Abstract:

Objective To analyze the correlation of interleukin （IL）-12B gene single nucleotide polymorphism （SNP） rs6887695 with clinical phenotypes （including age at onset, family history, clinical types, gender） of psoriasis vulgaris in Chinese Han population． Methods This study recruited 575 patients with psoriasis vulgaris and 1403 healthy controls. DNA samples were obtained from these subjects. PCR with Taqman fluorescent probe （ABI 7900 system） was performed to analyze the genotype of SNP rs6887695 in IL-12B gene. Statistical analysis was carried out by using the software SPSS 14.0, and Chi-square test was conducted to compare the frequency of the SNP rs6887695 genotypes and alleles between the patients and controls as well as between patients with different clinical phenotypes of psoriasis． Results The frequency of GG, GC and CC genotype of the SNP rs6887695 was 42.61%, 45.39% and 12.0% respectively in the patients, compared to 34.42%, 47.83% and 17.75% in the healthy controls （χ2 = 16.31, P < 0.01）; the frequency of G and C allele of the SNP rs6887695 was 65.30% and 34.70% respectively in the patients, compared to 58.34% and 41.66% respectively in the healthy controls （χ2 = 16.54, P<0.01）. Significant differences were observed in the distribution of genotypes and alleles of the SNP rs6887695 between patients with chronic plaque psoriasis （n = 543） and those with acute guttate psoriasis （n = 32, χ2 = 18.11, 12.19, both P < 0.01）. Increased frequency of G allele and GG genotype of the SNP rs6887695 were noted in the patients with psoriasis vulgaris compared with the healthy controls, and in the patients with plaque psoriasis compared with those with guttate psoriasis. However, there was no statistical difference in the distribution of SNP rs6887695 genotypes or alleles between 540 patients with adult onset psoriasis and 35 patients with child onset psoriasis, between 102 patients with family history and 440 patients without family history, or between 341 male patients and 234 female patients （all P > 0.05）. Conclusions The IL-12B SNP rs6887695 may be associated with the susceptibility to psoriasis vulgaris in Chinese Han population, especially with the susceptibility to plaque psoriasis, but seems unassociated with the age at onset, family history or gender of patients.

Key words: psoriasis, clinical phenotype, polymorphism，IL-12B