Human Leukocyte antigen-G Research Articles

Study of immune-tolerized cell lines and extracellular vesicles inductive environment promoting continuous expression and secretion of HLA-G from semiallograft immune tolerance during pregnancy

ABSTRACT An immune reaction is a protector of our body but a target to be overcome for all non-self-derived medicine. Extracellular Vesicles (EVs), noted as a primary alternative to cell therapy products that exhibit immune rejection due to mismatching-major histocompatibility complex (MHC), were discovered to have excellent curative effects through the delivery of various biologically active substances. Although EVs are sure to incur immune reaction by immunogenicity due to alloantigens from their parental cells, their immune rejection is rarely known. Hence, to develop cell lines and EVs as medicines with no immune rejection, we noted the immune tolerance where the foetus, as semi-allograft, is perfectly protected from the maternal immune system. We designed the ex-vivo culture systems to simulate in-vivo environmental factors inducing extravillous trophoblast (EVT)-specific Human Leukocyte Antigen-G (HLA-G) expression and secretion of HLA-G-bearing EVs at the mother-foetus interface. Using them, we confirmed that immune-tolerized stem cells (itSCs) continuously expressing and secreting HLA-G like EVTs during pregnancy can be induced. Also, EVs secreted from itSCs are verified as immune-tolerized EVs (itSC-EVs) containing HLA-G and not causing immune rejection through various analytical methods. These findings can provide a new perspective on the local and extensive immune tolerance environment where HLA-G is expressed and secreted by pregnancy-related hormones and different biological conditions. Furthermore, they show the new way to develop itSCs-EVs-based therapeutics that are free from time, space, and donor limitation causing immune rejection. Abbreviations CFSE: carboxyfluorescein succinimidyl ester; DC: dendritic cells; ELISA: enzyme-linked immunosorbent assay; EV: extracellular vesicles; EVT: extravillous trophoblast; FSH: follicle stimulating hormone; HA: hyaluronic acid; hCG: human chorionic gonadotropin; HLA-G: human leukocyte antigen G; iPSC: induced pluripotent stem cells; itSC-EVs: immune-tolerized extracellular vesicles from itSCs; itTBC-EVs: immune-tolerized extracellular vesicles from itTBCs; itSCs: immune tolerized stem cells; itTBCs: immune-tolerized trophoblast cells; LH: luteinizing hormone; MHC: major histocompatibility complex; MSC: mesenchymal stem cells; NK: natural killer cells; NTA: nanoparticle tracking analysis; PBMC: peripheral blood mononuclear cells; PHA: phytohemagglutinin; SP-IRIS: single particle interferometric reflectance imaging sensing; STB: syncytiotrophoblast

Evaluation of HLA-G immune checkpoint molecule in melanocytic lesions

ABSTRACT The human leukocyte antigen-G (HLA-G) is a non-classical molecule of the major histocompatibility complex. HLA-G has been associated with the process of tumorigenesis and tumor escape. In this study, we aim to evaluate the HLA-G expression in melanocytic lesions and in melanoma for determining when melanocytic lesions start its expression. Twenty-two skin biopsies samples were submitted to immunohistochemistry; HLA-G expression was detected in 63.6% of the samples. This expression in melanocytic cells was significantly higher in melanoma than in benign melanocytic lesions (p < 0.002). Our results suggest that HLA-G expression starts late in the process of tumorigenesis.

Dynamics of peripheral immune cells and their HLA-G and receptor expressions in a patient suffering from critical COVID-19 pneumonia to convalescence.

