Coexistence of anti-melanoma differentiation-associated protein 5 and anti-Ro52 antibodies in patients with idiopathic inflammatory myopathy: a retrospective cohort study.

introductionPatients with idiopathic inflammatory myopathy (IIM) and anti-melanoma differentiation-associated protein 5 (anti-MDA5) antibodies are at significant risk (50-90%) of developing interstitial lung disease (ILD), with a reported mortality rate of 33-60%. Notably, the coexistence of anti-MDA5 and anti-Ro52 antibodies is associated with a more severe ILD prognosis than that of anti-MDA5 antibodies alone. The aim of this study was to investigate the serological characteristics of ILD in patients with IIM who possess anti-MDA5 antibodies, with or without concurrent anti-Ro52 antibodies.

methodsWe retrospectively collected data from 32 patients diagnosed with anti-MDA5-positive IIM between May 2018 and December 2022. We reviewed these patients' clinical manifestations, serological parameters, HRCT images and outcomes. We compared the difference between the patients with and without anti-Ro-52 antibodies.

resultsOf the 32 patients with IIM and anti-MDA5 antibodies, 16 tested positive for anti-Ro52 antibodies. Patients positive for both autoantibodies had a higher prevalence of ILD (81.25% vs. 43.75%, p = 0.028), a higher frequency of ground-glass opacity (100% vs. 42.85%, p = 0.002) of HRCT findings, higher C-reactive protein levels (2.9 vs. 1.4 mg/L, p = 0.038), and were older (54.2 vs. 42.1 years, p = 0.021) than those without. Patients who were positive for the coexistence of anti-MDA5 and anti-Ro52 antibodies tended to have a lower survival rate, although this difference was not statistically significant (p = 0.124).

conclusionIndividuals with IIM coexistence of anti-MDA5 and anti-Ro52 antibodies may experience a greater inflammatory response, higher ILD frequency, and poorer prognosis than those without. KEY POINTS: • The coexistence of anti-MDA5 and anti-Ro52 antibodies in a small cohort of patients with IIM was found to be associated with a higher overall inflammatory features, including the presence of interstitial lung disease. • Coexistence of these antibodies and interstitial lung disease particularly relating to the radiological findings of ground glass opacities can be helpful in providing insights into evaluation and diagnostic pathways for clinicians. • A trend for a lower survival rate was observed for patients with the presence of these two antibodies than anti-MDA5 antibody alone.