HLA-G 3′UTR polymorphisms in high grade and invasive cervico-vaginal cancer

Human leukocyte antigen-G in hepatocellular carcinoma driven by chronic viral hepatitis or steatotic liver disease

Hepatocellular carcinoma (HCC) is the sixth most common cancer globally and the third leading cause of cancer-related mortality, primarily driven by viral infections (HCV, HBV) and steatotic liver diseases (SLD). Despite advances in treatment, early detection and accurate prognosis remain challenging. The Human leukocyte antigen G (HLA-G) molecule is dysregulated in various conditions, including cancers and viral infections. This study aimed to investigate HLA-G's role in viral-related and SLD-driven HCC. We analyzed a cohort of 116 HCC patients and 140 healthy controls to assess HLA-G genetic variants and soluble levels. Results showed significantly higher levels of soluble HLA-G in HCC patients compared to controls (Pc = 0.003). Moreover, overall survival (OS) was significantly lower in patients with the extended HLA-G*01:01:01/UTR-1 haplotype (Log-rank test, p = 0.002), a trend consistent in both HCV and/or HBV-related HCC (p = 0.025) and SLD-related HCC (p = 0.018). Elevated sHLA-G levels were associated with shorter OS across both subgroups (p = 0.034 (HBV/HCV) and p = 0.010 (SLD), respectively). The findings suggest that elevated levels of soluble HLA-G and specific genetic variants are associated with poor prognosis in HCC patients, highlighting the potential of HLA-G as a prognostic biomarker in both viral-related and steatotic liver disease-related HCC.

Associations of HLA-G 3'UTR polymorphisms and increased HLA-G expression with gastric cancer susceptibility and prognosis

BACKGROUND

Gastric cancer (GC) remains a serious health concern and is characterized by a multifactorial etiology involving both genetic and epigenetic factors. The aim of the current study was to examine the relationship between Human leukocyte antigen (HLA)-G 3'UTR polymorphisms and the expression of HLA-G in both tumor tissues and plasma samples from patients with GC in the Tunisian population.

METHODS

HLA-G 3'UTR polymorphisms (14pb Insertion/deletion and + 3142C/G) were identified by polymerase chain reaction (PCR) or Sanger sequencing. Plasma levels of sHLA-G (total sHLA-G, shed HLA-G1 and HLA-G5) were determined. Immunohistochemistry was used to evaluate the expression of HLA-G in tumor tissues.

RESULTS

The Del/Del genotype and Del allele frequencies were different between GC patients and healthy donors (HD) (OR [95 % CI] = 2.483 [1.070-5.410], p = 0.025 vs. OR [95 % CI] = 1.537 [0.924-2.584], p = 0.099; respectively). The C/C genotype and C allele frequencies were significantly greater in GC patients than in HD (OR [95 % CI] = 2.269[0.1.070-4.904], p = 0.033 vs. OR [95 % CI] = 1.746[1.045-2.878], p = 0.034; respectively). Interestingly, the Del/Del genotype and Del allele were significantly associated with an increased risk of GC in patients aged ≥55 years at diagnosis. HLA-G was highly expressed in GC tissues, particularly in tissues with advanced tumor invasion (T3 + T4). Compared with HD, GC patients had higher soluble HLA-G, shed HLA-G1 and HLA-G5 levels (Mann-Whitney: p = 0.001, p = 0.001 and p = 0.643, respectively). Assessment of patients' survival by Kaplan-Meier analysis indicated that the Del allele was significantly associated with reduced overall survival (OS) in GC patients at advanced stages III + IV (p = 0.043).

CONCLUSIONS

These results suggest that HLA-G 3'UTR polymorphisms are associated with GC susceptibility in Tunisian population. The expression of HLA-G in both the tissue and plasma may play an important role in the development and progression of GC. Therefore, the current study supported the recommendation of investigating HLA-G 3'UTR polymorphisms in GC and indicated that HLA-G molecules could serve as promising therapeutic targets in GC.

HLA-G - evolvement from a trophoblast specific marker to a checkpoint molecule in cancer, a narrative review about the specific role in breast- and gynecological cancer

Human leukocyte antigen G (HLA-G) is known as a non-classical molecule of the major histocompatibility complex class Ib and downregulates the mother's immune response against the fetus during pregnancy, thereby generating immune tolerance. Due to the latter effect, HLA-G is also referred to as an immune checkpoint molecule. Originally identified on extravillous trophoblasts, HLA-G is already known to induce immune tolerance at various stages of the immune response, for example through cell differentiation and proliferation, cytolysis and cytokine secretion. Because of these functions, HLA-G is involved in various processes of cancer progression, but a comprehensive review of the role of HLA-G in gynecologic cancers is lacking. Therefore, this review focuses on the existing knowledge of HLA-G in ovarian cancer, endometrial cancer, cervical cancer and breast cancer. HLA-G is predominantly expressed in cancer tissues adjacent to the extravillous trophoblast. Therefore, modulating its expression in the cancer target tissues of cancer patients could be a potential therapeutic approach to treat these diseases.

The 14-bp insertion/deletion as a promising gene polymorphism to understand cancer risk: Evidence from a systematic review and comprehensive meta-analysis

Background

HLA-G is associated with cancer cell escape. The 3'UTR polymorphism is involved in the regulation of membrane-bound HLA-G and soluble HLA-G proteins. The aim of our study was to assess the association of the HLA-G 14-bp insertion (I)/deletion (D) polymorphism with cancer susceptibility and its interaction with clinicopathological features and environmental factors.

Methods

A meta-analysis was performed to investigate the association between the HLA-G 14-bp I/D polymorphism and different types of cancers according to the Prisma guidelines.

Results

Thirty-nine publications that studied the 14-bp I/D polymorphism in cancers met our inclusion criteria. The findings of the meta-analysis showed a significant association between the 14-bp I/D polymorphism and cancer risk under the allelic contrast model D vs. I (OR = 1,112, 95 % CI = 1,009-1,227; P = 0,033) suggesting that the D allele was a risk factor for cancer susceptibility. Stratification by cancer type demonstrated a significant association of the 14-bp I/D polymorphism with breast cancer under the D vs. I contrast allele model (OR = 1,267, 95 % CI = 1,028-1,563; P = 0,027). No significant association was found for digestive, cervical, haematological and thyroid cancers. A comparison of groups stratified by ethnicity showed a significant association for Caucasians under the D vs. I model (OR = 1,147, 95 % CI = 1,002-1,313; P = 0,047); and for mixed ethnicities under the DD + DI vs. II (OR = 1,388, 95 % CI = 1,083-1,780; P = 0,010) and DI vs. II (OR = 1,402, 95 % CI = 1,077-1,824; P = 0,012) models. A comparison of cancer risks associated with the 14-bp I/D polymorphism according to geographic location revealed significant risks for the D allele and DD genotype in North Africa, the Middle East and South America. However, no significant susceptibility to cancer associated with the 14-bp I/D polymorphism was shown for Europe and North Asia. The findings of a meta-analysis of subgroups by disease stage showed a significant association in both early and advanced stages, with the 14-bp deletion variant being a risk factor. Similarly, a significant cancer risk was shown for the 14-bp deletion variant in both low- and high-grade cancers. Finally, the risk associated with the 14-bp I/D polymorphism was higher in cancers with concomitant viral infection with human papillomavirus (HPV), hepatitis B virus (HBV) or hepatitis C virus (HCV).

Conclusion

The findings of the overall meta-analysis showed a significant association between the HLA-G 14-bp I/D polymorphism and cancer susceptibility. The findings stratified analysis and subgroup comparisons showed that the 14-bp I/D deletion variant was associated with an increased risk of breast cancer. The HLA-G 14-bp I/D polymorphism may interact with individual and clinicopathological factors to alter cancer risk. These promising findings for cancer risk provide the basis for further studies that explore 14bp I/D polymorphism in cancer screening and immunotherapeutic approach.

