Distinct Clinical Characteristics of Anti-Ro/SSA Negative Primary Sjögren’s Syndrome: Data from a Cohort for Sjögren’s Syndrome in Korea

초록

Background/Purpose: To investigate clinical characteristics of patients with primary Sjögren’s syndrome (SS) who were negative for anti-Ro/SSA antibody but positive for minor salivary gland biopsy (MSGB) compared to patients who presented positivity for anti-Ro/SSA antibody. Methods: Data of 355 patients from the Korean Initiative of primary Sjögren’s Syndrome (KISS), a nationwide prospective cohort for primary SS in Korea, were analyzed. All patients fulfilled 2016 American College of Rheumatology/European League Against Rheumatism (EULAR) classification criteria. Of these patients, 326 were positive for anti-Ro/SSA antibody and 29 were antibody-negative, although they had positive findings in MSGB. Various clinical features including all kinds of tests for evaluating secretory function, disease-related clinical indices and serological values available in the cohort were compared between the two groups. Results: The anti-Ro/SSA negative group showed less rheumatoid factor positivity (p < 0.001), leucopenia (p = 0.003), hypergammaglobulinemia (p < 0.001), lower serum β2-microglobulin level (p = 0.034), more anti-centromere antibody positivity (p < 0.001), higher score in dryness domain of EULAR SS patient reported index (p = 0.048) and more positivity for peripheral nervous system domain in EULAR SS disease activity index and loss of teeth in SS disease damage index (p = 0.021 and 0.041, respectively) than patients who were positive for anti-Ro/SSA antibody. Conclusion: Primary SS patients who are negative for anti-Ro/SSA antibody have different clinical characteristics compared to patients who are positive for such antibody in Korea. Therefore, clinicians should consider MSGB in patients with suspicious symptoms who are anti-Ro/SSA negative.