −318 (C/T) polymorphisms, we conclude that the strongest association between CTLA4 gene polymorphisms and RA susceptibility occurs with the 3′ UTR polymorphism.

CTLA-4/CD 28 region polymorphisms in children from families with autoimmune hepatitis

Susceptibility to autoimmune hepatitis is associated with particular human leucocyte antigen class II alleles. However, non-HLA genetic factors are likely to be required for development of the disease. Among the candidate genes, the cytotoxic T-lymphocyte antigen 4 (CTLA-4) and CD28 genes, located on chromosome 2q33 in humans, encode a cell surface molecule playing a dominant role in the regulation of T-cell activation. The CTLA-4 and CD28 polymorphisms were investigated in children from 32 families with autoimmune hepatitis (AIH). The transmission/disequilibrium test revealed increased transmission of the (AT)8 (dinucleotide repeat) and A (exon 1) alleles of CTLA-4 gene from heterozygous parents to affected offspring (87.5% and 83.5%) with type 1 AIH, compared with unaffected offspring (50.0% for both, p = 0.009 and 0.02, respectively). In contrast, no deviation in transmission for CTLA-4 polymorphisms was found between type 2 AIH patients and unaffected offspring. No evidence for association was found between CD28 gene polymorphism or D2S72 genetic marker and both types of AIH. This study identified the CTLA-4 gene polymorphism as a non-HLA determinant that predisposes to AIH type 1 in children. The genetic heterogeneity seen in the present study provides a new argument in favor of pathogenic differences between type 1 and type 2 AIH.

Cytotoxic T-lymphocyte antigen 4 gene polymorphisms and susceptibility to acute allograft rejection.

Cytotoxic T-lymphocyte antigen 4 (CTLA4) has been shown to play a critical role in the down-regulation of the immune response. We retrospectively examined the association between acute rejection and two polymorphisms in the CTLA4 gene, the dinucleotide (AT)n repeat polymorphism in exon 3 and the single nucleotide polymorphism A/G at position 49 in exon 1, in a cohort of liver and kidney transplant recipients. A total of 207 liver and 167 renal transplant recipients were analyzed. In the case of the (AT)n repeat polymorphism we found an increased incidence of acute rejection in association with allele 3 and 4 in both liver and kidney (P=0.002 and 0.05, respectively). In addition, in liver transplant recipients, allele 7 was associated with acute rejection independent of ethnicity (P<0.05). Allele 1 was less frequently observed in African American as compared with Caucasian liver and kidney transplant recipients, with a frequency of 33.8% and 69%, respectively (P<0.0001). Those patients with allele 1 had a tendency toward a lower rate of rejection at 42% versus 57.8% (P=0.058), suggesting a potential protective effect of allele 1. Analysis of the A/G single nucleotide polymorphism demonstrated no association between either allele and the incidence of acute rejection in the patients studied. These initial observations provide the necessary basis to further investigate the risk stratification of transplant recipients based on specific CTLA4 gene polymorphisms.

No Association of Type 1 Diabetes with a Microsatellite Marker for CTLA-4 in a Japanese Population

Susceptibility to insulin-dependent (type 1) diabetes mellitus is determined by both environmental and genetic factors. The primary gene associated with predisposition to type 1 diabetes is the human leukocyte antigen (HLA) class II gene (IDDM1). Recent studies have described linkage and association of type 1 diabetes to the cytotoxic T lymphocyte antigen-4 (CTLA-4) gene (IDDM12)m Caucasians. CTLA-4 is a candidate gene for T-cell-mediated autoimmune diseases because it is a negative regulator of T-cell proliferation. We investigated distribution of a CTLA-4 (AT)n microsatellite marker in 118 Japanese patients with type 1 diabetes and 195 control subjects. We also investigated association between this CTLA-4 gene polymorphism and GAD65 antibody positivity in 103 of the patients. CTLA-4 microsatellite marker loci were determined by polymerase chain reaction amplification of genomic DNA and resolution of the products on sequencing gels. GAD65 antibody was detected by radioligand binding assay. There was no significant difference in the distribution of CTLA-4 alleles between patients and controls, and no difference was observed in the prevalence of CTLA-4 alleles when GAD65 antibody-positive and -negative individuals with the type 1 diabetes were compared. The present study did not support an association between the CTLA-4 microsatellite marker and type 1 diabetes in our Japanese study population