title: Distinct profiles of myositis-specific autoantibodies in Chinese and Japanese patients with polymyositis/dermatomyositis.
abstract: The study aims to comprehensively assess the profiles of myositis-specific autoantibodies (MSAs) in Chinese patients with polymyositis (PM)/dermatomyositis (DM) and compare them with a Japanese cohort. One hundred forty-five Chinese patients (68 classic DM, 25 clinically amyopathic DM [CADM], and 52 PM) and 165 Japanese patients (56 classic DM, 52 CADM, and 57 PM) were recruited. MSAs were measured with immunoprecipitation, enzyme-linked immunosorbent assay, or immunoprecipitation-immunoblotting. MSA frequencies were compared. The overall frequency of anti-melanoma differentiation-associated gene 5 (MDA5) antibodies was significantly higher in the Chinese patients than in the Japanese cohort (36.6 % [53/145] versus 15.8 % [26/165], respectively, P < 0.001), whereas the frequencies of anti-signal recognition particle (SRP) antibodies (1.4 % [2/145] versus 7.9 % [13/165], respectively, P = 0.008) and anti-aminoacyl-transfer RNA synthetase (anti-ARS) antibodies (27.6 % [40/145] versus 40 % [66/165], respectively, P = 0.02,) were significantly lower. The significantly lower frequency of anti-ARS antibodies and significantly higher frequency of anti-MDA5 antibodies in the Chinese patients were observed in the classic DM subset (14.7 % [10/68] versus 46.4 % [26/56], respectively, P < 0.001, and 45.6 % [31/68] versus 5.4 % [3/56], respectively, P < 0.001) and CADM subset (8.0 % [2/25] versus 28.8 % [15/52], respectively, P = 0.04, and 88.0 % [22/25] versus 44.2 % [23/52], respectively, P = 0.0002), but not in the PM subset. The first detailed profile of MSAs in Chinese patients with PM/DM was established. The differences in MSA frequencies in the Chinese cohort and Japanese cohort suggest underlying genetic and/or environmental differences between these two populations. Key Messages • A significantly higher frequency of anti-melanoma differentiation-associated gene 5 (MDA5) antibodies was observed in Chinese patients with polymyositis/dermatomyositis (PM/DM) than in Japanese patients. • Our findings suggest that distinct genetic and/or local environmental factors affect Chinese and Japanese patients with PM/DM, who have been considered a "homogeneous" population in previous studies.
authors.affiliation: Department of Rheumatology and Immunology, Affiliated Drum Tower Hospital, Nanjing University Medical School, 321 Zhongshan Road, Nanjing, 210008, China.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Hu
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Ziwei
authors.initials: Z
authors.lastname: Guo
authors.forename: Lingyun
authors.initials: L
authors.lastname: Sun
authors.forename: Masataka
authors.initials: M
authors.lastname: Kuwana
mesh_terms: D044466:Asian People / Q000208:ethnology*; D001323:Autoantibodies / Q000276:immunology*; D002681:China / Q000208:ethnology; D015331:Cohort Studies; D053487:DEAD-box RNA Helicases / Q000235:genetics*; D003882:Dermatomyositis / Q000208:ethnology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D047468:Immunoprecipitation; D000072640:Interferon-Induced Helicase, IFIH1; D007564:Japan / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D017285:Polymyositis / Q000208:ethnology*
chemical_list: D001323:Autoantibodies; C452815:IFIH1 protein, human; D053487:DEAD-box RNA Helicases; D000072640:Interferon-Induced Helicase, IFIH1