Abstract:

Objective To investigate the correlation between the methylation status of HLA classⅠgenes （HLA-A, -B and -C） in psoriatic epidermis and disease severity in patients with psoriasis vulgaris. Methods DNA 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. Results The 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.

Key words: methylation specific