Anti-Ro52 antibodies are associated with the prognosis of adult idiopathic inflammatory myopathy-associated interstitial lung disease.

OBJECTIVES: In the present study, we aimed to assess the prevalence and clinical significance of anti-Ro52 antibodies in a cohort of patients with idiopathic inflammatory myopathy-associated interstitial lung disease (IIM-ILD) with different myositis-specific autoantibodies (MSAs). METHODS: A cohort of 267 IIM-ILD patients, including 62 patients with PM, 126 patients with DM and 79 patients with clinically amyopathic DM (CADM) were retrospectively analysed in this study. Clinical and laboratory findings, pulmonary function tests (PFTs), HRCT patterns and treatment information were compared between patients with and without anti-Ro52 antibodies. The association between prognosis and anti-Ro52 antibodies was also evaluated based on different MSA subgroups. RESULTS: Anti-Ro52 antibodies were more frequent in patients with anti-MDA5 (62.1%, P < 0.01) and anti-Jo1 (64.9%, P < 0.01) antibodies than in those with other MSAs. The proportion of patients with anti-Jo1 antibodies was higher in the anti-Ro52 antibody-positive group than in the anti-Ro52 antibody-negative group. Patients with anti-Ro52 antibodies were more likely to exhibit the Gottron sign than the anti-Ro52 antibody-negative group (P < 0.001). Furthermore, it was a predictive factor for rapid progression interstitial lung disease (RP-ILD) (P = 0.001) and was also associated with a higher mortality rate (log-rank test, P = 0.001). Furthermore, RP-ILD was more frequently exhibited in anti-MDA5- and anti-Ro52-positive patients. Moreover, anti-Ro52 antibody positivity was closely associated with a higher mortality rate in anti-MDA5-ILD patients (log-rank test, P < 0.05). CONCLUSIONS: Anti-Ro52 antibodies were highly prevalent in patients with anti-MDA5 and anti-Jo1 antibodies. Within all patients with IIM-ILD, those with anti-Ro52 autoantibodies had a higher frequency of RP-ILD and a poorer prognosis, especially in the anti-MDA5 antibody subgroup.

Usefulness of serum Krebs von den Lungen-6 for the management of myositis-associated interstitial lung disease.

OBJECTIVE: To identify biomarkers for assessing myositis-associated interstitial lung disease (ILD). METHODS: We reviewed consecutive patients from our institution who had been newly diagnosed with PM, DM, or clinically amyopathic DM during the years 2002-2017. The patients were divided into two groups according to the presence of ILD, and the ILD group was further subdivided into three groups according to the clinical courses of induction failure, relapse and non-relapse. Baseline and time-course changes in the parameters were compared between groups. RESULTS: Among 110 patients enrolled, 75 (68%) had ILD. Baseline serum Krebs von den Lungen-6 (KL-6) was significantly higher in the ILD group than in the non-ILD group (1120 vs 236 U/ml; P < 0.001). In the ILD group consisting of the induction failure cases (n = 3), the relapse group (n = 24) and the non-relapse group (n = 48), baseline serum KL-6 was significantly different between the three groups [1971 vs 1870 vs 935 U/ml, respectively; P = 0.003 (relapse group vs non-relapse group)]. The time-course changes in serum KL-6 revealed that KL-6 significantly increased along with relapse, with the increase of 625 U/ml relevant to relapse. CONCLUSION: Serum KL-6 is a useful biomarker for assessing the disease activity of myositis-associated ILD.