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.