Cytotoxic T-lymphocyte Antigen-4 Gene Research Articles

Unraveling the role of CTLA-4 variants in acute kidney injury after ICI treatments.

e14682 Background: Immune checkpoint inhibitors (ICIs) often result in various immune-related adverse events (irAEs), which limit their therapeutic application and pose challenges to clinical decision-making. Among these irAEs, the incidence rate of ICI-related acute kidney injury (ICI-AKI) is on the rise. Understanding the genetic predisposition to ICI-AKI can inform personalized treatment plans, thereby minimizing risks and optimizing outcomes. This study aims to interrogate risk loci for AKI patients to gain insights into ICI-related AKI in cancer patients and to support the design of more personalized cancer therapies. Methods: This study comprehensively integrates meta-analysis, replication genome-wide association study (GWAS), fine-mapping, and mendelian randomization (MR) to explore potential genetic variants related with ICI-AKI. We first conducted a meta-analysis of 6 ICI pharmacogenomics studies, aggregating effect sizes from these studies using both fixed-effect and random-effects models to address heterogeneity and identified 186 significant genotypes. Subsequently, a GWAS was carried out over the 186 candidate genotypes in an independent cohort from the NIH All of Us program (N = 230,013) using logistic regression, identifying14,773 patients who developed AKI. To identify causal variants, we implemented fine-mapping techniques to further refine our genotype selection. Results: Our study identified genetic variants associated with an increased risk of AKI. Among these, the variant with the strongest association was located at the cytotoxic T lymphocyte antigen 4 (CTLA-4) gene locus, rs3087243 (chr2: 203874196, G>A,T). This genotype exhibited a significant inverse relationship with AKI risk (beta = -8.19e-2, P = 2e-11), suggesting that reduced activity of the CTLA-4 gene may be linked to an elevated risk of developing AKI. Our findings indicate that cancer patients with this genotype may have a lower risk of ICI-related AKI after immunotherapy. In our future study, we will continue investigating significant SNPs including rs3087243 in cancer patients for their ICI-AKI risk. Conclusions: We identified an AKI-tolerant genotype, rs3087243. Patients with this genotype may be safter from developing ICI-related AKI after immunotherapy treatment. This work also highlights the research potential of All of Us clinicogenomics data.

Mechanistic Insights into the Inhibition of a Common CTLA-4 Gene Mutation in the Cytoplasmic Domain.

Cytotoxic T-lymphocyte antigen 4 (CTLA-4) is a pivotal immune checkpoint receptor, playing a crucial role in modulating T-cell activation. In this study, we delved into the underlying mechanism by which a common mutation, G199R, in the cytoplasmic domain of CTLA-4 impacts its inhibitory function. Utilizing nuclear magnetic resonance (NMR) spectroscopy and biochemical techniques, we mapped the conformational changes induced by this mutation and investigated its role in CTLA-4 activity. Our findings reveal that this mutation leads to a distinct conformational alteration, enhancing protein-membrane interactions. Moreover, functional assays demonstrated an improved capacity of the G199R mutant to downregulate T-cell activation, underscoring its potential role in immune-related disorders. These results not only enhance our understanding of CTLA-4 regulatory mechanisms but also provide insights for targeted therapeutic strategies addressing immune dysregulation linked to CTLA-4 mutations.

Assessment of CTLA-4 Gene Expression Levels on CD8+ T Cells in Renal Transplant Patients and Relation with Serum sCTLA-4 Levels.

CTLA-4 (Cytotoxic T Lymphocyte Antigen-4) is an immune regulator molecule that is expressed on a variety of immune cells, including CD4+ and CD8+ T cells. After realizing the significance of this regulator molecule, researchers began to concentrate on its activation or inhibition in cancer. Even though there have been some studies on organ transplantation and autoimmunity, the role of the CTLA-4 molecule in renal transplantation has not been demonstrated. The goal of this study was to see how CTLA-4 gene expression and serum sCTLA-4 levels affected renal transplant patients. Peripheral blood samples were collected before and 1-3 months after renal transplantation from 29 recipients.CD8+ T lymphocytes were separated using magnetic beads and purity of the cells controlled by Flow cytometry. CTLA-4 mRNA levels were determined by Real-Time PCR while serum sCTLA-4 levels were assessed by ELISA. 55% of the patient had decreased level of CTLA-4 mRNA after transplantation when compared to pre-transplantation levels. Moreover 61% of the patient had lower serum sCTLA-4 levels after transplantation. sCTLA-4 levels were decreased 11% of the patients with rejection episode after transplantation when compared to stabile patients (5%). Kidney rejection is a complicated process influenced by numerous unknown factors. Several parameters should be evaluated together to precise rejection episodes or graft dysfunctions. Further research focused on the other immune checkpoint regulator molecules could give an opportunity to have an idea about the effect of these molecules on renal transplantation.

The Relationship Between CTLA-4 (-318 C/T) Polymorphism and Urothelial Cancer Carcinogenesis in Japanese Patients.

