Cytotoxic T Lymphocyte Associated-4 Research Articles

Graves Disease (Thyroid Storm) with Polyautoimmune Disorders (Autoimmune Hemolytic Anemia and Probable Autoimmune Hepatitis)

Graves' disease is caused by IgG antibodies that bind to the Thyroid Stimulating Hormone (TSH) receptor on the surfaceof the thyroid gland. These bonds drive the growth of stimulated thyroid follicular cells causing the glands to enlarge andincrease the production of thyroid hormones. Previous studies mention the association of HLA-B8 and HLA-DR3 withGraves' disease and the Cytotoxic T-lymphocyte-associated-4 (CTLA-4) gene on chromosome 2q33 as a result of reducingT-cell regulation, resulting in autoimmune disease. Autoimmune thyroid disease is often found together with otherautoimmune disorders (polyautoimmune). A 51-year-old male complained of dyspnea, yellowing of the body, and a lumpon the neck. One year ago, he was diagnosed with hyperthyroidism. Graves' disease was suspected due to a score of 22 forthe Wayne index, FT4 96.9 pmol/L, TSHs <0.01 μIU/mL, TRAb 10.8 IU/L, thyroid uptake test for toxic diffuse struma. Inaddition, the patient had atrial fibrillation and a thyroid storm with a Bruch Wartofsky index score of 65. Laboratoryexamination found normocytic normochromic anemia, thrombocytopenia, reticulocytosis, direct coomb test and autocontrol results positive one, SGOT 87 U/L, SGPT 59 U/L, alkali phosphatase 166 U/L, total bilirubin 38.13 mg/dL, directbilirubin 16.59 mg/dL, indirect bilirubin 21.54, LDH 318 U/L, establishing the diagnosis of Autoimmune Hemolytic Anemia(AIHA). Autoimmune hepatitis score: 15, so a diagnosis of probable autoimmune hepatitis was made.

Checkpoint inhibitor induced hepatitis and the relation with liver metastasis and outcome in advanced melanoma patients

BackgroundCheckpoint inhibitor-induced hepatitis is an immune-related adverse event of programmed cell death protein 1 (PD-1) inhibition, cytotoxic T-lymphocyte associated 4 (CTLA-4) inhibition or the combination of both. Aim of this study was to assess whether checkpoint inhibitor-induced hepatitis is related to liver metastasis and outcome in a real-world nationwide cohort.MethodsData from the prospective nationwide Dutch Melanoma Treatment Registry (DMTR) was used to analyze incidence, risk factors of checkpoint inhibitor-induced grade 3–4 hepatitis and outcome.Results2561 advanced cutaneous melanoma patients received 3111 treatments with checkpoint inhibitors between May 2012 and January 2019. Severe hepatitis occurred in 30/1620 (1.8%) patients treated with PD-1 inhibitors, in 29/1105 (2.6%) patients treated with ipilimumab and in 80/386 (20.7%) patients treated with combination therapy. Patients with hepatitis had a similar prevalence of liver metastasis compared to patients without hepatitis (32% vs. 27%; p = 0.58 for PD-1 inhibitors; 42% vs. 29%; p = 0.16 for ipilimumab; 38% vs. 43%; p = 0.50 for combination therapy). There was no difference in median progression free and overall survival between patients with and without hepatitis (6.0 months vs. 5.4 months progression-free survival; p = 0.61; 17.0 vs. 16.2 months overall survival; p = 0.44).ConclusionIncidence of hepatitis in a real-world cohort is 1.8% for PD-1 inhibitor, 2.6% for ipilimumab and 20.7% for combination therapy. Checkpoint inhibitor-induced hepatitis had no relation with liver metastasis and had no negative effect on the outcome.

MiR-181a/b-1 controls thymic selection of Treg cells and tunes their suppressive capacity.

