Background Anti-SSA/SSB positive Sjögren's syndrome is characterized by a higher risk for developing lymphoma (1), but no data already exist on systemic disease activity in subgroups of SS, as measured by validated scores for primary SS, such as the ESSDAI or ClinESSDAI.
Objectives Primary objective of the study was to demonstrate the differences between anti-SSA/SSB positive and anti-SSA/SSB negative SS patients as regards systemic disease activity.
Methods 955 patients affected by primary SS were included. All patients fulfilled the American-European Consensus Group Criteria for primary SS. Patients showing isolated anti-SSB positivity were excluded from these analyses. Patients were 911 female (95,4%), with a mean age of 52±14 years. ESSDAI and ClinESSDAI scores were measured (2, 3). Mann-Whitney U test was used to compare the ESSDAI and ClinESSDAI scores between anti-SSA/SSB positive and negative patients.
Results Patients with anti-SSA with or without anti-SSB antibodies were 684 (71.6%), while anti-SSA and anti-SSB antibody negative patients were 271 (28.4%). Median (range) ESSDAI and median (range) ClinESSDAI were 5 (0–54) and 6 (0–53) in anti-SSA/SSB positive patients, and 4 (0–63) and 4 (0–60) in anti-SSA/SSB negative patients, respectively. Both the ESSDAI and the ClinESSDAI scores were significantly higher in anti-SSA/SSB positive patients (p<0.001 and p=0.021, respectively). Importantly, these differences were determined by a significant difference in the frequency of some domains, i.e., “lymphadenopathy” (p=0.034, Chi-square test), “glandular” (p=0.0004, Chi-square test), “cutaneous” (p=0.017, Chi-square test), “hematological” (p<0.0001, Chi-square test) and “biological” (p<0.0001, Chi-square test) (table 1). Notably, anti-SSA/SSB positive patients were younger than anti-SSA/SSB negative patients (50±14 vs. 57±11 years, p<0.0001 by t-test). Rheumatoid factor positivity (p<0.0001, Chi-square test), low C3 (p<0.0001, Chi-square test), low C4 (p=0.045, Chi-square test) and the presence of serum cryoglobulins (p=0.022, Chi-square test) were also significantly linked to the presence of anti-SSA/SSB positivity.
Conclusions Clinical and biological signs of B-cell lymphoproliferation more specifically characterized anti-SSA/SSB positive patients, glandular, hematological and biological domains showing the most significant differences. This feature appears to clearly differentiate Sjögren's disease from Sjögren's syndrome.
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Disclosure of Interest None declared