Human Leukocyte antigen-G Expression Research Articles

HLA-G expression associates with immune evasion muscle-invasive urothelial cancer and drives prognostic relevance.

Urothelial bladder cancer is frequent and exhibits diverse prognoses influenced by molecular subtypes, urothelial subtype histology, and immune microenvironments. HLA-G, known for immune regulation, displays significant membranous expression in tumor tissues. We studied the protein expression of Human Leucocyte Antigen G (HLA-G) in 241 Muscle-Invasive Bladder Cancer (MIBC) patients, elucidating its potential clinical and biological significance. Protein expression levels were evaluated and correlated with molecular subtypes, histological characteristics, immune microenvironment markers, and survival outcomes. High HLA-G expression associates with poor overall survival (OS) and diseasespecific survival (DSS), independent of clinicopathological parameters. HLA-G expression varies among molecular subtypes and Urothelial Subtype Histology, e.g., elevated expression levels in basal/squamous MIBC and those with sarcomatoid differentiation. Notably, HLA-G is increased in MIBC with an immune evasive microenvironment (high PD-L1 tumor cell expression, NK cell depletion, granzyme B (GZMB)/CD8 ratio reduction, MHC class I (MHCI) expression reduction) that are characterized by immunosuppressive features and poor prognosis. Furthermore, HLA-G correlates with elevated levels of other immune checkpoint proteins (TIGIT, LAG3, CTLA-4), indicating its role in immune evasion. Our findings underscore HLA-G's role as a potential prognostic marker and interesting immunotherapeutic target in MIBC. Its impact on immune evasion mechanisms and broad expression, coupled with associations withpoor survival and distinct tumor phenotypes, positions HLA-G as a promising protein for further exploration in developing targeted immunotherapies for MIBC patients.

Safety and clinical activity of JNJ-78306358, a human leukocyte antigen-G (HLA-G) x CD3 bispecific antibody, for the treatment of advanced stage solid tumors

BackgroundJNJ-78306358 is a bispecific antibody that redirects T cells to kill human leukocyte antigen-G (HLA-G)-expressing tumor cells. This dose escalation study evaluated the safety, pharmacokinetics, pharmacodynamics, and preliminary antitumor activity of JNJ-78306358 in patients with advanced solid tumors.MethodsAdult patients with metastatic/unresectable solid tumors with high prevalence of HLA-G expression were enrolled. Dose escalation was initiated with once-weekly subcutaneous administration with step-up dosing to mitigate cytokine release syndrome (CRS).ResultsOverall, 39 heavily pretreated patients (colorectal cancer: n = 23, ovarian cancer: n = 10, and renal cell carcinoma: n = 6) were dosed in 7 cohorts. Most patients (94.9%) experienced ≥ 1 treatment-emergent adverse events (TEAEs); 87.2% had ≥ 1 related TEAEs. About half of the patients (48.7%) experienced CRS, which were grade 1/2. Nine patients (23.1%) received tocilizumab for CRS. No grade 3 CRS was observed. Dose-limiting toxicities (DLTs) of increased transaminases, pneumonitis and recurrent CRS requiring a dose reduction were reported in 4 patients, coinciding with CRS. No treatment-related deaths reported. No objective responses were noted, but 2 patients had stable disease > 40 weeks. JNJ-78306358 stimulated peripheral T cell activation and cytokine release. Anti-drug antibodies were observed in 45% of evaluable patients with impact on exposure. Approximately half of archival tumor samples (48%) had expression of HLA-G by immunohistochemistry.ConclusionJNJ-78306358 showed pharmacodynamic effects with induction of cytokines and T cell activation. JNJ-78306358 was associated with CRS-related toxicities including increased transaminases and pneumonitis which limited its dose escalation to potentially efficacious levels.Trial registration number ClinicalTrials.gov (No. NCT04991740).

