Influence of cytotoxic T lymphocyte-associated antigen 4 polymorphisms on the outcomes of hepatitis B virus infection

Cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) +49A>G (rs231775) gene polymorphism is not associated with COVID-19 severity and mortality in an Iranian population

Introduction

Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) regulates T cell immune responses as an immune activation inhibitor. Literature reviews suggest that COVID-19 is associated with dysregulation of the inflammatory immune response. The purpose of the present hospital-based case-control study was to evaluate the genetic association of the CTLA4 +49A > G (rs231775) Single Nucleotide Polymorphism (SNP) with COVID-19 severity and mortality among the Iranian people.

Method

Genomic DNA of peripheral blood nuclear cells was extracted from the 794 COVID-19 patients and 167 control individuals. The polymorphic site of rs231775 was genotyped using the PCR-RFLP technique. Also, to identify whether this genetic variation was related to CTLA-4 mRNA expression, total RNA was extracted from 178 COVID-19 patients and 70 controls. The mRNA levels of CTLA-4 were determined using real-time PCR.

Result

There were no statistically significant differences found in the genotype and allele frequencies among the different genetic models with regards to the severity and mortality of COVID-19. Furthermore, there was no significant association between rs231775 genotypes and CTLA-4 mRNA expression in patients.

Conclusion

Our findings demonstrated that SARS-CoV-2 infection is not associated with rs231775 in the Iranian people. More investigations are crucial to show how this genetic variation affects other ethnic groups. Given the importance of CTLA-4 in regulating immune responses, further studies are recommended to examine other CTLA-4 SNPs and the function of this gene in COVID-19 patients.

Association between CTLA4 + 49A/G polymorphism and risk of hepatocellular carcinoma: a systematic review and meta-analysis

The aim of this systematic review and meta-analysis was to compile the data examining the association between the CTLA4 + 49 A/G polymorphism and the risk for HCC. Multiple databases were systematically searched for eligible studies and the pooled odds ratios (ORs) were generated using five genetic models. Pooled data from 11 studies with 3,055 HCC patients and 3,450 controls found no statistically significant association between the polymorphism and HCC risk, both overall and in subgroup analyses. In conclusion, the current meta-analysis shows that the CTLA4 + 49 A/G polymorphism is not significantly associated with the risk of developing HCC.

Factors affecting HBV DNA suppression in chronic hepatitis B patients treated with tenofovir disoproxil fumarate

Background: This study aims to determine the factors affecting HBV DNA suppression in chronic hepatitis B patients with tenofovir disoproxil fumarate (TDF). Methods: A case-control was carried out from October 2021 to August 2022 on 182 chronic hepatitis B patients who had TDF therapy regularly for 24 weeks at H. Adam Malik and USU Hospitals in Medan, Indonesia. The history of the samples was obtained, followed by physical examination, and blood collection. CTLA-4 polymorphism examination was carried out using real-time PCR, while the serum CTLA-4 levels were assessed with ELISA. Results: The CTLA-4 -1661G>A polymorphism, genotype GG+AG, increased 1.52 times risk of not achieving HBV DNA suppression to TDF compared to genotype AA (p=0.041). High CTLA-4 levels increased 2.28 times risk, high HBV DNA levels increased 2.09 times risk, low ALT levels increased 1.95 times risk of not achieving HBV DNA suppression (p= 0.009, 0.026, 0.036, respectively). There was no relationship between gender, age, ethnicity, obesity, baseline AST, HBeAg, genotype, liver fibrosis and HBV DNA suppression after 24 weeks of treatment (p>0.05). Conclusions: The levels of CTLA-4, HBV DNA, ALT, and CTLA-4 -1661G>A polymorphism have a potential relationship with the suppression of HBV DNA in chronic hepatitis B patients with TDF.

Computational analysis of structural and functional evaluation of the deleterious missense variants in the human CTLA4 gene

CTLA-4 is an immune checkpoint receptor that negatively regulates the T-cell function expressed after T-cell activation to break the immune response. The current study predicted the genomic analysis to explore the functional variations of missense SNPs in the human CTLA4 gene using PolyPhen2, SIFT, PANTHER, PROVEAN, Fathmm, Mutation Assessor, PhD-SNP, SNPs&GO, SNAP2, and MutPred2. Phylogenetic conservation protein was predicted by ConSurf. Protein structural analysis was carried out by I-Mutant3, MUpro, iStable2, PremPS, and ERIS servers. Molecular dynamics trajectory analysis (RMSD, RMSF, Rg, SASA, H-bonds, and PCA) was performed to analyze the dynamic behavior of native and mutant CTLA-4 at the atomic level. Our in-silico analysis suggested that C58S, G118R, P137Q, P137R, P137L, P138T, and G146L variants were predicted to be the most deleterious missense variants and highly conserved residues. Moreover, the molecular dynamics analysis proposed a decrease in the protein stability and compactness with the P137R and P138T highlighting the impact of these variants on the function of the CTLA-4 protein.Communicated by Ramaswamy H. Sarma.

FoxP3, PD-1 and CTLA-4 are decreased significantly after a tenofovir therapy in patients with chronic hepatitis B

Background: FoxP3, PD-1 and CTLA-4 are upregulated in chronic viral infections, such as chronic HCV, chronic HBV and HIV infection. Materials & methods: During 1 year of tenofovir disoproxil fumarate (TDF) treatment in patients with chronic hepatitis B, we investigated the expression of FoxP3, PD-1 and CTLA-4. Peripheral blood mononuclear cells were isolated from the 30 study subjects at T0 (0 months), T3, T6 and T12 months after the commencement of TDF treatment. Results & conclusion: Expression of FoxP3, PD-1 and CTLA-4 was significantly decreased in T cells of patients with chronic hepatitis B under TDF treatment at T12, when compared with that at T0. A direct correlation was observed between FoxP3 and CTLA-4 expression in patients with chronic hepatitis B and the frequency of FoxP3 was positively associated with serum alanine aminotransferase levels.

