Cytotoxic T-lymphocyte associated antigen-4 gene polymorphisms and primary biliary cirrhosis: a systematic review

Early histopathologic changes in primary biliary cholangitis: does 'minimal change' primary biliary cholangitis exist? A pathologist's view

Primary biliary cholangitis (PBC), formerly known as primary biliary cirrhosis, is an autoimmune, slowly progressive, cholestatic liver disease characterized by nonsuppurative destructive cholangitis, and interlobular bile duct destruction. Necroinflammatory activities of the hepatic parenchyma and limiting plates of milder form along with late liver fibrosis may develop. Serum liver tests include elevated serum alkaline phosphatase along with a positive antimitochondrial antibody (AMA) in nearly 95% of patients. Liver biopsies are an important confirmatory and staging tool and are additionally very helpful when AMA is negative. More specifically, the earliest changes in liver biopsy suspicious for PBC can be detected, namely loss of the canals of Hering (CoH), as proposed by various authors recently. CoH loss has been described as an early feature of PBC. We focus on early histologic features of PBC, investigating through the literature the possible role of 'minimal change' supporting the clinical diagnosis of PBC, even in the absence of characteristic granulomatous duct destructive lesions.

Precision Cardio-Oncology: a Systems-Based Perspective on Cardiotoxicity of Tyrosine Kinase Inhibitors and Immune Checkpoint Inhibitors

Cancer therapies have been evolving from conventional chemotherapeutics to targeted agents. This has fulfilled the hope of greater efficacy but unfortunately not of greater safety. In fact, a broad spectrum of toxicities can be seen with targeted therapies, including cardiovascular toxicities. Among these, cardiomyopathy and heart failure have received greatest attention, given their profound implications for continuation of cancer therapies and cardiovascular morbidity and mortality. Prediction of risk has always posed a challenge and even more so with the newer targeted agents. The merits of accurate risk prediction, however, are very evident, e.g. facilitating treatment decisions even before the first dose is given. This is important for agents with a long half-life and high potential to induced life-threatening cardiac complications, such as myocarditis with immune checkpoint inhibitors. An opportunity to address these needs in the field of cardio-oncology is provided by the expanding repertoire of "-omics" and other tools in precision medicine and their integration in a systems biology approach. This may allow for new insights into patho-mechanisms and the creation of more precise and cost-effective risk prediction tools with the ultimate goals of improved therapy decisions and prevention of cardiovascular complications. Herein, we explore this topic as a future approach to translating the complexity of cardio-oncology to the reality of patient care.

Human DEF6 deficiency underlies an immunodeficiency syndrome with systemic autoimmunity and aberrant CTLA-4 homeostasis

Immune responses need to be controlled tightly to prevent autoimmune diseases, yet underlying molecular mechanisms remain partially understood. Here, we identify biallelic mutations in three patients from two unrelated families in differentially expressed in FDCP6 homolog (DEF6) as the molecular cause of an inborn error of immunity with systemic autoimmunity. Patient T cells exhibit impaired regulation of CTLA-4 surface trafficking associated with reduced functional CTLA-4 availability, which is replicated in DEF6-knockout Jurkat cells. Mechanistically, we identify the small GTPase RAB11 as an interactor of the guanine nucleotide exchange factor DEF6, and find disrupted binding of mutant DEF6 to RAB11 as well as reduced RAB11⁺CTLA-4⁺ vesicles in DEF6-mutated cells. One of the patients has been treated with CTLA-4-Ig and achieved sustained remission. Collectively, we uncover DEF6 as player in immune homeostasis ensuring availability of the checkpoint protein CTLA-4 at T-cell surface, identifying a potential target for autoimmune and/or cancer therapy.

CTLA-4 is critical for balancing protective immunity with self-tolerance. Here the authors identify homozygous DEF6 mutations in patients with severe autoimmunity, one of which received and responds to CTLA-4-Ig, and show that DEF6 is crucial for CTLA-4 cell surface trafficking and immune regulatory function.

Genetic Polymorphisms of Cytotoxic T-Lymphocyte Antigen 4 in Primary Biliary Cholangitis: A Meta-Analysis

Background and Aim

The connection between gene polymorphisms of cytotoxic T-lymphocyte-associated protein 4 (CTLA4) and primary biliary cholangitis (PBC) is still vague and blurred. The purpose of this study is to precisely estimate the association of the polymorphisms of CTLA4 with the risk of PBC by using a meta-analysis.

