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