Overview of Sjögren's syndrome.

Sjögren's syndrome, a chronic inflammatory and autoimmune disorder (Shoenfeld and Schwartz, 1984; Smith and Steinberg, 1983), is characterized by diminished lacrimal and salivary gland secretion (sicca complex), resulting in keratoconjunctivitis sicca (KCS) and xerostomia. As originally described, the syndrome consisted of a triad of dry eyes, dry mouth, and rheumatoid arthritis. We now know that other connective tissue diseases (e.g., systemic lupus erythematosus, progressive systemic sclerosis, and polymyositis) may be present in place of rheumatoid arthritis, and that the sicca complex can exist as a primary pathologic entity with no associated disorder (Strand and Talal, 1980; Talal, 1985). Moreover, generalized lymphoproliferation, pseudolymphoma, or even lymphoid malignancy may appear in some patients (Talal and Bunim, 1964; Talal et al., 1967). More than 90% of patients are women, with a mean age of 50 years at diagnosis. The disease occurs in all races and all ages.