HLA-G expression is irrelevant to prognosis in patients with acute myeloid leukemia

Human leukocyte antigen (HLA)-G could contribute to escape of cancer cells from host anti-tumor responses, and its potential clinical relevance in various malignancies was also addressed. However, the prognostic value of HLA-G in acute myeloid leukemia (AML) remains debated. In this study, HLA-G expression in malignant blasts was analyzed from 77 de novo AML patients (AML-M2, n = 26; AML-M3, n = 24; AML-M4, n = 10; AML-M5, n = 17) with flow cytometry. The proportion of HLA-G expressing blasts varied from 0% to 93.96% (median: 0.42%; 95% CI: 0–89.0%). Blasts with 0.5% or fewer HLA-G expressing were defined as negative according to its expression in normal CD34⁺CD45⁺ cells (n = 20, range: 0–0.5%; median: 0.13%; 95% CI: 0–0.42%). HLA-G expression status on leukemic blasts was not associated with the clinical parameters such as patient age at diagnosis, sex, sub-type of AML, percentage of blasts at diagnosis. Survival analysis revealed that HLA-G expression status on leukemic blasts is unrelated to the prognosis (p = 0.884). The mean overall survival time for the HLA-G negative and positive patients was 20.7 months (95% CI: 16.1–25.3) and 20.1 months (95% CI: 14.3–25.8), respectively. Taken together, our findings indicated that HLA-G expression is of no significance for the prognosis of patients with AML.     

High level of soluble HLA-G in amniotic fluid is correlated with congenital transmission of Toxoplasma gondii

The expression of human leukocyte antigen (HLA)-G on cytotrophoblast cells contributes to maternal-fetal tolerance. Soluble forms of HLA-G (sHLA-G) can be detected in amniotic fluid (AF) and a decrease of sHLA-G is known to be correlated to fetal loss. In this work we investigated the role of sHLA-G in the transplacental passage of the protozoan parasite Toxoplasma gondii, responsible for congenital toxoplasmosis in about 30% of fetuses when primary infection (PI) occurs during pregnancy. We determined the sHLA-G concentration in 61 AF from women with PI and 24 controls. Our results showed higher sHLA-G levels in AF from PI than in controls (p<0.001). Moreover sHLA-G level from congenitally infected fetuses (n=12) was higher than in fetus in whom congenital infection was ruled out (n=49, p<0.05). These data suggest that sHLA-G could participate in immunomodulation necessary to avoid fetal loss due to Toxoplasma infection, but that over-expression could favor congenital transmission.     

Analysis of the sex ratio in preimplantation embryos from B6.K1 and B6.K2 Ped gene congenic mice

Purpose: The mouse preimplantation embryo development (Ped) gene product, Qa-2, which is the homolog of human HLA-G, influences the rate of preimplantation embryonic development and overall reproductive success. The sex ratio in preimplantation embryos from Ped gene congenic mice was examined in order to determine whether embryo sex is a confounding factor in the control of the rate of preimplantation development. Methods: B6.K1 (Ped slow) and B6.K2 (Ped fast) congenic mice differ only in the absence (B6.K1) or presence (B6.K2) of the genes encoding Qa-2 protein. We analyzed the sex of B6.K1 (n=221) and B6.K2 (n=260) preimplantation embryos by using Real-Time PCR with primers specific for the X and Y chromosomes. Results: We found that there was no statistically significant difference in the ratio of male to female preimplantation embryos in either strain. Conclusions: We conclude that the sex of the embryos is not a confounding factor that affects the Ped gene control of the rate of preimplantation development. Therefore, the Ped gene is entirely responsible for mediating the faster development of B6.K2 embryos compared to B6.K1 embryos.There is no confounding effect of the sex of preimplantation embryos on the rate of preimplantation development controlled by the Ped gene.     

Association of the maternal 14-bp insertion polymorphism in the HLA-G gene in women with recurrent spontaneous abortions

Human leukocyte antigen (HLA)-G has been postulated as an important immunotolerant molecule in maintaining fetal-maternal relationship. Recent reports indicated that the 14-bp deletion/insertion polymorphism in exon 8 of HLA-G gene influences HLA-G mRNA stability and isoform splicing patterns, thus modulating the levels of HLA-G expression. This might play an immunomodulatory role of HLA-G during implantation and pregnancy. In the present study, 109 unrelated fertile control women and 79 women who had experienced recurrent spontaneous abortion (RSA) were genotyped for the 14-bp insertion/deletion polymorphism. No significant difference was observed in the distribution of 14-bp insertion/deletion genotype between controls and the RSA group. However, a greater number of 14-bp insertion alleles exist in the RSA group than in the controls.     

Intercellular communication by exosomes in placenta: A possible role in cell fusion?

Exosomes are nanovesicles released from viable cells and have attracted increasing interest due to their role in intercellular communication and biological functions. More recently exosomes have been shown to be released by trophoblasts and to carry molecules involved in placental physiology. This involves proteins such as fibronectin, syncytin, Wnt/βcatenin-related molecules, galectin-3, and HLA-G, but also bioactive lipids such as the immunosuppressive PGE2, the PPARγ ligand 15d-PGJ2, or microRNAs that appear as immunomodulators in pregnancy and are able to confer viral resistance.     

