Expression of HLA class I and II on peripheral blood lymphocytes in HBV infection:

Downregulation of the H-2Kd gene by siRNA affects the cytotoxicity of murine LAK cells

To investigate the effect of the H-2K^d gene on the lymphocyte membrane, we constructed a small interfering RNA (siRNA) that targets the H-2K^d gene and compared the cytotoxicity of mouse lymphokine-activated killer (LAK) cells with different H-2K^d expression states. H-2K^d-targeting siRNA was transfected into spleen lymphocytes of BALB/C mice. Flow cytometry (FCM) was then performed to examine the expression of the H-2K^d gene in the transfected and control cells. Additionally, the cytotoxicity of the transfected cells toward the H22 and K562 cell lines was evaluated in vitro using the LDH release assay. H-2K^d-targeting siRNA significantly reduced the expression levels of the target protein, whereas pure transMessenger and non-silencing siRNA did not inhibit H-2K^d expression at the concentrations tested. The cytotoxicity of siRNA-treated LAK cells toward H22 and K562 cells was reduced significantly. The knockdown of H-2K^d gene expression by siRNA may be associated with LAK cell cytotoxicity toward neoplasm cell lines.

HLA Class I Expressions on Peripheral Blood Mononuclear Cells in Colorectal Cancer Patients

OBJECTIVE

To investigate the expression change of human leukocyte antigen (HLA) class I on human peripheral blood mononuclear cells (PBMCs) at both mRNA and protein levels, and to evaluate its roles in the development of colorectal cancer (CRC).

METHODS

In the present study, 50 patients with CRC, 35 patients with benign colorectal lesion and 42 healthy volunteers were enrolled. Expression levels of HLA class I mRNA and protein were determined using real-time quantitative reverse transcription PCR (RT-PCR) and flow cytometry analysis, respectively.

RESULTS

The expression levels of HLA class I mRNA and proteins were not influenced by age and gender. The relative ratios of HLA class I mRNA were 0.99±0.27 in healthy controls, 0.76±0.19 in benign patients, and 0.48±0.21 in CRC patients. Mean fluorescence intensities of HLA class I were 145.58±38.14 in healthy controls, 102.05±35.98 in benign patients and 87.44±34.01 in CRC patients. HLA class I on PBMCs was significantly down-regulated at both mRNA and protein levels in patients with stage III and IV CRC. CRC patients with lymph node metastasis also showed a decreased HLA class I expression at protein level.

CONCLUSION

HLA class I expressions on PBMCs are associated with staging of CRC and lymph node metastasis. Monitoring the expression of HLA class I on PBMCs may provide useful information for diagnosis and metastasis judgement of CRC.

Human leukocyte antigen class I on peripheral blood mononuclear cells as a non-invasive biomarker for esophageal cancer

Esophageal cancer (EC) is a common malignant cancer threatening people's health. There are no universally accepted parameters for its early diagnosis. The aim of this study was to observe the expression of human leukocyte antigen class I (HLA-I) on peripheral blood mononuclear cells (PBMCs) of EC patients and in individuals of high-incidence area of EC so as to evaluate the feasibility of using this parameter as a potential non-invasive biomarker for the early diagnosis of EC. The present study enrolled 58 pathological confirmed EC patients, 46 patients with benign esophageal disease, and 65 healthy volunteers. Expression levels of HLA-I protein and mRNA on PBMCs were determined by flow cytometry and quantitative reverse transcriptase polymerase chain reaction, respectively. Then, 181 volunteers from Lijiadian, a village with high morbidity of EC, and 153 age- and gender-matched health volunteers were involved in this study to observe HLA-I expressions in individuals of high-incidence area of EC. Compared with benign esophageal disease and health volunteers, the expressions of HLA-I protein and mRNA on PBMCs of EC patients are significantly decreased, especially in patients with stage III and IV EC, but was not influenced by patient's age and gender. Furthermore, individuals of high-incidence area of EC also show downregulated HLA-I protein, but not mRNA, expression on PBMCs. Altogether, HLA-I expression on PBMCs of EC patients and individuals from high-incidence area of EC is downregulated, and this parameter might be used as a potential predictor of EC.

The amount of surface HLA-I on T lymphocytes decreases in breast infiltrating ductal carcinoma patients

Human leucocyte antigen class I (HLA-I), which includes HLA-A, -B and -C, is an essential immune factor participating in the antitumour immune response. The changes in HLA-I expression in peripheral blood T lymphocytes in cancer patients have yet to be defined. This study examined the expression of HLA-I on CD4(+) and CD8(+) T lymphocytes in female patients with stage I - IV breast infiltrating ductal carcinoma, benign breast tumour diseases (mammary intraductal papilloma or breast fibroadenoma), and in healthy controls. HLA-I was down-regulated on CD4(+) T lymphocytes from patients with stage III and IV cancer, and on CD8(+) T lymphocytes in patients with stage I - IV cancer compared with healthy controls. HLA-I expression in T lymphocytes may contribute towards immune-balance disorders in tumour patients.

Immunopathology of hepatitis B virus infection

The interaction between immune responses and hepatitis B virus (HBV) is coordinated between innate and adaptive immunity. Anti-HBs antibodies protect the host by blocking the binding ability of HBV. Anti-HBc antibodies are detected with persistent HBV infection. The presence of anti-HBe antibodies is often associated with recovery from active diseases and is clinically used as a benchmark to assess response to treatment. Our studies have revealed that the anti-HBV immunoglobulins secreted are different in subclass patterns in different HBV infection status populations. These revelations may help to understand HBV escape and persistent infection and to develop strategies for prevention and therapeutic management of HBV infection.