Background Urothelial cancer is one of the most common types of urinary system cancer and there are several factors that can influence its growth. One of the most prominent factors among these is genetics. The Cytotoxic T-Lymphocyte Antigen-4 (CTLA-4) gene is suspected to be a susceptibility gene in urothelial carcinoma. The aim of this study is to investigate polymorphism in the CTLA-4 gene (CTLA-4 -318 C/T) and whether it is associated with urothelial cancer. Methods The study population consisted of 253 cases and 272 controls. In this case-control study, DNA was extracted from peripheral blood cells, and the CTLA-4 -318C/T genotypes were detected using polymerase chain reaction-restriction fragment length polymorphism. Results C/T (adjusted OR (aOR) 3.37; 95%CI: 1.98-5.74) genotype, C/T + T/T (aOR 3.25; 95%CI: 1.96-5.39) genotype, and T allele (aOR 2.94 95%CI: 1.87-4.62) all indicated they are significant risk factors for urothelial cancer, with the effects of polymorphism being higher in the nonsmoker group than in the smoker group. Furthermore, the association between polymorphism and urothelial cancer carcinogenesis was similar among men and women. Conclusions This is the first study examining the association between CTLA-4 -318C/T polymorphism and urothelial carcinoma in Japanese patients. A significant association between CTLA-4 -318C/T polymorphism and urothelial cancer among Japanese patients was detected in this study. This supports the development of research on polymorphisms in urothelial cancer and is an important root of immunoreactions in cancer. We believe this study will be beneficial to clarify the relationship between CTLA-4 polymorphism and urothelial cancer.

Unveiling the Etiopathogenic Spectrum of Hypophysitis: A Narrative Review.

Hypophysitis, a rare inflammatory disorder of the pituitary gland, has seen an uptick in reported cases in recent years. Our objective is to summarize the most recent research on the etiopathogenesis, molecular mechanisms, and genetics of both primary and secondary hypophysitis. Primary autoimmune hypophysitis (PAH): During the acute phase of the disease, the pituitary gland in enlarged due to the infiltration of T and B lymphocytes. The chronic phase is characterized by progressive and irreversible pituitary atrophy. APA may play a role in the management, diagnosis, and prognosis of PAH. Specific autoantibodies such as anti-GH, anti-PIT-1, and anti-T-PIT have been found in patients with hypophysitis and hypopituitarism. A recent study suggested that a mechanism of escaping clonal deletion and mounting an immune response against self antigens can explain the unusual nature of the immune response observed in PAH patients. A cytokine array shows the presence of gamma-interferon and interleukin-17. Patients carrying mutations in the PIT1 or PROP1 genes may present PAH. Individuals carrying the HLA DQ8 haplotype are four times more likely to develop PAH. Immune checkpoint inhibitors induce hypophysitis (IIHs): IIHs is an increasingly frequent toxicity of in patients on treatment with inhibitors targeting cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed cell death-1 (PD-1). ICIs inhibit the CTLA-4 pathway, leading to overactivation of T lymphocytes. The binding of PD-1/PD-L1 suppresses the activity of T cells, promotes the conversion of T-helpers into T-regulatory cells, and activates pro-survival signaling pathways in cancer cells. Cytokines play a crucial role in IIHs. B-cell infiltration has been observed in IIHs, suggesting that antibody-mediated pituitary injury may contribute. Genetic polymorphisms of CTLA-4 and PD-1 genes can increase the risk of IIHs. HLA alleles may also be involved in the onset of IIHs; this HLA association presents a possible alternative mechanistic hypothesis. IIHs may also be linked to a paraneoplastic syndrome triggered by ectopic expression of pituitary specific antigens. SARS-CoV-2-related hypophysitis: Recently, the literature has reported occurrences of hypophysitis associated with the SARS-CoV-2 virus; long COVID-19 may also present as infundibulo-neuro-hypophysitis. The virus enters the central nervous system because of its distinct interaction with angiotensin-converting enzyme receptors via spike proteins binding the capillary endothelium, and it directly damages the pituitary cells. The effect of SARS-CoV-2 can occur indirectly through inflammation and the release of cytokines. The exact mechanism remains ambiguous. The available data on endocrine complications associated with the SARS-CoV-2 vaccine are scant. Nonetheless, isolated cases of hypophysitis have been documented. Treatment of hypophysitis: Glucocorticoids are the cornerstone in managing primary hypophysitis, given their targeted action on inflammation. A better understanding of the etiopathogenesis and molecular mechanism of hypophysitis can lead to more effective and personalized treatment strategies.

Evidence of Association between CTLA-4 Gene Polymorphisms and Colorectal Cancers in Saudi Patients.