补肾安胎方对人绒毛膜外滋养层细胞HTR-8分泌功能及HLA-G基因表达的调控作用

目的?观察补肾安胎方对人绒毛膜外滋养层细胞HTR-8分泌功能及人类白细胞抗原G（HLA-G）基因表达的调控,探讨其免疫保胎机制。方法?雌性SD大鼠灌胃制备空白血清和补肾安胎方含药血清。将人绒毛膜外滋养层细胞HTR-8细胞分为4组:空白对照组、低剂量组（5%中药血清组）、中剂量组（10%中药血清组）、高剂量组（20%中药血清组）,培养24?h后,ELISA法测定培养上清液中雌二醇（E₂）、孕激素(P）、人绒毛膜促性腺激素(HCG)及辅助性T细胞（Th）调控因子白介素-4(IL-4) 和干扰素 -γ（IFN-γ）水平,RT-PCR法测定HLA-G mRNA表达。结果?与空白对照组相比,低剂量组在促进E₂、P分泌方面无统计学意义（P>0.05）,中、高剂量组可有效提高细胞上清E₂、P含量,且高剂量组高于中剂量组（P<0.05）。3组含药血清均能明显提高滋养细胞HCG的分泌水平（P<0.05）,3组间差异无显著性意义（P>0.05）。低剂量组即可促进Th2型细胞因子IL-4分泌,但差异无统计学意义（P>0.05）,中、高剂量组可有效促进Th2型细胞因子IL-4含量,组间差异无统计学意义（P>0.05）。3组含药血清均能显著抑制Th1型细胞因子IFN-γ（P<0.05）,中、高剂量组均可增加HLA-G mRMA的表达,有显著差异（P<0.05）,且高剂量组高于中剂量组（P<0.05）。结论?补肾安胎方含药血清可以改善滋养细胞分泌功能,使母胎免疫向Th2型转化,并可能部分通过上调HLA-G基因表达实现。      

靶向人类白细胞抗原G1(HLA-G1)的siRNA真核表达载体的构建及表达

目的:构建靶向人类白细胞抗原G1(HLA-G1)的小干扰RNA(siRNA)真核表达载体(pSUPER-HLA-G1),并检测其在滋养细胞系HTR-8/SVneo中的敲减效率。方法:将设计的HLA-G1 siRNA寡聚脱氧核苷酸链与真核表达载体pSUPER连接,构建重组pSUPER-HLA-G1真核表达载体,并用脂质体法将其转染入HTR-8/SVneo细胞系中。pSUPER-HLA-G1质粒转染后采用RT-PCR检测HLA-G1在HTR-8/SVneo细胞中的基因转录情况,Western blotting检测HLA-G1蛋白的表达情况。结果:构建的真核表达载体pSUPER-HLA-G1可在HTR-8/SVneo细胞中表达,HLA-G1 mRNA和其蛋白表达抑制率分别为74.85±7.43%和71.07±6.11%。结论:构建的人HLA-G1 siRNA蛋白真核表达载体pSUPER-HLA-G1有效地沉默了HLA-G1在HTR-8/SVneo滋养细胞中的基因表达及蛋白表达,为今后以HLA-G1为靶点的基因研究奠定了基础。     

Combined analysis of HLA class I,HLA-E and HLA-G predicts prognosis in colon cancer patients

Background:

Evasion of immune surveillance and suppression of the immune system are important hallmarks of tumour development in colon cancer. The goal of this study was to establish a tumour profile based on biomarkers that reflect a tumour''s immune susceptibility status and to determine their relation to patient outcome.

Methods:

The study population consisted of 285 stage I-IV colon cancer patients of which a tissue micro array (TMA) was available. Sections were immunohistochemically stained for the presence of Foxp3+ cells and tumour expression of HLA Class I (HLA-A, -B, -C) and non-classical HLA-E and HLA-G. All markers were combined for further analyses, resulting in three tumour immune phenotypes: strong immune system tumour recognition, intermediate immune system tumour recognition and poor immune system tumour recognition.

Results:

Loss of HLA class I expression was significantly related to a better OS (P-value 0.005) and DFS (P-value 0.008). Patients with tumours who showed neither HLA class I nor HLA-E or -G expression (phenotype a) had a significant better OS and DFS (P-value <0.001 and 0.001, respectively) compared with phenotype b (OS HR: 4.7, 95% CI: 1.2–19.0, P=0.001) or c (OS HR: 8.2, 95% CI: 2.0–34.2, P=0.0001). Further, the tumour immune phenotype was an independent predictor for OS and DFS (P-value 0.009 and 0.013, respectively).

Conclusion:

Tumours showing absence of HLA class I, HLA-E and HLA-G expressions were related to a better OS and DFS. By combining the expression status of several immune-related biomarkers, three tumour immune phenotypes were created that related to patient outcome. These immune phenotypes represented significant, independent, clinical prognostic profiles in colon cancer.