ObjectivesHost immune responses are indispensable to combat the disease. We report the dynamics of peripheral immune cells, cytokines, and human leucocyte antigen‐G (HLA‐G) and its receptor expressions in a patient suffering from critical COVID‐19 pneumonia to convalescence.MethodsClinical data of the patient were collected from medical records. The expressions of HLA‐G and receptors ILT2, ILT4 and KIR2DL4 in peripheral immune cells were measured with flow cytometry.ResultsFrom critical COVID‐19 to the convalescent stage, early lymphopenia was improved (median: 0.6 × 109 L−1 vs. 0.9 × 109 L−1, P = 0.009), and an obvious fluctuation in WBC and neutrophil counts was observed. Initially, low levels of CD4+ T cells (from 120 to 528 μL−1) and CD8+ T cells (from 68 to 362 μL−1) gradually increased to normal levels. Meanwhile, high IL‐6 (from 251.8 to 6.32 pg mL−1), IL‐10 (from 39.53 to 5.21 pg mL−1) and IFN‐γ (from 13.55 to 3.16 pg mL−1) levels decreased, and IL‐4 (from 2.36 to 3.19 pg mL−1) and TNF‐α (from 2.27 to 20.2 pg mL−1) levels increased quickly when the viral RNA returned negative. Moreover, the percentage of HLA‐G+ T cells, B cells and monocytes follows high–low–high pattern, while the percentage of receptors ILT2‐, ILT4‐ and KIR2DL4‐expressing cells remained relatively stable.ConclusionOur findings provide valuable information on the dynamics of early peripheral immunological responses in SARS‐CoV‐2 infection. CD4+ and CD8+ T cells, cytokines and HLA‐G+ immune cells are associated with the natural history of the critical COVID‐19 patient; however, future studies are necessary.

Expression of membrane-bound human leucocyte antigen-G in systemic sclerosis and systemic lupus erythematosus

Human leucocyte antigen-G (HLA-G) is a nonclassical class I major histocompatibility complex (MHC) molecule characterized by complex immunoregulatory and tolerogenic functions. Membrane-bound HLA-G is expressed on the surface of different cell populations in both physiological and pathological conditions. Systemic sclerosis (SSc) is a multisystem autoimmune disease characterized by widespread tissue fibrosis, vascular lesions and immunological alterations. Systemic lupus erythematosus is the prototypic systemic autoimmune disease affecting virtually any organ system, such as skin, joints, central nervous system, or kidneys. In SSc and SLE patients, the membrane expression of HLA-G on monocytes (0.88 ± 1.54 and 0.43 ± 0.75, respectively), CD4+ (0.42 ± 0.78 and 0.63 ± 0.48, respectively), CD8+ (2.65 ± 3.47 and 1.29 ± 1.34, respectively) and CD4+ CD8+ double-positive cells (13.87 ± 15.97 and 3.79 ± 3.11, respectively) was significantly higher than in healthy controls (0.12 ± 0.07; 0.01 ± 0.01; 0.14 ± 0.20 and 0.32 ± 0.38, respectively) (p < 0.0001). Our results show that in SSc and SLE the membrane expression of HLA-G by different subpopulations of peripheral blood mononuclear cells (PBMC) is increased, suggesting a potential role of HLA-G molecules in the complex immunological pathogenesis of these two autoimmune disorders.

Plasma soluble HLA-G levels in a cohort of heart failure patients exposed to chemicals

Heart failure (HF) is a syndrome caused by structural and/or functional cardiac abnormalities, resulting in a reduced cardiac output and/or elevated intracardiac pressures. Several studies reported a crucial role of immune activation and inflammation in the chronic heart failure (HF) pathogenesis, suggesting that pro-inflammatory and anti-inflammatory mediators could be predictive markers of the HF development and/or progression. Human Leukocyte Antigen-G (HLA-G), a tolerogenic and anti-inflammatory class I non-classical major histocompatibility complex molecule, was reported to be upregulated in patients diagnosed with HF, suggesting a tentative to regulate the inflammatory condition. We evaluated soluble (s)HLA-G plasmatic levels in patients with stable chronic heart failure at baseline visit and after 6 and 12 months. The 14 bp Insertion/Deletion polymorphisms of the HLA-G gene was also analyzed. We showed that in HF subjects, sHLA-G levels were higher in NYHA class II and III subjects (mild-severe symptoms) (6.11 ± 1.15 ng/ml; 8.25 ± 2.27 ng/ml, respectively) in comparison with NYHA class I subjects (no symptoms) (2.35 ± 0.43 ng/ml) (I vs II: p = 0.0156; I vs III: p = 0.0122). Moreover, the exposure to chemicals seems to affect sHLA-G levels, with higher sHLA-G levels in exposed patients (3.36 ± 5.12 ng/ml) in comparison with unexposed subjects (2.01 ± 2.84 ng/ml). The HLA-G 3′UTR 14 bp INS/DEL polymorphism correlated with sHLA-G, with the 14 bp INS/INS genotype associated with higher sHLA-G levels during the 12 months follow-up in unexposed subjects (p = 0.008). In conclusion, these results support a correlation between sHLA-G levels, genetics and HF disease in presence of work chemical exposition.