The interdependence of selective cues during development of regulatory T cells (Treg cells) in the thymus and their suppressive function remains incompletely understood. Here, we analyzed this interdependence by taking advantage of highly dynamic changes in expression of microRNA 181 family members miR-181a-1 and miR-181b-1 (miR-181a/b-1) during late T-cell development with very high levels of expression during thymocyte selection, followed by massive down-regulation in the periphery. Loss of miR-181a/b-1 resulted in inefficient de novo generation of Treg cells in the thymus but simultaneously permitted homeostatic expansion in the periphery in the absence of competition. Modulation of T-cell receptor (TCR) signal strength in vivo indicated that miR-181a/b-1 controlled Treg-cell formation via establishing adequate signaling thresholds. Unexpectedly, miR-181a/b-1–deficient Treg cells displayed elevated suppressive capacity in vivo, in line with elevated levels of cytotoxic T-lymphocyte–associated 4 (CTLA-4) protein, but not mRNA, in thymic and peripheral Treg cells. Therefore, we propose that intrathymic miR-181a/b-1 controls development of Treg cells and imposes a developmental legacy on their peripheral function.

Actualités et perspectives concernant l’immunothérapie en oncologie thoracique

STATE OF THE ART AND PERSPECTIVES: Immune checkpoint inhibitors (ICI) are monoclonal antibodies that inhibit molecular interaction between an immune checkpoint and its ligand, which leads to increased anti-tumoral immune response, Programmed Death 1 (PD-1) and Cytotoxic T-Lymphocyte Associated-4 (CTLA-4) are the most commonly known immune checkpoints. ICIs are currently placed early in the course of the treatment of patients with non-small cell lung cancer (NSCLC). In France, approvals have been pronounced for nivolumab and pembrolizumab (anti-PD-1 antibodies) as second-line treatments after chemotherapy in patients with advanced NSCLC, and pembrolizumab has been approved as a first-line treatment in patients with advanced NSCLC, without EGFR mutation or ALK rearrangement, with strong (≥50%) PD-L1 (Programmed Death Ligand 1) expression. Atezolizumab is currently soon to be approved as a second-line treatment. Numerous studies are currently evaluating ICIs in thoracic oncology. In this article, we will develop perspectives regarding ICIs for early stage or locally advanced NSCLCs, ICIs used in other thoracic cancers (small cell lung cancer, malignant pleural mesothelioma, thymic epithelial tumors), and trials with combinations involving ICIs: two ICIs combined, or ICIs combined with chemotherapy, radiotherapy or other anti-cancer treatments.

Actualités et perspectives concernant l’immunothérapie au cours des CBNPC

Immune checkpoint inhibitors (ICI) are monoclonal antibodies that inhibit molecular interaction between an immune checkpoint and its ligand, which leads to increased anti-tumoral immune response. Programmed Death-1 (PD-1) and Cytotoxic T-lymphocyte Associated 4 (CTLA-4) are the most commonly known immune checkpoints.ICI now have their place in the management of non-small cell lung cancer (NSCLC), with FDA approvals after chemotherapy for nivolumab, pembrolizumab (anti-PD-1 antibodies) and atezolizumab (anti-PD-LI antibody), and as 1st line treatment for advanced NSCLC without EGFR mutation or ALK rearrangement, with strong (≥50%) PD-L1 (Programmed Death Ligand 1) expression for pembrolizumab.More recently, durvalumab (anti-PD-LI antibody) was approved as consolidation after chemo-radiotherapy for locally advanced NSCLC.In this chapter, we will develop the prospects for ICI in localized perioperative stages and recent results regarding combinations of ICI with chemotherapy or other ICIs in 1st line treatment for advanced NSCLC.

Association of the CTLA4 gene CT60/rs3087243 single-nucleotide polymorphisms with Graves' disease.