LILRB1-HLA-G axis defines a checkpoint driving natural killer cell exhaustion in tuberculosis

Chronic infections, including Mycobacterium tuberculosis (Mtb)-caused tuberculosis (TB), can induce host immune exhaustion. However, the key checkpoint molecules involved in this process and the underlying regulatory mechanisms remain largely undefined, which impede the application of checkpoint-based immunotherapy in infectious diseases. Here, through adopting time-of-flight mass cytometry and transcriptional profiling to systematically analyze natural killer (NK) cell surface receptors, we identify leukocyte immunoglobulin like receptor B1 (LILRB1) as a critical checkpoint receptor that defines a TB-associated cell subset (LILRB1+ NK cells) and drives NK cell exhaustion in TB. Mechanistically, Mtb-infected macrophages display high expression of human leukocyte antigen-G (HLA-G), which upregulates and activates LILRB1 on NK cells to impair their functions by inhibiting mitogen-activated protein kinase (MAPK) signaling via tyrosine phosphatases SHP1/2. Furthermore, LILRB1 blockade restores NK cell-dependent anti-Mtb immunity in immuno-humanized mice. Thus, LILRB1-HLA-G axis constitutes a NK cell immune checkpoint in TB and serves as a promising immunotherapy target.

Immune cells and checkpoints in pancreatic adenocarcinoma: Association with clinical and pathological characteristics.

Pancreatic adenocarcinoma is an extremely aggressive neoplasm, with many challenges to be overcome in order to achieve a truly effective treatment. It is characterized by a mostly immunosuppressed environment, with dysfunctional immune cells and active immunoinhibitory pathways that favor tumor evasion and progression. Thus, the study and understanding of the tumor microenvironment and the various cells subtypes and their functional capacities are essential to achieve more effective treatments, especially with the use of new immunotherapeutics. Seventy cases of pancreatic adenocarcinoma divided into two groups 43 with resectable disease and 27 with unresectable disease were analyzed using immunohistochemical methods regarding the expression of programmed cell death ligand 1 (PD-L1), programmed cell death ligand 2 (PD-L2), and human leukocyte antigen G (HLA-G) molecules as well as the populations of CD4+ and CD8+ T lymphocytes, regulatory T cells (Tregs), and M2 macrophages (MM2). Several statistical tests, including multivariate analyses, were performed to examine how those immune cells and immunoinhibitory molecules impact the evolution and prognosis of pancreatic adenocarcinoma. CD8+ T lymphocytes and M2 macrophages predominated in the group operated on, and PD-L2 expression predominated in the unresectable group. PD-L2 was associated with T stage, lymph node metastasis, and clinical staging, while in survival analysis, PD-L2 and HLA-G were associated with a shorter survival. In the inoperable cases, Tregs cells, MM2, PD-L1, PD-L2, and HLA-G were positively correlated. PD-L2 and HLA-G expression correlated with worse survival in the cases studied. Tumor microenvironment was characterized by a tolerant and immunosuppressed pattern, mainly in unresectable lesions, where a broad positive influence was observed between immunoinhibitory cells and immune checkpoint proteins expressed by tumor cells.

The implication of serum HLA-G in angiogenesis of multiple myeloma

BackgroundDespite the advances of therapies, multiple myeloma (MM) remains an incurable hematological cancer that most patients experience relapse. Tumor angiogenesis is strongly correlated with cancer relapse. Human leukocyte antigen G (HLA-G) has been known as a molecule to suppress angiogenesis. We aimed to investigate whether soluble HLA-G (sHLA-G) was involved in the relapse of MM.MethodsWe first investigated the dynamics of serum sHLA-G, vascular endothelial growth factor (VEGF) and interleukin 6 (IL-6) in 57 successfully treated MM patients undergoing remission and relapse. The interactions among these angiogenesis-related targets (sHLA-G, VEGF and IL-6) were examined in vitro. Their expression at different oxygen concentrations was investigated using a xenograft animal model by intra-bone marrow and skin grafts with myeloma cells.ResultsWe found that HLA-G protein degradation augmented angiogenesis. Soluble HLA-G directly inhibited vasculature formation in vitro. Mechanistically, HLA-G expression was regulated by hypoxia-inducible factor-1α (HIF-1α) in MM cells under hypoxia. We thus developed two mouse models of myeloma xenografts in intra-bone marrow (BM) and underneath the skin, and found a strong correlation between HLA-G and HIF-1α expressions in hypoxic BM, but not in oxygenated tissues. Yet when stimulated with IL-6, both HLA-G and HIF-1α could be targeted to ubiquitin-mediated degradation via PARKIN.ConclusionThese results highlight the importance of sHLA-G in angiogenesis at different phases of multiple myeloma. The experimental evidence that sHLA-G as an angiogenesis suppressor in MM may be useful for future development of novel therapies to prevent relapse.

