Abstract:

Objective To assess the association between the amino acid polymorphism （Arg64Gln） within the interferon-γ receptor 2 gene（IFN-γR2） and psoriasis vulgaris in Chinese Hans. Methods Blood samples were collected from 182 patients with psoriasis vulgaris and 114 healthy human controls in Jiangsu and Anhui provinces. The amino acid polymorphism（Arg64Gln） within the IFN-γR2 was examined by PCR-restriction fragment length polymorphism （RFLP） and DNA sequencing. Results No significant difference was observed in the amino acid polymorphism （Arg64Gln） within the IFN-γR2 between the psoriatic patients and healthy controls （P > 0.05）. There was a significant difference between patients with nail involvement and those without in the frequency of Gln64/Gln64 genotype （57.5% vs 38.1%, χ2 = 5.33, P < 0.05）, and Arg 64 （Gln64） allele ［19.3% （80.7%） vs 30% （70%）, χ2 = 5.03, P < 0.05］. The frequencies of Gln64/Arg64 genotype and Gln64/Gln64 genotype in psoriatic patients with nail involvement significantly differed from those in the controls （29.8% vs 49.1%, χ2 = 5.48, P < 0.05; 57.5% vs 35.1%, χ2 = 6.23, P < 0.05）, while no significant difference was found between the psoriatic patients without nail involvement and controls. Moreover, significant difference was noted between patients with prior upper respiratory tract infection （as inducements） and those without in the frequency of Arg64/Arg64 genotype （33.3% vs 15.5%, χ2 = 4.94, P < 0.05） and Gln64 （Arg64） allele ［51.9% （48.1%） vs 35.2% （64.8%）, χ2 = 5.46, P < 0.05］. Conclusion The amino acid polymorphism （Arg64Gln） within the IFN-γR2 may be associated with the nail involvement and upper respiratory tract infection in patients with psoriasis vulgaris.