It has been widely reported that the CT60 single-nucleotide polymorphism (SNP), which is in the 3'-untranslated region of the cytotoxic T lymphocyte associated 4 (CTLA4) gene, is strongly correlated with certain immune-mediated diseases. The present case-control study aimed to investigate the genetic association between the CT60 SNP within the CTLA4 gene and Graves' disease (GD). A total of 288 patients with GD and 290 control subjects were recruited for the study. The CT60 SNP of the CTLA4 gene was detected by direct DNA sequencing. The results indicated that the frequencies of the GG genotype and G allele in the case group were evidently higher than that in the control group (P=4×10-6 and P=2.9×10-5, respectively). Furthermore, the G/G genotype of the CT60 SNP was associated with an increased risk for GD (odds ratio=2.223). In conclusion, these results suggested that the CT60 SNP is associated with susceptibility to GD. The frequency of the disease-susceptible G allele of CT60 was significantly associated with an increased risk of GD development.

Psoriasis is characterized by deficient negative immune regulation compared to transient delayed-type hypersensitivity reactions

Diphencyprone (DPCP) is a hapten that causes delayed-type hypersensitivity (DTH) reactions in human skin, and is used as a topical therapeutic for alopecia areata, warts, and cutaneous melanoma metastases. We examined peak DTH reactions induced by DPCP (3 days post-challenge) by comprehensive gene expression and histological analysis. To better understand how these DTH reactions naturally resolve, we compared our DPCP biopsies to those from patients with psoriasis vulgaris, a chronic inflammatory disease that does not resolve. By both microarray and qRT-PCR, we found that psoriasis lesional skin has significantly lower expression of many negative immune regulators compared to peak DPCP reactions. These regulators include: interleukin-10, cytotoxic T lymphocyte-associated 4 (CTLA4), programmed cell death 1 (PD1), programmed cell death 1 ligand 1 (PDL1), programmed cell death 1 ligand 2 (PDL2), and indoleamine 2,3-dioxygenase (IDO1). Their decreased expression was confirmed at the protein level by immunohistochemistry. To more completely determine the balance of positive vs. negative immune regulators in both DPCP reactions and psoriasis, we developed one comprehensive gene list for positive regulatory (inflammatory) genes, and another for negative regulatory (immunosuppressive) genes, through Gene Ontology terms and literature review. With this approach, we found that DPCP reactions have a higher ratio of negative to positive regulatory genes (both in terms of quantity and expression levels) than psoriasis lesional skin. These data suggest that the disease chronicity that distinguishes psoriasis from transient DTH reactions may be related to absence of negative immune regulatory pathways, and induction of these is therefore of therapeutic interest. Further study of these negative regulatory mechanisms that are present in DPCP reactions, but not in psoriasis, could reveal novel players in the pathogenesis of chronic inflammation. The DPCP system used here thus provides a tractable model for primary discovery of pathways potentially involved in immune regulation in peripheral tissues.

Psoriasis is characterized by deficient negative immune regulation compared to transient delayed-type hypersensitivity reactions.

Diphencyprone (DPCP) is a hapten that causes delayed-type hypersensitivity (DTH) reactions in human skin, and is used as a topical therapeutic for alopecia areata, warts, and cutaneous melanoma metastases. We examined peak DTH reactions induced by DPCP (3 days post-challenge) by comprehensive gene expression and histological analysis. To better understand how these DTH reactions naturally resolve, we compared our DPCP biopsies to those from patients with psoriasis vulgaris, a chronic inflammatory disease that does not resolve. By both microarray and qRT-PCR, we found that psoriasis lesional skin has significantly lower expression of many negative immune regulators compared to peak DPCP reactions. These regulators include: interleukin-10, cytotoxic T lymphocyte-associated 4 (CTLA4), programmed cell death 1 (PD1), programmed cell death 1 ligand 1 (PDL1), programmed cell death 1 ligand 2 (PDL2), and indoleamine 2,3-dioxygenase (IDO1). Their decreased expression was confirmed at the protein level by immunohistochemistry. To more completely determine the balance of positive vs. negative immune regulators in both DPCP reactions and psoriasis, we developed one comprehensive gene list for positive regulatory (inflammatory) genes, and another for negative regulatory (immunosuppressive) genes, through Gene Ontology terms and literature review. With this approach, we found that DPCP reactions have a higher ratio of negative to positive regulatory genes (both in terms of quantity and expression levels) than psoriasis lesional skin. These data suggest that the disease chronicity that distinguishes psoriasis from transient DTH reactions may be related to absence of negative immune regulatory pathways, and induction of these is therefore of therapeutic interest. Further study of these negative regulatory mechanisms that are present in DPCP reactions, but not in psoriasis, could reveal novel players in the pathogenesis of chronic inflammation. The DPCP system used here thus provides a tractable model for primary discovery of pathways potentially involved in immune regulation in peripheral tissues.