Investigation the role of Human Leukocyte Antigen-G in Iraqi patients with papillary thyroid carcinoma

Human leukocyte antigen G (HLA-G) is a non-classical major histocompatibility complex (MHC) protein with well-known immunomodulatory characteristics. It is also believed to be an important sign of immune tolerance in cancer cells. Immune Escape. HLA-G is also associated with disease development and prognosis in cancer patients. The goal of this study was to compare soluble HLA-G (sHLA-G) levels before and after radioactive iodine therapy (RAI) by enzyme immunoassay (ELISA). Immunohistochemistry was used to examine HLA-G protein expression in thyroid tissues from patients with papillary thyroid cancer (PTC) to investigate the relationship between HLA-G expression and patients' clinical variables. Prospective research included 138 blood samples from patients and controls, as well as 25 thyroid paraffin-embedded tissues from individuals suffering from papillary thyroid cancer (PTC) and controls. Our findings demonstrated a significant difference in the means of people who had radioactive iodine therapy against those who did not (Mean SE = 4.19 0.31, 2.216 0.08, respectively). HLA-G staining, on the other hand, was identified in tumor cells in papillary thyroid cancer, all sections were positive, strongly stained and completely membranous, indicating the presence of HLA-G protein in the tested material. These findings suggest that HLA-G may be involved in the pathogenesis of papillary thyroid cancer.

Expression and clinical implications of HLA-G and PD-L1 following kidney transplantation: A cohort study.

Kidney transplantation (KT) is the preferred treatment for end-stage renal diseases. Human leukocyte antigen G (HLA-G) and programmed death-ligand 1 (PD-L1) have notable clinical and therapeutic significance in transplantation because of their roles in promoting tolerance. This study aimed to assess HLA-G and PD-L1 levels at various stages following KT. A cohort of 12 patients was monitored from the pretransplant phase to 12 months post-surgery. Blood samples were taken at specific intervals: before kidney transplantation (T0), and then on the 7th (T7), 30th (T30), 90th (T90), 180th (T180), and 365th days post transplantation. Renal biopsies were performed in patients with graft dysfunction. Plasma levels of soluble HLA-G (sHLA-G) and PD-L1 were quantified using enzyme-linked immunosorbent assays. Additionally, immunohistochemistry was used to detect the presence of both molecules in biopsy samples. Multivariate analysis indicated that episodes of rejection were correlated with decreased expression of sHLA-G (P < .001) and PD-L1 (P < .001). Over the course of the study, the sHLA-G levels also declined (P < .001). Patients who had been transfused had lower PD-L1 levels (P = .03). Furthermore, kidney recipients from related live donors had increased HLA-G expression (P < .001). Our findings suggest that diminished HLA-G and PD-L1 levels correlate with an increased risk of graft rejection. Notably, HLA-G expression significantly decrease after the third-month posttransplantation.

HLA-G 3'UTR haplotype analyses in HCV infection and HCV-derived cirrhosis, hepatocellular carcinoma and fibrosis.

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease. Chronic HCV infection is also an important cause of hepatic fibrosis, cirrhosis and hepatocellular carcinoma (HCC). HCV has the capacity to evade immune surveillance by altering the host immune response. Moreover, variations in immune-related genes can lead to differential susceptibility to HCV infection as well as interfere on the susceptibility to the development of hepatic fibrosis, cirrhosis and HCC. The human leucocyte antigen G (HLA-G) gene codes for an immunomodulatory protein known to be expressed in the maternal-foetal interface and in immune-privileged tissues. The HLA-G 3' untranslated region (3'UTR) is important for mRNA stability, and variants in this region are known to impact gene expression. Studies, mainly focusing in a 14bp insertion/deletion polymorphism, have correlated HLA-G 3'UTR with susceptibility to viral infections, but other polymorphic variants in the HLA-G 3'UTR might also affect HCV infection as they are inherited as haplotypes. The present study evaluated HLA-G 3'UTR polymorphisms and performed linkage disequilibrium test and haplotype assembly in 286 HCV infected patients who have developed fibrosis, cirrhosis or HCC, as well as in 129 healthy control subjects. Haplotypes UTR-1, UTR-2 and UTR-3 were the most observed in HCV+ patients, in the frequencies of 0.276, 0.255 and 0.121, respectively. No statistically significant difference was observed between HCV+ and control subjects, even when patients were grouped according to outcome (HCC, cirrhosis or fibrosis). Despite that, some trends in the results were observed, and therefore, we cannot rule out the possibility that variants associated to high HLA-G expression can be involved in HCV infection susceptibility.