Cytotoxic T lymphocyte antigen-4 (CTLA-4) has been identified as an immunosuppressive molecule involved in the negative regulation of T cells. It is highly expressed in several types of autoimmune diseases and cancers including colorectal cancer (CRC). (1) Objective: To explore the association between CTLA-4 single nucleotide polymorphisms (SNP) and risk to (CRC) in the Saudi population. (2) Methods: In this case-control study, 100 patients with CRC and 100 matched healthy controls were genotyped for three CTLA-4 SNPs: rs11571317 (-658C > T), rs231775 (+49A > G) and rs3087243 (CT60 G > A), using TaqMan assay method. Associations were evaluated using odds ratios (ORs) and 95% confidence intervals (95% CIs) for five inheritance models (co-dominant, dominant, recessive, over-dominant and log-additive). Furthermore, CTLA-4 expression levels were evaluated using quantitative real-time PCR (Q-RT-PCR) in colon cancer and adjacent colon tissues. (3) Results: Our result showed a significant association of the G allele (OR = 2.337, p < 0.0001) and GG genotype of the missense SNP +49A > G with increased risk of developing CRC in codominant (OR = 8.93, p < 0.0001) and recessive (OR = 16.32, p < 0.0001) models. Inversely, the AG genotype was significantly associated with decreased risk to CRC in the codominant model (OR = 0.23, p < 0.0001). In addition, the CT60 G > A polymorphism exhibited a strong association with a high risk of developing CRC for the AA genotype in codominant (OR = 3.323, p = 0.0053) and in allele models (OR = 1.816, p = 0.005). No significant association was found between -658C > T and CRC. The haplotype analysis showed that the G-A-G haplotype of the rs11571317, rs231775 and rs3087243 was associated with high risk for CRC (OR = 57.66; p < 0.001). The CTLA-4 mRNA gene expression was found significantly higher in tumors compared to normal adjacent colon samples (p < 0.001). (4) Conclusions: Our findings support an association between the CTLA-4 rs231775 (+49A > G) and rs3087243 (CT60 G > A) polymorphisms and CRC risk in the Saudi population. Further validation in a larger cohort size is needed prior to utilizing these SNPs as a potential screening marker in the Saudi population.

Analysis of combination therapy of immune checkpoint inhibitors in osteosarcoma.

One of the most common primary bone malignant tumors is osteosarcoma (OS), possessing a high tendency of local invasion and distant metastasis. Although surgery combined with chemotherapy can extend the patients’ survival time, the prognosis for most patients with metastases or relapses is poor. Immunotherapy has been proved to be a promising treatment alternative for malignant tumors. Although there is a significant amount of animal- and cell-based evidence supporting the relationship between immune checkpoint inhibitors (anti-PD-1, anti-PD-L1, anti-CTLA-4) and cancers, no pan-cancer analysis is available. Simultaneously, immune checkpoint inhibitors have demonstrated satisfactory clinical results in some tumors; however, only a small fraction of patients with certain cancer types have been benefitted. Therefore, based on the TCGA dataset, we first explored the potential roles of immune checkpoints in 33 tumors. Programmed death receptor 1 (PD-1), programmed cell death ligand 1 (PD-L1), and cytotoxic T lymphocyte antigen 4 (CTLA-4) were not consistently expressed in the same direction in all tumors; however, the direction of expression change was the same in most immune cells. Although there is no well-established relationship between the expression of PD-1/PD-L1/CTLA-4 genes and the prognosis of patients with sarcomas, their interaction and extent of immune cell infiltration into sarcomas are probably the key determinants of therapeutic response. Our first pan-cancer study provides a relatively comprehensive understanding of immune checkpoint inhibitors in different sarcomas.

Association of Cytotoxic T-Lymphocyte Antigen-4 Gene Polymorphism with Type 1 Diabetes Mellitus: In silico Analysis of Biological Features of CTLA-4 Protein on Ethiopian Population.

BackgroundT1DM is a chronic organ-specific T-cell-mediated autoimmune disease characterized by the selective destruction of β-cells in the islets of Langerhans, resulting in insulin deficiency and hyperglycemia. Genes for cytotoxic T lymphocyte-associated antigen 4 have been hypothesized as possible contender genes for T1DM vulnerability. However, it has not been studied in the Ethiopian population yet.ObjectiveThe aim of the study was to investigate CTLA-4 exon 1 was linked to A49G polymorphism with T1DM and its biological features of CTLA-4 among T1DM patients, in Ethiopia.MethodsA case–control study was done from December 2019 to March 2020 on 210 study participants (105 T1DM patients and 105 healthy controls). Polymerase Chain Reaction amplification with forward and reverse primers was followed by restriction fragment length polymorphism and gel electrophoresis to determine gene polymorphism. Bioinformatics data of SNP was retrieved from National Centers for Biotechnology Information databases. The chi-square test and logistic regression were used. Statistical significance was defined as a P-value of less than 0.05.ResultsThe CTLA-4 (+A49G) gene polymorphism was observed on 56 (26.7%) study participants, 39 (18.57%) of T1DM patients, and 17 (0.08%) were controls. In T1DM and controls, the frequency of the A allele was 73.3% and 89.5%, while the G allele was 26.7% and 10.5%, respectively. The G allele was found to be associated with T1DM (OR=3.1; 95% CI, 1.82 −5.32; P=0.001). Statistical analysis revealed an association between the likelihood of T1DM and GG genotype of the CTLA-4 (+A49G) gene polymorphism (OR=3.11; 95% CI, 1.37–10.90; P=0.01). Further in silico analyzed the SNP to assess its biological features.ConclusionThe study showed as CTLA-4 (+A49G) gene polymorphism is linked with T1DM in the Ethiopian population.

