Association of anti-NXP2 antibody with clinical characteristics and outcomes in adult dermatomyositis: results from clinical applications based on a myositis-specific antibody.

Objectives: The aim was to study and compare the clinical manifestations, auxiliary examinations, and therapeutic responses in patients with different myositis-specific antibody (MSA) types. Method: We retrospectively investigated the medical records of 143 hospitalized dermatomyositis patients, all of whom were tested for MSAs, and performed follow-up. Patients were divided into groups with and without anti-nuclear matrix protein 2 (NXP2) antibodies (17 vs 126 patients). Demographic, clinical manifestation (occurring at any time during the disease course), imaging, laboratory, treatment response, and survival data were collected for statistical analyses. Results: Adult dermatomyositis patients with anti-NXP2 antibodies were more prone to dysphagia (P<0.001), had higher levels of muscle injury markers (CK peak, P=0.007; CK peak>1000 IU/L, P<0.001; CK-MB, P=0.002), were younger at onset (P=0.008), and were less likely to present with interstitial lung disease (P=0.016) than the anti-NXP2 antibody-negative subgroup. Multivariable logistic regression analysis showed that onset age (OR=0.96 CI 95%: 0.924–0.999, P=0.043) and dysphagia (OR=7.088, CI 95%: 1.824–27.536, P=0.005) were independent risk factors for anti-NXP2 antibody positivity. Kaplan-Meier survival analysis did not reveal that dermatomyositis patients with anti-NXP2 antibodies have a relatively worse prognosis. However, the disease course was more frequently polycyclic, and 68.75% of patients had a relapsing-remitting disease course. More than half (52.94%) of those who showed no response to treatment used at least 3 disease-modifying antirheumatic drugs. Conclusions: We show the important clinical features of and risk factors for this unique antibody-mediated form of dermatomyositis. Although these patients had a relatively low mortality rate, they were prone to recurrence, and treatment was challenging. Key points • The clinical features and risk factors for adult dermatomyositis patients with anti-NXP2 antibodies. • The impact of anti-NXP2 antibody on survival outcomes. [ABSTRACT FROM AUTHOR]