Infection is not rare in patients with idiopathic inflammatory myopathies.

OBJECTIVES: To assess the prevalence and characteristics of infections in patients with idiopathic inflammatory myopathies (IIM) and analyse risk factors for infection using clinical presentation and biochemical findings of IIM. METHODS: Retrospective review of the medical records of patients with IIM followed up in a single medical centre from January 2008 to January 2018. RESULTS: Of the 779 patients with IIM, 215 (27.6%) suffered from infections. The prevalence of infection in dermatomyositis (DM) (29.8%) was more than polymyositis (PM) (18.5%). The lung was the most common infection site (66.5%). Multivariate analyses demonstrated that methylprednisolone pulse (MP) (OR=3.22; 95% CI=1.60 - 6.48; p=0.001), age of onset >50 years (OR=1.02; 95% CI=1.00 - 1.03; p=0.011), anti-melanoma differentiation-associated gene 5 (MDA5) antibody (OR=1.93; 95% CI=1.20 - 3.11; p=0.007), lymphocyte count <1200/mm3 (OR=2.85; 95% CI=1.89 - 4.30; p<0.001), and interstitial lung diseases (ILD) (OR=2.03; 95% CI=1.30 - 3.71; p=0.002) are independent risk factors for infection. Survival analysis demonstrated that the three-year survival rate in the infection group was lower than the no-infection group (75.3% vs. 94.7%, p < 0.001). CONCLUSIONS: Among hospitalised individuals with IIM, infection is frequent and the leading cause of mortality. The anti-MDA5 antibody, lymphopenia, ILD, old age, and treatment with MP are contributing factors in the development of infections in patients with IIM.

Clinical characteristics of anti-isoleucyl-tRNA synthetase antibody associated syndrome and comparison with different patient cohorts.

OBJECTIVES: This study aimed to analyse the clinical features of anti-isoleucyl-tRNA synthetase (OJ) antibodies in Chinese patients and to compare with previously published cohorts. We reviewed the clinical data of anti-OJ antibody positive patients, including their long-term follow-up. RESULTS: Anti-OJ antibodies were present in 10 of 1269 (0.8%) patients with idiopathic inflammatory myopathies (IIMs), and 10/320 (3.1%) patients with anti-synthetase syndrome (ASS). Of the anti-OJ antibody-positive patients, 90% had interstitial lung disease (ILD), of whom three (30%) developed rapidly progressive ILD (RP-ILD). Half (50%) of the patients were febrile and developed myocardial involvement; 40% of patients experienced myositis, mechanic's hands and arthritis. Compared to the anti-Jo-1 group, the levels of C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) in the anti-OJ antibody-positive group were higher (p<0.05). From a review of the literature regarding the clinical features of anti-OJ, fever was more common in the eastern cohort (41.7% vs. 8.3%, p=0.002), whereas patients in western countries were more likely to develop arthritis (20.9% vs. 58.1%, p=0.001). With complete follow-up of the present cohort, 80% improved with treatment, including one patient who underwent lung transplant. CONCLUSIONS: The anti-OJ antibody occurred infrequently in Chinese patients, ILD was the major clinical feature, but myocardial injury was also a prominent associated complication. Anti-OJ positive patients were responsive to treatment.

A novel autoantibody targeting calreticulin is associated with cancer in patients with idiopathic inflammatory myopathies.

OBJECTIVES: To investigate the prevalence and clinical significance of anti-calreticulin autoantibodies (anti-CRT Ab) in a large cohort of idiopathic inflammatory myopathy (IIM) patients. METHODS: Sera from 469 patients with IIM, 196 patients with other connective tissue diseases, 28 patients with solid tumors and 81 healthy controls were screened for anti-CRT Ab by enzyme-linked immunosorbent assay using human recombinant CRT protein. Sera from 35 IIM patients were tested using an immunoprecipitation assay to confirm the presence of anti-CRT Ab. Subsequently, IIM-cancer patients were identified and divided into new-onset, remission and recurrent groups based on their cancer status. The relationships between anti-CRT Ab levels and IIM disease activity were also investigated. RESULTS: Serum anti-CRT Ab was detected positive in 81 of the 469 (17.3%) IIM patients. Immunoprecipitated bands were observed at a molecular weight of 60 kDa corresponding to the CRT protein. The IIM patients with anti-CRT Ab more frequently had cancers compared to the patients without anti-CRT Ab. Moreover, the prevalence of anti-CRT Ab differed according to the cancer status. The IIM patients with recurrent cancers had a much higher prevalence of anti-CRT Ab than those with cancers in remission. Also, serum anti-CRT Ab levels positively correlated with disease activity at baseline and at follow-up visits. CONCLUSION: We report the existence of serum anti-CRT Ab in IIM patients and demonstrate the possible association of anti-CRT Ab with malignancy in IIM patients. Serum anti-CRT Ab could serve as a novel candidate marker of cancer in IIM patients.