Association of HLA-G Expression, Its Genetic Variants and Related Neuro-Immunomodulation with Characteristics of Bladder Carcinoma

BACKGROUND

Human leukocyte antigen G (HLA-G) is an immune checkpoint molecule with immunosuppressive and anti-inflammatory activities. It belongs to class I non-classical major histocompatibility complex molecules and has been upregulated in various cancer types. In bladder cancer (BC) tumors, the association of HLA-G with cancer progression has to be explained.

METHODS

A total of 89 BC patients and 74 control subjects were genotyped for the HLA-G 14 bp ins/del polymorphism. In urine cell samples, HLA-G mRNA expression was analyzed using real-time PCR. Soluble HLA-G (sHLA-G) serum levels were measured by ELISA. The associations between the HLA-G 14 bp ins/del polymorphism, HLA-G mRNA expression, and/or sHLA-G levels and selected variables including tumor grade, disease stage, body mass index, and heart rate variability (HRV) parameters were evaluated.

RESULTS

The protective HLA-G 14 bp ins/ins genotype under the recessive genetic model was associated with lower HLA-G mRNA expression in the BC group (p = 0.049). Significantly higher HLA-G mRNA expression was detected in patients with pT2 + pT3 as compared to those with pTa + pT1 stages (p = 0.0436). Furthermore, higher HLA-G mRNA expression was observed in high-grade muscle-infiltrating BC (MIBC) than in the low-grade non-MIBC group (p = 0.0365). Patients with a level of sHLA-G above 29 U/mL had shorter disease-free survival than patients with lower sHLA-G levels. Furthermore, the opposite HRV correlations with sHLA-G levels in BC patients as compared to controls probably reflect the different roles of HLA-G in health and cancer.

CONCLUSIONS

Our results suggest the impact of the HLA-G 14 bp ins/del variant, HLA-G expression, and autonomic nervous system imbalance on advanced stages of BC.

HLA-G Gene Variability Is Associated with Papillary Thyroid Carcinoma Morbidity and the HLA-G Protein Profile

Human leukocyte antigen (HLA)-G is an immune checkpoint molecule that is highly expressed in papillary thyroid carcinoma (PTC). The HLA-G gene presents several functional polymorphisms distributed across the coding and regulatory regions (5'URR: 5' upstream regulatory region and 3'UTR: 3' untranslated region) and some of them may impact HLA-G expression and human malignancy. To understand the contribution of the HLA-G genetic background in PTC, we studied the HLA-G gene variability in PTC patients in association with tumor morbidity, HLA-G tissue expression, and plasma soluble (sHLA-G) levels. We evaluated 185 PTC patients and 154 healthy controls. Polymorphic sites defining coding, regulatory and extended haplotypes were characterized by sequencing analyses. HLA-G tissue expression and plasma soluble HLA-G levels were evaluated by immunohistochemistry and ELISA, respectively. Compared to the controls, the G0104a(5'URR)G*01:04:04(coding)UTR-03(3'UTR) extended haplotype was underrepresented in the PTC patients, while G0104a(5'URR)G*01:04:01(coding)UTR-03(3'UTR) was less frequent in patients with metastatic and multifocal tumors. Decreased HLA-G tissue expression and undetectable plasma sHLA-G were associated with the G010102a(5'URR)G*01:01:02:01(coding)UTR-02(3'UTR) extended haplotype. We concluded that the HLA-G variability was associated with PTC development and morbidity, as well as the magnitude of the encoded protein expression at local and systemic levels.

Evaluation of HLA-G 14bp Ins/Del and +3142 C/G Polymorphisms in Type 1 Diabetes among South Indian Population

Background

Type 1 diabetes (T1D) is a multifactorial autoimmune disease, involving strong genetic components with familial predisposition. Human leukocyte antigen-G (HLA-G) is a non-classical HLA-class I molecule having several immunomodulatory functions. Polymorphisms in HLA-G are associated with several autoimmune diseases including T1D. This study aims to evaluate the association of HLA-G 14bp Ins/Del and +3142 C/G polymorphisms with T1D among the South Indian population.

Methods

The study was performed in a cohort of 123 T1D patients along with their 51 siblings and 126 parents. The association and linkage of HLA-G 14bp Ins/Del and +3142 C/G polymorphisms with T1D were analysed, and transmission disequilibrium test (TDT) was performed.

Results

Significantly increased frequencies of HLA-G 14bp Del/Del genotype (OR = 2.16, pc = 0.0302) and Del allele (OR = 1.71, pc = 0.0398) were observed in female patients compared to parents. Higher frequencies of DelDel/GG combined genotype (OR = 4.45, pc = 0.0049) and Del/G haplotype (OR = 2.91, pc = 0.0277) were observed in female patients compared to parents. TDT also revealed over-transmission of Del/G haplotype (25T vs 7UT; P = 0.0015) and a strong linkage disequilibrium between the studied polymorphisms.

Conclusion

This familial study shows the association of HLA-G 3'UTR 14bp Ins/Del polymorphism with the risk of T1D among the South Indian population, especially in females.

The relationship of 3'UTR HLA-G14-bp insertion/deletion and +3142 C/G polymorphisms and soluble HLA-G expression with gynecological cancers: An updated meta-analysis

OBJECTIVES

Human leukocyte antigen-G (HLA-G) is implicated in several cancers and is considered to be an immune checkpoint regulator. We determined the association between polymorphisms in the 3' untranslated region of HLA-G and soluble HLA-G (sHLA-G) expression with gynecological cancers (GCs).

METHODS

A meta-analysis was conducted to examine the association between HLA-G14-bp insertion (I)/deletion (D) and +3142C/G polymorphism in GC and to evaluate sHLA-G expression RESULTS: We revealed a significant association between the +3142C/G polymorphism and invasive cervical cancer (ICC) based on the allelic model G versus C (odds ratio [OR] = 0.738, 95% confidence interval [CI] = 0.563-0.966, p = 0.027), dominant GG+GC versus CC (OR = 0.584, 95% CI = 0.395-0.862, p = 0.007), and codominant GG versus CC (OR = 0.527, 95% CI = 0.312-0.891, p = 0.017) models, suggesting that the G allele and GG genotype are protective against ICC. In gynecological precancerous patients with human papillomavirus (HPV) infection, we found that the 14-bp I/D under the codominant DD versus DI model (OR = 0.492, 95% CI = 0.241-1.004, p = 0.051) was of borderline significance. Soluble HLA-G levels were significantly higher in patients compared with healthy controls (standardized mean differences [SMD] = 1.434, 95% CI = 0.442-2.526, p = 0.005). Stratification by cancer type revealed that the sHLA-G levels were significantly increased in cervical cancer (SMD = 4.889, 95% CI = 0.468-9.310, p = 0.030) and in subjects of Asian ethnicity (SMD = 4.889, 95% CI = 0.467-9.309, p = 0.030).

CONCLUSIONS

HLA-G14-bp I/D and +3142 C/G polymorphisms are associated with GC and HPV-associated cervical cancer. In addition, we found significantly increased sHLA-G levels in cancer patients. These results provide a basis for further studies in diagnostics and immunotherapy of GC.

