Seronegative patients with primary Sjögren's syndrome and non-pSS sicca test positive for anti-SSA/Ro52 and -Ro60 in saliva

Sarah Kamounah; Fang Wei; Jin Kyun Park; Yeong-Wook Song; David Chia; David T W Wong; Anne Marie Lynge Pedersen

doi:10.1016/j.bbadis.2024.167168

Seronegative patients with primary Sjögren's syndrome and non-pSS sicca test positive for anti-SSA/Ro52 and -Ro60 in saliva

Biochim Biophys Acta Mol Basis Dis. 2024 Apr 17;1870(5):167168. doi: 10.1016/j.bbadis.2024.167168. Online ahead of print.

Authors

Sarah Kamounah¹, Fang Wei², Jin Kyun Park³, Yeong-Wook Song³, David Chia⁴, David T W Wong², Anne Marie Lynge Pedersen⁵

Affiliations

¹ Center of Oral/Head & Neck Oncology Research, UCLA School of Dentistry, Los Angeles, CA, USA; Department of Odontology, Section of Oral Biology and Immunopathology/Oral Medicine & Pathology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark. Electronic address: saka@sund.ku.dk.
² Center of Oral/Head & Neck Oncology Research, UCLA School of Dentistry, Los Angeles, CA, USA.
³ Division of Rheumatology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea.
⁴ Department of Pathology & Laboratory Medicine, David Geffen UCLA School of Medicine, Los Angeles, CA, USA.
⁵ Department of Odontology, Section of Oral Biology and Immunopathology/Oral Medicine & Pathology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark. Electronic address: amlp@sund.ku.dk.

PMID: 38641012
DOI: 10.1016/j.bbadis.2024.167168

Abstract

Objectives: Testing for anti-SSA/Ro antibodies in serum is essential in the diagnostic work-up for primary Sjögren's syndrome (pSS). In this study, we aimed to validate our previous assay for detection of salivary anti-SSA/Ro52, and to develop assays for detection of salivary anti-SSA/Ro60 and for detection of anti-Ro52 and -Ro60 in plasma using the electric field-induced release and measurement (EFIRM) platform.

Methods: Whole saliva samples from two independent Danish cohorts (DN1 and DN2) including 49 patients with pSS, 73 patients with sicca symptoms, but not fulfilling the classification criteria for pSS (non-pSS sicca), and 51 healthy controls (HC), as well as plasma samples from the DN1 cohort were analyzed using EFIRM to detect anti-SSA/Ro52 and -Ro60.

Results: In the DN1 cohort, 100 % in the pSS group and 16 % in the non-pSS sicca group were serum anti-SSA/Ro positive by ELISA. EFIRM detected anti-SSA (Ro52 and/or -Ro60) in plasma and saliva in 100 % and 96 % patients with pSS, and 16 % and 29 % with non-pSS sicca. In the DN2 cohort, 80 % patients with pSS and 26 % with non-pSS sicca were serum anti-SSA/Ro positive. Salivary anti-SSA discriminated patients with pSS from HC and non-pSS sicca with an AUC range of 0.74-0.96 in the DN1 and DN2 cohorts. EFIRM discriminated pSS from non-pSS sicca with an AUC of 0.98 in plasma.

Conclusion: Our findings suggest that salivary anti-SSA/Ro antibodies are potential discriminatory biomarkers for pSS, which may also identify seronegative patients, addressing the unmet clinical need of early detection and stratification of pSS.

Keywords: Autoantibody; Biomarker; SSA/Ro; Saliva; Sjögren's syndrome.