Methods

PubMed and the Chinese National Knowledge Infrastructure (CNKI) database were used to search correlative literatures, and the documents which were about the relationships between the polymorphisms of CTLA4 (rs231775, rs231725, rs3087243, and rs5742909) and PBC were collected as of June 2016. The strength of correlation based on odds ratios (ORs) and its 95% confidence intervals (95%CIs) was computed by STATA.

Results

Generally, in rs231775, a significant risk was found in G allele, the value of OR was 1.32, and its 95%CI was 1.19 to 1.47. The same situation was found in A allele of rs231725, the value of OR was 1.33, and its 95%CI was 1.22 to 1.45. As genotypic level, different genotypic models were also found to have obvious relevance with PBC in rs231775 and rs231725. No obvious connections were found in other SNPs.

Conclusion

This study indicated that the polymorphisms of rs231775 and rs231725 would be the risk factors of PBC.

Primary Biliary Cholangitis: Disease Pathogenesis and Implications for Established and Novel Therapeutics

Primary Biliary Cholangitis is a progressive, autoimmune cholestatic liver disorder. Cholestasis with disease progression may lead to dyslipidemia, osteodystrophy and fat-soluble vitamin deficiency. Portal hypertension may develop prior to advanced stages of fibrosis. Untreated disease may lead to cirrhosis, hepatocellular cancer and need for orthotopic liver transplantation. Classically, diagnosis is made with elevation of alkaline phosphatase, demonstration of circulating antimitochondrial antibody, and if performed: asymmetric destruction/nonsupperative cholangitis of intralobular bile ducts on biopsy. Disease pathogenesis is complex and results from innate and adaptive (cell-mediated and humoral) responses that lead to inflammation of biliary duct epithelium. Ongoing damage is amplified and sustained through bile acid toxicity. Use of weight based (13-15mg/kg) ursodeoxycholic acid is well established in retarding disease progression and improving survival; however, is ineffective in achieving complete biochemical remission in many. Recently, a Farnesoid X Receptor agonist, obeticholic acid, has been approved for use. A number of ongoing clinical studies are underway to evaluate utility of fibric acid derivatives, biologics, antifibrotics, and stem cells as monotherapy or in combination with ursodeoxycholic acid for primary biliary cholangitis. The aim of this review is to discuss disease pathogenesis and highlight rationale/implications for both established and novel therapeutics.

CTLA-4 and MDR1 polymorphisms increase the risk for ulcerative colitis: A meta-analysis

AIM: To evaluate the correlations between cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) and multi-drug resistance 1 (MDR1) genes polymorphisms with ulcerative colitis (UC) risk.

METHODS: PubMed, EMBASE, Web of Science, Cochrane Library, CBM databases, Springerlink, Wiley, EBSCO, Ovid, Wanfang database, VIP database, China National Knowledge Infrastructure, and Weipu Journal databases were exhaustively searched using combinations of keywords relating to CTLA-4, MDR1 and UC. The published studies were filtered using our stringent inclusion and exclusion criteria, the quality assessment for each eligible study was conducted using Critical Appraisal Skill Program and the resultant high-quality data from final selected studies were analyzed using Comprehensive Meta-analysis 2.0 (CMA 2.0) software. The correlations between SNPs of CTLA-4 gene, MDR1 gene and the risk of UC were evaluated by OR at 95%CI. Z test was carried out to evaluate the significance of overall effect values. Cochran’s Q-statistic and I² tests were applied to quantify heterogeneity among studies. Funnel plots, classic fail-safe N and Egger’s linear regression test were inspected for indication of publication bias.

RESULTS: A total of 107 studies were initially retrieved and 12 studies were eventually selected for meta-analysis. These 12 case-control studies involved 1860 UC patients and 2663 healthy controls. Our major result revealed that single nucleotide polymorphisms (SNPs) of CTLA-4 gene rs3087243 G > A and rs231775 G > A may increase the risk of UC (rs3087243 G > A: allele model: OR = 1.365, 95%CI: 1.023-1.822, P = 0.035; dominant model: OR = 1.569, 95%CI: 1.269-1.940, P < 0.001; rs231775 G > A: allele model: OR = 1.583, 95%CI: = 1.306-1.918, P < 0.001; dominant model: OR = 1.805, 95%CI: 1.393-2.340, P < 0.001). In addition, based on our result, SNPs of MDR1 gene rs1045642 C > T might also confer a significant increases for the risk of UC (allele model: OR = 1.389, 95%CI: 1.214-1.590, P < 0.001; dominant model: OR = 1.518, 95%CI: 1.222-1.886, P < 0.001).

