[Clinical and pathological features of Sjögren's syndrome associated with autoimmune thyroid diseases]

Sjögren's syndrome (SS) is a chronic inflammatory disease of the exocrine glands accompanied by mononuclear cell infiltration. The histopathological features of the salivary and lacrimal glands of SS resemble those of the thyroid glands of autoimmune thyroiditis (chronic thyroiditis; CT). In addition, both SS and CT frequently recognized in the patients with other organ-specific or systemic autoimmune diseases (collagen-vascular diseases; CVD). We analyzed the incidences of CT among patients with SS or CVD, and compared clinical, immunological and endocrinological profiles between the SS patients with and those without CT. CT was the most frequent organ-specific auto-immune disease recognized in both primary and secondary SS patients. The thyroid disease similarly associated with CVD patients, regardless of the presence of SS. Several studies have also suggested that subclinical diseases are frequent in both CT and SS patients. The clinical and immunohematological features were almost identical between SS patients with and those without CT. Furthermore, the clinical, serological and endocrinological profiles of thyroid disease were very similar between SS patients with CT and CT patients without SS. These results indicate that CT and SS are independent autoimmune diseases, and the thyroid involvement observed in patients with primary or secondary SS is not an extraglandular manifestation of SS.