Association of the CTLA4 Gene with Graves' Disease in the Chinese Han Population

To determine whether genetic heterogeneity exists in patients with Graves' disease (GD), the cytotoxic T-lymphocyte associated 4 (CTLA-4) gene, which is implicated a susceptibility gene for GD by considerable genetic and immunological evidence, was used for association analysis in a Chinese Han cohort recruited from various geographic regions. Our association study for the SNPs in the CTLA4 gene in 2640 GD patients and 2204 control subjects confirmed that CTLA4 is the susceptibility gene for GD in the Chinese Han population. Moreover, the logistic regression analysis in the combined Chinese Han cohort revealed that SNP rs231779 (allele frequencies p = 2.81×10−9, OR = 1.35, and genotype distributions p = 2.75×10−9, OR = 1.42) is likely the susceptibility variant for GD. Interestingly, the logistic regression analysis revealed that SNP rs35219727 may be the susceptibility variant to GD in the Shandong population; however, SNP, rs231779 in the CTLA4 gene probably independently confers GD susceptibility in the Xuzhou and southern China populations. These data suggest that the susceptibility variants of the CTLA4 gene varied between the different geographic populations with GD.

Identification of New Susceptibility Genes for Type 1 Diabetes: An Update

With a relative failing of linkage and candidate gene association studies, there has been much sceptism about the ability of geneticists to identify genes for common, complex disorders. In the field of the genetics of type 1 diabetes (T1D), more than twenty years of labor-intensive and cost-expensive effort has resulted in the identification of only four T1D- predisposing loci, which are as follows: Human Leucocyte Antigens (HLA) class II, insulin gene region, cytotoxic T-lymphocyte associated 4 (CTLA-4), and protein tyrosine phosphatase, non-receptor member 22 (PTPN22). Recent technological advances and a better understanding of the genetic architecture of complex diseases has led to the development of the genome-wide association (GWA) study, which is a powerful new approach to identifying genes influencing predisposition to common, complex disease. For T1D, the implication of the GWA approach in 2005 resulted in rapid progress in the discovery of new etiological variants. To date, the involvement in T1D pathogenesis is proven for several new genes such as interleukin 2 receptor alpha (IL2RA/CD25), interferon-induced helicase domain 1 (IFIH1), and small ubiquitin-related modifier 4 (SUMO4). An extended list of likely candidates for T1D susceptibility identified through the GWA approach includes PTPN2, CD226, PPARG2, IL2/IL21, ADAM33, and some other genes. A great benefit to clinical medicine is expected in the years to come, and whilst prediction of disease and pharmacogenetics may eventually prove valuable, the greatest clinical benefit of GWA studies is likely to come from etiological insights into disease processes. Keywords: Genome-wide association, susceptibility, type 1 diabetes

Clinical manifestations and analyses of the cytotoxic T-lymphocyte associated-4 gene in two Japanese families with systemic lupus erythematosus

