[Sjögren's syndrome (SS), a review of the subject and saliva as a diagnostic method].

Sjögren's syndrome is a chronic autoimmune disease whose main clinical manifestation is oral dryness (xerostomia) and ocular dryness (xerophthalmia). It is characterized by progressive mononuclear infiltration of the exocrine glands and can affect a variety of organ systems. The prevalence of primary Sjögren's syndrome varies from 0.01 up to 4.8%; this variability reflects differences in definition, application of diagnostic criteria, and geographic differences in age groups. The etiology of primary Sjögren's syndrome is unknown, but the interaction between genetic and environmental factors (viruses, hormones, vitamins, stress) is important. There are few reported cases of concordance in monozygotic twins, and it is common for patients with primary Sjögren's syndrome to have relatives with other autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, thyroid disease, psoriasis, and multiple sclerosis. Among the most common findings is hypergammaglobulinemia. Elevated levels of γ-globulins contain autoantibodies directed against nonspecific antigens such as rheumatoid factor, antinuclear antibodies, and cellular antigens SS-A/Ro and SS-B/La. Regarding diagnosis, there have been 11 different published criteria for Sjögren's syndrome since 1965; none have been approved by the American College of Rheumatology or the European League Against Rheumatism. The current criteria were published in 2012 jointly with the progressive advance in the knowledge of the human salivary proteome that has gained wide acceptance in Sjögren's syndrome, with the possibility of using saliva as a useful tool in both diagnosis and prognosis in this field because the analysis of salivary proteins may reflect the state of locally underlying disease of the salivary glands, which are the target organs in this disease.