AB0238 ASSOCIATION OF Ro52 WITH INTERSTITIAL LUNG DISEASE AND REDUCED SURVIVAL IN DERMATOMYOSITIS

Background: In antisynthetase syndrome, anti-Ro52 antibodies appear to be linked to a higher incidence of pulmonary interstitial disease, but not to a worse prognosis. Less data is available on dermatomyositis (DM). Objectives: The aim of this study was to investigate the clinical and prognostic significance of Ro52 positivity in patients with DM. Methods: All patients from a local inflammatory myositis registry (IN.MY.RE.) who fulfilled 2017 ACR/EULAR classification criteria for DM were analyzed. Patients were divided into two groups: DM patients with Ro52 (Ro52+) and DM patients without Ro52 (Ro52-) antibodies. Myositis-specific antibodies (MSA) (Jo1, PL7, PL12, EJ, OJ, Mi2 a/b, TIF1G, MDA5, NXP2, SAE1/2, SRP) were tested using immunodot assay (MYO12D-24, D-Tek, Belgium). Ro52 antibodies were confirmed using ELISA (Enzyme Linked ImmunoSorbent Assay). Patients with antisynthetase syndrome were excluded from the analysis. Results: Eighty-nine patients with DM were included, of whom 15 (16.85%) were Ro52+ and the remaining 74 (83.15%) were Ro52-. No significant differences in clinical characteristics (sex, age, diagnostic delay, DM subset) were found between Ro52+ and Ro52-. Dysphagia was observed more frequently in Ro52- group (13.3% Ro52+ and 51.4% Ro52-, p<0.05), whereas interstitial lung disease (ILD) was more common in Ro52+ DM patients (66.7% Ro52+ and 10.8% Ro52-, p<0.05). None of the patients with anti-NXP2 antibodies exhibited Ro52, while Ro52 was more commonly observed in patients with anti-MDA5 (26.7%), anti-SAE1/2 (20%) and seronegative (33.3%) DM. Logistic regression analysis adjusted for age, sex, DM subset and MSA revealed that Ro52 was independently associated with ILD (HR: 27.5, 95%CI 3.97-191). Among the 18 DM patients with ILD, diffuse alveolar damage (DAD) was only observed in Ro52+ DM (40% Ro52+ and 0% Ro52-) (Table 1). During the follow-up, 7/15 Ro52+ DM patient (46.6%) and 16/74 Ro52- DM patients (21.6%) died. Kaplan Meier analysis showed lower survival in Ro52+ group (Figure 1, log rank test: 0.004). Cox regression model adjusted for sex, age, DM subset and MSA, showed that Ro52+ was a poor prognostic factor (HR 3.35, CI 1.19-9.37). Abbreviations: DM: dermatomyositis; HDM: hypomyopathic dermatomyositis; CADM: clinical amyopathic dermatomyositis; ILD: interstitial lung disease; RP-ILD: rapidly progressive ILD; CT: computer tomography; NSIP: nonspecific interstitial pneumonia; OP: organizing pneumonia; UIP: usual intestitial pneumonia; DAD: diffuse alveolar damage Conclusion: The study findings suggest that Ro52 is most frequently associated with ILD, specifically the DAD subtype, and represent a poor prognostic factor in DM patients. REFERENCES: [1] Anti-Ro52 antibodies positivity in antisynthetase syndrome: a single centre cohort study. Clin Exp Rheumatol. 2022 May;40 Suppl 134(5):27-31. Acknowledgements: NIL. Disclosure of Interests: None declared.