Salivary gland ultrasonography in patients with connective tissue diseases: a multi-centre observational study.

OBJECTIVE: US of salivary glands (SGUS) is a non-invasive tool that allows for diagnosing primary SS (pSS) or secondary SS (sSS). However, little is known about the prevalence of US findings of SS in other CTDs. The aim of this multi-centre observational study was to evaluate, in CTD patients with or without SS, the prevalence of abnormal SGUS findings and the possible association of the findings with clinical or biological phenotypes.

METHODS: B-Mode SGUS was performed by one operator blinded to clinical data. Each SG was semi-quantitatively rated on a scale from 0 to 4 according to the Jousse-Joulin score; a score ≥2 was considered pathological.

RESULTS: Data for 194 patients were analysed (pSS, n = 30; sSS, n = 39; other CTDs, n = 77; controls, n = 48). SGUS findings were abnormal in 80%, 67%, 25% and 2% of patients, respectively. Independent of the underlying disease, age and sex, abnormal SGUS findings were significantly associated with presence of anti-SSA antibodies (P < 0.001), pSS (P < 0.001) and sSS (P < 0.01). Among SS patients, abnormal SGUS findings were associated with the presence of hypergammaglobulinemia, anti-SSA antibodies, objective eye dryness and increased anti-nuclear antibody level, with no difference in EULAR SS Disease Activity Index.

CONCLUSION: Abnormal SGUS findings were associated with anti-SSA antibody positivity independent of the underlying disease. In SS patients, abnormal findings were associated with immunologic features and mouth involvement. Among CTD patients, SGUS changes may be associated with a particular immune profile.