THU0258 SJOGREN'S SYNDROME WITH AND WITHOUT AND AUTOIMMUNE THYROIDITIS: IS THERE ANY DIFFERENCE?

Abstract

Background: Sjögren's syndrome (SS) is a systemic autoimmune disease mainly affecting exocrine glands and characterized by a progressive lymphocytic infiltration of salivary and lacrimal glands with consequent loss of function and development of sicca symptoms. Autoimmune thyroiditis (AT) is the most frequent autoimmune disease associated with SS and detectable in about 10-30% of cases1. Interestingly, patients with concomitant SS and AT seem to display a more attenuated phenotype compared to patients with solely SS. It is also noteworthy that up to 30% of patients with AT experience sicca symptoms without a clear diagnosis SS2. At the light of these evidences, it is unclear whether SS and AT represent two distinct nosological entities or different expressions of the same pathology. Objectives: Aim of this study is to evaluate the prevalence of AT in a large monocentric cohort of patients with SS and to define its clinical and laboratory characteristics compared to isolated SS. Methods: Consecutive patients with SS (AECG criteria) referring to our “Sjögren Clinic” (Sapienza University of Rome) were enrolled and divided in two groups: SS with AT (group 1) and SS without AT (group 2). Group 1 was further divided in two subgroups depending on the presence (1a) or absence (1b) of anti Ro/SSA antibodies. The following clinical and laboratory data were retrospectively collected for all patients: concomitant celiac disease, arthralgia, lung involvement, purpura, lymphoma, presence of ANA, anti-Ro/SSA, anti-La/ SSB, rheumatoid factor, cryoglobulins, leukopenia and hypergammaglobulinaemia. These characteristics were compared between the following groups: group 1, group 2, group 1a and 1b. For statistic Chi Square and Fisher's test analysis were performed. Results: Six-hundred and three SS patients were enrolled (group 1 n=135; group 2 n=381; group 1a n=96; group 1b n=39). The prevalence of AT was 135/603 (22.3%). When comparing SS patients with or without AT (group 1 vs group 2) the frequency of rheumatoid factor was significantly higher in group 2 compared to group 1 (p=0.006). No case of lymphoma was recorded in group 1 while 14 cases of lymphoma were ascertained in group 2 (p=0,08). Conversely, celiac disease was higher in group 1 compared to group 2 (p=0.01). No other differences between these groups were identified. Stratifying SS patients with AT according to the presence (group 1a) or not (group 1b) of anti Ro/SSA antibodies, ANA, rheumatoid factor and hypergammaglobulinemia were significantly more positive in group 1a compared to group 1b (p=0.0002, p=0.002, p=0.02, respectively); no clinical differences were identified. Conclusion: In this study, we confirm the presence of a less aggressive disease in patients with SS and AT compared to solely SS. The higher prevalence of rheumatoid factor and lymphoma occurrence in SS without AT, strictly suggest a more severe phenotype in this subset. Although is known that in SS patients with anti Ro/SSA+ antibodies and RF there is a more aggressive disease, in SS with AT the presence or absence of such autoantibodies do not seems to associate with any difference in clinical severity. Follow up studies are presently being carried out in order to provide conformation of a less sever phenotype and a better disease outcome in patients with associated SS and AT.