HLA-G alleles and their impacts on placental HSV-1 infection in women from southern Brazil

The Human Leukocyte Antigen G (HLA-G) is an immunoregulatory molecule with a critical role in pregnancy success. HLA-G alleles are associated with differential susceptibility to multiple conditions, including gestational problems, infectious diseases, and viral persistence. Of note, both herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) can impair HLA-G expression, interfering with HLA-G-associated immunoregulation. On the other hand, the impacts of HLA-G alleles on susceptibility to Herpesviridae infection is a neglected issue. Therefore, this study evaluated HLA-G allele frequencies and their associations with placental Herpesviridae infection in women from southern Brazil. Placenta samples were collected soon after delivery, and detection of viral DNA of HSV-1, HSV-2 and human cytomegalovirus (HCMV) was performed by polymerase chain reaction (PCR). A fragment of HLA-G (exons 2–4) was amplified by PCR, sequenced, and analyzed to allele determination. One hundred and seventy women had their alleles determined. Overall, 25 HLA-G alleles were found, distributed into 56 different genotypes. The most frequent alleles were G* 01:01:01 and G* 01:01:02, found in 37.9 % and 16.5 % of samples, respectively. Among the 170 women, 89 (52.4 %) tested positive for Herpesviridae DNA in the placenta, 55 (32.3 %) tested negative, 3 (1.8 %) were negative for HSV-1 and HSV-2 (with absent HCMV data), and 23 (13.5 %) were undetermined. The G* 01:01:01 allele was significantly associated with an increased risk of placental HSV-1 infection (p = 0.0151; OR=1.837; IC=1.108–3.045). This study describes new information concerning placental HLA-G alleles in women from southern Brazil and helps explain how genetic background can modify susceptibility to placental infections.

Biological profile of the follicular fluid. A pilot study

BACKGROUND: One of the most important research areas in the field of reproductive medicine is the search for biochemical and immunological parameters of oocyte quality and predicting the effectiveness of assisted reproductive technology protocols.&#x0D; AIM: The aim of this study was to evaluate the expression of follicular fluid soluble human leukocyte antigen-G, human leukocyte antigen-E, human leukocyte antigen-C, progesterone-inducing blocking factor, and relaxin levels in women with reproductive disorders.&#x0D; MATERIALS AND METHODS: This prospective cohort study included 22 patients undergoing infertility treatment in a superovulation stimulation protocol using gonadotropin-releasing hormone antagonists. The inclusion criteria were age from 25 to 39 years, tubal-peritoneal factor infertility, and voluntary participation informed consent. The levels of soluble human leukocyte antigen-G, human leukocyte antigen-E, human leukocyte antigen-C, progesterone-inducing blocking factor, and relaxin in follicular fluid samples were determined on the day of transvaginal follicle puncture by enzyme immunoassay.&#x0D; RESULTS: We established an inverse correlation between the expression levels of progesterone-inducing blocking factor and relaxin (r = 0.450) in the follicular fluid, antibodies to thyroperoxidase (r = 0.649), and thyroid-stimulating hormone (r = 0.519). We also found a direct correlation between human leukocyte antigen-E parameters in the follicular fluid, age (r = 0.813) and Body Mass Index (r = 0.866), as well as between human leukocyte antigen-C expression levels and total testosterone (r = 0.960). No data were obtained on any significant correlations between the studied biomarkers and the number of received oocytes.&#x0D; CONCLUSIONS: In this comprehensive study, we were the first who found the expression levels of five different follicular fluid components, namely, soluble human leukocyte antigen-G, human leukocyte antigen-E, human leukocyte antigen-C, progesterone-inducing blocking factor, and relaxin. Such a complex assessment of the follicular fluid can allow for establishing the quality of the oocyte to predict the onset of pregnancy in an in vitro fertilization protocol.

