Introduction: Juvenile dermatomyositis (JDM) exhibits varying clinical features depending on myositis-specific autoantibodies (MSA), with racial differences.The association between JDM and human leukocyte antigen (HLA) has been reported, but data from Japan are lacking.Therefore, this study aimed to investigate HLA susceptibility in patients with JDM in Japan.Methods: Data of patients with JDM from six facilities across Japan were collected and compared to those of healthy controls.HLA analysis was performed using a next-generation sequencer, covering 11-loci. Results:The study included 39 patients with JDM: female 23 (59%), mean age at onset 6.2 years.Among MSA, anti-TIF1 antibody was present in 12/35 (34.3%), anti-MDA5 antibody in 7/35 (20%), anti-NXP2 antibody in 6/28 (21.4%), and MSA negative in 3/35 (8.6%).Five HLA alleles were detected more frequently in patients with JDM.HLA-DPA1*02:02 (odds ratio (OR) 8.84, corrected p-value (pc) <0.001), HLA-DPB1*05:01 (OR 5.35, pc <0.001), HLA-C*14:02 (OR 4.07, pc 0.037), DQB1*04:01 (OR 3.01, pc 0.049), and HLA-DRB4*01:03 (OR 2.92, pc 0.008) were significantly more common in patients with JDM than in healthy controls.HLA-DRB1*04:05 was associated with interstitial lung disease (ILD) (OR 5.7; 95% CI 1.09-30.07,p = 0.043).Conclusion: HLA-DPA1*02:02, HLA-DPB1*05:01, HLA-C*14:02, HLA-DQB1*04:01, and HLA-DRB4*01:03 are potentially novel susceptibility HLA in Japanese patients with JDM.The high incidence of ILD in Asian patients with anti-MDA5 antibodies may be attributable to HLA-DRB1*04.
Yamasaki et al. (Fri,) studied this question.