Wei-Hua Yan

The 14 bp deletion polymorphisms in HLA-G gene play an important role in the expression of soluble HLA-G in plasma

Soluble human leukocyte antigen-G (sHLA-G) functions as a multiple immunoregulator. A 14 bp insertion (+14 bp)/deletion (-14 bp) polymorphism in exon 8 of the HLA-G gene has been proposed to be associated with HLA-G mRNA stability and the expression of HLA-G. In the current study, a total of 150 normal Chinese Han population had been genotyped for the +14 bp/-14 bp polymorphism, and the expression of plasma sHLA-G was determined with enzyme-linked immunosorbent assay in these case-matched plasma. Data showed that genotype of 14 bp polymorphism was significantly associated with sHLA-G expression. Plasma sHLA-G level with the +14 bp/+14 bp genotype was dramatically lower than that with +14 bp/-14 bp (P = 0.004) and -14 bp/-14 bp genotypes (P = 0.003), while no dramatic difference was observed between the +14 bp/-14 bp and -14 bp/-14 bp genotypes (P > 0.05). In both males and females, plasma sHLA-G with the +14 bp/+14 bp genotype was also significantly lower when compared with other two respective 14 bp genotypes. Data also showed that sHLA-G expression was unrelated to gender. This study suggests that the 14 bp deletion polymorphism in the HLA-G gene plays an important role in sHLA-G expression and that interpretation of the potential biological functions of sHLA-G should be made with caution, taking the polymorphism into consideration.

Aberrant human leucocyte antigen‐G expression and its clinical relevance in hepatocellular carcinoma

The clinical relevance of human leucocyte antigen‐G (HLA‐G) has been postulated in malignancies. Hepatocellular carcinoma (HCC) is a major contributor to cancer incidence and mortality worldwide; however, potential roles of HLA‐G in HCC remain unknown. In the current study, HLA‐G expression in 219 primary HCC lesions and their adjacent non‐tumourous samples was analysed with immunohistochemistry. Correlations among HLA‐G expression and various clinical parameters were evaluated. Meanwhile, functional analysis of transfected cell surface HLA‐G expression on NK cell cytolysis was performed in vitro. HLA‐G expression was observed in 50.2% (110/219) of primary HCC lesions, and undetectable in corresponding adjacent normal liver tissues. HLA‐G expression was found in 37.8%, 41.9% and 71.4% of stage I, II and III HCC lesions, respectively. Data revealed that HLA‐G expression in HCC was strongly correlated to advanced disease stage (I versus II, P= 0.882; I versus III, P= 0.020; II versus III, P= 0.037). HLA‐G expression was also more frequently observed in elder patients (≥median 52 years, 57.5%versus 43.4%, P= 0.004). Meanwhile, plasma soluble HLA‐G in HCC patients was significantly higher than that in normal controls (median, 92.49U/ml versus 9.29U/ml, P= 0.000). Functional assay showed that HLA‐G expression in transfected cells could dramatically decrease the NK cell cytolysis (P= 0.036), which could be markedly restored by the blockade of HLA‐G (P= 0.004) and its receptor ILT2 (P= 0.019). Our finding indicated that HLA‐G expression was strongly correlated to advanced disease stage, and more frequently observed in elder patients. Its relevance to HCC progression might be result from the inhibition of NK cell cytolysis.

Upregulation of human leukocyte antigen-G expression and its clinical significance in ductal breast cancer