Prognostic value of human leukocyte antigen G (HLA-G) expression in solid tumors: A systematic review and meta-analysis.

e14639 Background: Identification of modulators of the immune response with inhibitory properties that could be susceptible for therapeutic intervention is a key goal in cancer research. An example is the human leukocyte antigen G (HLA-G), a nonclassical major histocompatibility complex (MHC) class I molecule, involved in cancer progression. Methods: We performed a systematic review and meta-analysis on the role of HLA-G expression and outcome in solid tumors. A total of 25 studies met the inclusion criteria comprising data from 4871 patients reporting overall survival (OS) outcomes, and 961 patients, in 5 studies, for disease free survival (DFS). This study was performed in accordance with PRISMA guidelines and registered in PROSPERO. Results: HLA-G expression was associated with worse OS (HR 2.09, 95% CI = 1.67 to 2.63; P &lt; .001), that was higher in gastric (HR = 3.40; 95% CI = 1.64 to 7.03), pancreatic (HR = 1.72; 95% CI = 0.79 to 3.74) and colorectal (HR = 1.55; 95% CI = 1.16 to 2.07) cancer. No significant differences were observed between the most commonly utilized antibody (4H84) and other methods of detection. HLA-G expression was associated with DFS which approached but did not meet statistical significance. Conclusions: We describe the first meta-analysis associating HLA-G expression and worse survival in a variety of solid tumors.

Prognostic value of human leukocyte antigen G expression in solid tumors: a systematic review and meta-analysis.

Identification of modulators of the immune response with inhibitory properties that could be susceptible for therapeutic intervention is a key goal in cancer research. An example is the human leukocyte antigen G (HLA-G), a nonclassical major histocompatibility complex (MHC) class I molecule, involved in cancer progression. In this article we performed a systematic review and meta-analysis on the association between HLA-G expression and outcome in solid tumors. This study was performed in accordance with PRISMA guidelines and registered in PROSPERO. A total of 25 studies met the inclusion criteria. These studies comprised data from 4871 patients reporting overall survival (OS), and 961 patients, reporting disease free survival (DFS). HLA-G expression was associated with worse OS (HR 2.09, 95% CI = 1.67 to 2.63; P < .001), that was higher in gastric (HR = 3.40; 95% CI = 1.64 to 7.03), pancreatic (HR = 1.72; 95% CI = 0.79 to 3.74) and colorectal (HR = 1.55; 95% CI = 1.16 to 2.07) cancer. No significant differences were observed between the most commonly utilized antibody (4H84) and other methods of detection. HLA-G expression was associated with DFS which approached but did not meet statistical significance. In summary, we describe the first meta-analysis associating HLA-G expression and worse survival in a variety of solid tumors. https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022311973.

Pemetrexed combined with dual immune checkpoint blockade enhances cytotoxic T lymphocytes against lung cancer.

Chemotherapy, in combination with immune checkpoint blockade (ICB) targeting to programmed death-1 (PD-1) or its ligand PD-L1, is one of the first-line treatments for patients with advanced non-small-cell lung cancer (NSCLC). However, a large proportion of patients, especially those with PD-L1 negative tumors, do not benefit from this treatment. This may be due to the existence of multiple immunosuppressive mechanisms other than the PD-1/PD-L1 axis. Human leukocyte antigen-G (HLA-G) has been identified as an immune checkpoint protein (ICP) and a neoexpressed tumor-associated antigen (TAA) in a large proportion of solid tumors. In this study, we evaluated the induction of HLA-G as well as PD-L1 using sublethal doses of chemotherapeutics including pemetrexed in different NSCLC cell lines. Except for gefitinib, most of the chemotherapeutic agents enhanced HLA-G and PD-L1 expression in a dose-dependent manner, whereas pemetrexed and carboplatin treatments showed the most consistent upregulation of PD-L1 and HLA-G in each cell line. In addition to protein levels, a novel finding of this study is that pemetrexed enhanced the glycosylation of HLA-G and PD-L1. Pemetrexed potentiated the cytotoxicity of cytotoxic T lymphocytes (CTLs) to treat NSCLC. Both in vitro and in vivo experiments revealed that CTL-mediated cytotoxicity was most pronounced when both anti-PD-L1 and anti-HLA-G ICBs were combined with pemetrexed treatment. In conclusion, anti-HLA-G could be an intervention strategy in addition to the anti-PD-1/PD-L1 pathway for NSCLC. Moreover, dual targeting of PD-L1 and HLA-G combined with pemetrexed might have a better extent of CTL-based immunotherapy.

