The Association of Sjögren Syndrome and Autoimmune Thyroid Disorders.

Sjögren's syndrome (SS) and autoimmune thyroid diseases (AITD) may frequently coexist in clinical practice, resulting in a complex overlapping disorder that represents a particular example of the expression of heterogeneity in patients with autoimmune disorders. Objective of this review was to describe the prevalence of the SS-AITD association in the most recent literature, exploring in particular to what extent the presence of AITD might influence the clinical expression of SS and vice versa . Moreover, we summarized some of the proposed genetic, biologic, and molecular mechanisms implied in the pathogenesis of AITD-SS association. Finally, we explored risk factors for lymphoma development in both AITD and SS. We performed a Medline search of English language articles published in the PubMed database in order to provide a critical overview of the recent literature on pathogenesis and clinical features of AITD-SS overlapping disease. All the articles were critically analyzed to select the most relevant contributions.