Haplotype associations of the major histocompatibility complex with psoriasis in Northeastern Thais.

BACKGROUND

To evaluate the distributions of the human leukocyte antigen (HLA) at class I and II loci that may contribute to the genetic susceptibility to psoriasis patients in the north-eastern Thai population.

MATERIALS AND METHODS

We analyzed the allelic frequencies of HLA class I and II by using the polymerase chain reaction-amplification refractory mutation system (PCR-ARMS) technique and polymerase chain reaction-single stranded conformation polymorphism (PCR-SSCP), respectively, in 140 north-eastern Thais with psoriasis that were sudivided into two groups: one with age at onset < 40 years (type I psoriasis; 95 cases) and the other with age at onset > 40 years (type II psoriasis; 45 cases). Three hundred healthy unrelated north-eastern Thais were used as controls.

RESULTS

HLA-A01, -A0207, -A30, -B08, -B13, -B4601, -B57, -Cw01, -Cw0602, and -DRB107 were positively associated with type I psoriasis, whereas HLA-A24, -A33, and -Cw04 were negatively associated with type I psoriasis with statistical significance when compared to the controls. The Cw0602 allele showed the strongest correlation with this type. In addition, the frequencies of HLA-A0207, -A30, -Cw01, and -DRB11401 were significantly increased in type II psoriasis. HLA-A207, -B4601, -Cw01, -DRB109, -DQB10303 (AH46.1), HLA-A01-B57-Cw0602-DRB107-DQB10303 (AH57.1), and HLA-A30, -B13, -Cw0602, -DRB107, and -DQB1*02 (AH13.1) were identified as high-risk major histocompatibility complex (MHC) halotypes for psoriasis patients in the early onset group in north-eastern Thais.

CONCLUSIONS

This study demonstrates not only the differential association between HLA markers and types of psoriasis according to age at onset, but also a newly found high-risk and a protective haplotype in Thai psoriasis patients.