The effects of mesenchymal stem cells on the IDO, HLA-G and PD-L1 expression of breast tumor cells MDA-MB-231 and MCF-7

Aim: Mesenchymal stem cells (MSCs) are strong immunomodulatory cells and a component of the tumor microenvironment. In this study, we aimed to investigate the effects of MSCs derived from adipose tissue on the expressions of immune evasive molecules indoleamine 2,3-dioxygenase (IDO), human leukocyte antigen G (HLA-G) and programmed death-ligand 1 (PD-L1) of breast tumor cell lines MDA-MB-231 and MCF-7. Methods: For this purpose, MSCs, MDA-MB-231 and MCF-7 cells were cultured with increased doses of interferon gamma (IFN-g). In another plate, tumor cells were cultured in transwell inserts using the same IFN-g stimulation to evaluate the effect of MSCs. At the end of the culture period, the HLA-G and PD-L1 expression was detected by flow cytometry, and IDO expression by the Luminex method. Results: We found that in low-dose IFN-g stimulation (10 ng/mL), MSCs led to a significant increase in the HLA-G and PD-L1 expression of MCF-7 cells. On the contrary, at a high dose of IFN-g (50 ng/mL), their expression significantly decreased in both tumor cells. In addition, we observed that the IDO expression of MDA-MB-231 cells was significantly increased in the presence of MSCs, but MCF-7 cells were not affected. Conclusion: In conclusion, for MDA-MB-231 cells, MSCs may play a protective role because they reduce the expression of HLA-G and PD-L1 that are involved in the suppression of cytotoxic cells and exhaustion of T cells. On the other hand, MSCs may be an important source of high IDO levels, and therefore may negatively affect the antitumor immune response. However, our data should be supported by further studies.

AAV-mediated expression of HLA-G1/5 reduces severity of experimental autoimmune uveitis

Non-infectious uveitis (NIU) is an intractable, recurrent, and painful disease that is a common cause of vision loss. Available treatments of NIU, such as the use of topical corticosteroids, are non-specific and have serious side effects which limits them to short-term use; however, NIU requires long-term treatment to prevent vision loss. Therefore, a single dose therapeutic that mediates long-term immunosuppression with minimal side effects is desirable. In order to develop an effective long-term therapy for NIU, an adeno-associated virus (AAV) gene therapy approach was used to exploit a natural immune tolerance mechanism induced by the human leukocyte antigen G (HLA-G). To mimic the prevention of NIU, naïve Lewis rats received a single intravitreal injection of AAV particles harboring codon-optimized cDNAs encoding HLA-G1 and HLA-G5 isoforms one week prior to the induction of experimental autoimmune uveitis (EAU). AAV-mediated expression of the HLA-G-1 and -5 transgenes in the targeted ocular tissues following a single intravitreal injection of AAV-HLA-G1/5 significantly decreased clinical and histopathological inflammation scores compared to untreated EAU eyes (p < 0.04). Thus, localized ocular gene delivery of AAV-HLA-G1/5 may reduce the off-target risks and establish a long-term immunosuppressive effect that would serve as an effective and novel therapeutic strategy for NIU, with the potential for applications to additional ocular immune-mediated diseases.