The Role of Cytotoxic T-Lymphocyte Antigen 4 in the Pathogenesis of Multiple Sclerosis.

Multiple sclerosis (MS) is an autoimmune neurodegenerative disorder of the central nervous system that presents heterogeneous clinical manifestations and course. It has been shown that different immune checkpoints, including Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4), can be involved in the pathogenesis of MS. CTLA-4 is a critical regulator of T-cell homeostasis and self-tolerance and represents a key inhibitor of autoimmunity. In this scopingreview, we resume the current preclinical and clinical studies investigating the role of CTLA-4 in MS with different approaches. While some of these studies assessed the expression levels of CTLA-4 on T cells by comparing MS patients with healthy controls, others focused on the evaluation of the effects of common MS therapies on CTLA-4 modulation or on the study of the CTLA-4 blockade or deficiency in experimental autoimmune encephalomyelitis models. Moreover, other studies in this field aimed to discover if the CTLA-4 gene might be involved in the predisposition to MS, whereas others evaluated the effects of treatment with CTLA4-Ig in MS. Although these results are of great interest, they are often conflicting. Therefore, further studies are needed to reveal the exact mechanisms underlying the action of a crucial immune checkpoint such as CTLA-4 in MS to identify novel immunotherapeutic strategies for MS patients.

Comprehensive Analysis of 29,464 Cancer Cases and 35,858 Controls to Investigate the Effect of the Cytotoxic T-Lymphocyte Antigen 4 Gene rs231775 A/G Polymorphism on Cancer Risk.

In our previous studies, we found that the rs231775 polymorphism of cytotoxic T-lymphocyte antigen 4 (CTLA-4) is associated with risks of different cancer types; however, the association remains controversial and ambiguous, so we conducted an in-depth meta-analysis to verify the association. A complete search of the PubMed, Google Scholar, Embase, Chinese databases, and Web of Science was conducted without regard to language limitations, covering all publications since November 20, 2021. The search criteria for cancer susceptibility associated with the polymorphism in the CTLA-4 gene rs231775 resulted in 87 case-control studies with 29,464 cases and 35,858 controls. The association strength was analyzed using odds ratios and 95% confidence intervals. Overall, we found that the CTLA-4 rs231775 polymorphism may reduce cancer risk. A stratified cancer type analysis showed that CTLA-4 rs231775 polymorphism was a risk factor for colorectal cancer and thyroid cancer; on the other hand, it was a protective factor for breast cancer, liver cancer, cervical cancer, bone cancer, head and neck, and pancreatic cancer. We also classified cancer into five systems and observed an increased association with digestive tract cancer, decreased associations with orthopedic tumors, tumors of the urinary system, and gynecological tumors. In the subgroup based on race, decreased relationships were observed in both Asians and Caucasians. The same decreased association was also shown in the analysis of the source of control analysis. Our present study indicates that the CTLA-4 rs231775 polymorphism contributes to cancer development and aggression.

CTLA-4 polymorphism contributes to the genetic susceptibility of epithelial ovarian cancer.

Cytotoxic T-lymphocyte antigen-4 (CTLA-4), an inhibitory molecule on T-cells, plays a key role in tumorigenesis and progression. In the present study, we investigated the effects of three polymorphisms in the CTLA-4 gene on the risk of epithelial ovarian cancer and the clinical outcomes of patients. A case-control study was performed in 527 epithelial ovarian cancer patients and 532 controls. Genotypes of three polymorphisms were determined by polymerase chain reaction/ligase detection reaction. A survival analysis was performed in 346 patients who were followed up for more than 3 years and 208 patients who were followed up for more than 5 years. There were significant differences in the genotype and allele distribution frequencies of the rs5742909 C/T polymorphism in CTLA-4 between patients and controls (p=0.009 and p=0.04, respectively). Compared with the CC genotype, the CT + TT genotype may significantly decrease the risk of developing epithelial ovarian cancer (OR=0.69, 95% CI=0.52-0.91). However, no significant association between the rs231775 G/A and rs3087243 G/A polymorphisms and epithelial ovarian cancer risk was observed. The survival analysis showed that three polymorphisms may not be related to the clinical outcomes of patients. Our results suggested that the rs5742909 C/T polymorphism of CTLA-4 may decrease the genetic susceptibility to epithelial ovarian cancer among northern Chinese women.

