Detection of promoter methylafion of three human leukocyte antigen (HLA) class I genes (HLA-A, -B and -C) in patients with psoriasis vulgaris / 中华皮肤科杂志

ObjectiveTo investigate the correlation between the methylation status of HLA class Ⅰ genes(HLA-A, -B and -C) in psoriatic epidermis and disease severity in patients with psoriasis vulgaris. MethodsDNA specimens were obtained from the lesional and nonlesional epidermis of 46 patients with psoriasis vulgaris and from the normal skin of 28 human controls. Methylation specific PCR (MSP) was conducted to detect the methylation status of CpG islands in the promoter region of HLA-A, -B and -C genes. The severity of psoriasis was evaluated by psoriasis area and severity index(PASI) scores. ResultsThe percentage of promoter methylation of HLA-B and HLA-C genes was 4.35％(2/46) and 21.74％(10/46), respectively in nonlesional epidermis, 4.35％ (2/46) and 4.35％ (2/46), respectively in lesional epidermis from these patients. No methylation was observed for the promoter of HLA-A, -B or -C gene in the normal control epidermis or for that of HLA-A gene in the nonlesional or lesional epidermis from the patients. The frequency of HLA-C gene promoter methylation in the nonlesional epidermis was significantly higher than that in the lesional epidermis and control epidermis, but was uncorrelated to the disease severity. No significant difference was observed for the methylation frequency of HLA-A or -B gene promoter among the three groups of specimens. Conclusion Abnormal methylation of HLA-C gene promoter is observed in patients with psoriasis vulgaris.

The Cold Preservation of Mice Hepatocytes Induces Apoptosis but Not over Expression of MHC Class I Antigen / 대한이식학회지

Hepatocyte transplantation is a potential treatment modality for liver diseased patients. Purified hepatocytes stimulates allospecific cytotoxicity by expressing the MHC class I antigen. Also, during cold preservation, hepatocytes are damaged by lipid peroxidation with oxygen free radicals, which may induce apoptosis on cold preserved hepatocyte. For measuring the degree of antigenicity on cold- preserved mice hepatocytes with UW solution, we studied the expression of MHC class I antigen in various time period by FACS and RT-PCR. For analysis of apoptotic hepatocyte death, we studied morphological changes and DNA fragmentation. We used flow cytometry techniques with rhodamine 123,3,3'-dihexiloxadicarbocyanine (DiOC6 (3)) and propidium iodide (PI). DiOC6 (3) is mitochondrial probe to measure the mitochondrial transmembrane potential that drops early in apoptosis. The percentage of cells undergoing chromatinolysis (subdiploid cells) was determined by ethanol fixation followed by RNA digestion and PI staining. The cold preserved hepatocytes expressed MHC class I constitutively, but revealed no significant differences among various preservation period. However, apoptosis of hepatocytes occured progressively during cold preservation. These results provides that the cold preservation of mice hepatocyte induces apoptosis with involvement of an oxidative process, but does not stimulate over expression of MHC class I antigen.