Detection of serum soluble HLA-G levels in patients with acute ischemic stroke: A pilot study

The aim of this study was to investigate the potential role of soluble Human Leukocyte Antigen-G (sHLA-G) molecules as biomarkers predicting outcome in acute ischemic stroke (AIS). Serum levels of total sHLA-G (sHLA-G1/HLA-G5) and its soluble isoforms sHLA-G1 and HLA-G5/G6 were measured by enzyme-linked immunosorbent assay (ELISA) in 92 AIS patients and healthy donors (HD). Incidence of hemorrhagic transformation (HT), size of final infarct volume (FIV) and clinical outcome at 3 months were recorded in AIS patients. Detectable serum levels of sHLA-G1/HLA-G5, HLA-G5/G6 and sHLA-G1 were present in a small proportion of AIS patients (26.1%, 17.4% and 16.3%, respectively) and HD (12.5%, 10.7% and 10.7%, respectively) and were more elevated in AIS patients without HT than in those with HT (p < 0.01; p < 0.05; p < 0.01, respectively). HT was less frequent (p < 0.01) in AIS patients with measurable serum concentrations of sHLA-G1/HLA-G5 and HLA-G5/G6. Serum levels of sHLA-G1/HLA-G5 and sHLA-G1 were inversely correlated to FIV (p < 0.02), whereas good outcome was more common (p < 0.01) in AIS patients with detectable serum concentrations of sHLA-G1/HLA-G5. Taken together, these findings suggest that total sHLA-G could exert a protective effect in a subset of AIS patients, irrespective of its soluble isoforms sHLA-G1 and HLA-G5/G6, and indicate that the prognostic value of serum levels of sHLA-G remains to be established.

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 14BP POLYMORPHISM DONOR/RECIPIENT MATCHING PROTECTS AGAINST DEVELOPMENT OF POST-TRANSPLANT MALIGNANCY FOLLOWING HEART TRANSPLANTATION

Post-transplant malignancy (PTM) is a major cause of morbidity and mortality following heart transplantation. Human leukocyte antigen-G (HLA-G) is an immune checkpoint molecule which functions to dampen the immune response. HLA-G expression was initially thought to be restricted to cytotrophoblast cells, where it was shown to confer protection to the semi-allograft fetus from the maternal immune system. Since its discovery, HLA-G has been implicated as an important mediator in a variety of pathological situations, such as transplantation and cancer.

NK Cells as Potential Targets for Immunotherapy in Endometriosis

Endometriosis is a common gynecological disease defined by the presence of endometrial-like tissue outside the uterus, most frequently on the pelvic viscera and ovaries, which is associated with pelvic pains and infertility. It is an inflammatory disorder with some features of autoimmunity. It is accepted that ectopic endometriotic tissue originates from endometrial cells exfoliated during menstruation and disseminating into the peritoneum by retrograde menstrual blood flow. It is assumed that the survival of endometriotic cells in the peritoneal cavity may be partially due to their abrogated elimination by natural killer (NK) cells. The decrease of NK cell cytotoxic activity in endometriosis is associated with an increased expression of some inhibitory NK cell receptors. It may be also related to the expression of human leukocyte antigen G (HLA-G), a ligand for inhibitory leukocyte immunoglobulin-like receptor subfamily B member 1 (LILRB1) receptors. The downregulated cytotoxic activity of NK cells may be due to inhibitory cytokines present in the peritoneal milieu of patients with endometriosis. The role of NK cell receptors and their ligands in endometriosis is also confirmed by genetic association studies. Thus, endometriosis may be a subject of immunotherapy by blocking NK cell negative control checkpoints including inhibitory NK cell receptors. Immunotherapies with genetically modified NK cells also cannot be excluded.