Autoimmune thyroid patients with CTLA-4 (+49A/G) GG/AG genotypes have high seropositivity to thyroid peroxidase than thyroglobulin

Despite increasing burden of autoimmune thyroid disease (AITD) in India, there is paucity of data for the genetic susceptibility in Indian population which represents an important aspect to uncover the genetic factors for the cause or progression of different forms of AITD. It is known that production of auto-antibodies to thyroglobulin (TG) and thyroid peroxidase (TPO) is a characteristic feature of AITD. Production of high titres of auto-antibodies against TG and TPO is one the hallmarks of AITD that often precedes the development of clinical disease. The gene coding for cytotoxic T lymphocyte antigen-4 (CTLA-4) is considered an important candidate gene for susceptibility to AITD and also determines seropositivity. Earlier studies have demonstrated that polymorphic variants in CTLA-4 gene are linked to determine seropositivity. Hence, this study investigates a relationship between CTLA-4 (+49A/G) genotypes and seropositivity to anti-TPO and anti-TG antibodies in AITD patients. A total of 85 Indian participants were included and genotyped for CTLA-4 (+49A/G) single nucleotide polymorphism and further analyzed for seropositivity of TPO and TG auto-antibodies in mean age group of 35.76 ± 12.42 years of both the genders. The TPO seropositivity was reported higher in G allele containing genotypes GG and AG (66.66% and 58%, respectively) compared to AA (44.8%) genotype. Whereas, TG auto-antibodies showed highest seropositivity for genotype AA (55.17%) compared to AG (36%) and GG (16.6%). Higher median titre values were observed for TPO antibodies with GG genotype (1587.461 U/mL). In contrast to this, higher titres of auto-antibodies to TG were observed for individuals with AA genotype (520.746 U/mL). In conclusion, this study demonstrates a relationship between CTLA4 (+49A/G) genotype and seropositivity to thyroid auto antigens TPO and TG in Indian patients with clinical manifestation of Hashimoto's thyroiditis and Graves' disease, two different forms of AITD.

Regulation of CTLA-4 and PD-L1 Expression in Relapsing-Remitting Multiple Sclerosis Patients after Treatment with Fingolimod, IFNβ-1α, Glatiramer Acetate, and Dimethyl Fumarate Drugs

Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system (CNS) that is characterized by inflammation which typically results in significant impairment in most patients. Immune checkpoints act as co-stimulatory and co-inhibitory molecules and play a fundamental role in keeping the equilibrium of the immune system. Cytotoxic T-lymphocyte antigen-4 (CTLA-4) and Programmed death-ligand 1 (PD-L1), as inhibitory immune checkpoints, participate in terminating the development of numerous autoimmune diseases, including MS. We assessed the CTLA-4 and PD-L1 gene expression in the different cell types of peripheral blood mononuclear cells of MS patients using single-cell RNA-seq data. Additionally, this study outlines how CTLA-4 and PD-L1 expression was altered in the PBMC samples of relapsing-remitting multiple sclerosis (RRMS) patients compared to the healthy group. Finally, it investigates the impact of various MS-related treatments in the CTLA-4 and PD-L1 expression to restrain autoreactive T cells and stop the development of MS autoimmunity.

Cytotoxic T Lymphocyte Antigen 4 (CTLA4) Single Nucleotide Polymorphisms Do Not Impact Outcomes After Unrelated Donor Transplant: A Center For International Blood and Marrow Transplant Research Analysis

