2029: Distinctive Clinical Profiles Associated with anti-SSA/Ro60, anti-Ro52/TRIM21 and Anti-SSB/La Reactivity

Liselotte Deroo¹, Helena Achten², Kristel De Boeck², Eva Genbrugge², Wouter Bauters², Dimitri Roels², Frederick Dochy², David Creytens², Filip Van den bosch³, Dirk Elewaut⁴ and isabelle peene⁵, ¹Ghent University, Gent, Belgium, ²Ghent University Hospital, Gent, Belgium, ³Department of Internal Medicine and Paediatrics, Ghent University and VIB Centre for Inflammation Research, Ghent, Belgium, ⁴Department of Rheumatology, Ghent University Hospital, Belgium, VIB-UGent Center for Inflammation Research, Ghent University, Heusden, Belgium, ⁵Ghent University Hospital, Ghent, Belgium

Background/Purpose: Presence of anti-SSA/Ro antibodies is one of the 2016 ACR-EULAR classification criteria for primary Sjögren's Syndrome (pSS). Anti-SSA/Ro antibodies comprise reactivity against Ro52 and/or Ro60. Although that detection of anti-SSB/La antibodies is no classification criterium anymore, they are present in 23-52% of pSS patients, most frequently together with anti-SSA/Ro antibodies. The value of separate anti-Ro52, anti-Ro60 and anti-SSB/La detection in relation to pSS diagnosis and phenotypical features has not been extensively studied. This study aimed to explore disease characteristics of anti-SSA/Ro positive, suspected and definite pSS patients, in relation to serological profiles based on anti-Ro52, anti-Ro60 and anti-SSB/La reactivity.

Methods: Data of 187 anti-SSA/Ro positive patients included in the Belgian Sjögren's Syndrome Transition Trial (BeSSTT) were analyzed. Of those, 151 were considered definite pSS patients, due to fulfilment of the 2016 ACR-EULAR classification criteria, and 36 suspected, due to reactivity against SSA/Ro without presence of other criteria. None of the patients met any of the ACR-EULAR exclusion criteria for pSS. Patient groups were based on the presence of anti-Ro52, anti-Ro60 and anti-SSB/La antibodies.

Results: Reactivity against isolated Ro60, isolated Ro52, Ro52/Ro60 (double) and Ro52/Ro60 in combination with SSB (triple) was detected in respectively 30, 23, 70 and 60 patients. Mono-anti-Ro60 positive patients showed least pSS features. Mono-anti-Ro52 positive patients reported a significantly higher dryness burden (p=0.016) and tended toward more salivary gland ultrasound (SGUS) abnormalities (p=0.054) than mono-anti-Ro60 positives. Double positive patients showed similar characteristics as mono-anti-Ro52 positive patients, whereas triple positive patients showed more extreme phenotypes with lowest unstimulated salivary flow rates (p=0.002) and Schirmer tests (p=0.002), highest ocular staining scores (p< 0.001), most positive labial salivary gland biopsies (p=0.039), most laboratory abnormalities compatible with B-cell hyperactivity and highest SGUS scores (p< 0.001).

Conclusion: These data indicate that separate detection of anti-Ro52, anti-Ro60 and anti-SSB/La reactivity is not only relevant towards pSS diagnosis, but markedly aids in patient stratification and evaluation of disease burden. In this context, our results point to a stepwise model in which mono-reactivity against Ro60 displayed the least pSS features, whereas these were most present in patients showing triple reactivity against Ro60, Ro52 and SSB/La.
Table 1 Clinical and laboratory parameters amongst serology-based patient groups. Continuous data presented as mean±SD and categorical data as number of patients (%) unless otherwise indicated. P-values refer to comparison of endotypes amongst definite and suspected pSS subgroups, based on Kruskal-Wallis or Chi-squared tests. Abbreviations: ESSPRI=EULAR Sjögren's syndrome patient reported index; USFR=unstimulated salivary flow rate; OSS=ocular staining score; FS=focus score; ESSDAI=EULAR Sjögren's syndrome disease activity index.

Figure 1 Radar chart illustration pSS key features amongst serological profiles
Radar chart illustrates prevalence in percentage of key phenotypical features related to pSS amongst patient groups defined by presence of anti-Ro60, anti-Ro52 and anti-SSB/La antibodies. Abbreviations: OSS=ocular staining score; USFR=unstimulated salivary flow rate; FS=focus score.
Disclosures: L. Deroo, None; H. Achten, None; K. De Boeck, None; E. Genbrugge, None; W. Bauters, None; D. Roels, None; F. Dochy, None; D. Creytens, None; F. Van den bosch, AbbVie, Lilly, Galapagos, Janssen, Merck, Novartis, Pfizer, UCB, Amgen, Bristol-Myers Squibb(BMS), Celgene; D. Elewaut, AbbVie, Eli Lilly, Galapagos, Novartis, UCB Pharma; i. peene, None.