Evaluating the HLA-G (rs1063320) genetic variant and risk of human papillomavirus infection: a meta-analysis of 953 cases and 877 controls

Human leukocyte antigen-G (HLA-G) has immune-modulatory functions. Although the role of genetic variant HLA-G (rs1063320) in susceptibility to human papillomavirus (HPV) infection has been widely considered, it is still a matter of discussion. In order to shed light on the issue, we, therefore, conducted a meta-analysis to evaluate the common impact of the HLA-G (rs1063320) variant on susceptibility to HPV infection. Subsequently, the distribution of genotypes, genotyping techniques and ethnicity groups was collected, and general analyses were performed. A total number of five studies with 953 cases and 877 controls were found to meet our criteria. The polymorphism of HLA-G (rs1063320) was evaluated. This is the first meta-analysis to explore the connection between the HLA-G 3' UTR + 3142C/G (rs1063320) genetic variant and the risk of HPV infection. Our results showed no association between the variant of HLA-G 3' UTR + 3142C/G (rs1063320) and susceptibility to HPV infection in studied target populations.Impact StatementWhat is already known on this subject? Human papillomavirus (HPV) is the most widespread sexually transmitted infection in both men and women all over the world. It is correlated with prominent load of diseases and malignancies, including anogenital warts and anogenital and oropharyngeal cancers. In recent years, several studies manifested that different SNPs located on special genes seems to influence HPV infection risk.What the results of this study add? Our findings disclosed no relation between the variant of HLA-G 3' UTR + 3142C/G (rs1063320) and vulnerability to HPV infection in the target individuals.What are the implications of these findings for clinical practice and/or further research? The findings in current survey may offer a basis for further study on HLA-G variant in future investigation.

microRNA Levels in Cervical Cancer Samples and Relationship with Lesion Grade and HPV Infection

BACKGROUND

miR-21, miR-214, and miR-let-7a are three validated and well-known miRNAs. miR-21 is described as an "oncomir," while miR-214 and miR-let-7a are described mainly as tumor suppressors. The role of these miRNAs remains unclear in cervical cancer, an important malignancy among women worldwide and responsible for many deaths every year.

OBJECTIVE

The objective of this study was to describe the expression profile of miR-21, miR-214, and miR-let-7a in plasma and cervical scraping from a control group and patients with different grades of cervical lesions and invasive cervical cancer, and then correlate with HPV infection groups.

METHODS

Plasma and cervical scraping were submitted to DNA and RNA extraction. HPV detection and typing were performed by conventional PCR followed by PAGE to amplicons interpretation. The miRNA relative expression in plasma and cervical scraping samples was performed by real-time PCR using specific TaqMan probes.

RESULTS

miR-21 (p=0.0277) and miR-214 (p=0.0151) were up-regulated in cervical scraping samples of the invasive cervical cancer (ICC) group. However, miR-214 was also up-regulated in the LSIL group (p=0.0062). Both miRNAs were not related to HPV infection. However, miR-let-7a was higher in HPV positive plasma samples (p=0.0433) than in HPV negative plasma samples, and the correlation analysis confirmed the association between the levels of this miRNA with the presence of HPV (p=0.0407; r=0.3029), but not with lesion grade (p>0.05).

CONCLUSION

Our results suggest that miR-21 is related to cervical cancer progression and miR-214 appears to have an ambiguous role in cervical lesions. miR-let-7a may be upregulated at the systemic level in patients with HPV infection.

HLA-G and single nucleotide polymorphism (SNP) associations with cancer in African populations: Implications in personal medicine

The immune system plays an important role in protecting the body against malignancy. During cancer immunoediting, the immune system can recognize and keep checking the tumor cells by down-expression of some self-molecules or by increasing expression of some novel molecules. However, the microenvironment created in the course of cancer development hampers the immune ability to recognize and destroy the transforming cells. Human Leukocyte Antigen G (HLA-G) is emerging as immune checkpoint molecule produced more by cancer cells to weaken the immune response against them. HLA-G is a non-classical HLA class I molecule which is normally expressed in immune privileged tissues as a soluble or membrane-bound protein. HLA-G locus is highly polymorphic in the non-coding 3′ untranslated region (UTR) and in the 5′ upstream regulatory region (5′ URR). HLA-G expression is controlled by polymorphisms located in these regions, and several association studies between these polymorphic sites and disease predisposition, response to therapy, and/or HLA-G protein expression have been reported. Various polymorphisms are demonstrated to modulate its expression and this is increasingly finding more significance in cancer biology. This review focuses on the relevance of the HLA-G gene and its polymorphisms in cancer development. We highlight population genetics of HLA-G as evidence to espouse the need and importance of exploring potential utility of HLA-G in cancer diagnosis, prognosis and immunotherapy in the currently understudied African population.

HLA-G: Function, polymorphisms and pathology

HLA-G immune modulatory genes and molecules are presently being studied by a widespread number of research groups. In the present study, we do not aim to be exhaustive since the number of manuscripts published every year is overwhelming. Instead, our aim is pointing out facts about HLA-G function, polymorphism and pathology that have been confirmed by several different researchers, together with exposing aspects that may have been overlooked or not sufficiently remarked in this productive field of study. On the other hand, we question whether performing mainly studies on HLA-G and disease associations is going to give a clear answer in the future, since 40 years of study of classical HLA molecules association with disease has still given no definite answer on this issue.

The Role of HLA-G in Human Papillomavirus Infections and Cervical Carcinogenesis

Human leukocyte antigen (HLA)-G, a non-classical HLA-class I molecule, has a low polymorphism frequency, restricted tissue distribution and immunoinhibitory property. HLA-G expression in tumor cells and cells chronically infected with virus may enable them to escape from host immune surveillance. It is well-known that the HLA-G molecule is a novel biomarker and potential therapeutic target that is relevant in various types of cancers, but its role in cervical cancer has not been fully explored. In this review, we aim to summarize and discuss the immunologic role of the HLA-G molecule in the context of HPV infections and the process of cervical cancer carcinogenesis. A better understanding of the potential impact of HLA-G on the clinical course of persistent HPV infections, cervical epithelial cell transformation, tumor growth, recurrence and metastasis is needed to identify a novel diagnostic/prognostic biomarker for cervical cancer, which is critical for cervical cancer risk screening. In addition, it is also necessary to identify HLA-G-driven immune mechanisms involved in the interactions between host and virus to explore novel immunotherapy strategies that target HLA-G/immunoglobulin-like transcript (ILT) immune checkpoints.

HLA-G 14 bp In/Del and +3142 C/G genotypes are differentially expressed between patients with grade IV gliomas and controls

Aim: Human Leukocyte Antigen-G (HLA-G) is a non-classical class I molecule that is involved in maternal-fetal immunotolerance. In cancer, this molecule contributes to the tumor escape. The aim of this study was to evaluate the 14 bp In/Del and +3142 C > G polymorphisms of the HLA-G 3' UTR and its relation with plasma and tissue HLA-G expression in patients with grade IV (high-grade) and grade I/II (low-grade) gliomas and controls.Patients and methods: Peripheral blood and tumor biopsies were collected from 85 patients with gliomas and blood samples from 94 controls. Polymorphisms were analyzed from blood DNA. Soluble HLA-G (sHLA-G) was measured by ELISA in plasma of the subjects and the tissue expression by immunohistochemistry on patient's tissue.Results: Higher levels of sHLA-G were observed in grade IV gliomas patients than in controls (p < 0.0001). In grade IV patients, the heterozygous 14pb In/Del, +3142 C/G genotypes and Del/C*In/G haplotype were associated with higher sHLA-G levels (p < 0.0001) when compared with controls. GBM patients were stratified into high and low sHLA-G expression and an association was found between +3142 C allele and high sHLA-G plasmatic levels (p = 0.0095). Tissue HLA-G immunolabel was higher in high-grade than low-grade gliomas (p = 0.0033).Conclusion: This was the first study evaluating HLA-G 3' UTR polymorphisms and expression in patients with gliomas. The 14 bp In/Del and +3142 C/G genotypes and haplotypes showed high influence over sHLA-G expression, suggesting a heterozygous advantage in the tumor context and may contribute to a worse prognosis in glioma patients.