Cytotoxic T Lymphocyte Antigen 4 (CTLA4) is a critical T cell molecule that inhibits T cell activation and plays an essential role in T cell homeostasis and immune responses. Genetic variations in the CTLA4 gene have been hypothesized to be possible biologic markers that are predictive of transplant outcomes. Previous investigators have studied single nucleotide polymorphisms (SNPs) of the CTLA4 gene and its impact on hematopoietic cell transplantation (HCT) outcomes with discordant results. AA and AG genotypes in the donor CTLA4 regulatory region involving SNP rs4553808 in patients after unrelated donor (URD) HCT have recently been shown to be an independent predictor of improved relapse free survival (RFS) and overall survival (OS) compared to the GG genotype. To validate these preliminary findings, a Center for International Blood and Marrow Research (CIBMTR) study was performed in a larger, more homogenous cohort of patients.Adult patients with acute myeloid leukemia (AML) and advanced myelodysplastic syndrome (MDS) undergoing a first 8/8 or 7/8 HLA matched URD HCT after myeloablative, non-myeloablative, or reduced intensity conditioning from 2002 to 2007 in first or second complete remission with available donor research samples from the National Marrow Donor Program research repository were included. The primary goal was to evaluate the impact of SNP rs4553808 on RFS, OS, and NRM and the cumulative incidence of acute graft-versus-host disease (aGVHD), and chronic graft-versus-host disease (cGVHD). Any GVHD prophylaxis could be used except in vitro T-cell depletion or use of in vivo/in vitro alemtuzumab. Patients receiving T cell depletion with anti-thymocyte globulin (ATG) were oversampled to allow analysis of any effects on outcomes. An exploratory analysis of 9 other tagSNPs that encompass the entire CTLA4 gene (rs231775, rs231779, rs11571315, rs231777, rs3087243, rs16840252, rs231725, rs10197010, rs11571316) was performed to evaluate for any additional potential associations with clinical outcomes.Each SNP was analyzed in multivariable models adjusting for clinically significant variables using the Cox proportional hazards model. Due to multiple testing, p-values <0.005 were considered significant. The interaction with CTLA4 SNPs and use of ATG was also specifically analyzed. The final analysis included 780 patients with a median followup of 63 months. Median age of recipients and donors was 50 and 34, respectively. 90% of recipients were identified to be of Caucasian descent (N=709). 80% of patients had AML (N=624) and 20% MDS (N=156). Conditioning was 61% ablative, 28% reduced intensity and 11% non-myeloablative, with 74% receiving peripheral blood grafts. 75% were HLA-matched and 25% single locus mismatched. Tacrolimus with methotrexate or mycophenolate mofetil GVHD prophylaxis was given to 62%, cyclosporine-based prophylaxis to 15% while 23% received other regimens. By design, 50% of patients received ATG. Genotyping showed that 552 (71%) were AA, 208 (27%) were AG and 19 (2%) were GG (AG, and particularly GG, were associated with worse outcomes in the prior study). Multivariable analysis adjusting for significant donor and recipient characteristics showed no significant association between SNP rs4553808 and OS (p=0.07), RFS (p=0.41), NRM (p=0.25), and incidence of acute and chronic GVHD (Figure 1). Multivariable analysis of the other 9 tagSNPs also showed no association with transplant outcomes (p>0.005). No interaction was found between the CTLA4 SNPs and use of ATG on outcomes. These results indicate that CTLA4 SNPS do not have impact on outcomes. Other genomic or cellular biomarkers need to be studied to risk stratify patients at high risk of negative clinical events, especially as therapies targeting CTLA4 and PD-1 evolves. [Display omitted] [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Germline Mutations in CTLA4 and Spectrum of Bone Marrow Features Overlapping with Aplastic Anemia and Large Granular Lymphocyte Lymphocytosis

Introduction: CTLA4 haploinsufficiency due to germline heterozygous mutations in the cytotoxic T-lymphocyte antigen-4 gene (CTLA4) results in severe systemic immune dysregulation; infiltrative lymphocytic lesions of lungs (e.g. lymphocytic pneumonitis), GI tract (e.g.lymphocytic colitis), and CNS; and a spectrum of autoimmunity, immunodeficiency and peripheral blood cytopenias. We describe the hematologic, bone marrow (BM), and flow cytometry (FC) features of CTLA4 haploinsufficiency of a cohort of 14 patients, which show overlapping morphologic features with acquired aplastic anemia (acAA), and large granular lymphocyte lymphocytosis (LGL) in a subset of patients. We compared the findings to those in a separate cohort of 20 age matched patients diagnosed with acAA. There were significant differences between acAA and CTLA4 deficiency based on analysis of BM lymphocyte subsets and marrow lymphocyte infiltration patterns.Materials and Methods: Peripheral blood (PB), BM and FC analysis of patients with germline mutations in CTLA4, and acAA was performed along with review of clinical, molecular and laboratory data. Statistical comparisons were made using Mann Whitney test, with p < 0.05 for significance.Results: Median age at initial evaluation for patients with CTLA4 haploinsufficiency was 23.5 years (range 11-71 years), with a male-to-female ratio of 11:3. 11 out of 14 patients had cytopenias. Of those with cytopenias 2/11 had pancytopenia, 4/11 had bicytopenia and 5/11 had unilineage cytopenia. Hypogammaglobulinemia was common (13/14). In some cases cytopenias were recognized as autoimmune in etiology with immune thrombocytopenic purpura and autoimmune hemolytic anemia, among the most common hematologic manifestations. Three patients met criteria for a diagnosis of moderate AA, 1 for severe AA, and 1 for LGL. Overall bone marrow biopsies were hypocellular for age (10/14) with a subset (29% [4/14]) showing severe trilineage hypoplasia with ≤20% cellularity. Atypical interstitial CD8-positive T-cell infiltrates with prominent non-paratrabecular CD4-positive T-cell aggregates were evident by immunohistochemistry in most cases (10/14), accompanied by a near absence of B-cells. T-cell clonality was assessed by T-cell receptor (TCR) gamma PCR and showed abnormal oligoclonal T-cell populations in 3/8, and one case with a clonal T-cell receptor gene rearrangement. B-cell IgH PCR reactions were polyclonal. In all cases, cytogenetic studies were either negative or showed only minor abnormalities (i.e. loss of Y chromosome). Given the morphologic overlap of a subset of CTLA4 cases with acAA, we compared bone marrow flow cytometry analysis of 8 CTLA4 cases with 20 acAA cases. CTLA4 patients showed >5 fold reduction in the median percentage of B-cells in comparison to acAA (p=0.0005). While acAA cases demonstrated relative preservation the B-cell compartment with intact B-cell maturation sequence; in contrast CTLA4 cases showed abnormal B-cell maturation patterns in half of cases characterized by few detectable early B-cell precursors, and progressive loss of intermediate and mature forms. T-cell populations in CTLA4 showed inverted CD4:CD8 ratios with relatively increased CD57+ T-cells, and atypical dim expression of CD20 on T-cells. Morphologically, when the markedly hypocellular CTLA4 cases were compared to acAA on core biopsies, little difference in marrow cellularity was seen; however, the CTLA4 cases showed multiple large atypical T-cell aggregates and near total absence of B-cells, which was not seen in acAA; acAA cases showed scattered background T-cells and B-cells.Conclusions: CTLA-4 deficiency presents with cytopenias, autoimmunity, and immunodeficiency with a subset of patients that have features overlapping with bone marrow failure, specifically AA and LGL. Herein we demonstrate a combination of abnormal BM findings, previously unreported, comprising hypocellularity, CD8-positive interstitial T-cell infiltrates with atypical CD4-positive T-cell aggregates, marked B-cell lymphopenia, increased LGLs and abnormal T-cell clonality patterns by PCR. These features may help identify patients harboring CTLA4 mutations for early detection and optimal therapeutic management. DisclosuresYoung:Novartis/GSK to institute: Research Funding. Townsley:Novartis/GSK to institute: Research Funding.

