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

The aim was to study and compare the clinical manifestations, auxiliary examinations, and therapeutic responses in patients with different myositis-specific antibody (MSA) types.

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.

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.

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.