Human leukocyte antigen-G polymorphisms in periodontitis

Objective: This study evaluated human leucocyte antigen-G gene polymorphisms in patients with periodontitis and healthy controls.Material and methods: The insertion/deletion polymorphism of 14 bp and a single nucleotide polymorphism (SNP) C > G on the position +3142 of the 3′ untranslated region of the gene were analyzed in chronic periodontitis (n = 62), aggressive periodontitis (n = 24) patients and healthy individuals (n = 47).Results: Considering the 14 bp insertion/deletion, a significant deviation from Hardy-Weinberg expectations in the chronic periodontitis group was observed, but not in the other groups. No significant deviations were observed in patients and control groups considering the +3142 C > G SNP. A significant increased frequency of homozygotes for the 14 bp deletion allele was observed in the chronic periodontitis group as compared to controls. This group also presented a higher frequency of the deletion allele, which was marginally not significant. Concerning this polymorphism, no significant differences were observed between the aggressive periodontitis and healthy control groups. In addition, no significant differences were seen amongst patients and controls when considering the +3142 C > G frequencies.Conclusion: No differences were found amongst patients and controls when considering the +3142 C > G SNP haplotypes frequencies, but a significant increased frequency of homozygotes for the 14 bp deletion allele was observed in chronic periodontitis patients compared to healthy controls, suggesting a susceptibility role of this polymorphism in the pathogenesis of this condition.

Human leukocyte antigen-G 3′ untranslated region polymorphism +3142G/C (rs1063320) and haplotypes are associated with manifestations of the American Tegumentary Leishmaniasis in a Northeastern Brazilian population

While the role of cytokine genes has been well documented in the context of Leishmania (Viannia) braziliensis infection, no studies have addressed the influence of human leukocyte antigen-G (HLA-G) in susceptibility/resistance to American Tegumentary Leishmaniasis (ATL). Here, we evaluated the influences of HLA-G, IL-10, TNF-A and IFN-G in the susceptibility and clinical manifestations of ATL.DNA of 114 ATL patients and 346 healthy individuals were sequenced for well-documented polymorphisms in HLA-G 3′ untranslated region (UTR), in IL-10 and TNF-A promoters and in IFN-G intron 1. Soluble HLA-G (sHLA-G) and cytokine levels were evaluated by ELISA and flow cytometry, respectively. Analyses were performed using GraphPad and R-package software.Individuals bearing HLA-G +3142G/G showed an association with increased risk for ATL, whereas those carrying the HLA-G +3142C/G and one copy of UTR6 haplotype, showed an association with decreased risk for ATL. sHLA-G was overexpressed in “susceptible” patients compared to the “resistant’’ one, and also in patients bearing +3142G/G genotype.From these results, HLA-G +3142G/G may be considered as genotype of susceptibility and UTR6 as marker of protection to ATL. Our findings showed a participation of HLA-G in the pathogenesis of the ATL.

Association of human leukocyte antigen-G 14 bp polymorphism with recurrent pregnancy loss in European countries: a meta-analysis of literature studies

To study the controversial association between human leukocyte antigen-G (HLA-G) 14bp polymorphism and recurrent pregnancy loss (RPL). We performed a meta-analysis of studies in the literature that enrolled only women of European countries who experienced RPL spontaneously or after undergoing IVF. Systematic meta-analysis of articles published before January 2019 pertaining the association of HLA-G genotype and RPL. The search was performed in electronic databases (PubMed, Web of Science, Scopus, EMBASE), without any language or publication year restriction. Academic hospitals and private clinics. Women who experienced RPL spontaneously or after undergoing IVF. Genotyping of 14bp polymorphism (insertion/insertion, insertion/deletion, deletion/deletion) in exon 8 of the HLA-G gene. Meta-analyses of the association between HLA-G 14bp polymorphism in homozygosis (insertion/insertion) and heterozygosis (insertion/deletion) in women with RPL compared with pregnant controls with at least one live birth and no history of RPL. Ten studies were analyzed comprising 1,091 women with RPL and 808 controls without RPL. Women with RPL showed significantly higher prevalence of HLA-G 14bp insertion/insertion genotype compared with women without RPL (19.8% vs. 14.1%; odds ratio = 1.562; 95% confidence interval, 1.203-2.027), and this result was also confirmed when separately analyzing women with RPL during a spontaneous pregnancy (odds ratio, 1.562; 95% confidence interval, 1.203-2.027) and those undergoing IVF (odds ratio, 1.990; 95% confidence interval, 0.978-4.051). Women of European countries with the HLA-G 14bp insertion/insertion genotype have a significantly higher prevalence of RPL.

Quantitative analysis of the sHLA-G protein in seminal plasma.

