Early Detection of Sjögren’s Syndrome; Sensitivity and Specificity of the Sjö® Diagnostic Test

Abstract

Purpose : Sjögren’s syndrome (SS) is a systemic autoimmune disease involving the dysfunction of moisture-producing glands. Conventional serological markers used in SS diagnosis lack detectability early in the disease process and are limited in sensitivity and specificity. The Sjö® diagnostic test incorporates the traditional markers in addition to 3 proprietary biomarkers which may allow for earlier detection, and here we evaluate the sensitivity and specificity of the advanced Sjö panel.

Methods : Antibodies to the traditional markers (SSA [Ro], SSB [La], antinuclear antibody [ANA], and rheumatoid factor [RF]) and the novel biomarkers (salivary protein-1 [SP1], carbonic anhydrase-6 [CA6] and parotid secretory protein [PSP]) in patient sera samples were detected using the Sjö panel. To assess sensitivity, sera samples from 267 confirmed SS patients across 3 clinical studies were analyzed with Sjö. To assess specificity, sera samples from 125 age- and sex-matched controls, as well as 64 pediatric controls, were analyzed with Sjö.

Results : Overall, the cumulative sensitivity of the complete Sjö panel was 91.4% (244/267); sensitivity of SSA/SSB alone was 74.9% (200/267), while sensitivity for the novel biomarkers alone was 49.8% (133/267). The cumulative specificity for the complete Sjö panel was 79.8% (151/189), and the cumulative specificity for the novel biomarkers was 83.5% (158/189).

Conclusions : An early and accurate diagnosis of SS is an important factor in limiting complications of the disease. The Sjö panel incorporates traditional and novel markers and increases the sensitivity in the diagnosis of SS by over 25% without compromising specificity. Patients who may have SS would benefit from screening with the Sjö panel to facilitate early diagnosis and contribute to better management of dry eye symptoms and other systemic manifestations.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

 

*All patients had a positive test for the traditional serological markers (Ro/La/ANA/RF antibodies) plus dry eye and dry mouth symptoms, and had either a labial salivary gland focus score <1 (mild) or a labial salivary gland focus score >3 (moderate).