Prognostic Implications of Myositis-Specific Autoantibodies on Mortality, Relapse, and Remission in Dermatomyositis...

To explore the clinicopathological features and treatment prognosis including death, relapse and remission of dermatomyositis (DM) based on myositis-specific autoantibody (MSAs) stratification.

Patients with DM come from a provincial neuromuscular center in northern China. Patients who underwent biopsy from 2010 to 2023 were collected, and the follow-up time was all more than 6 months. Clinical characteristics, serum samples, and muscle biopsies were collected. Kaplan-Meier analysis, Cox regression, and competing risk model were used for analysis.

Our study included 140 patients with DM. Among the 25 juvenile patients, 9 (36%) were anti-NXP2 antibody positive. About 80.95% of the patients with anti-TIF1-γ antibodies had neck flexion weakness. Patients with anti-Mi-2 antibodies showed a predominance of severe muscle fiber necrosis/regeneration (76.19%) rather than perifascicular atrophy (14.29%). Compared to the seronegative subgroup, the short- and long-term risks of death were higher in anti-TIF1-γ-positive patients, and the 3-year risk of death was higher in anti-MDA5 patients. The short- and long-term dangers of relapse were consistently higher in anti-Mi-2-positive patients, with a higher 3-year relapse risk in the anti-NXP2 subgroup. In the case of death as a competing risk of relapse, patients with anti-Mi-2 and patients with anti-NXP2 had higher short- and long-term risks of relapse. No difference was found in the clinical remission rate based on the DM-MSA stratification.

Evaluating the characteristics and prognosis of DM subgroups based on serum MSA stratification is helpful for patient management and treatment strategies.