HLA-G expression in transitional bladder carcinoma. Relationship with tumor invasion level and patient survival: Experience in a public hospital in Argentina

Transitional carcinoma (TC) is the most common neoplasm of the bladder (80%). The immune checkpoint (IC) Human leukocyte antigen G (HLA-G) expression has been demonstrated within numerous types of cancer and correlates with the degree of malignancy. This study aims for HLA-G expression in the bladder TC in a public hospital in Argentina linking its malignancy grade with the survival of the patients. We study thirty TC samples, in which we determine the invasion level and the HLA-G expression by immunohistochemistry. From all analyzed cases, 23 correspond to high-grade TC, of whom 91% presented HLA-G immunostaining and 83% compromised the muscularis propria layer of the bladder. Four patients in this group have not exceeded 5 years of survival. This data confirms that HLA-G expression in the bladder TC is associated with greater aggressiveness. Therefore, adding this immunostaining to the immunohistochemical panel used in the routine diagnosis of this neoplasm would be very useful.

Abstract 2961: HLA-G-TCB (RG6353), a T cell bispecific antibody for the treatment of solid tumors in monotherapy and combination with immunomodulator agents

Abstract T-cell bispecific antibodies (TCB) represent a class of therapeutic agents that specifically activate T cells to attack and kill tumor cells. TCBs have demonstrated efficacy in the clinic and are also approved. TCB mediated efficacy in solid tumors, however, has been more challenging to demonstrate. HLA-G-TCB specifically targets human leukocyte antigen G (HLA-G) on tumor cells and cluster of differentiation 3 epsilon chain (CD3ε) expressed on T cells. HLA-G is expressed in a broad range of solid tumor indications and its role in mediating immune suppression makes it an attractive cancer immunotherapy target. Anti-tumor activity of HLA-G-TCB was demonstrated in vitro using different HLA G positive tumor cell lines. T-cell activation, IFN𝛾; secretion, and cytotoxicity induced by HLA G-TCB were shown to be dose dependent and correlating to the HLA G density on cell surface and the percentage of HLA G positive cells. Administration of HLA-G TCB as monotherapy (5mg/kg) to hematopoietic stem cell-humanized NSG mice (Humice) bearing SKOV3 HLA-G tumors resulted in strong tumor growth inhibition resulting in tumor-free animals (7 out of 8). Additionally, in a patient derived xenograft (PDX) tumor model with physiological (low/patchy) HLA-G expression, a significant dose-dependent efficacy ranging from 10-90% was achieved in monotherapy (0.05-5 mg/kg). Treatment of Humice bearing PDX tumors with a combination of HLA-G-TCB and a co-stimulatory immunomodulator resulted in remarkable anti-tumor activity resulting in tumor eradication in 100% of the mice treated with the combination (8 out of 8). A strong synergistic effect was also observed in checkpoint inhibitor resistant PDX tumor model, also resulting in tumor-free mice (5 out of 8) treated with a combination of HLA-G TCB and an immunomodulatory bispecific antibody. In line with the mode of action of TCBs, tumor growth inhibition was accompanied by increased cytokine secretion (including IFN𝛾;), tumoral T cell infiltration and activation as reflected by increased expression of T cell activation markers including CD69, CD25 and Granzyme B. Evaluation of HLA-G expression on tumor cell lines upon IFN𝛾; stimulation in vitro and in PDX tumors treated with HLA-G TCB revealed that HLA-G expression can be upregulated upon IFN𝛾; stimulation and TCB treatment respectively and may positively impact the anti-tumor activity of HLA-G-TCB in vivo. These promising preclinical findings reflect the potential and support the clinical evaluation of HLA-G TCB in treating patients with solid tumors in monotherapy and in combination. HLA-G TCB (RG6353) is being advanced to the clinic in BP44068, an open-label, multicenter, phase 1 study to evaluate safety, pharmacokinetics, and preliminary anti-tumor activity in patients with unresectable and/or metastatic HLA-G expressing solid tumors. Citation Format: Meher Majety, Carina Hage, Alexander Bujotzek, Anneliese Schneider, Martin Lechmann, Nitya Nair, Stefan Zimmerman, Anthony Morel, Christian Klein, Pablo Umana. HLA-G-TCB (RG6353), a T cell bispecific antibody for the treatment of solid tumors in monotherapy and combination with immunomodulator agents [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2961.