Human leukocyte antigen(HLA)-G could inhibit functions of immune cells and induce regulatory T cells (Treg) and could be involved in antitumor immune responses. In the current study, HLA-G expression in 58 primary breast cancer lesions was analyzed with immunohistochemistry. Plasma soluble HLA-G was detected with enzyme-linked immunosorbent assay in 92 breast cancer patients and in 70 normal healthy donors. The proportion of CD4(+)CD25(+)FoxP3(+) Treg was analyzed with flow cytometry in 64 breast cancer patients and 23 normal controls. HLA-G expression was observed in 70.7% (41/58) of breast cancer lesions. Lesion HLA-G expression was more frequently observed in advanced disease stage (I/II vs III/IV, p = 0.044) and tumor grade (I/II vs III/IV, p = 0.021). sHLA-G was dramatically increased in patients when compared with normal controls (median 82.19 vs 9.65 U/ml, p < 0.001); The area under the receiver operating characteristic (ROC) curve for sHLA-G was 0.953 (95% confidence interval [CI] = 0.926-0.981, p < 0.001). However, sHLA-G was irrelevant to the disease stage and tumor grade. Moreover, CD4(+)CD25(+)FoxP3(+) Treg are markedly increased in the breast cancer patients compared with normal controls (4.46+/-1.36% vs 2.67+/-1.45%, p < 0.001), and the increased frequency of Treg was strongly correlated to sHLA-G levels (R = 0.582, p = 0.001). Our findings indicated that HLA-G could play critical roles in the progression of breast cancer, and plasma sHLA-G levels might be a useful preoperative biomarker for diagnosis.

Possible Roles of KIR2DL4 Expression on uNK Cells in Human Pregnancy

To investigate possible roles of the natural killer (NK) cell receptor killer immunoglobulin‐like receptor (KIR)2DL4 expressed on uterine NK (uNK) cells during pregnancy, we investigated KIR2DL4 expression on uNK cells isolated from patients with early recurrent spontaneous abortion (RSA) and normal early pregnancy women, and functions of KIR2DL4 was analyzed in vitro.

Clinical relevance and functional implications for human leucocyte antigen-g expression in non-small-cell lung cancer.

HLA‐G has been documented both in establishment of anti‐tumour immune responses and in tumour evasion. To investigate the clinical relevance of HLA‐G in non‐small‐cell lung cancer (NSCLC), expression status and potential significance of HLA‐G in NSCLC were analysed. In this study, HLA‐G expression in 101 NSCLC primary lesions and plasma soluble HLA‐G (sHLA‐G) from 91 patients were analysed with immunohistochemistry and ELISA, respectively. Correlations between HLA‐G status and various clinical parameters including survival time were evaluated. Meanwhile, functional analysis of transfected cell surface HLA‐G expression and plasma sHLA‐G form NSCLC patients on natural killer (NK) cell cytolysis were performed. Data revealed that HLA‐G was expressed in 41.6% (42/101) NSCLC primary lesions, while undetectable in adjacent normal lung tissues. HLA‐G expression in NSCLC lesions was strongly correlated to disease stages (P= 0.002). Plasma sHLA‐G from NSCLC patients was markedly higher than that in normal controls (P= 0.004), which was significantly associated with the disease stages (I versus IV, P= 0.025; II versus IV, P= 0.029). Patient plasma sHLA‐G level (≥median, 32.0 U/ml) had a significantly shorter survival time (P= 0.044); however, no similar significance was observed for the lesion HLA‐G expression. In vitro data showed that both cell surface HLA‐G and patient plasma sHLA‐G could dramatically decrease the NK cell cytolysis. Our findings indicated that both lesion HLA‐G expression and plasma sHLA‐G in NSCLC is related to the disease stage and can exert immunosuppression to the NK cell cytolysis, indicating that HLA‐G could be a potential therapeutic target. Moreover, plasma sHLA‐G in NSCLC patients could be used as a prognosis factor for NSCLC.