Circulating CTLA-4 levels and CTLA4 polymorphisms associate with disease condition and progression and hepatocellular carcinoma patients' survival in chronic hepatitis B virus infection

BACKGROUND

CTLA-4 is involved in the immune dysfunction of hepatitis B virus (HBV) infection and hepatocellular carcinoma (HCC). This study analyzed the association of circulating CTLA-4 levels and CTLA4 polymorphisms with disease condition and progression in chronic HBV infection.

METHODS

Serum CTLA-4 levels and CTLA4 rs231775 and rs5742909 polymorphisms were determined in patients with various HBV-related diseases [53 asymptomatic HBV carrier status (ASC), 147 chronic hepatitis, 130 cirrhosis and 102 HCC] and nearly a 10-year follow-up.

RESULTS

Serum CTLA-4 levels were stepwisely increased from ASC, chronic hepatitis, cirrhosis to HCC and independently associated with HCC (OR 2.628, P < 0.001). HCC patients had lower frequencies of rs231775 genotype GA, genotype AA and allele A than ASC, chronic hepatitis and cirrhosis patients. Rs231775 genotype GG was independently associated with HCC (OR 2.324, P = 0.010) and higher CTLA-4 levels in patients with HBV infection. In the follow-up, higher baseline CTLA-4 levels and CTLA4 rs231775 genotype GG significantly associated with disease progression from chronic hepatitis to cirrhosis (OR 2.561, P = 0.011 and OR 2.799, P = 0.015, respectively) or from cirrhosis to HCC (OR 2.673, P = 0.008 and OR 2.097, P = 0.023, respectively) and with a shorter overall survival in HCC patients (HR 0.317, P = 0.018 and HR 0.682, P = 0.026, respectively). Rs5742909 had no significant association with CTLA-4 levels and disease progression.

CONCLUSION

CTLA-4 levels and CTLA4 rs231775 polymorphism associate with the disease condition and progression and HCC development in chronic HBV infection and their determination may be used for monitoring disease progression and predicting patient prognosis.

Pemphigus vulgaris and pemphigus foliaceus determined by CD86 and CTLA4 polymorphisms

Pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are rare autoimmune blistering diseases with presumed T-cell-dependent pathology. Activation of naïve T cells is dependent on antigen recognition, subsequent signaling through the T-cell receptor complex (signal 1), and various other interactions of T cells with antigen presenting cells that may be collectively designated as signal 2, which is unconditionally required for T-cell activation both in response to infection and to autoantigens. Among the best described interactions contributing to signal 2 are those mediated by B7 family molecules, such as CD80 and CD86 with their ligands; CD28, providing activation signals; and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), conferring inhibition. Single nucleotide polymorphisms (SNPs) within genes encoding those molecules may alter the signaling process. It is not known whether functional genetic polymorphisms within genes encoding the aforementioned proteins may increase risk for developing PV and PF and, if so, whether they might serve as biomarkers for susceptibility to these diseases. To address those questions, we examined functional single nucleotide polymorphisms within CD86 (rs1129055) and CTLA4 (rs733618 and rs5742909) genes in 61 pemphigus patients and 486 healthy controls. We found statistically significant differences in allele and genotype frequencies between PV patients and controls for rs1129055, as well as for rs5742909 among PV and PF patients. Namely, the rs1129055 A allele was significantly more common in PV patients compared with controls (35.4% versus 25.7%, respectively; P = .040), whereas the rs5742909 T allele was significantly more common in PF compared with PV patients (19.2% versus 5.2%, respectively; P = .035). The frequency of the rs5742909 T allele did not, however, differ significantly in PF or in PV compared with controls (10.5%; P = .187 and P = .100, respectively). We report a novel association of SNPs within CD86 and CTLA4 genes with pemphigus. The CD86 rs1129055 A allele appears to confer susceptibility to PV but not to PF. © 2016 Elsevier Inc. All rights reserved.

Restoring homeostasis of CD4+ T cells in hepatitis-B-virus-related liver fibrosis

Immune-mediated liver injury is widely seen during hepatitis B virus (HBV) infection. Unsuccessful immune clearance of HBV results in chronic hepatitis and increases the risk of liver cirrhosis and hepatocellular carcinoma. HBV-related liver fibrosis (HBVLF), occurring as a result of HBV-induced chronic hepatitis, is a reversible, intermediate stage of chronic hepatitis B (CHB) and liver cirrhosis. Therefore, defining the pathogenesis of HBVLF is of practical significance for achieving better clinical outcomes. Recently, the homeostasis of CD4⁺ T cells was considered to be pivotal in the process of HBVLF. To better uncover the underlying mechanisms, in this review, we systematically retrospect the impacts of different CD4⁺ T-cell subsets on CHB and HBVLF. We emphasize CD4⁺ T-cell homeostasis and the important balance between regulatory T (Treg) and T helper 17 (Th17) cells. We discuss some cytokines associated with Treg and Th17 cells such as interleukin (IL)-17, IL-22, IL-21, IL-23, IL-10, IL-35 and IL-33, as well as surface molecules such as programmed cell death protein 1, cytotoxic T lymphocyte-associated antigen 4, T cell immunoglobulin domain and mucin domain-containing molecule 3 and cannabinoid receptor 2 that have potential therapeutic implications for the homeostasis of CD4⁺ T cells in CHB and HBVLF.