Recent studies revealed that maternal and embryonic contributions impact on HLA-G protein expression and might contribute to pregnancy success or failure. The main objective of this study was to examine the paternal levels of the immunoregulatory soluble human leukocyte antigen-G (sHLA-G) protein in seminal plasma and testicular biopsy samples during artificial reproductive technique (ART) treatment and to investigate possible correlations with other semen parameters, age, and pregnancy outcome of the female partner. Soluble HLA-G levels of 106 seminal plasma samples and eight testicular biopsy samples were determined using a commercial sHLA-G Enzyme-linked immunosorbent assay (ELISA) kit. We observed a significant negative correlation of male age with total sHLA-G amount (P0.023, R-0.221) and semen volume (P=0.047, R-0.193). Testicular biopsy samples were analyzed and tested positively with sHLA-G ELISA. Levels of sHLA-G in seminal plasma samples from men with normozoospermia did not deviate significantly from those with reduced semen quality. No significant difference of sHLA-G levels in seminal plasma and pregnancy outcome of the female partner was detected. Our data showed that age of men with normozoospermia was significantly lower when the female partner conceived after ART treatment (P=0.016, Mann-Whitney U test). High sHLA-G levels in seminal plasma of the male partner appear not to be required for pregnancy but might contribute among other factors to the success of establishing and maintaining pregnancy through long-term priming of the female uterine milieu.

Donor human leukocyte antigen-G single nucleotide polymorphisms are associated with post-lung transplant mortality.

Human leukocyte antigen (HLA)-G is a non-classical HLA that inhibits immune responses. Its expression is modified by single nucleotide polymorphisms (SNPs), which are associated with transplant outcomes. Our aim was to investigate the association of donor and recipient HLA-G SNPs with chronic lung allograft dysfunction (CLAD) and mortality after lung transplantation.In this single-centre study, we examined 11 HLA-G SNPs in 345consecutive recipients and 297donors of a first bilateral lung transplant. A multivariable Cox proportional hazards model assessed associations of SNPs with death and CLAD. Transbronchial biopsies (TBBx) and bronchoalveolar lavage (BAL) samples were examined using quantitative PCR, ELISA and immunofluorescence.Over a median of 4.75 years, 142patients (41%) developed CLAD; 170 (49%) died. Multivariable analysis revealed donor SNP +3142 (GG+CG versus CC) was associated with increased mortality (hazard ratio 1.78, 95% CI 1.12-2.84; p=0.015). In contrast, five donor SNPs, -201(CC), -716(TT), -56(CC), G*01:03(AA) and 14 bp INDEL, conferred reduced mortality risk. Specific donor-recipient SNP pairings reduced CLAD risk. Predominantly epithelial HLA-G expression was observed on TBBx without rejection. Soluble HLA-G was present in higher concentrations in the BAL samples of patients who later developed CLAD.Specific donor SNPs were associated with mortality risk after lung transplantation, while certain donor-recipient SNP pairings modulated CLAD risk. TBBx demonstrated predominantly epithelial, and therefore presumably donor-derived, HLA-G expression in keeping with these observations. This study is the first to demonstrate an effect of donor HLA-G SNPs on lung transplantation outcome.

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

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. 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. 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. 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.

MiR‑148a modulates the viability, migration and invasion of oral squamous cell carcinoma cells by regulating HLA‑G expression.