Although still incompletely understood, the etiology of systemic lupus erythematosus (SLE) is considered to involve both genetic and environmental factors. We encountered two boys with severe SLE from unrelated families and analyzed the gene that encodes cytotoxic T-lymphocyte-associated (CTLA)-4, a protein important in T-cell activation and immune tolerance. Abnormal function of the gene may participate in causation of autoimmune disease, including SLE. In family 1, a boy showed serious cardiovascular complications associated with heart failure, and his mother also had clinically active SLE, including nephritis. A boy in family 2 developed severe renal complications and peripheral vasculitis accompanied by disseminated petechiae in the lower extremities. His paternal grandfather had died from fibrinous pneumonia caused by SLE. They showed high SLE Disease Activity Index (SLEDAI) score. Analysis of the CTLA-4 gene indicated that the boy in family 1 and his mother and the boy in family 2 possess a GG genotype in CTLA-4 exon 1 at +49 together with a 106-bp fragment length of the 3' untranslated region (UTR) in exon 4. No association with disease activity was found for polymorphism of the promoter region in exon 1 at -318 in either family. Disorders of the CTLA-4 gene, especially a GG genotype in exon 1 at +49 and/or 106-bp fragment length of the 3'UTR in exon 4, may be involved in early development of SLE in Japanese children, such as the boys described here.

Susceptible Genes of Autoimmune Thyroid Diseases

The genetic basis of autoimmune thyroid disease (AITD), which includes Graves’ disease (GD) and Hashimoto’s thyroiditis (HT), is thought to be polygenic. The genetic factors have been shown by twin studies and familial aggregation, including clustering of GD and HT within the same families. While the genetic basis of AITD is unclear, it is believed to be polygenic. Identification of genetic factors will contribute to not only the understanding of pathogenesis of AITD, but also the prevention and treatment of the diseases. Several genetic factors associated with AITD susceptibility have been tentatively identified. Some are molecules related to immune responses including the human leukocyte antigen (HLA) and the cytotoxic T lymphocyte associated-4 (CTLA-4) genes. Others are those related to thyroid-specific autoantigens including the thyrotropin receptor (TSHR) gene. As part of a genome scan to locate familial GD and HT genes, other additional chromosomal locations including chromosome 8q and 5q have been reported in a Japanese population. As the next step, ZFAT (zinc-finger gene in AITD susceptibility region) gene was identified as one of the susceptibility genes in 8q23-q24. In addition, we found that a particular allele of intron 7 or near this region of the TSHR gene may contribute to GD susceptibility. Here, I introduce our recent studies on genetics of AITD.

HLA, CTLA-4 and PTPN22: the shared genetic master-key to autoimmunity?

Several genetic loci appear to be involved in susceptibility to autoimmune disease. Some loci are disease specific, whereas others appear to exert a general effect on the autoimmune disease process. Despite a large number of studies of many different diseases, consistent associations with multiple autoimmune disorders have been restricted to three gene regions: the human leukocyte antigen (HLA) class II region on chromosome 6p21, the gene encoding cytotoxic T lymphocyte-associated 4 (CTLA-4) on chromosome 2q33, and the PTPN22 gene encoding lymphoid tyrosine phosphatase (LYP) on chromosome 1p13. Each of these loci is likely to encode molecules that are crucial in the immune cascade and are actively involved in T-cell activation. Moreover, gene polymorphisms that affect function might contribute to the triggering of autoimmune disease by as-yet-unknown mechanisms. This review summarises recent developments and current understanding of the way in which molecules encoded by these susceptibility loci contribute to T-cell activation, and hypothesises how aberrant function of these molecules might trigger autoimmunity.

A study of costimulatory factors in tonsils of pustulosis palmaris et plantaris

Pustulosis palmaris et plantaris (PPP) is known to be closely related to tonsillar focal infections and tonsillectomy is quite effective. Hyper-immune response to alpha streptococci in patients with PPP was reported. On the other hand, costimulatory factors were studied on autoimmune disease. CD28 and cytotoxic T lymphocyte-associated 4 (CTLA4) participate in these factors. CD28 take part in T-cell activation, while CTLA4 take part in T-cell suppression. Therefore, we investigated CD28 and CTLA4 mRNA levels by reverse transcription-polymerase chain reaction (RT-PCR) in tonsillar tissues and CD3 positive lymphocytes from patients with PPP, recurrent tonsillitis (RT), and obstructive sleep apnea syndrome (OSAS). We also investigated the expression levels of CD28 and CTLA4 by flow cytometry analysis in tonsillar mononuclear cells stimulated with alpha streptococci in these patients. It was revealed that the CTLA4 mRNA in tonsillar CD3 positive lymphocytes from PPP patients was expressed at lower level than non-PPP patients. Then, the expression levels of CTLA4, comparison before and after stimulation, were lower level in PPP patients than non-PPP patients. These results suggest that the lower expression level of CTLA4 in PPP may cause hyper-immune response to alpha streptococci and abnormal regulation of T-cell activation.