Elevation of plasma soluble human leukocyte antigen–G in patients with chronic hepatitis C virus infection

The subversion of immune responses that hepatitis C virus (HCV) uses to escape immune surveillance and to establish persistent infection has been poorly understood. The immune-suppressive molecule human leukocyte antigen-G (HLA-G) has been supposed to play important roles in viral infection. In the current study, HCV genotype was analyzed in 67 chronic HCV-infected (CHC) patients. Plasma soluble sHLA-G (including sHLA-G1 and HLA-G5), interleukin-10 (IL-10), and interferon-γ (IFN-γ) levels were determined in these CHC patients and in healthy subjects by enzyme-linked immunosorbent assay, and the sHLA-G isoforms present in plasma were determined by Western blot. Data showed that HCV 1b was the predominant genotype, with a prevalence of 64.2%. sHLA-G was dramatically increased in CHC patients (median: 85.54 U/ml, range: 19.40-204.07) over that in normal controls (median: 9.13 U/ml, range: 5.07-69.56) (p < 0.001). Western blotting revealed that plasma sHLA-G was derived from sHLA-G1 and HLA-G5. IL-10 and IFN-γ levels were also significant higher in CHC patients than in normal controls (median: 16.3 pg/ml vs 1.8 pg/ml, p < 0.001, and 1025.3 pg/ml vs 858.3 pg/ml, p = 0.03, respectively). No significant association was observed for the HCV genotype and viral RNA load with the levels of sHLA-G, IL-10, and IFN-γ in CHC patients. These results indicate that elevation of sHLA-G expression in HCV patients was independent of viral genotype and viral RNA load. Given its immunotolerant property, an increase in sHLA-G may play a role in the persistency of HCV infection.

Induction of Both Membrane-Bound and Soluble HLA-G Expression in Active Human Cytomegalovirus Infection

BACKGROUND Alteration of HLA expression or cytokine production plays a crucial role in the pathogenesis of human cytomegalovirus (HCMV) infection. HLA-G has been suggested to be involved in HCMV infection, and modulation of HLA-G expression by interferon (IFN)-gamma and interleukin (IL)-10 has been reported. However, the clinical relevance of HLA-G in HCMV infection remains unknown. METHODS The study included 75 patients with active HCMV infection (age range, 1-4.5 years) and 150 sex- and age-matched healthy control subjects (age range, 1-5 years). HLA-G expression in peripheral monocytes from patients (n=38) and control subjects (n=20) was analyzed using flow cytometry. Plasma levels of soluble HLA-G (in 75 patients and 150 control subjects), IL-10 (in 75 patients and 40 control subjects), and IFN-gamma (in 75 patients and 40 control subjects) were determined using enzyme-linked immunosorbent assay. RESULTS The mean percentage of HLA-G-positive monocytes among patients with active HCMV infection was dramatically increased, compared with that among healthy control subjects (6.33% vs 1.64%; P<.001). Similarly, significant increases were observed in soluble HLA-G level (median, 54.91 vs 21.32 U/mL; P<.001) and IL-10 level (median, 9.24 vs 1.82 ng/mL; P<.001). Although the expression of IFN-gamma was higher in patients with active HCMV infection than in healthy control subjects, the difference was not statistically significant (median, 1254.46 vs 887.05 ng/mL; P=.070). Furthermore, no correlation was established between HLA-G expression and levels of IL-10 or IFN-gamma. CONCLUSIONS HLA-G expression in monocytes and plasma soluble HLA-G and IL-10 levels were increased during active HCMV infection.

Unfavourable clinical implications for HLA-G expression in acute myeloid leukaemia.

Human leukocyte antigen‐G (HLA‐G) molecule exerts multiple immunoregulatory functions that have been suggested to contribute to the immune evasion of tumour cells. Studies on HLA‐G expression in malignant haematopoietic diseases are controversial, and the functions of HLA‐G on this context are limited. In the current study, HLA‐G expression was analysed in different types of patients: de novo acute myeloid leukaemia (AML, n = 54), B cell acute lymphoblastic leukaemia (B‐ALL, n= 13), chronic myeloid leukaemia (CML, n= 9) and myelodysplastic syndrome (MDS, n= 11). HLA‐G expression was observed in 18.5% cases of AML, 22.2% in CML and 18.2% in MDS, but not in B‐ALL patients. In AML, HLA‐G‐positive patients had a significant higher bone marrow leukaemic blast cell percentage when compared with that of HLA‐G‐negative patients (P < 0.01). Total T‐cell percentage was dramatically decreased in HLA‐G‐positive patients (P < 0.05). Cytogenetic karyotyping results showed that all HLA‐G‐positive AML patients (n= 5) were cytogenetically abnormal, which was markedly different from that of HLA‐G‐negative patients (P < 0.01). Ex vivo cytotoxicity analysis revealed that HLA‐G expression in AML leukaemic cells could directly inhibit NK cell cytolysis (P < 0.01). These findings indicated that HLA‐G expression in AML is of unfavourable clinical implications, and that HLA‐G could be a potential target for therapy.