CONCLUSION: CTLA-4 gene rs3087243 G > A and rs231775 G > A, and MDR1 gene rs1045642 C > T might confer an increase for UC risk.

Vitamin D Antagonises the Suppressive Effect of Inflammatory Cytokines on CTLA-4 Expression and Regulatory Function

The immune suppressive protein CTLA-4 is constitutively expressed by Tregs and induced in effector T cells upon activation. Its crucial role in adaptive immunity is apparent from the fatal autoimmune pathology seen in CTLA-4 knockout mice. However, little is known regarding factors that regulate CTLA-4 expression and their effect upon its function to remove CD80 and CD86 from antigen presenting cells by transendocytosis. Th17 cells are emerging as significant players in autoimmunity as well as other diseases. Therefore, in this study we have examined the effects of Th17 polarising conditions on CTLA-4 expression and function in human T cells and show that Th17 conditions can suppress the expression of CTLA-4 and its transendocytic function. In contrast to Th17 cells, vitamin D is inversely associated with autoimmune disease. We have previously shown a striking ability of 1,25 dihydroxyvitamin D₃ (1,25(OH)₂D₃) to enhance CTLA-4, however, its effects upon B7 transendocytosis and its activity in the context of inflammation remained unknown. Here we show that induction of CTLA-4 by 1,25(OH)₂D₃ can actually be enhanced in the presence of Th17 polarising cytokines. Furthermore, its transendocytic function was maintained such that T cells generated in the presence of Th17 conditions and 1,25(OH)₂D₃ were highly effective at capturing CTLA-4 ligands from antigen presenting cells and suppressing T cell division. Taken together, these data reveal an inhibitory effect of Th17 polarising conditions upon CTLA-4-mediated regulation and show that 1,25(OH)₂D₃ counteracts this effect. Given the importance of CTLA-4-mediated suppression in the control of autoimmune diseases, our novel data highlight the importance of vitamin D in inflammatory settings.

Primary biliary cirrhosis: Pathophysiology, clinical presentation and therapy

Primary biliary cirrhosis (PBC) is an autoimmune, slowly progressive, cholestatic, liver disease characterized by a triad of chronic cholestasis, circulating anti-mitochondrial antibodies (AMA), and characteristic liver biopsy findings of nonsuppurative destructive cholangitis and interlobular bile duct destruction. About 10% of PBC patients, however, lack AMA. A variant, called PBC-autoimmune hepatitis (AIH) overlap, is characterized by the above findings of PBC together with findings of elevated serum alanine aminotransferase, elevated serum immunoglobulin G, and circulating anti-smooth muscle antibodies, with liver biopsy demonstrating periportal or periseptal, lymphocytic, piecemeal necrosis. PBC is hypothesized to be related to environmental exposure in genetically vulnerable individuals. It typically occurs in middle-aged females. Prominent clinical features include fatigue, pruritis, jaundice, xanthomas, osteoporosis, and dyslipidemia. The Mayo Risk score is the most widely used and best prognostic system. Ursodeoxycholic acid is the primary therapy. It works partly by reducing the concentration and injury from relatively toxic bile acids. PBC-AIH overlap syndrome is treated with ursodeoxycholic acid and corticosteroids, especially budesonide. Obeticholic acid and fibrate are promising new, but incompletely tested, therapies. Liver transplantation is the definitive therapy for advanced disease, with about 70% 10-year survival after transplantation. Management of pruritis includes local skin care, dermatologist referral, avoiding potential pruritogens, cholestyramine, and possibly opioid antagonists, sertraline, or rifaximin. Management of osteoporosis includes life-style modifications, administration of calcium and vitamin D, and alendronate. Statins are relatively safe to treat the osteopenia associated with PBC. Associated Sjogren’s syndrome is treated by artificial tears, cyclosporine ophthalmic emulsion to stimulate tear production; and saliva substitutes, cholinergic agents, and scrupulous oral and dental care. Complications of cirrhosis from advanced PBC include esophageal varices, ascites, spontaneous bacterial peritonitis, hepatorenal syndrome, and hepatoma formation.

