SAT0451 The HLA Class II Profile in Korean Patients with Inflammatory Myositis

Background Polymyositis (PM) and dermatomyositis (DM) is known to be associated with certain HLA alleles in several ethnic groups including Caucasians, African-Americans, and the Japanese. Objectives To investigate the profile of HLA class II alleles in Korean patients with PM and DM Methods Sequencing based genotyping for HLA-DRB1 and -DPB1 was performed in 140 Korean patients with DM (n=104) or PM (n=36) and in 207 healthy controls. Associations of each HLA-DR or -DP allele with myositis or clinical subsets of myositis were examined. Results HLA-DRB1*14:54 (odds ratio [95% confidence interval] 1.05 [1.01-1.09]), -DRB1*15:02 (2.44 [1.03-5.81]), -DRB1*16:02 (1.04 [1.00-1.07], and -DPB1*09:01 (2.44 [1.03-5.81]) were found to be susceptibility alleles while HLA-DRB1*14:01 (0.93 [0.90-0.97]) and -DRB1*15:01 (0.38 [0.18-0.79]) to be protective alleles for inflammatory myositis (Table 1). In DM, HLA-DRB1*15:02 (3.14 [1.30-7.62]) and -DPB1*09:01 (2.87 [1.17-7.05]) carriers were more frequent while HLA-DRB1*14:01 (0.93 [0.90-0.97]), -DRB1*15:01 (0.30 [0.12-0.74]), and -DPB1*04:02 (0.44 [0.20-0.94]) carriers were less frequent than controls. In PM, HLA-DRB1*14:03 (6.52 [1.78-23.81]), and -DRB1*14:54 (1.13 [1.00-1.23]) carriers were more frequently observed. When PM and DM were compared, HLA-DRB1*14:03 carriers were more frequently observed in PM (5.43 [1.23-24.02]). When the association between each allele and clinical subsets was examined, patients with interstitial lung disease (ILD) carried HLA-DRβ1*04:03 (6.34 [1.35-29.76]), -DRβ1*07:01 (0.22 [0.08-0.64]), -DRβ1*09:01 (0.16 [0.05-0.60]) -DRβ1*12:02 (2.91 [1.16-8.01]) DRβ1*15:01 (0.10 [0.01-0.80]), -DPβ1*14:01 (8.90 [1.08-73.21]), and -DPβ1*17:01 (0.11 [0.01-0.92]) more frequently than patients without. DM patients with ILD showed higher frequency of HLA-DRβ1*04:05 than DM patients without ILD (4.68 [1.24-17.74]). Other associations included dysphagia with HLA-DRβ1*08:02 (6.73 [1.51-30.00]), -DRβ1*14:54 (5.19 [1.09-24.57]), and -DPβ1*03:01 (5.19 [1.09-24.57]), arthralgia with HLA-DRβ1*03:01 (4.79 [1.21-18.98]) and -DPβ1*02:01 (2.30 [1.10-4.82]), and mechanic9s hand with HLA-DRB1*08:03 (3.25 [1.12-9.45]) and -DRB1*12:02 (5.04 [1.66-15.29]). Regarding skin rashes, heliotrope rash was associated with HLA-DRβ1*09:01 (2.98 [1.05-8.46]) and -DPβ1*05:01 (0.41 [0.18-0.87]), Gottron9s papules with HLA-DRβ1*14:05 (8.77 [1.07-72.17]), -DPβ1*02:01 (2.29 [1.11-4.73]), -DPB1*02:02 (0.086 [0.01-0.67]), and -DPB1*05:01 (0.41 [0.20-0.85]), and shawl sign with HLA-DRB1*14:05 (4.67 [1.15-18.99]) and -DPB1*14:01 (4.67 [1.15-18.99]). Cancer development was associated with HLA-DRB1*12:01 (7.25 [1.65-31.89]) and -DRB1*13:02 (0.81 [0.74-0.88]). No HLA-DRB1 or -DPB1 allele was found to be associated with anti-Jo1 antibody. Conclusions Korean patients with inflammatory myositis showed a unique profile of HLA-DR and -DP alleles compared with other ethnic groups. Alleles associated with disease susceptibility were different between PM and DM. Clinical subsets, particularly ILD, showed different immunogenetic backgrounds. Disclosure of Interest None declared