Evaluation of Plasma Levels of Soluble HLA-G and HLA-G Genotypes in Kidney Transplant Recipients

In the field of transplantation, expression of HLA-G, a nonclassical HLA molecule with immunosuppressive functions and limited gene polymorphism, is considered beneficial for graft acceptance; various studies have aimed to demonstrate this role in transplantation. Recently, in other clinical conditions, it has been observed that insulin resistance was associated with HLA-G14bpins/del polymorphism, the most studied regulatory polymorphism of this molecule. In the present study, plasma levels of the soluble form of HLA-G (sHLA-G) were analyzed in kidney transplant recipients (n = 103) with different HLA-G14bpins/del genotypes. In a group of 26 recipients, sHLA-G was detected before and after transplantation (1 year) to evaluate early variations. In 77 recipients, sHLA-G was detected after transplantation (3-24 years) and correlated with occurrence of long-term post-transplant morbidity (diabetes mellitus, hyperlipidemia, hypertension, obesity, etc.).

METHODS

Levels of sHLA-G were measured in plasma with an enzyme-linked immunosorbent assay; HLA-G14bpins/del and HLA-G+3142C>G genotypes were assessed using direct polymerase chain reaction.

RESULTS

Plasma levels of sHLA-G significantly decreased during the first year after transplantation (P = .019); no significant correlations were found with genotypes or early post-transplant events. Lower levels of sHLA-G were found in recipients with post-transplant diabetes mellitus or obesity carrying the HLA-G14bpins/ins (P = .006 and P = .003, respectively) or HLA-G+3142G/G genotypes.

CONCLUSIONS

A complex modulation of HLA-G, which includes both immunologic and metabolic effects, could affect the risk for long-term post-transplant morbidity in kidney transplant recipients. Associations of HLA-G, diabetes, and obesity deserve to be investigated by deeply exploring HLA-G regulatory variants.

HLA-G Ins/Del polymorphism and +3142C/G SNP are not related to neuromyelitis optica spectrum disorder (NMOSD) development, disability status or anti-aquaporin 4 presence in Brazilian patients

We analyzed the association of polymorphisms from the 3' untranslated region of the HLA-G gene in 70 neuromyelitis optica spectrum disorder (NMOSD) patients and 162 healthy controls. No associations were found between the polymorphisms in NMOSD when compared to healthy controls, serology of the anti-AQP4 NMOSD biomarker and Expanded Disability Status Scale (EDSS). In conclusion, the 3' untranslated region 14 bp Ins/Del and +3142C/G polymorphisms seem not to be associated with NMOSD susceptibility, autoantibody production, nor a neurological deficit in patients.

Association of HLA-G 3'UTR 14-bp Ins/Del polymorphism with breast cancer among South Indian women

AIM

Human leucocyte antigen-G (HLA-G) and tumour necrosis factor-alpha (TNF-α) are potent immune mediators implicated in the pathogenesis of breast cancer. The polymorphisms in the 3' untranslated region (3'UTR) of HLA-G and promoter region of TNF-α are well known to influence their expression levels and may consequently contribute to varied disease predisposition. Therefore, in the present study, we explored the effect of HLA-G 3'UTR (14-bp Ins/Del and +3142 C/G) and TNF-α promoter (-238 G/A and -308 G/A) polymorphisms on breast cancer risk among South Indian women.

METHODS

A total of 342 women (100 patients with breast cancer, 142 patients with benign breast disorder and 100 healthy women volunteers) were enrolled for this study. Genotyping of HLA-G and TNF-α polymorphisms were performed by direct PCR DNA amplification and amplification refractory mutation system PCR methods, respectively.

RESULTS

Significantly higher frequencies of HLA-G 14-bp Ins allele and Ins/+3142G haplotype were observed in patients with breast cancer than healthy controls (OR=1.56, P_c=0.036) and patients with benign breast disorder (OR=1.47, P_c=0.046). Similarly, subgroup analysis based on age at diagnosis (age≤50 years and >50 years) of breast cancer revealed higher frequencies of 14-bp Ins allele and Ins/+3142G haplotype in the patients of age >50 years than healthy controls (OR=1.77, P_c=0.03). Additionally, the extended haplotypes and multifactor dimensionality reduction analysis of the studied polymorphisms revealed significant contribution of HLA-G 14-bp Ins/Del polymorphism towards breast cancer risk.

CONCLUSION

The findings of the present study suggest that the HLA-G 14-bp Ins/Del polymorphism could influence breast cancer pathogenesis among South Indian women.

HLA-G 3' untranslated region gene variants are promising prognostic factors for BK polyomavirus replication and acute rejection after living-donor kidney transplant

The immunosuppressive non-classical human leukocyte antigen-G (HLA-G) promotes transplant tolerance as well as viral immune escape. HLA-G expression is associated with regulatory elements targeting certain single nucleotide polymorphisms (SNPs) in the HLA-G 3' untranslated region (UTR). Thus, we evaluated the impact of HLA-G 3'UTR polymorphisms as surrogate markers for BK polyomavirus (BKPyV) replication or nephropathy (PyVAN) and acute cellular and antibody mediated rejection (ACR/AMR) in 251 living-donor kidney-transplant recipient pairs. After sequencing of the HLA-G 3'UTR, fourteen SNPs between +2960 and +3227 and the 14 bp insertion/deletion polymorphism, which arrange as UTR haplotypes, were identified. The UTR-4 haplotype in donors and recipients was associated with occurrence of BKPyV/PyVAN compared to the other UTR haplotypes. While the UTR-4 recipient haplotype provided protection against AMR, the UTR-2 donor haplotype was deleteriously associated with ACR/AMR. Deduction of the UTR-2/4 haplotypes to specific SNPs revealed that the +3003C variant (unique for UTR-4) in donors as well as in recipients is responsible for BKPyV/PyVAN and also provides protection against AMR; whereas the +3196G variant (unique for UTR-2) promotes allograft rejection. Thus, HLA-G 3'UTR variants are promising genetic predisposition markers both in donors and recipients that may help to predict susceptibility to either viral infectious complication of BKPyV or allograft rejection.

HLA-G +3142 C>G polymorphism and cancer risk: Evidence from a meta-analysis and trial sequential analysis

BACKGROUND

Human leukocyte antigen-G (HLA-G) plays an important role in the development of human cancers. Several published studies have investigated the relationship between the HLA-G +3142 C>G (rs1063320) polymorphism and cancer susceptibility in different populations. However, the results have yet to reach a consensus in different types of cancers. Therefore, we performed a meta-analysis to evaluate the effect of the HLA-G +3142 C>G polymorphism on cancer risk.

METHODS

A systematic literature search was performed in PubMed, Web of Science, CNKI, VIP, and Wanfang databases to acquire eligible studies up to February 20, 2019. The pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were used to assess the correlation between the HLA-G +3142 C>G polymorphism and cancer risk in a fixed-effects or random-effects model. Publication bias assessments, sensitivity analysis and stratified analyses were performed. To reduce the risk of type I error and assess whether the present evidence of the results was adequate and conclusive, trial sequential analysis (TSA) was also performed.

RESULTS

Eight case-control studies comprising 1546 cases and 1595 controls were included in the present meta-analysis. The results revealed that the HLA-G +3142 C>G mutation significantly decreased the total cancer risk in recessive comparison model and allelic comparison model. Further stratified analyses showed that the HLA-G +3142 C>G mutation significantly decreases the risk of cancer in Asian populations. No similar relationship was found in other subgroups. No publication bias was identified in our present study. Omitting a single study at a time had no significant impact on the pooled OR of the sensitivity analysis assessing the association between the HLA-G +3142 C>G polymorphism and cancer risk, which demonstrates the stability of the current meta-analysis. TSA also identified our current findings.