Association of CTLA-4 variation with type I diabetes in Filipinos.

The role of non-HLA single nucleotide polymorphisms from a panel of candidate genes in genetic susceptibility to type I diabetes (TID) among Filipinos was examined by PCR/SSOP typing of 90 patients and 94 controls, previously typed for the HLA class I and class II loci. We report the association of CTLA-4 A49G variation (cytotoxic T-lymphocyte associated-4) to TID among Filipinos, consistent with some but not all previous reports in other ethnic groups. The G allele frequency (0.61 versus 0.45, P=0.003) and GG genotype frequency (0.42 versus 0.22, P=0.004) were each increased in patients compared to controls, respectively. Among Filipinos, the CTLA-4 genotypes are associated with disease only in the presence of the predisposing DR3, 4, and 9 haplotypes (P=0.012). Compared to the AA genotype, the increased risk of diabetes predisposition is greatest in genotype GG bearing the DR susceptible alleles (DR3, 4, and 9) (odds ratio=4.6, P=0.001), demonstrating that non- HLA loci, acting in concert with HLA, can play potent roles in modifying susceptibility to TID.

Polymorphism of the CTLA-4 gene is associated with autoimmune hypothyroidism in the United Kingdom.

The cytotoxic T-lymphocyte-associated-4 (CTLA-4) molecule plays an important role in immune regulation by downregulating activation of T cells by antigen-presenting cells. Polymorphisms of the CTLA-4 gene have been shown to be associated with susceptibility to a number of autoimmune diseases. Some, but not all, studies suggest association between the CTLA-4 gene and autoimmune hypothyroidism. The aim of this study was to determine whether allelic association was present between the A-G single nucleotide polymorphism (SNP) at position 49 in exon 1 of the CTLA-4 gene and autoimmune hypothyroidism. The study was performed in 158 patients with autoimmune hypothyroidism and 384 control subjects. All subjects were white Caucasians from the United Kingdom. Genotyping was carried out by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) using the restriction enzyme Bbv1. There was a significant excess of the G allele in patients with autoimmune hypothyroidism compared with controls (43% vs. 32% respectively; chi2 = 10.7, p = 0.001; odds ratio 1.57). The GG and the AG genotypes were found to be more frequent in patients with autoimmune hypothyroidism than controls (17% vs. 8.8% and 50% vs. 46% respectively; chi2 = 11.7, p = 0.003). These results suggest that the CTLA-4 gene region on chromosome 2q33 is a susceptibility locus for autoimmune hypothyroidism in the United Kingdom.

Étude de l'association entre diabète type 1 et polymorphisme du gène CTLA-4 dans une population tunisienne

Susceptibility to type 1 diabetes mellitus is strongly associated with particular HLA class II alleles. However, non HLA genetic factors are likely to be required for the development of disease. The candidate genes include the cytotoxic T lymphocyte associated 4 (CTLA-4) located on chromosome 2q33 and designated (IDDM12), which encodes a cell surface negative signal T molecule providing for activation. We investigated CTLA-4 exon 1 dimorphism in 74 type 1 patients and a control group of 48 healthy subjects from Tunisia using two methods PCR (polymerase chain reaction) allele specific and polymerase chain reaction restriction fragment length polymorphism (PCR RFLP). The CTLA-4/G allele was found on 68.9% in type 1 patients as compared to 51.02% in controls (p = 0.002), mostly in homozygous from 43.24% versus 22.45% (p = 0.0058). This results indicate that CTLA-4/G allele was significantly associated with predisposition to type 1 diabetes in our group from Tunisian population.

