POS1459 THE WEIGHT OF ANTI-LA/SSB ANTIBODIES IN RO/SSA-POSITIVE PATIENTS WITH A NEWLY DIAGNOSED SJÖGREN’S SYNDROME: A PHENOTYPE CHARACTERIZED BY A MORE SEVERE MAJOR AND MINOR GLANDULAR INVOLVEMENT AND A HIGHER BIOLOGICAL ACTIVITY

Background Recently, a growing interest has arisen in investigating the association between patients’ serological profiles and different clinical phenotypes primary Sjӧgren’s syndrome (pSS). The double positivity for anti-Ro52/anti-Ro60 been associated with B-cell hyperactivity more prominent INF-a signature. Whether of anti-La/SSB antibodies influences features triple positive pSS patients at time diagnosis remains controversial. Objectives 1.To compare clinical, biological, histological ultrasonographic distinctive presenting those diagnosis. 2. To specifically describe comparison anti- Ro52/anti-Ro60. Methods This is cross-sectional study including newly diagnosed (ACR/EULAR 2016 criteria) enrolled prospectively from 2018 to 2022. Patients were stratified five groups according profile (i.e seronegative, isolated anti-Ro52, anti-Ro60, positive). Demographic, biological data compared among groups. Ultrasonographic major minor salivary glands also analyzed. Data presented as mean±SD or percentage frequency, appropriate. Intergroup comparisons made using t-test/Mann–Whitney test continuous variables Fisher’s exact categorical variables. Results We included 199 (M:F= 19:180, mean age 56±13.7 years). 33/199 (16.58%) 50/199 (25.12%) 49/199 (24.62%) had positivity, 55/199 (27.64%) 12/199 (6.03%) Ro60 antibodies. Triple positives younger than seronegatives. No further differences demographic detected found have complex infiltrate gland biopsies higher Focus Score (2.34±2.05 vs 1.32±0.84, p=0.005) number ectopic lymphoid structures (2.40±2.88 1.21±1.25, p=0.004). Regarding ultrasound (SGUS), score ≥2, OMERACT system, frequently other (p = 0.001, Figure 1). Particularly, SGUS abnormalities (68.9 43.6%, p=0.03). same findings observed Ultra-high frequency ultrasonography (UHFUS) (Figure Indeed, highest UHFUS scores (p= 0.01). Furthermore, ESSDAI 0.001) due disease activity glandular domains. Conclusion Triple-positive characterized by severe involvement documented histology activity. These results support amount suggesting that separate detection anti-Ro60 anti-La/ SSB may significantly contribute stratification diagnosis, thus paving new avenues tailored approaches pSS. REFERENCES: NIL. Acknowledgements: Disclosure Interests None Declared.