Oral squamous cell carcinoma (OSCC) is a common malignancy of the oral and maxillofacial regions. MicroRNAs (miRs) are a group of endogenous small noncoding RNAs that inhibit gene expression by binding to the mRNA of target genes, and serve important roles in numerous biological processes. Reverse transcription-quantitative polymerase chain reaction and western blotting were used to detect gene and protein expression levels, respectively. Cell proliferation, migration and invasion were detected using MTT, wound healing and Matrigel assays, respectively. The association between miR-148a and human leukocyte antigen-G (HLA-G) was analyzed using Targetscan and Luciferase reporter assays. In the present study, miR-148a was revealed to be significantly downregulated in OSCC cells. To further investigate the functions of miR-148a in OSCC, the viability, migration, and invasive abilities of SCC-9 cells were investigated following transfection with miR-148a mimics or miR-148a inhibitor. It was revealed that transfection with miR-148a mimics significantly reduced the viability, migration and invasion of cells, whereas miR-148a inhibitor significantly enhanced these properties. In addition, HLA-G was identified as a direct target of miR-148a and demonstrated to be downregulated in OSCC cells. Furthermore, it was revealed that transfection with miR-148a mimics decreased the expression levels of HLA-G mRNA and protein in SCC-9 cells, whereas transfection with miR-148a inhibitor increased the expression of HLA-G mRNA and protein. The results indicated that there was an association between miR-148a and HLA-G expression, and suggested that miR-148a may be a potential target in the treatment of OSCC.

Association of HLA-G Polymorphisms in the 3‘UTR Region and Soluble HLA-G with Kidney Graft Outcome

ABSTRACTBackground: Human leukocyte antigen G (HLA-G) belongs to nonclassical HLA I molecule involving in the suppression of immune response. Besides its profound effect to induce fetal tolerance, HLA-G expression has been associated with allograft acceptance. For the regulation of HLA-G levels, polymorphic sites within the 3′ untranslated region (3′UTR) are of crucial importance. The aim of the study was to analyze the association between several HLA-G 3′UTR variants (+3003T/C, +3010C/G, +3027C/A, +3035C/T, +3142G/C, +3187A/G, and +3196C/G), soluble HLA-G (sHLA-G) level, and kidney graft outcome in the Slovak Caucasian population.Methods: We investigated 69 kidney transplant recipients (45 males, 24 females) of age 27–65 years. Out of this group, 37 recipients developed acute rejection that was biopsy proven. Recipient’s plasma was obtained at 1 day before transplantation and analyzed by ELISA. The HLA-G 3′UTR polymorphisms were typed by direct sequencing.Results: In the recipients with stable allograft function, significantly higher values of sHLA-G were found in the homozygous +3010GG, +3142CC, +3187GG, and +3196CC carriers in comparison to the acute rejection recipients (P = 0.01-0.05).Conclusion: The study demonstrated genetic association between HLA-G 3′UTR variants and sHLA-G level in kidney recipients leading to graft acceptance. We suggest to monitor the pretransplantation sHLA-G level as additional marker to predict kidney graft outcome. Abbreviations: AMR: Antibody-mediated rejection; APC: antigen-presenting cell; CD: cluster of designation; del: deletion; HLA: human leukocyte antigen; ILT: immunoglobulin-like transcript; ins: insertion; KIR: killer-cell immunoglobulin-like receptor; NK: natural killer; sHLA-G: soluble HLA-G; SNP: single nucleotide polymorphism; TCMR: T cell-mediated rejection; URR: upstream regulatory region; UTR: untranslated region

The Relationship between the HLA-G Polymorphism and sHLA-G Levels in Parental Pairs with High-Risk Pregnancy.

Human leukocyte antigen G (HLA-G) is observed in immune system cells and other organs. It is a class Ib molecule, which plays a pivotal role in the implantation and maintenance of pregnancy. The aim of this study was to assess the relationship between serum sHLA-G levels and the HLA-G allele in parental pairs with complicated obstetric histories. The clinical material consisted of 210 women and 190 men with the experience of a complicated or an unsuccessful pregnancy. The control group included parents―89 women and 86 men―lacking complicated obstetric histories. We applied genetic analysis methods: isolation of genomic DNA, sequencing, and determination of serum sHLA-G levels. There were no statistically significant differences in the frequencies of the HLA-G −725 C>G polymorphism between particular experimental groups compared with the control group (p > 0.05). The median sHLA-G levels in the women with the HLA-G10101 allele (15.4 U/mL) were significantly higher than in the women with other alleles (p < 0.05). The HLA-G 10101 allele seems to protect against antiphospholipid syndrome, which may be associated with increased serum sHLA-G levels in its carriers. The relationship between serum sHLA-G levels and the HLA-G polymorphisms in the Polish population requires further investigation.