Polymorphisms of tumor necrosis factor (TNF) α and β genes in Korean patients with psoriasis

To evaluate the association of TNF-alpha (TNFA) and TNF-beta (TNFB) polymorphisms with psoriasis in the Korean population, we investigated TNF-alpha -238 and -308 promoter region and TNF-beta NcoI polymorphism using PCR-RFLP in 103 Korean psoriasis patients and 125 normal controls. The carriage and allele frequencies of TNFB*2 were significantly increased in patients with psoriasis compared with normal controls. However, TNFB*1/1 homozygote and TNFB*1 allele were significantly decreased in the patients. There were no significant differences in the polymorphism of TNF-alpha promoter -238 and -308 between the patients and controls. We also analyzed the frequencies of TNFB alleles according to the clinical characteristics of the psoriasis patients, but no significant differences were found. However, female patients with early-onset psoriasis showed an association with the TNFB*2 allele. In conclusion, our results suggest that polymorphisms of the TNFB gene may contribute to a predisposition to psoriasis in the Korean population.