The role of cytotoxic T-Lymphocyte antigen-4+49A/G gene polymorphism in cutaneous leishmaniasis

BackgroundCutaneous Leishmaniasis (CL) is a parasitic disease caused by intracellular protozoa belonging to the Leishmania genus. In endemic areas, only a proportion of exposed subjects develop the disease under almost similar circumstances, reflecting the role of genetic inheritance in resistance and susceptibility to infection. This study aimed To evaluate the association of cytotoxic T-lymphocyte antigen-4 (CTLA-4)+49G/A single nucleotide polymorphism (SNP) with incidence and severity of CL. MethodsThis cross-sectional study includes 110 patients with confirmed CL (60 newly diagnosed and 50 patients undergoing treatment) and 60 healthy subjects of similar age and sex. The CTLA-4 gene fragment corresponding to CTLA-4+49G/A polymorphism was amplified and genotyped using tetra primer amplification refractory mutation- polymerase chain reaction system (TARMS-PCR) methods. Soluble CTLA-4 (sCTLA-4) was estimated in the serum using an enzyme-linked immunosorbent assay (ELISA). ResultsThe GG genotype of CTLA-4+49G/A polymorphism was significantly more common in controls than in patients (OR = 0.11, 95% CI = 0.02–0.58, p = 0.009). At allelic level, G allele was much more common in controls than in patients (30.83% vs. 17.73%) with a significant difference (OR = 2.07, 95% CI = 1.23–3.48, p = 0.006). However, there was no significant difference in the frequency of genotypes and alleles between newly diagnosed and treated patients. Median serum concentration of sCTLA-4 in newly diagnosed patients was 72.6 pg/ml (range 15.6–127 pg/ml) which was higher than either controls (median = 16.3 pg/ml, range 0.8–48.5 pg/ml) or treated patients (median = 17.9 pg/ml, range 2.9–74.7 pg/ml) with highly significant differences, while there was no significant difference between controls and treated patients. The median sCTLA-4 level was comparable across genotypes of the CTLA-4+49G/A polymorphism, with no significant difference. ConclusionsCollectively, these results show the protective role of allele G of the SNP CTLA-4+49G/A against CL and increased serum sCTLA-4 in newly diagnosed CL patients, which may be used as an additional diagnostic tool. Different genotypes of the CTLA-4+49G/A polymorphism have no effect on sCLTA-4 serum levels.

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

ObjectivesIn recent years, more and more studies have been focusing on the association between Cytotoxic T lymphocyte antigen-4 (CTLA-4) (+49 A/G) gene polymorphism and autoimmune diseases. However, the results of previous studies are still controversial. The meta-analysis is aiming at determining the association in CTLA-4 (+49 A/G) gene rs231775 polymorphism and ankylosing spondylitis (AS), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE). MethodsWe searched PubMed, Web of Science, Chinese National Knowledge Infrastructure (CNKI) and Chinese Biomedical Database (CBM) up to November 2020, use random or fixed-effect models to perform meta-analysis to compare alleles and other genetic models, including homozygous, heterozygous, recessive and dominant models. The odds ratio (OR) with a 95% confidence interval (95% CI) was used to assess the correlation between CTLA-4 (+49 A/G) gene polymorphism and the genetic affectability of AS, RA, and SLE. Meanwhile, we used sequential trial analysis (TSA) to analyze the reliability of the results. Finally, we searched the relevant data of genome-wide association studies (GWAS) to further verify the accuracy of the experimental results. Results47 studies with 11,893 cases and 12,032 healthy controls were included. The rs231775 G allele was relevant to high risk of autoimmune disease over all people (P < 0.05). The G allele of rs231775 was significantly related to RA susceptibility (P < 0.05), but not with AS or SLE. Subgroup analysis by ethnicity indicated that rs231775 G allele was closely related to RA in Caucasian populations and Mongolian populations (P < 0.05). A strong connection within rs231775 G allele and AS affectability was uncovered in Caucasian populations (P < 0.05). The analysis of the TSA shows that the meta-analysis can draw the conclusion. ConclusionCTLA-4 (+49 A/G) gene rs231775 G allele increases the risk of autoimmune diseases in Caucasian populations. And it also increases the risk of RA in Caucasian and Mongolian populations. More sample size and more elaborately designed studies are needed to elucidate the relationship in CTLA-4 (+49 A/G) gene rs231775 G allele and autoimmune diseases, especially AS, SLE.

