Increased severity and relapse rate in adult anti-nuclear matrix protein 2 antibody positive myositis patients with distal limb weakness: a retrospective study in China.

Purpose: This study aimed to examine the clinical features and prognosis of patients with distal limb weakness in anti-nuclear matrix protein 2 antibody (anti-NXP2) positive myositis. Patients and methods: This retrospective study included the medical records of patients with anti-NXP2 antibody and follow-up data. Clinical features and prognosis of patients with and without distal limb weakness were compared. The differences in groups and survival analysis were analyzed using SPSS. Results: Of 110 enrolled adult patients with anti-NXP2 positive myositis, 53 showed distal limb weakness. The frequency of distal limb weakness in patients with anti-NXP2 positive myositis was highest when compared with other dermatomyositis (DM) patients. In the patients with anti-NXP2 positive myositis, the mean onset age of distal limb weakness group was younger, when compared with those without distal limb weakness (38.40 ± 13.36 vs. 46.26 ± 15.02 years, Conclusion: Adult patients with anti-NXP2 positive myositis and distal limb weakness were younger at disease onset and exhibited increased disease activity, including a higher prevalence of multi-system involvement, as well as a higher incidence of relapse during follow-up.