AAV-mediated expression of HLA-G for the prevention of experimental ocular graft vs. host disease

Ocular graft versus host disease (OGvHD) develops after allogeneic hematopoietic stem cell transplantation (HSCT) and manifests as ocular surface inflammatory disease. This study evaluated the efficacy of adeno-associated virus (AAV) gene therapy encoding human leukocyte antigen G (HLA-G) to inhibit OGvHD. A major histocompatibility mismatch chronic OGvHD murine model was evaluated. 7days after HSCT, mice were dosed subconjunctivally with scAAV8-HLA-G1/5 (1 x 109 vg/eye), topical cyclosporine (twice daily), or left untreated. Body weights and tear production (red thread test) were recorded, and eyelid, corneal opacity, and corneal fluorescein retention were scored through day 44 after HSCT. Tissues were collected for vector biodistribution, ocular histology, and immunofluorescence. Compared with untreated HSCT eyes, those dosed with scAAV8-HLA-G1/5 had significantly reduced clinical inflammatory signs of OGvHD. On histology, eyes that received scAAV8-HLA-G1/5 or cyclosporine had a significantly lower mean limbal mononuclear cell count when compared with non-treated HSCT eyes. HLA-G immunofluorescence was detected in the subconjunctiva and peripheral cornea in HSCT animals treated with scAAV8-HLA-G1/5. Vector genomes were detected in the lacrimal gland, but not in the other tested organs. These results provide evidence that subconjunctival AAV targets ocular surface and corneal disease and support that HLA-G-based gene therapy may be an effective treatment for OGvHD.

Peripheral HLA-G/ILT-2 immune checkpoint axis in acute and convalescent COVID-19 patients

The immunosuppressive non-classical human leukocyte antigen-G (HLA-G) can elicits pro-viral activities by down-modulating immune responses. We analysed soluble forms of HLA-G, IL-6 and IL-10 as well as on immune effector cell expression of HLA-G and its cognate ILT-2 receptor in peripheral blood obtained from hospitalised and convalescent COVID-19 patients. Compared with convalescents (N = 202), circulating soluble HLA-G levels (total and vesicular-bound molecules) were significantly increased in hospitalised patients (N = 93) irrespective of the disease severity. During COVID-19, IL-6 and IL-10 levels were also elevated. Regarding the immune checkpoint expression of HLA-G/ILT-2 on peripheral immune effector cells, the frequencies of membrane-bound HLA-G on CD3+ and CD14+ cells were almost identical in patients during and post COVID-19, while the frequency of ILT-2 receptor on CD3+ and CD14+ cells was increased during acute infection. A multi-parametric correlation analysis of soluble HLA-G forms with IL-6, IL-10, activation markers CD25 and CD154, HLA-G, and ILT-2 expression on immune cells revealed a strong positive correlation of soluble HLA-G forms with membrane-bound HLA-G molecules on CD3+/CD14+ cells only in convalescents. During COVID-19, only vesicular-bound HLA-G were positively correlated with the activation marker CD25 on T cells. Thus, our data suggest that the elevated levels of soluble HLA-G in COVID-19 are due to increased expression in organ tissues other than circulating immune effector cells. The concomitant increased expression of soluble HLA-G and ILT-2 receptor frequencies supports the concept that the immune checkpoint HLA-G/ILT-2 plays a role in the immune-pathogenesis of COVID-19.