Associations between the cytotoxic T lymphocyte antigen 4 polymorphisms and risk of bone sarcomas

Cytotoxic T lymphocyte antigen 4 (CTLA-4) genetic polymorphisms are implicated to be associated with susceptibility to bone sarcomas, but published studies have reported inconclusive results. The objective of our study was to conduct a meta-analysis investigating the associations between CTLA-4 gene polymorphisms and risk of bone sarcomas. PubMed and Embase databases were searched for all articles published up to June 2, 2013. Odds ratio (OR) with a 95 % confidence interval (95 % CI) was used to assess the association. Finally, 11 individual studies with a total of 2,951 cases with bone sarcomas and 3,396 controls were included in the meta-analysis. There were four studies on the CTLA-4 49G/A polymorphism, three studies on CTLA-4 318C/T polymorphism, two studies on CTLA-4 1661A/G polymorphism, and two studies on CTLA-4 60A/G polymorphism. Overall, CTLA-4 49G/A polymorphism was obviously associated with risk of bone sarcomas (A vs. G: OR = 1.36, 95 % CI = 1.20-1.54; AA vs. GG: OR = 2.24, 95 % CI = 1.67-2.99; AA vs.

AG/GG

OR = 2.00, 95 % CI = 1.53-2.62; AA/GA vs. GG: OR = 1.35, 95 % CI = 1.14-1.61). However, CTLA-4 318C/T, 1661A/G, and 60A/G polymorphisms were not associated with risk of bone sarcomas. The current meta-analysis suggests that CTLA-4 49G/A polymorphism is obviously associated with risk of bone sarcomas. More studies are needed to further evaluate the associations between CTLA-4 polymorphisms and risk of bone sarcomas.

HLA-DR polymorphism and primary biliary cirrhosis: evidence from a meta-analysis

BACKGROUND AND AIMS

We undertook this study to review and quantitatively analyze the association between human leukocyte antigen (HLA) DR polymorphisms and susceptibility of primary biliary cirrhosis (PBC).

METHODS

All relevant publications on the association between HLA-DR polymorphisms and PBC were searched through June 2013. Odds ratios (OR) and confidence intervals (CI) for the comparisons between case and control group were calculated. Statistical analysis was performed using Stata 11.0 software.

RESULTS

Nineteen articles (or 20 studies including the substudies) were identified. For DR*7 allele, the ORs (95% CIs) were 1.530 (1.310, 1.788), 1.757 (1.285, 2.403) and 1.495 (1.211, 1.845) in overall, Asian and European populations, respectively. For DR*8 alleles, the ORs (95% CIs) were 3.158 (1.822, 5.475), 2.803 (2.420, 3.247) and 3.056 (2.573, 3.629) in Asian, American and European subgroups, respectively. The subgroup analysis for DR*11 and DR*13 showed a significant association in Asian and European population. For DR*12 and *15 alleles, the overall ORs (95% CIs) were 0.551 (0.404, 0.753) and 0.721 (0.607, 0.857). However, in subgroup analysis for DR*12 allele, the association was only found in Asian population. In addition, statistical significance exists in American and European populations in the subgroup analysis for DR*15 allele.

CONCLUSION

Our meta-analysis suggested that HLA-DR *7 and *8 allele polymorphisms contributed to the susceptibility of PBC, whereas DR*11, *12, *13 and *15 allele polymorphisms are protective factors in certain population.

The CTLA-4 +49GG genotype is associated with susceptibility for nephrotic kidney diseases

BACKGROUND

The pathogenesis of primary nephrotic kidney diseases is not completely understood. As T-cell involvement is suspected, cytotoxic T-lymphocyte antigen 4 (CTLA-4) expressed on activated T cells could play a role in the immune response. Single-nucleotide polymorphisms (SNPs) in the CTLA-4 gene are associated with several autoimmune-related diseases.

METHODS

Our goal was to study the occurrence of the SNPs -318C/T, +49A/G and CT60 on the CTLA-4 gene in healthy blood donors (N = 156) compared with nephrotic patients with biopsy-proven minimal-change disease (MCD, N = 160), focal segmental glomerulosclerosis (FSGS, N = 159) and membranous nephropathy (MN, N = 185). Odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated to estimate the strength of the association.

RESULTS

The +49GG genotype was significantly (P < 0.001) associated with the risk for MCD, FSGS and MN (AA versus GG: OR = 3.403, 95% CI = 1.748-6.622, OR = 3.846, 95% CI = 1.945-7.604 and OR = 2.381, 95% CI = 1.257-4.511, respectively). No further significant associations, neither with the heterozygous genotype of +49A/G nor for the -318C/T or CT60 SNP, were detected.

CONCLUSIONS

The +49GG genotype of the +49A/G SNP in the CTLA-4 gene is associated with the risk for MCD, FSGS and MN, suggesting a possible role for CTLA-4 in a proposed common final pathway in the pathogenesis of primary nephrotic kidney diseases.

