POS0817 THE ROLE OF IGG N-LINKED SIALYLATION AND GALACTOSYLATION IN PRIMARY SJÖGREN’S SYNDROME IN ITS POTENTIAL AS A MARKER OF DISEASE STATE AND DISEASE ACTIVITY

Background Primary Sjögren’s Syndrome (pSS) is characterized by the presence of antibodies (Ab). Their effector function mainly depends upon glycan structures attached to their Fc-fragment. Our study first address value IgG glycosylation profiles in relation disease state, salivary gland ultrasound (SGUS) and auto-Ab patients with probable (prob pSS) definite pSS (def pSS). Objectives To investigate N-glycosylation from Belgian Transitial Trial (BeSSTT) activity, SGUS Ab SSA/Ro52, SSA/Ro60 SSB. Methods The relative amount sialylated (sial) galactosylated (gal) was determined capillary electrophoresis after endo-S glycosidase assay. 314 sera BeSSTT, an observational cohort def pSS, fulfilling 2016 ACR/EULAR classification criteria, suspected due either objective sicca or one immunological criterion, were used. Groups made based on absence complaints, sicca, anti-SSA histopathology focus score. Hocevar categorized negative (0-14), low positive (15-26) high (27-48)[1]. Disease activity using Eular index (ESSDAI) (0-4), moderate (5-13) (14-123). Differences sial gal levels One-way ANOVA Kruskal-Wallis testing. P-values ≤0.05 considered statistically significant. Bonferroni correction applied. Results state addressed well-defined groups: only anti-SSA/SSB reactivity pSS. Def had a significantly lower median percentage compared Ab. No significant difference seen between latter three groups (Figure 1). Patients ESSDAI versus those ESSDAI. In SGUS-score, noted score Mono-anti-Ro52 reactivity, double-anti-Ro52Ro60 triple-anti-Ro52Ro60 SSB negative. Strikingly, anti-Ro5260+ anti-Ro52Ro60 SSB+ mono anti-Ro60 Conclusion These results indicate that involvement serology profile strongly associated different This highlights potential role for as diagnostic marker biomarker its pathophysiology. Reference [1]Mossel E, et al. J Rheumatol. 2021 May;48(5):717-727 Figure 1. Table N Relative area (α=0.05) Sial Gal Mdn Sicca complaint 24 0.080 0.60 <0.001 58 0.067 0.56 Prob 37 0.075 0.59 183 0.057 0.47 M 0-14 160 0.064 0.538 15-26 72 0.532 27-48 82 0.050 0.434 0-4 264 0.062 0.52 <0.01 5-13 31 0.055 0.48 14-123 5 0.022 0.35 SEROLOGY 104 0.070 Mono anti-Ro52 28 35 0.073 Double 79 0.056 Triple 62 0.045 0.45 Acknowledgements: NIL. Disclosure Interests None Declared.