CERTAIN ASPECTS OF GENETIC PREPOSITION TO THE DEVELOPMENT OF COMBINED AUTOIMMUNE DISEASES IN CHILDREN WITH TYPE 1 DIABETES MELLITUS

Genotyping of 64 children of the main group with combined with type 1 diabetes mellitus (type 1 diabetes) autoimmune diseases (autoimmune thyroiditis (AIT) and/or celiac disease) and 135 pediatric patients of the comparison group with isolated type 1 diabetes mellitus was performed by predictor gene alleles not related to HLA: CT60 (+6230G&gt;A) (rs3087243), c.49A&gt;G (rs231775) of the cytotoxic T lymphocyte antigen-4 (CTLA4) gene, c.1858C&gt;T&#x0D; (rs2476601) of the tyrosine phosphatase lymphocyte (PTPN22) gene, a microsatellite repeat in exon 5 of the gene of non-canonical histocompatibility class I MICA molecules. In patients with combined AIT type 1 diabetes mellitus, an association was established between the c.49AA genotype (rs231775) and the A allele at the CT60 (+6230G&gt;A) (rs3087243) loci of the CTLA4 gene with the risk of transient antibodies to gliadin. In all groups of patients, the MICA 5.1 STR allele prevailed. The presence of the MICA A5.1/ A5.1 homozygous genotype in patients with type 1 diabetes doubles (OR = 2.13, 95% CI: 1.0003-4.5321, P = 0.0499) the risk of AIT development.

Cytotoxic T-lymphocyte Antigen-4 (CTLA-4) Gene Polymorphism (rs3087243) Is Related to Risk and Survival in Patients With Colorectal Cancer.

Cytotoxic T-lymphocyte antigen-4 (CTLA-4), transiently expressed on T cells, plays a pivotal role in the negative feedback regulation of T-cell activation and proliferation. The aim of the present study was to examine the influence of CTLA-4 gene polymorphism rs3087243 on CRC susceptibility and long-term survival in Swedish patients with CRC. Genotypes of 491 patients and 433 healthy controls were determined, using TaqMan single nucleotide polymorphism (SNP) assays based on polymerase chain reaction. Patients carrying allele A were found to be at a higher risk of CRC and this allele was found to be more common in patients with disseminated disease compared to localized disease in the right colon. Kaplan-Meier analysis of cancer-specific survival showed that carriers of allele A had the highest risk of CRC-related death. The SNP rs3087243 of the CTLA-4 gene was associated with CRC risk and, therefore, it could be a prognostic marker for Swedish patients with CRC.

Determination the CTLA-4 and PTPN22 Gene Polymorphism in Graves’ Disease Patients

Graves’ disease (GD) is a multifactorial autoimmune disease with contribution from both genetic andepigenetic factors in its causation. Gene “protein tyrosine phosphatase non receptor 22” (PTPN22) is animportant immune regulatory gene preventing hyper responsiveness of T cells by negatively regulatingtheir signal transduction. Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4) gene polymorphisms belong to themain genetic factors determining the susceptibility to development Graves’ disease. This study aimed toanalyze whether 1858 C/T SNP in PTPN22 and 1822 C/T SNP in CLTA-4 genes have any association withGD in Iraqi population. PCR-RFLP was performed for genotyping 1858 C/T SNP and 1822 C/T SNP withinPTPN22 and CLTA-4 respectively, in patients with GD and healthy controls. Among the patients with GD,the frequencies CLTA-4 CC, CT, and TT genotypes were 43.3%, 45%, and 11.6%, respectively, whereas inhealthy controls the frequencies of CC, CT genotypes were 60%, 30%, and 10%, respectively. While thereis no mutation recorded in PTPN22 1858 C/T SNP in both PCR-RFLP and DNA sequence analysis. Theseresults indicated that there is no significant association was found between PTPN22 1858 C/T SNP andCLTA-4 in patients with GD. It has been concluded that GD is not associated with PTPN22 1858 C/T SNPand 1822 C/T SNP of CLTA-4 in Iraqi population.