CAR-T cells targeting HLA-G as potent therapeutic strategy for EGFR-mutated and overexpressed oral cancer

Oral squamous cell carcinoma (OSCC) is a common malignancy in the world. Recently, scientists have focused on therapeutic strategies to determine theregulation of tumors and design molecules for specific targets. Some studies have demonstrated the clinical significance of human leukocyte antigen G (HLA-G) in malignancy and NLR family pyrin domain-containing 3 (NLRP3) inflammasome in promoting tumorigenesis in OSCC. This is the first study to investigate whether aberrant epidermal growth factor receptor (EGFR) induces HLA-G expression through NLRP3 inflammasome-mediated IL-1β secretion in OSCC. Our results showed that the upregulation of NLRP3 inflammasome leads to abundant HLA-G in the cytoplasm and cell membrane of FaDu cells. In addition, we also generated anti-HLA-G chimeric antigen receptor (CAR)-T cells and provided evidence for their effects in EGFR-mutated and overexpressed oral cancer. Our results may be integrated with OSCC patient data to translate basic research into clinical significance and may lead to novel EGFR-aberrant OSCC treatment.

Donor and recipient human leukocyte antigen-G polymorphisms modulate the risk of adverse immunologic events following lung transplantation

The long-term benefits of lung transplantation (LTx) are limited by pathogenic alloimmune responses that drive injury, inflammation, and chronic dysfunction. Human leukocyte antigen-G (HLA-G) plays a key role in the modulation of these pathways. This study assesses the impact of the HLA-G genotype on immunologic risk and survival following LTx.This retrospective cohort study included 289 bilateral LTx. Recipient and donor HLA-G genotypes were analyzed to identify associations with de novo donor-specific antibodies, acute rejection, chronic lung allograft dysfunction, and allograft survival. We further assessed these associations, both individually and in paired analysis, based on a grouped haplotype classification of HLA-G expression.Donor HLA-G single nucleotide polymorphisms were associated with allograft injury, the onset of chronic lung allograft dysfunction following injury, and allograft survival. Recipient HLA-G single nucleotide polymorphisms were associated with allograft injury, cellular rejection, and donor-specific antibody formation. “Low HLA-G expression” donor haplotypes were associated with impaired allograft survival, as were “low HLA-G expression” donor-recipient haplotype pairs.This study provides compelling evidence for the role of HLA-G in modulating immunologic risk after LTx. Our results highlight the importance of both donor and recipient HLA-G genotypes on the overall risk profile and underscore the lasting influence of donor genotype on lung transplant outcomes.

Altered Expression of the HLA-G and IL10RB Genes in Placental Tissue of Women with Recurrent Pregnancy Loss.

Several lines of evidence strongly suggest that the contribution of human leukocyte antigen-G (HLA-G) and interleukin 10 receptor (IL10R) to maternal immunological tolerance toward paternal alloantigens of the embryo limits the activation and function of the maternal immune system. This study is aimed to assess the varia-tion of the mRNA expression levels of HLA-G and IL10RB genes in placental tissue of women with recurrent pregnancy loss (RPL). Placental tissue samples were collected from 78 women with a history of at least two consecutive miscarriages and 40 healthy women with no history of pregnancy loss. The expression of HLA-G and IL10RB in placental tissue specimens was evaluated by the quantitative real-time PCR (qPCR) method. Moreover, the correlation be-tween the expression levels of these genes and clinicopathological parameters was analyzed. The results showed that the expression of HLA-G was down-regulated in placental tissues samples of RPL patients compared to healthy subjects, while the expression of IL10RB was up-regulated, but none of them was statistically significant (p-value > 0.05). The mRNA expression levels of HLA-G and IL10RB in placental tissue of RPL patients were negatively correlated with age and number of miscarriages (p-value > 0.05). A significant positive correlation was observed between the expression levels of HLA-G and IL10RB in women with RPL (p-value < 0.05). The altered expression of HLA-G and IL10RB in placental tissue may contribute to the pathogenesis of RPL and therefore serve as potential therapeutic targets for its prevention.