Diagnostic Utility of Minor Salivary Gland Biopsy for Primary Sjögren Syndrome in Patients With Negative Anti-SSA Antibodies

Background: Sjögren syndrome is a systemic autoimmune disease characterized by lacrimal and salivary gland inflammation resulting in dry eyes and mouth. Although it is a common disease, diagnosis can be challenging due to its heterogeneous presentation. A positive minor salivary gland biopsy is mandatory to fulfill the 2016 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria for primary Sjögren syndrome in patients who are seronegative for anti-SSA/Ro antibodies. The objective of our study was to evaluate the validity of minor salivary gland biopsy for patients who are SSA antibody-negative yet are suspected of having primary Sjögren syndrome because of compelling symptoms. Methods: We conducted a retrospective chart review of adult patients with a negative anti-SSA antibody test who underwent minor salivary gland biopsy to assess suspected Sjögren syndrome at Henry Ford Rheumatology Clinics between January 2005 and December 2019. Patient characteristics and clinical features are described. Sensitivity, specificity, positive predictive value, and negative predictive value are assessed. Results: A total of 47 patients were included: 46 (97.9%) females and one (2.1%) male. The mean age was 57.2 ± 13.8 years. There were 14 (29.8%) patients who had a positive minor salivary gland biopsy result and 15 (31.9%) patients who had a final diagnosis of Sjögren syndrome. Minor salivary gland biopsy had 93.3% sensitivity (95% confidence interval (CI): 68%-99.8%), 100% specificity (95% CI: 89.1%-100%), 100% positive predictive value (95% CI: 76.8%-100%), and 97% negative predictive value (95% CI: 84.2%-99.9%). Conclusion: The diagnostic value of minor salivary gland biopsy is high for patients who do not have anti-SSA antibodies yet are suspected of having Sjögren syndrome. The results of the study support the consideration of routine minor salivary gland biopsy for identifying Sjögren syndrome in these patients.