Clinical features of anti-RNP-positive primary Sjögren's syndrome.

Objective: This study sought to explore the clinical features exhibited by individuals with anti-RNP antibodies who had primary Sjögren's syndrome (pSS).

Methods: Various clinical data of 410 pSS patients from our hospital between September 2018 and August 2023 were retrospectively analysed. Each individual fulfilled the 2016 American College of Rheumatology/European League Against Rheumatism (EULAR) classification criteria for pSS. Comparative analyses were conducted between pSS individuals with and without anti-RNP antibodies. Logistic regression analysis was utilized to ascertain relevant factors.

Results: Among the cohort, 38 (9.3%) of pSS patients were anti-RNP positive and 372 were anti-RNP negative. Anti-RNP-positive individuals had a higher median EULAR Sjögren's syndrome disease activity index at diagnosis (p = 0.001) and more frequent extraglandular manifestations (p < 0.001), including articular, pulmonary and muscular involvement (p = 0.001, p < 0.001 and p = 0.024, respectively) and Raynaud's phenomenon (p < 0.001). Additionally, patients possessing anti-RNP antibodies had a higher frequency of hypergammaglobulinemia and positive antinuclear and anti-Ro/SSA antibodies (p < 0.001, p = 0.006 and p = 0.042, respectively), but a lower frequency of anti-centromere positivity (p = 0.010). Multivariate analysis identified anti-RNP positivity as independent variable significantly associated with interstitial lung disease (OR = 2.60, 95% CI 1.22-5.53; p = 0.014) and Raynaud's phenomenon (OR = 6.26, 95% CI 3.01-13.01; p < 0.001) in pSS patients.

Conclusion: The presence of anti-RNP antibodies may defined a specific subset of pSS patients characterized by distinct phenotypic attributes, especially in terms of higher prevalence of interstitial lung disease and Raynaud's phenomenon. Key Points • Anti-RNP antibodies were detected in 9.3% of patients with primary Sjögren's syndrome (pSS), which was related to increased systemic disease activity and more frequent extraglandular manifestations. • pSS patients carrying anti-RNP antibodies displayed higher prevalence of interstitial lung disease, Raynaud's phenomenon and hypergammaglobulinemia. • Anti-RNP positivity was identified as independent predictors of interstitial lung disease and Raynaud's phenomenon in pSS.