Salivary anti-SSA/Ro and -SSB/La are early detection biomarkers for Sjögren’s syndrome

Objectives: The diagnostic work-up for Sjögren’s syndrome is complex and invasive including testing for serum autoantibodies to SSA/Ro and SSB/La and a labial salivary gland biopsy. Furthermore, the diagnosis is often delayed. In this study, we tested the hypothesis that anti-SSA/Ro autoantibodies are detectable in whole saliva of patients with primary Sjögren’s syndrome (pSS) as the disease affects the salivary glands, and display greater discriminatory performance than in serum.
Methods: Whole saliva samples from 34 patients with pSS and 35 patients with sicca symptoms, but not fulfilling the classification criteria for pSS (non-pSS/sicca) and 41 age- and gender-matched healthy control subjects were on analyzed by means of a recent developed electrochemical platform (electric field-induced release and measurement, EFIRM) to detect anti-SSA/Ro in saliva.
Results: In the pSS group, 84.8% and 63.6% were serum anti-SSA/Ro and -SSB/La positive, but none in the non-pSS/sicca group. Salivary anti-SSA/Ro autoantibodies were detected by EFIRM assays in all patients with positive serum autoantibodies, and in 14% of the non-pSS patients, but in none of the healthy control subjects. The discriminatory values of salivary anti-SSA/Ro to differentiate pSS and non-pSS/sicca patients from healthy controls were ROC/AUC of 0.96 and 0.86, respectively. Salivary anti-SSA/Ro could discriminate patients with pSS and non-pSS patients from healthy controls with ROC/AUC of 0.91.
Conclusions: Salivary EFIRM measurements of anti-SSA/Ro and anti-SSB/La presented two advancements in the early detection of pSS. Salivary antibodies to SSA/Ro and anti-SSB/La are robust discriminatory biomarkers for detection of Sjögren’s syndrome, addressing the unmet clinical needs of early detection of the disease. The robust detection of salivary anti-SSA/Ro in seronegative patients with sicca addresses the unmet clinical need to detect the precursor state of Sjögren’s syndrome.