CONCLUSIONS

The results of our meta-analysis show that the HLA-G +3142 C>G polymorphism plays a protect role in the occurrence of human cancers, particularly in Asian populations. More case-control studies with different types of cancer in various ethnicities are needed to verify the findings.

Genetic variation in the HLA-G 3'UTR 14-bp insertion/deletion and the associated cancer risk: evidence from 25 case-control studies

Human leucocyte antigen-G (HLA-G) plays an important role in the progression of human cancers. A growing number of published studies have investigated the correlation between the HLA-G 3' untranslated region (3'UTR) 14-bp insertion/deletion (Ins/Del) polymorphism and the associated cancer risk in different populations. However, results from previous studies are inconclusive and inconsistent for the different type of cancers. Therefore, we undertook a meta-analysis to assess the effects of the HLA-G 14-bp Ins/Del polymorphism on cancer risk. A systematic literature search was conducted in PubMed, Web of Science, CNKI, VIP, and Wanfang databases to obtain relevant studies up to 28 January 2019. The pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were used. Twenty-five published case-control studies comprising 4981 cases and 6391 controls were included in the current meta-analysis. The results of the overall analysis revealed that the HLA-G 14-bp Ins/Ins genotype and Ins allele were associated with the total cancer risk in the homozygote comparison model (Ins/Ins vs. Del/Del: OR = 0.80, CI = 0.64-1.00; P=0.049) and the allelic comparison model (Ins vs. Del: OR = 0.89, CI = 0.81-0.99; P=0.035), with a protective role. Further subgroup analyses indicated that the HLA-G 14-bp Ins/Del polymorphism was associated with the risk of breast cancer and oesophageal cancer (EC), and significant risk of cancer was also observed in Mixed populations and population-based (PB). The results of our meta-analysis show that the HLA-G 14-bp Ins/Del polymorphism plays an important role in cancer risk, particularly in breast cancer and esophageal cancer in Mixed populations. Additional case-control studies with different types of cancer spanning different ethnicities are needed to extend the present findings.

Detection of FZD4, LRP5 and TSPAN12 Genes Variants in Malay Premature Babies with Retinopathy of Prematurity

Purpose:

To determine the mutational analyses of familial exudative vitreoretinopathy (FEVR)-causing genes in Malay patients with retinopathy of prematurity (ROP) to obtain preliminary data for gene alterations in the Malay community.

Methods:

A comparative cross-sectional study involving 86 Malay premature babies (ROP = 41 and non-ROP = 45) was performed from September 2012 to December 2014. Mutation analyses in (FEVR)-causing genes (NDP, FZD4, LRP5, and TSPAN12) were performed using DNA from premature babies using polymerase chain reaction (PCR) and direct sequencing. Sequencing results were confirmed with PCR-Restriction Fragment Length Polymorphism (RFLP).

Results:

We found variants of FZD4, LRP5, and TSPAN12 in this study. One patient from each group showed a non-synonymous alteration in FZD4, c.502C>T (p.P168S). A synonymous variant of LRP5 [c.3357G>A (p.V1119V)] was found in 30 ROP and 28 non-ROP patients. Two variants of TSPAN12, c.765G>T (p.P255P) and c.*39C>T (3′UTR), were also recorded (29 and 21 in ROP, 33 and 26 in non-ROP, respectively). Gestational age and birth weight were found to be significantly associated with ROP (P value < 0.001 and 0.001, respectively).

Conclusion:

Analysis of data obtained from the ROP Malay population will enhance our understanding of these FEVR-causing gene variants. The c.3357G>A (p.V1119V) variant of LRP5, and c.765G>T (p.P255P) and c.*39C>T variants of TSPAN12 could be common polymorphisms in the Malay ethnic group; however, this requires further elucidation. Future studies using larger groups and higher numbers of advanced cases are necessary to evaluate the relationship between FEVR-causing gene variants and the risk of ROP susceptibility in Malaysian infants.

HLA-G 3' untranslated region variants +3187G/G, +3196G/G and +3035T define diametrical clinical status and disease outcome in epithelial ovarian cancer

Expression of the non-classical human leukocyte antigen-G (HLA-G) promotes cancer progression in various malignancies including epithelial ovarian cancer (EOC). As single nucleotide polymorphisms (SNPs) in the HLA-G 3' untranslated region (UTR) regulate HLA-G expression, we investigated HLA-G 3'UTR haplotypes arranged by SNPs in healthy controls (n = 75) and primary EOC patients (n = 79) and determined soluble HLA-G (sHLA-G) levels. Results were related to the clinical status and outcome. Although haplotype frequencies were similar in patients and controls, (i) sHLA-G levels were increased in EOC independent of the haplotype, (ii) homozygosity for UTR-1 or UTR-2 genotypes were significantly associated with metastases formation and presence of circulating tumor cells before therapy, whereas (iii) the UTR-5 and UTR-7 haplotypes were significantly associated with a beneficial clinical outcome regarding negative nodal status, early FIGO staging, and improved overall survival. Lastly, (iv) the ambivalent impact on clinical EOC aspects could be deduced to specific SNPs in the HLA-G 3'UTR: +3187G, +3196G and +3035T alleles. Our results give evidence that even if the genetic background of the HLA-G 3'UTR is identical between patients and controls, certain SNPs have the potential to contribute to diametrical clinical status/outcome in EOC.

Association of HLA-G 3' UTR polymorphism and expression with the progression of cervical lesions in human papillomavirus 18 infections

Background

Human leukocyte antigen (HLA)-G is an immune checkpoint molecule, which expression in cervical cancer cells enables them to escape immunosurveillance. To date, limited information has been published on the association of HLA-G genetic background in malignant cells with levels of HLA-G expression and the clinical outcome of patients.

Methods

We investigated the influence of the HLA-G 14 bp In/Del (rs66554220) and + 3142C/G (rs1063320) polymorphisms in 130 cases of HPV16 infection, 130 cases of HPV18 infection and 185 age-matched, unrelated, HPV-negative, and cytologically normal Chinese Han women. Case-matched cervical biopsy tissues were evaluated by immunohistochemistry.

Results

Our findings show that the frequency of alleles, 14 bp In (38.5% vs 29.2%, OR = 1.52, P < 0.05) and + 3142G (72.7% vs 57.0%, OR = 2.01, P < 0.05), were significantly increased in the HPV18-infected group compared with the control group. The HLA-G polymorphisms (alleles 14 bp In and + 3142G) are also associated with the progression of HPV18-related cervical lesions. Moreover, HLA-G expression increased from CIN1 to CIN2/3 lesions and was highest in patients with adenocarcinoma; however, a significant association between these characteristics and the HLA-G polymorphisms was not observed.

Conclusion

Our results support that the HLA-G 14 bp In and + 3142G alleles are risk factors for HPV18 infections and influence the progression of HPV18-related cervical lesions. This suggests that HLA-G-driven immune mechanisms play an important role in cervical carcinogenesis.

