The value of separate detection of anti-Ro52, anti-Ro60 and anti-SSB/La reactivities in relation to diagnosis and phenotypes in primary Sjögren's syndrome
Liselotte Deroo, Helena Achten, Kristel De Boeck, Eva Genbrugge, Wouter Bauters, Dimitri Roels, Frederick Dochy, David Creytens, Joke Deprez, Filip Van den Bosch, Dirk Elewaut, Isabelle Peene
Abstract
OBJECTIVES: Autoantibody detection is an essential step in pSS diagnosis. However, the value of separate anti-Ro52, anti-Ro60 and anti-SSB/La detection in pSS diagnosis and phenotyping 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: Of 187 anti-SSA/Ro positive patients included in the Belgian Sjögren's Syndrome Transition Trial (BeSSTT), 155 were considered definite pSS patients, due to fulfilment of the 2016 ACR-EULAR classification criteria, and 32 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. Patients were grouped based on the presence of anti-Ro52, anti-Ro60 and anti-SSB/La antibodies. RESULTS: Mono-reactivity against Ro60 or Ro52, double reactivity against Ro52/Ro60 and triple reactivity against Ro52/Ro60 and SSB was detected in respectively 30, 23, 70 and 60 patients. Mono-anti-Ro60 positive patients showed the 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 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) compared to other patient groups. CONCLUSIONS: 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. Our results suggest a stepwise model in which mono-reactivity against Ro60 displayed the least objective and subjective glandular pSS features, whereas glandular abnormalities and signs of B-cell hyperactivity were most present in patients showing triple reactivity against Ro60, Ro52 and SSB/La.