Objective: To investigate the significance of anti-histidyl tRNA synthetase (Jo-1) antibody in idiopathic inflammatory myopathies (IIM) and its diseases spectrum.
Methods: We enrolled all the patients who were tested positive for anti-Jo-1 antibody by immunoblotting in Peking University People's Hospital between 2016 and 2022. And the patients diagnosed with anti-synthetase antibody syndrome (ASS) with negative serum anti-Jo-1 antibody were enrolled as controls. We analyzed the basic information, clinical characteristics, and various inflammatory and immunological indicators of the patients at the onset of illness.
Results: A total of 165 patients with positive anti-Jo-1 antibody were enrolled in this study. Among them, 80.5% were diagnosed with connective tissue disease. And 57.6% (95/165) were diagnosed with IIM, including ASS (84/165, 50.9%), immune-mediated necrotizing myopathy (7/165, 4.2%) and dermatomyositis (4/165, 2.4%). There were 23.0% (38/165) diagnosed with other connective tissue disease, mainly including rheumatoid arthritis (11/165, 6.7%), undifferentiated connective tissue disease (5/165, 3.0%), interstitial pneumonia with autoimmune features (5/165, 3.0%), undifferentiated arthritis (4/165, 2.4%), Sjögren's syndrome (3/165, 1.8%), systemic lupus erythematosus (3/165, 1.8%), systemic vasculitis (3/165, 1.8%), and so on. Other cases included 3 (1.8%) malignant tumor patients, 4 (2.4%) infectious cases and so on. The diagnoses were not clear in 9.1% (15 /165) of the cohort. In the analysis of ASS subgroups, the group with positive serum anti-Jo-1 antibody had a younger age of onset than those with negative serum anti-Jo-1 antibody (49.9 years vs. 55.0 years, P=0.026). Clinical manifestations of arthritis (60.7% vs. 33.3%, P=0.002) and myalgia (47.1% vs. 22.2%, P=0.004) were more common in the ASS patients with positive anti-Jo-1 antibody. With the increase of anti-Jo-1 antibody titer, the incidence of the manifestations of arthritis, mechanic hands, Gottron sign and Raynaud phenomenon increased, and the proportion of abnormal creatine kinase and α-hydroxybutyric dehydrogenase index increased in the ASS patients. The incidence of myalgia and myasthenia were significantly more common in this cohort when anti-Jo-1 antibody-positive ASS patients were positive for one and more myositis specific antibodies/myositis associated autoantibodies (P < 0.05).
Conclusion: The disease spectrum in patients with positive serum anti-Jo-1 antibody includes a variety of diseases, mainly ASS. And anti-Jo-1 antibody can also be found in many connective tissue diseases, malignant tumor, infection and so on.
目的: 探究抗组氨酰tRNA合成酶(histidyl tRNA synthetase，Jo-1)抗体在特发性炎性肌病(idiopathic inflammatory myopathies，IIM)及其他疾病谱的意义。
方法: 入组北京大学人民医院2016—2022年利用免疫印迹法检测抗Jo-1抗体阳性的患者，同时入组抗Jo-1抗体阴性的抗合成酶综合征(anti-synthetase syndrome，ASS)患者作为对照，分析患者的基本信息、临床特征以及炎症和免疫学指标。
结果: 共入组165例抗Jo-1抗体阳性患者，结缔组织病(connective tissue disease，CTD)占80.6%(133/165)，其中IIM占总数的57.6%(95/165)，包括ASS(84/165，50.9%)、免疫介导坏死性肌病(7/165，4.2%)以及皮肌炎(4/165，2.4%)，其他CTD占23.0%(38/165)，包括类风湿关节炎(11/165，6.7%)、未分化结缔组织病(5/165, 3.0%)、具有自身免疫特征的间质性肺炎(5/165，3.0%)、未分化关节炎(4/165，2.4%)、干燥综合征(3/165，1.8%)、系统性红斑狼疮(3/165，1.8%)和系统性血管炎(3/165，1.8%)等；其他疾病包括恶性肿瘤(3/165，1.8%)和感染(4/165，2.4%)等；未明确诊断患者占9.1%(15/165)。在ASS亚组分析中，抗Jo-1抗体阳性的ASS患者相比于抗体阴性者起病年龄更低(49.9岁vs. 55.0岁，P=0.026)，更多表现为关节炎(60.7% vs. 33.3%，P=0.002)和肌痛(47.1% vs. 22.2%，P=0.004)。ASS患者随着抗Jo-1抗体滴度的升高，关节炎、技工手、Gottron征、雷诺现象(Raynaud phenomenon)以及肌酸激酶、α-羟丁酸脱氢酶指标异常的发生率升高。抗Jo-1抗体阳性ASS患者在合并一种以上其他肌炎抗体阳性时，肌痛、肌无力的发生率升高(P < 0.05)。
结论: 抗Jo-1抗体阳性患者疾病谱广，以ASS为主，但也可见于其他CTD、肿瘤、感染等疾病，应注意鉴别。
Keywords: Anti-histidyl tRNA synthetase antibody; Anti-synthetase syndrome; Connective tissue disease.