Expression Of HLA In Peripheral Blood Mononuclear Cell Of Gastric Cancer Patients

Objective(1)To develop a real-time fluorescent quantitative RT-PCR(FQ-RT-PCR) method detecting human leukocyte antigen HLA-A,-B,-DP,-DR,-G mRNA and a flow cytometry(FCM) method detecting HLA-Ⅰand HLA-G molecules on peripheral blood mononuclear cell(PBMC).(2) To investigate the expression level of HLA-A,-B,-DP,-DR,-G in host PBMC of gastric cancer patients and its clinical significance.Methods The genes in conservative region were selected to design the specific primers of HLA-A,-B,-DP,-DR and HLA-G;referring the related documents and the gene sequence on GenBank.The mRNA of HLA-A,-B,-DP,-DR,-G in PBMC were detected by real-time relative quantitative PCR method in 43 patients with gastric cancer,22 healthy individuals.The HLA-Ⅰand HLA-G molecule on PBMC were evaluated by FCM method in 10 patients with gastic cancer and 5 healthy individuals. All data were processed by the SPSS statistical software,version 10.0.Results(1) The relative expression level of HLA-A,-B,-DP,-DR,-G in PBMC was 0.71±0.26,0.61±0.37,0.91±0.33,0.90±0.38,0.77±0.27 in gastirc cancer group and 1.23±0.60,1.17±0.60,1.07±0.68,1.12±0.55,0.98±0.37 in healthy group, respectively.The expression level of HLA-A,-B,-G in PBMC in gastric cancer group was significantly lower than healthy group(p＜0.05),while there was no significantly difference in HLA-DP,-DR between two groups(p＞0.05).(2) The relative expression level of HLA-A,-B,-DP,-DR,-G in PBMC of well-differentiated and moderately differentiated group(n=8) was 0.79±0.24, 0.58±0.36,0.78±0.20,0.83±0.26,0.70±0.22 while poorly differentiated group(n=35) was 0.70±0.27,0.63±0.38,0.95±0.36,0.92±0.40,0.79±0.28.The relative expression level of HLA-A,-B,-DP,-DR,-G in PBMC ofⅠgrade andⅡgrade group(n=12) was 0.73±0.32,0.59±0.43,0.84±0.39,0.83±0.32,0.99±0.22 whileⅢgrade andⅣgrade group(n=31)was 0.71±0.25,0.62±0.36,0.94±0.32,0.92±0.39,0.68±0.23.(3)The expression level of HLA-A,-B and -G in PBMC didn't show correlation with the clinical stageing and histological grading or gastric cancer (p＞0.05) except that the expression level of HLA-G inⅢ+Ⅳgrade group was lower than inⅠ+Ⅱgrade group(p＜0.05).(4) The mean fluorescence intensity of HLA-Ⅰantigen of gastric cancer group(n=10) and health group(n=5) was 390.1±72.8 and 552.6±68.8,which was statistically significant difference(p＜0.05).While there was roughly the same in expressive percentage of two group(p＞0.05),respectively 94.2%and 98.4%.(5) HLA-G molecule mainly expressed on CD4~+CD8~- T lymphocyte.(6) The expressive percentage(%) of HLA-G molecule on CD4~+CD8~- T lymphocyte of gastric cancer group(n=10) and health group(n=5) was 0.48±0.12 and 0.69±0.16,the cancer group was with a downward tendency,while there was no significantly difference(P＞0.05).Conclusions HLA-A,-B,-G may play a critical role in the tumor immunity response.The expression level in PBMC of HLA-A,-B and -G was reduced significantly when the gastric cancer occurs.It may provide a novel diagnosis and reseach tool for gastric cancer.