Association between cytotoxic T-lymphocyte antigen 4 gene polymorphisms and primary biliary cirrhosis in Chinese population: data from a multicenter study

BACKGROUND AND AIMS

The cytotoxic T-lymphocyte antigen 4 (CTLA4) gene polymorphisms have been shown to be associated with the risk of primary biliary cirrhosis (PBC). The study aimed to confirm the associations of CTLA4 gene polymorphisms with risk of PBC and patients' quality of life in Chinese population.

METHODS

A total of 312 female PBC patients from Chinese Han population were included as case, and 375 age-matched female healthy volunteers were included as control. Four single nucleotide polymorphisms (SNPs) including rs231775, rs3087243, rs231725, and rs5742909 were genotyped. The differences of genotype and allele distributions between PBC patients and healthy controls were assessed. The relationship between CTLA4 gene polymorphisms and healthy status of PBC patients were then investigated through comparisons of the domain scores of PBC-40 questionnaire between different genotype categories of each single nucleotide polymorphism.

RESULTS

The frequencies of G allele at rs231775 and A allele at rs231725 were both significantly increased in PBC patients when compared with normal controls (P < 0.001, odds ratio = 1.44, 95% confidence interval = 1.24-1.67 for rs231775; P < 0.001, odds ratio = 1.29, 95% confidence interval = 1.12-1.48 for rs231725). Besides, patients carrying A allele of rs3087243 had significantly lower score of fatigue domain than those carrying G allele (2.5 ± 0.8 vs 3.9 ± 1.3, P < 0.001).

CONCLUSIONS

This study revealed that CTLA4 gene polymorphism might be associated with susceptibility of PBC. G allele of rs231775 and A allele of rs231725 were significantly associated with the risk of PBC. In addition, patients carrying A allele of rs3087243 could have significantly better quality of life than those carrying G allele.

The role of vitamin d in primary biliary cirrhosis: possible genetic and cell signaling mechanisms

Primary biliary cirrhosis (PBC) is an immune-mediated chronic inflammatory disease of the liver of unknown etiology. Vitamin D deficiency is highly prevalent in patients with PBC, and many studies have demonstrated the significant effect of calcitriol on liver cell physiology. Vitamin D has antiproliferative and antifibrotic effects on liver fibrosis. Genetic studies have provided an opportunity to determine which proteins link vitamin D to PBC pathology (e.g., the major histocompatibility complex class II molecules, the vitamin D receptor, toll-like receptors, apolipoprotein E, Nramp1, and cytotoxic T lymphocyte antigen-4). Vitamin D also exerts its effect on PBC through cell signaling mechanisms, that is, matrix metalloproteinases, prostaglandins, reactive oxygen species, and the transforming growth factor betas. In conclusion, vitamin D may have a beneficial role in the treatment of PBC. The best form of vitamin D for use in the PBC is calcitriol because it is the active form of vitamin D3 metabolite, and its receptors are present in the sinusoidal endothelial cells, Kupffer cells, and stellate cells of normal livers, as well as in the biliary cell line.

Recent advances in understanding the pathogenesis of primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic progressive cholestatic autoimmune liver disease characterized by the destruction of small intrahepatic bile ducts and the presence of highly specific serum antimitochondrial antibodies (AMAs). The human leukocyte antigen (HLA) gene has been proved to have strongest association with PBC susceptibility, and non-HLA genes, including IL12A, IL12RB2, STAT4, IRF5-TNPO3, ORMDL3/IKZF3, MMEL1, SPIB, CTLA-4, FCRL3 and A2BP1, are also closely associated with PBC susceptibility. Four AMAs including anti-M2, anti-M4, anti-M8 and anti-M9, and antinuclear antibodies (ANAs), such as antinuclear dot antibodies (SP100, PML, NDP52, SP140), antinuclear pore antibodies (gp210, p62), antinuclear envelope antibodies (Lamin and Lamin B receptor), and anti-centromere antibodies, may also be involved in the pathogenesis of PBC. The imbalance between Th17 cells and regulatory T lymphocytes (Treg) may also play an important role in the pathogenesis of PBC. In addition, senescence, autophagy, apoptosis of biliary epithelial cells (BECs), and environmental factors, such as Epstein-Barr virus (EBV) infection and smoking, may also contribute to the pathogenesis of PBC. Understanding of the mechanisms responsible for the pathogenesis of PBC has important implications for the treatment of PBC.