A simple method for non-radioactive PCR-SSCP using MDE™ gel solution and a midi gel format:: Application for the detection of variants in the GLUT1 and CTLA-4 genes

The need to identify disease-causing mutations and DNA polymorphisms has increased with the continuing identification of new candidate genes. PCR single-strand conformation polymorphism (PCR-SSCP) is one of the techniques most widely used to identify a mutant sequence or a polymorphism in a known gene. However, the original SSCP protocols using the incorporation of radioactive label and polyacrylamide gel electrophoresis on sequencing gels for detection were labour intensive and time-consuming. Here we describe a simple SSCP protocol using MDE™ gel solution and a midi gel format to detect SSCP variations in the glucose transporter gene GLUT1, that we have previously analysed with the standard radioactive SSCP protocol, and we have also tested this method on the previously described point mutation (A/G transition in exon 1) of the CTLA-4 (cytotoxic T lymphocyte associated-4) gene. All known variants were detected. Based on the results, this technique appears to be simple, with no use of radioactive labels and with easy handling of the gel. Furthermore, it needs little optimisation, is relatively rapid and highly sensitive. We propose this method for the first screening for candidate gene variants.

A single nucleotide polymorphism in exon 1 of cytotoxic T-lymphocyte-associated-4 (CTLA-4) is not associated with rheumatoid arthritis.

Rheumatoid arthritis (RA) is an oligogenic disease for which only one susceptibility locus has been identified to date. Genes involved in T-cell regulation are potential candidates. Association to cytotoxic T-lymphocyte-associated-4 (CTLA-4) protein, a negative regulator of T-cell activation, has previously been described in a subset of German RA patients carrying the HLA DRB1*0401 subtype. Linkage and association with another oligogenic autoimmune disease, insulin-dependent diabetes mellitus, has also been described in a Spanish population. To investigate the association of CTLA-4 with RA in Spanish and UK subjects. Caucasoid UK RA patients (n=192), UK controls (n=96), Spanish RA patients (n=136) and Spanish controls (n=144) were typed for an A/G bi-allelic polymorphism in exon 1 of CTLA-4 using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) (enzyme). No significant differences in the frequency of the G allele or the GG genotype were found in either the UK or Spanish RA patients compared with controls. No significant evidence was found of an association between RA and CTLA-4.

No evidence for allelic association of a human CTLA-4 promoter polymorphism with autoimmune thyroid disease in either population-based case-control or family-based studies.

The cytotoxic T lymphocyte associated-4 (CTLA-4) gene is a candidate for T-cell mediated autoimmune disease and polymorphism has been reported to be associated with both type 1 diabetes and autoimmune thyroid disease. A previously unreported polymorphism of the promoter region of the human CTLA-4 gene has recently been described in a sample of a normal control population. We investigated the distribution of this polymorphism, situated at position -318 to the ATG start codon and resulting in a C-T change leading to an Mse I restriction site, in both population based case control studies and family studies in patients with Graves' disease (Caucasian and Hong Kong Chinese), autoimmune hypothyroidism and systemic lupus erythematosus (SLE). Target DNA was amplified using the polymerase chain reaction and the resulting product was digested using the Mse I restriction enzyme. One hundred and ninety-one white UK Caucasian and 98 Hong Kong Chinese patients with Graves' disease, 78 white UK Caucasian patients with Graves' disease plus family members, 92 white UK Caucasian patients with autoimmune hypothyroidism, 13 white UK Caucasian patients with autoimmune hypothyroidism plus family members, 132 white UK Caucasian patients with systemic lupus erythematosus, 355 white UK Caucasian control subjects and 82 Hong Kong Chinese control subjects. Frequencies of the C and T alleles were compared between patients and control subjects using the chi 2-test and Fisher's exact test for small numbers. No association with the T allele was observed in any of the patient groups studied. These data suggest that the C-T change in exon 1 of the promoter region of the CTLA-4 gene does not play a role, nor is in linkage disequilibrium with a disease causing mutation, in the development of autoimmune disease.