Association of HLA - DR Genes with Systemic Sclerosis in Koreans

Kang, Sung Ha; Park, Myoung Hee; Song, Yeong Wook; Cha, Hoon Suk; Han, Chang Wan; Lee, Eun Bong; Baek, Han Joo

Abstract

OBJECTIVE
This study was conducted to elucidate the associations of HLA with systemic sclerosis (SSc) in Koreans.
METHODS
HLA associations with SSc according to SSc-specific autoantibody status and clinical subsets (diffuse and limited) were investigated. HLA-A, B, and C antigens were typed by the serological method using microlymphocytotoxicity test, and HLA-DR by DNA typing method using PCR-reverse hybridization and PCR-SSCP in 56 Korean patients with SSc and 226 healthy controls. For SSc patients, anti-Scl-70 and anicentromere antibodies were tested by double immunodiffusion and indirect immunofluorescence, respectively.
RESULTS
The results of HLA class I antigen typing showed that the frequencies of HLA-A24, B52 and B62 were increased, whereas those of A33, B44 and B58 were decreased in SSc patients compared to healthy controls. The frequency of HLA-DR2 was significantly increased, whereas that of HLA-DR13 was decreased in patients with SSc compared to controls. Among HLA-DR2 alleles, both HLA-DRB1*1501 and *1502 were increased in SSc patients compared to controls. According to clinical status, HLA-DRB1*1501 was increased in limited SSc patients and that of DRB1*1502 was increased both in diffuse and limited SSc patients compared to controls. According to autoantibody status, HLA- DRB1 1502 was significantly increased in anti-Scl-70-positive SSc patients and that of DRB1 1501 was increased in anti-Scl-70-negative SSc patients compared to controls. The association of HLA-DR2 alleles with SSc according to clinical subsets and anti-Scl-70 antibody status revealed that the frequency of HLA- DRB1 *1501 was significantly increased in anti-Scl-70-negative limited SSc patients compared to controls.
CONCLUSIONS
These results suggest that different HLA-DR2 alleles are associated with different types of SSc in Koreans. HLA-DRB1 1502 shows strong association with anti-Scl-70-positive SSc, and DRB1 1501 with anti-Scl-70-negative limited SSc. It is concluded that the pathogenesis of SSc in Koreans is in part, based on the same genetic background.