Variation sites at the HLA-G 3' untranslated region confer differential susceptibility to HIV/HPV co-infection and aneuploidy in cervical cell

Post-transcriptional regulatory elements associated with transcript degradation or transcript instability have been described at the 3' untranslated region (3'UTR) of the HLA-G gene. Considering that HPV infection and aneuploidy, which causes gene instability, are associated with cervical cell malignancy, as well as the fact that HIV infection and HLA-G may modulate the immune response, the present study aimed to compare the frequencies of HLA-G 3'UTR polymorphic sites (14-base pair insertion/deletion, +3142C/G, and +3187A/G) between 226 HIV+ women co-infected (n = 82) or not with HPV (n = 144) and 138 healthy women. We also evaluated the relationship between those HLA-G 3'UTR variants and aneuploidy in cervical cells. HPV types and HLA-G polymorphisms were determined by PCR and sequencing of cervical samples DNA. Aneuploidy in cervical cell was measured by flow cytometry. The HLA-G 3'UTR 14-bp ins/del was not associated with either HIV nor HIV/HPV co-infection. The +3142G allele (p = 0.049) and +3142GG genotype (p = 0.047) were overrepresented in all HIV-infected women. On the other hand, the +3187G allele (p = 0.028) and the +3187GG genotype (p = 0.026) predominated among healthy women. The +3142G (p = 0.023) and +3187A (p = 0.003) alleles were associated with predisposition to HIV infection, irrespective of the presence or not of HIV/HPV co-infection. The diplotype formed by the combination of the +3142CX (CC or CG) and +3187AA genotype conferred the highest risk for aneuploidy in cervical cell induced by HPV. The HLA-G 3'UTR +3142 and +3187 variants conferred distinct susceptibility to HIV infection and aneuploidy.

Genetic association between HLA-G 14-bp polymorphism and diseases: A systematic review and meta-analysis

BACKGROUND

HLA-G is an immune checkpoint molecule. Since a differential molecule expression has been reported even for healthy individuals, many studies have focused on polymorphisms at HLA-G regulatory regions, particularly the 3' untranslated region (3'UTR). The presence/absence of a 14-bp sequence was the first polymorphism described and it is the most studied in association between HLA-G and disorders.

METHODS

In this study, we performed a systematic review and meta-analysis of all association studies published regarding the HLA-G 14-bp.

RESULTS

We verified association between 14-bp alleles and diseases in the following situations: (1) presence of 14-bp (insertion) conferred susceptibility to preeclampsia (child alleles evaluated) and systemic lupus erythematosus (OR = 1.42; 95%CI = 1.04-1.93; p = 0.026 and OR = 1.13; 95%CI = 1.01-1.27, p = 0.028); (2) 14-bp absence (deletion) was associated with increased risk to breast cancer (OR = 1.23; 95%CI = 1.06-1.43; p = 0.006) and human Cytomegalovirus infection (OR = 2.06; 95%CI = 1.60-2.64; p < 0.0001); and (3) a risk association was observed between the group of reproductive disorders and the 14-bp insertion (OR = 1.12; 95%CI = 1.01-1.24; p = 0.034).

CONCLUSIONS

Considering that others 14-bp associations were inconclusive and that other variation sites observed at HLA-G 3'UTR exhibit a proven role on post-transcriptional regulation of HLA-G expression, the complete 3'UTR segment should be analyzed in terms of disease susceptibility, instead of a single polymorphism.

Human leukocyte antigen-G 3' untranslated region polymorphisms are associated with asthma severity

Asthma is a genetically complex chronic inflammatory airway disorder, and according to disease pathogenesis, clinical manifestations may vary according to asthma severity. A gene region close to the human leukocyte antigen-G (HLA-G) gene was identified as an independent susceptibility marker for asthma. Considering that the HLA-G immune checkpoint molecule may modulate inflammation, we evaluated the diversity of the HLA-G 3' untranslated region (3'UTR) in asthmatic patients stratified according to disease severity. We evaluate the entire HLA-G 3'UTR segment in 115 Brazilian patients stratified into mild (n=29), moderate (n=21) and severe asthmatics (n=65), and in 116 healthy individuals. HLA-G 3'UTR typing was performed using Sanger sequencing. The multiple comparisons among patients stratified according to disease severity revealed several associations; however, after Bonferroni's correction, the following results remained significant: i) the +3010C and +3142G alleles were overrepresented in mild asthma patients when compared to controls; ii) the +3010G and +3142C alleles were overrepresented in severe asthma patients in comparison to patients with mild asthma. In conclusion, the +3010C/G and +3142C/G HLA-G 3'UTR variation sites were differentially associated according to asthma severity.

Human leukocyte antigen-G expression and polymorphisms promote cancer development and guide cancer diagnosis/treatment

Human leukocyte antigen-G (HLA-G) is a non-classical HLA molecule, predominantly expressed in cytotrophoblast cells to protect the fetus during pregnancy. Notably, a high frequency of HLA-G expression has been observed in a wide variety of cancer types in previous studies. Furthermore, HLA-G expression in cancer has been considered to be detrimental, since it can protect cancer cells from natural killer cell cytotoxic T lymphocyte-mediated destruction, promote tumor spreading and shorten the survival time of patients by facilitating tumor immune evasion. In addition, HLA-G polymorphisms have been investigated in numerous types of cancer and are considered as risk factors and predictive markers of cancer. This review focuses on HLA-G expression and its polymorphisms in cancer, analyzing the mechanisms of HLA-G in promoting cancer development, and evaluating the potential and value of its clinical application as a diagnostic and prognostic biomarker, or even as a prospective therapeutic target in certain types of tumors.

"HLA-G 3'UTR gene polymorphisms and rheumatic heart disease: a familial study among South Indian population"

BACKGROUND

Rheumatic heart disease (RHD) is an autoimmune disease where cross reactive CD4⁺ T cells are involved in the pathogenesis of valvular damage. Human Leukocyte Antigen-G (HLA-G), an immunosuppressive molecule playing a crucial role in the inhibition of T cell response is associated with the pathogenesis of various autoimmune and inflammatory diseases. Genetic polymorphisms within the 3'untranslated region (UTR) of HLA-G influences its expression and thus disease pathogenesis. Hence, the present study aims to unravel the association of 14 bp Ins/Del (rs66554220) and +3142 C/G (rs1063320) polymorphisms in 3' UTR of HLA-G with RHD.

METHODS

This familial study consists of 99 RHD families (99 RHD patients, 140 parents and 126 healthy siblings). The 14 bp Ins/Del and +3142 C/G polymorphisms were evaluated by PCR using sequence specific primers and its transmission disequilibrium (TD) was tested by TD test in 70 trio families.

RESULTS

The frequency of +3142 C/C genotype was high in patients with combined valvular lesions (CVL) (OR = 5.88; p_c = 0.012) and pooled RHD patients (P: OR = 2.76; p = 0.043; p_c = 0.076) when compared to healthy siblings. Under the additive (OR = 5.50; p_c = 0.026) and recessive genetic model (OR = 5.88; p_c = 0.012), the +3142 C/C genotype was significantly associated with CVL in patients.

CONCLUSION

The results suggest that the +3142 C/C genotype may be associated with minor risk for the development of RHD and is more likely to influence the severity of the disease.

A pilot study on Hla-G locus control region haplotypes and cervical intraepithelial neoplasias

Human papillomavirus (HPV) can induce cervical intraepithelial neoplasias (CIN) grades 1, 2 and 3. Untreated, these lesions may progress to cervical cancer (CC) which is the third most common cancer in women worldwide. HLA-G plays an immunotolerant role in the immune response. The aim of this study was to characterize the configuration of SNPs located at the distal promoter of HLA-G in patients with CIN2 and CIN3 and control women. The study sample was composed of 207 women as follows: 73 diagnosed with CIN2 lesions, 56 with CIN3 and 78 healthy control women. Genotyping was performed by sequence base typing. Eleven haplotype configurations subdivided in two main haplogroups (H1dist and H2dist), were characterized and compared between patients and controls. The haplotypes H1.1Dist (GAGAACGC) and H2.1Dist (AGGTACAC) were more frequent in Euro-Descendants as well as in Brazilian Mixed. Nevertheless, the haplotype H2.1Dist standed out as a susceptibility haplotype in Brazilian Mixed patients while the H1.1Dist presented a protector effect in this same ethnic group. Whether such LCR haplotype configurations can impact on HLA-G gene expression levels in women who developed cervical intraepithelial neoplasia is still unknown and it is of utmost importance that more investigation on this field be pursued.

