Up-regulation of Human Leukocyte Antigen G Expression in Primary Cutaneous Malignant Melanoma Associated with Host-vs-tumor Immune Response

Human leukocyte antigen G （HLA-G） is one of the molecules implicated in immunotolerance. To investigate the role of HLA-G in primary cutaneous malignant melanoma （CMM）, a series of 47 skin melanocytic lesions were immunohistochemically evaluated. The correlation between HLA-G expression and CMM clinicohistopahtological data and Bcl-2 expression was also analyzed. HLA-G expression was detected in a variety of cell types. No significant difference in HLA-G expression was observed between malignant and non-malignant melanocytic lesions. HLA-G expression was significantly correlated with the inflammatory infiltration and Bcl-2 expression, whereas no significant correlation with ulceration, tumor thickness, clinical stage, histopathological subtypes were observed. HLA-G expression may be the result of host immune reaction in tumor microenvironment rather than a malignant feature of CMM.

Soluble Human Leukocyte Antigen-G Expression in Pregnancy Success and Early Pregnancy Loss in Korle-Bu Teaching Hospital

Introduction: Human leukocyte antigen G (HLA-G) is a non-classical major histocompatibility complex (MHC) class Ib antigen characterized by a limited polymorphism. The expression of HLA-G at immune privileged sites and its ability to inhibit the effectors functions of immune cells has set HLA-G as a molecule of immune tolerance. This expression pattern is unique among HLA genes and suggests that HLA-G may be involved in interactions that are critical in establishing and/or maintaining pregnancy. Methods: Soluble HLA-G (sHLA-G) levels were measured using a BioVendor sHLA-G ELISA kit following the manufacturer’s protocol. The study participants include women undergoing spontaneous abortion, non-pregnant women, males and an archive sample of women who had normal vaginal deliveries without any complications and any history of malaria infection from gestation to delivery. Results: Soluble HLA-G levels were higher among women undergoing spontaneous abortion as compared to women who had normal vaginal delivery and non-pregnant women. Soluble HLA-G levels were also higher in second trimester as compared to first trimester in both women who had spontaneous abortions and women who had normal delivery. Conclusion: Although sHLA-G levels were higher among women undergoing spontaneous abortion as compared to non-pregnant women and women who had normal delivery, this may be playing a role in the maintenance of maternal immune tolerance to fetal antigen, since plasma sHLA-G levels increased with increasing trimester in both women who had normal delivery and women undergoing spontaneous abortion.

Expression of HLA-G in patients with hepatocellular carcinoma

BACKGROUND:Human leukocyte antigen G(HLA-G)is a non-classical major histocompatibility complex class I molecule that has multiple immune regulatory functions including the induction of immune tolerance.The detection of HLA-G expression might serve as a clinical marker in the prediction of clinical outcomes for certain types of carcinoma.Currently, we investigated whether or not HLA-G is also expressed in patients with hepatocellular carcinoma(HCC),and whether the expression has clinical value. METHODS:Serum levels of secreted HLA-G(sHLA-G)were measured by ELISA in 36 patients with HCC,25 patients with liver cirrhosis(LC)and 25 healthy individuals.The expression of HLA-G in liver tissue was further studied using Western blotting in 36 patients with HCC and 25 with LC.The correlations between HLA-G status and various clinicopathological parameters including survival were analyzed. RESULTS:The ELISA assay showed that the serum levels of sHLA-G in the HCC,LC and healthy groups were 132.6± 31.4,63.5±22.1,and 47.0±15.5 U/ml,respectively.Analysis of variance was used for inter-group comparison and differences were found between the HCC group and the other two groups (both P<0.01),while no difference was found between the LC group and the healthy group(P=0.112).HLA-G protein expression in liver tissue was found in 66.7%(24/36)of the primary sites of HCC,but not in benign lesions(LC). Further,the HLA-G expression in tumors had no significant correlation with the parameters of age,gender,histological grade and alpha-fetoprotein level.However,patients with HLA-G-positive tumors had a shorter postoperative survival time than those with HLA-G-negative tumors(P=0.014).Also, univariate analysis showed that HLA-G was an independent prognostic factor.CONCLUSION:Our results indicated that the expression of HLA-G was a characteristic feature of HCC and patients with positive expression of HLA-G in malignant liver tissue had a poor prognosis.