Chapter 31 - Sjögren Syndrome

Abstract

Sjögren syndrome (SS) is an autoimmune disorder characterized by exocrine gland dysfunction and destruction, mainly the salivary and lachrymal glands, leading to dryness of mouth and eyes. Sjögren syndrome has been long regarded as an autoimmune disease, due to the presence of lymphoid infiltrates in the exocrine glands, the plethora of serum autoantibodies, the various hyperimmune clinical complications, as well as its frequent association with other autoimmune disorders. Exocrinopathy is associated with dense lymphocytic infiltrates of glandular tissues and B-cell hyper-reactivity. Sjögren syndrome appears unique for two reasons. First, it has a broad clinical presentation, extending from local exocrinopathy to involvement of multiple organs. It may be found alone, primary SS or in association with other autoimmune diseases, secondary SS. Although clinical, serologic, and genetic features may distinguish primary from secondary SS, it remains unclear whether these entities are etiologically and pathogenically different. Second, it is a model disorder where a benign process can evolve into a lymphoid malignancy. Thus, the study of SS may provide insights into the pathogenesis of autoimmune disorders and lymphoid malignancy.