WITHDRAWN: Lack of association between the HLA-G 3'UTR 14-bp ins/del polymorphism and cancer risk: A meta-analysis of case-control study

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Genetic polymorphisms and expression of HLA-G and its receptors, KIR2DL4 and LILRB1, in non-small cell lung cancer

Human leukocyte antigen-G (HLA-G) is a nonclassical HLA class I molecule absent from most normal tissues but detected in many malignant tumors. It is recognized by cells of the immune system using LILRB1, KIR2DL4 and LILRB2 receptors. We attempted to find out whether some polymorphisms of HLA-G, LILRB1 and KIR2DL4 genes are associated with susceptibility to nonsmall cell lung cancer (NSCLC). Four polymorphisms in HLA-G, i.e. -964A>G (rs1632947), -725C>G>T (rs1233334), -716T>G (rs2249863) in the promoter, and a 14 base pair insertion/deletion (14 bp indel) in the 3'-untranslated region (3'UTR), and five in LILRB1 - 5651G>A (rs41308748) in intron 14, 5717C>T L622L (rs1061684), 5724G>A E625K (rs16985478), 5774 C>A P641P (rs41548213) in exon 15, and 5806C>T (rs8101240) in 3'UTR - as well as 9620 9A/10A (rs11410751) polymorphism in exon 7 of KIR2DL4 were typed using different laboratory techniques. Only one single nucleotide polymorphism (SNP) in HLA-G (-964A>G) and one in LILRB1 (5724G>A) were found to influence the risk of NSCLC. In addition, 5724G>A was associated with protection from tumor cell infiltration of regional lymph nodes. Most importantly, we detected HLA-G and LILRB1 expression in tumor specimens, but no correlation with genetic polymorphisms was observed. HLA-G and LILRB1 protein expression levels in tumor tissue were significantly correlated with tumor stage.

Methylenetetrahydrofolate reductase polymorphisms at 3'-untranslated region are associated with susceptibility to preterm birth

BACKGROUND

Etiology and mechanism of preterm birth (PTB) is complicated. Genetic susceptibility is one of the key factors involved in the pathogenic mechanism underlying PTB.

METHODS

A subset of single nucleotide polymorphisms (SNPs) selected by bioinformatics approach from 3'-untranslated region (3'-UTR) of methylenetetrahydrofolate reductase (MTHFR) gene were subjected to SNaPshot analysis in a case-control study. Three SNPs (rs45451599, rs1537515, rs1537516) were simultaneously tested in one tube, among 1,135 DNA samples including 480 PTBs and 655 term controls.

RESULTS

Two perfectly correlated (r(2)=1) SNPs, rs1537515 and rs1537516, were found significantly associated with PTB susceptibility [P=0.012; OR: 0.65; 95% confidence interval (CI), 0.47-0.91]. The frequencies of the minor alleles were lower in PTB cases than in controls, which the frequencies were 0.066 in PTB cases and 0.095 in controls. G and T allele frequencies of rs1537515 were the same with rs1537516 (P=0.011; OR: 0.666; 95% CI, 0.49-0.91). Rs45451599 was not found associated with PTB (P=0.52; OR: 0.76; 95% CI, 0.33-1.74). The 18-25 nucleotides in length of microRNAs (miRNAs) which can regulate gene expressions are involved in binding partial complementary sequences within 3'-UTR. The two loci are at 3'-UTR of MTHFR mRNA. Rs1537516 is a potential target of miR-1304-3p, while rs1537515 is miR-1224-3p and miR-3150-5p.

CONCLUSIONS

In conclusion, rs1537515 and rs1537516 within the 3'-UTR of the MTHFR gene may be associated with susceptibility to PTB.

HLA-G Molecules in Autoimmune Diseases and Infections

Human leukocyte antigen (HLA)-G molecule, a non-classical HLA-Ib molecule, is less polymorphic when compared to classical HLA class I molecules. Human leukocyte antigen-G (HLA-G) was first detected on cytotrophoblast cells at the feto-maternal interface but its expression is prevalent during viral infections and several autoimmune diseases. HLA-G gene is characterized by polymorphisms at the 3' un-translated region and 5' upstream regulatory region that regulate its expression and are associated with autoimmune diseases and viral infection susceptibility, creating an unbalanced and pathologic environment. This review focuses on the role of HLA-G genetic polymorphisms, mRNA, and protein expression in autoimmune conditions and viral infections.

Human leukocyte antigen (HLA)-G and cervical cancer immunoediting: a candidate molecule for therapeutic intervention and prognostic biomarker?

While persistent infection with oncogenic types of human Papillomavirus (HPV) is required for cervical epithelial cell transformation and cervical carcinogenesis, HPV infection alone is not sufficient to induce tumorigenesis. Only a minor fraction of HPV infections produce high-grade lesions and cervical cancer, suggesting complex host-virus interactions. Based on its pronounced immunoinhibitory properties, human leukocyte antigen (HLA)-G has been proposed as a possible prognostic biomarker and therapeutic target relevant in a wide variety of cancers and viral infections, but to date remains underexplored in cervical cancer. Given the possible influence of HLA-G on the clinical course of HPV infection, cervical lesions and cancer progression, a better understanding of HLA-G involvement in cervical carcinogenesis might contribute to two aspects of fundamental importance: 1. Characterization of a novel diagnostic/prognostic biomarker to identify cervical cancer and to monitor disease stage, critical for patient screening; 2. Identification of HLA-G-driven immune mechanisms involved in lesion development and cancer progression, leading to the development of strategies for modulating HLA-G expression for treatment purposes. Thus, this systematic review explores the potential involvement of HLA-G protein expression and polymorphisms in cervical carcinogenesis.

Dense genotyping of immune-related loci identifies variants associated with clearance of HPV among HIV-positive women in the HIV epidemiology research study (HERS)

Persistent high-risk human papillomavirus (HR-HPV) is a necessary and causal factor of cervical cancer. Most women naturally clear HPV infections; however, the biological mechanisms related to HPV pathogenesis have not been clearly elucidated. Host genetic factors that specifically regulate immune response could play an important role. All HIV-positive women in the HIV Epidemiology Research Study (HERS) with a HR-HPV infection and at least one follow-up biannual visit were included in the study. Cervicovaginal lavage samples were tested for HPV using type-specific HPV hybridization assays. Type-specific HPV clearance was defined as two consecutive HPV-negative tests after a positive test. DNA from participants was genotyped for 196,524 variants within 186 known immune related loci using the custom ImmunoChip microarray. To assess the influence of each single-nucleotide polymorphism (SNP) with HR-HPV clearance, the Cox proportional hazards model with the Wei-Lin-Weissfeld approach was used, adjusting for CD4+ count, low risk HPV (LR-HPV) co-infection, and relevant confounders. Three analytical models were performed: race-specific (African Americans (n = 258), European Americans (n = 87), Hispanics (n = 55), race-adjusted combined analysis, and meta-analysis of pooled independent race-specific analyses. Women were followed for a median time of 1,617 days. Overall, three SNPs (rs1112085, rs11102637, and rs12030900) in the MAGI-3 gene and one SNP (rs8031627) in the SMAD3 gene were associated with HR-HPV clearance (p<10(-6)). A variant (rs1633038) in HLA-G were also significantly associated in African American. Results from this study support associations of immune-related genes, having potential biological mechanism, with differential cervical HR-HPV infection outcomes.