Human leukocyte antigen‐G expression is associated with a poor prognosis in patients with esophageal squamous cell carcinoma

Human leukocyte antigen (HLA)‐G inhibits functions of immune component cells and promotes malignant cells evading from antitumor immunity. We investigated the clinical relevance of HLA‐G expression in esophageal squamous cell carcinoma (ESCC). In our study, HLA‐G expression in 79 primary ESCC lesions and corresponding adjacent normal tissues were analyzed with immunohistochemistry. Soluble HLA‐G (sHLA‐G) in plasma was detected with enzyme‐linked immunosorbent assay (ELISA) in 41 ESCC patients (including 19 case‐matched lesions and plasma samples) and in 153 normal healthy controls. HLA‐G expression was observed in 65.8% (52/79) of the ESCC lesions but not in adjacent normal esophageal tissues. HLA‐G expression was more frequently observed in patients with advanced disease stage (III/IV vs. I/II, p = 0.01). Patients with HLA‐G expression had a significantly worse survival, and HLA‐G could be an independent prognostic factor. sHLA‐G levels in plasma were significantly increased in patients compared to normal controls (median: 152.4 U/ml vs. 8.9 U/ml, p < 0.001). The area under receiver‐operating characteristic (ROC) curve for sHLA‐G in plasma was 0.992. However, no significant correlation was found between sHLA‐G in plasma and clinical parameters studied. In conclusion, our findings indicated that HLA‐G expression in ESCC is associated with poor survival and could be a prognostic indicator. Furthermore, increased levels of sHLA‐G in plasma might be a useful preoperative biomarker for diagnosis.

Plasma soluble human leukocyte antigen-G expression is a potential clinical biomarker in patients with hepatitis B virus infection.

The significance of upregulated soluble human leukocyte antigen-G (sHLA-G) expression under various pathologic conditions has been discussed. In this study, we evaluated the potential significance of plasma sHLA-G expression in patients with hepatitis B virus (HBV) infection. The study included 90 acute hepatitis B patients (AHB), 131 chronic hepatitis B patients (CHB), 152 resolved hepatitis B individuals (RHB), and 129 normal controls. sHLA-G were determined using enzyme-linked immunosorbent assay. A receiver operating characteristic (ROC) curve was used to evaluate the feasibility of plasma sHLA-G as a biomarker for distinguishing patients with HBV infection. sHLA-G levels in AHB (median, 193.1 U/mL; p < 0.001), CHB (median, 324.6 U/mL; p < 0.001), and RHB (median, 14.8 U/mL; p = 0.006) patients was much higher than that in normal controls (median, 9.0 U/mL). A significant difference for sHLA-G levels was also observed between patients with HBV infection (AHB vs CHB, AHB vs RHB, and CHB vs RHB; all p < 0.001). The area under the ROC curve for sHLA-G levels was 1.000 (p < 0.001) for AHB, 0.993 (p < 0.001) for CHB, and 0.604 (p = 0.003) for RHB patients versus normal controls, respectively. Data also indicated that the percentage of CD4(+)CD25(+)FoxP3(+) T regulatory cells and HLA-G(+)CD14(+) monocytes was significantly increased in AHB and CHB patients compared with normal controls (all p < 0.001). Our findings indicated that induction of HLA-G expression may play a role in HBV immune evasion and sHLA-G levels could be a useful biomarker in HBV infection.