HLA-G 3' untranslated region polymorphisms influence the susceptibility for human papillomavirus infection

Human leukocyte antigen (HLA)-G molecule acts as a potential factor for the regulation of immune responses and its expression in virus-infected cells may enable them to escape immunosurveillance. Besides its polymorphic promoter region, the 3' untranslated region (UTR) seems to play an important role in regulating HLA-G expression. In this study, we investigated the influence of HLA-G 14 bp (rs66554220) and +3142 (rs1063320) polymorphisms in 179 women with active human papillomavirus (HPV) infection and 143 age-matched, unrelated, HPV-negative, normal Chinese Han population. Our findings showed that frequency of the allele +3142 C [31.3% vs 44.4%, odds ratio (OR) = 0.57, Pc < 0.01] and the genotype +3142 CC (10.6% vs 21.7%, OR = 0.43, Pc = 0.012) was significantly decreased in HPV infected patients compared with normal controls. Furthermore, the haplotype -14 bp/C was associated with a reduced risk for HPV infection (OR = 0.57, Pc = 0.001). Our findings also showed that HLA-G homozygous +14 bp/+14 bp genotype was significantly associated with an increased risk for HPV18 infection (OR = 12.95, P < 0.01), whereas HLA-G heterozygous +14 bp/-14 bp genotype increased risk for HPV58 (OR = 5.55, P < 0.05). Furthermore, frequency of the haplotype +14 bp/G was significantly increased in HPV18 infected patients (60.0% vs 27.3%, OR = 4.00, Pc < 0.05). Taken together, our results supported a role of the HLA-G 3' UTR polymorphisms as a susceptible factor for the active HPV infection, and suggested a possible interference of the HLA-G molecule in the response to virus infection.

HLA-G expression on blasts and tolerogenic cells in patients affected by acute myeloid leukemia

Human Leukocyte Antigen-G (HLA-G) contributes to cancer cell immune escape from host antitumor responses. The clinical relevance of HLA-G in several malignancies has been reported. However, the role of HLA-G expression and functions in Acute Myeloid Leukemia (AML) is still controversial. Our group identified a subset of tolerogenic dendritic cells, DC-10 that express HLA-G and secrete IL-10. DC-10 are present in the peripheral blood and are essential in promoting and maintaining tolerance via the induction of adaptive T regulatory (Treg) cells. We investigated HLA-G expression on blasts and the presence of HLA-G-expressing DC-10 and CD4⁺ T cells in the peripheral blood of AML patients at diagnosis. Moreover, we explored the possible influence of the 3′ untranslated region (3′UTR) of HLA-G, which has been associated with HLA-G expression, on AML susceptibility. Results showed that HLA-G-expressing DC-10 and CD4⁺ T cells are highly represented in AML patients with HLA-G positive blasts. None of the HLA-G variation sites evaluated was associated with AML susceptibility. This is the first report describing HLA-G-expressing DC-10 and CD4⁺ T cells in AML patients, suggesting that they may represent a strategy by which leukemic cells escape the host's immune system. Further studies on larger populations are required to verify our findings.

The 14 bp Del/Ins HLA-G polymorphism is related with high blood pressure in acute coronary syndrome and type 2 diabetes mellitus

Immunologic and inflammatory processes are involved in the pathogenesis of acute coronary syndrome (ACS) and type 2 diabetes mellitus (DM2). Human leukocyte antigen-G (HLA-G) is a negative regulator of the immune response. This study evaluates the 14 bp Del/Ins HLA-G polymorphism in ACS and DM2. Three hundred and seventy individuals from Western Mexico were recruited and categorized into three groups: ACS (86), DM2 without coronary complications (70), and healthy subjects (214). Genotyping of the 14 bp Del/Ins HLA-G polymorphism was performed by PCR and Native-PAGE. The most common risk factors were hypertension and overweight in ACS and DM2, respectively. The genetic distribution of the 14 bp Del/Ins HLA-G polymorphism showed no significant differences between groups (P ≥ 0.23). Nonetheless, the Ins/Ins genotype was associated with high blood pressure (HBP) in the DM2 group (OR_c = 1.65, P = 0.02). The genetic recessive model showed similar findings (OR_c = 3.03, P = 0.04). No association was found in ACS, with a P of 0.05; nevertheless, the prevalence of Ins/Ins carriers was quite similar to that found in the DM2-HBP group. The 14 bp Del/Ins HLA-G polymorphism was not a susceptibility factor for ACS or DM2; however, the Ins/Ins genotype might have contributed to the development of HBP in the studied groups.

Polymorphic sites at the 3' untranslated region of the HLA-G gene are associated with differential hla-g soluble levels in the Brazilian and French population

HLA-G molecule has well-recognized tolerogenic properties, and the encoding gene shows lower frequency of polymorphism at the coding region but higher variability at regulatory 5' and 3' untranslated (3'UTR) regions. At least three 3'UTR polymorphic sites have been associated with HLA-G mRNA regulation, including the 14 base pair (14bp) Insertion/Deletion, +3142C-G and +3187A-G. We studied the association of polymorphic sites at 3'UTR (sequencing analysis, encompassing the 14bp Ins-Del/+3003T-C/+3010C-G/+3027C-A/+3035C-T/+3142C-G/+3187A-G/+3196C-G polymorphic sites) with plasma soluble HLA-G levels (sHLA-G, detected by ELISA) in 187 French and 153 Brazilian healthy individuals. Allele and genotype frequencies were closely similar in both populations; however, Brazilians showed a higher HLA-G 3'UTR haplotype diversity. Considering sHLA-G levels in both populations altogether, individuals presenting 14bp Del/Del showed higher levels compared to 14bpIns/Ins genotype (P <0.05); those presenting +3010C/G showed higher levels compared to the +3010C-C genotype (P< 0.05); those presenting +3027C-C showed higher levels than the +3027A-A genotype (P< 0.05); and those bearing +3035C-C showed higher levels compared to the +3035C-T (P < 0.01) and +3035T-T (P < 0.05) genotypes. The analyses of 3'UTR haplotypes showed that UTR-1 (DelTGCCCGC) was associated with higher expression of sHLA-G, whereas UTR-5 (InsTCCTGAC) and UTR-7 (InsTCATGAC) with lower expression and other UTRs (UTR-2/3/4/6) exhibited intermediate levels. Since the differential expression of HLA-G may be beneficial or harmful depending on the underlying condition, the identification of individuals genetically programmed to differentially express HLA-G may help on defining novel strategies to control the immune response against the underlying disorder.

The association between human leukocyte antigen (HLA)-G polymorphisms and human papillomavirus (HPV) infection in Inuit women of northern Quebec

BACKGROUND

The human leukocyte antigen (HLA)-G molecules act as negative regulators of the immune response. We analyzed the associations between HLA G polymorphisms and human papillomavirus (HPV) infection and squamous intraepithelial lesions (SIL) in Inuit women from Nunavik, northern Quebec.

METHODS

Cervical specimens from a cohort study of 548 Inuit women were tested for HPV DNA. HPV genotypes were classified according to tissue-tropism groupings of alpha-papillomavirus species: alpha group 1 includes low risk (LR) cervical species, group 2 includes high risk (HR) cervical species, and group 3 includes LR vaginal species. HLA-G alleles were typed using direct DNA sequencing.

RESULTS

HLA-G(∗)01:01:01 was associated with an increased risk of period prevalent alpha groups 1 (OR = 2.23, 95% CI:1.08-4.59) and 3 (OR = 1.70, 95% CI:1.09-2.65). The homozygous HLA-G(∗)01:04:01 genotype was associated with a decreased risk of alpha group 3 infection period prevalence (OR = 1.69 95% CI = 1.07-2.67). No HLA-G alleles were significantly associated with HPV persistence. HLA-G(∗)01:01:02, G(∗)01:04:01 and G(∗)01:06 were associated with high grade (HG)SIL, but the association did not reach statistical significance.

CONCLUSIONS

These results suggest that HLA-G polymorphisms play a role in the natural history of HPV infection, likely at the stage of host immune recognition. HLA-G polymorphisms interacted differently with the three alpha papillomavirus groups.