Etiology and pathogenesis of Sjogren's syndrome: an overview

Sjogren's syndrome (SS) is a systemic autoimmune disease characterised by lymphocytic infiltrates in exocrine glands, particularly in salivary and lachrymal glands, and in about 20% of patients also in some internal organs, like kidney and lung. The pathogenesis of SS is poorly understood. Genetic and environmental factors appear to have a key role in favouring the disease development. in particular some viral infections have been demonstrated to be able to trigger the disease process. The majority of the infiltrating cells in target organs are CD4 + CD27 + memory cells. Furthermore, a number of B cells are present in the infiltrates and several features of SS are attributed to their presence. The presence of autoantibodies, such as anti-SSA and -SSB is related to the presence of reactive B cell against ubiquitous nuclear antigens, probably released during the apoptotic process of glandular epithelial cells. The presence of specific anti-muscarinic (M3) receptor antibodies may have some importance in reducing the glandular secretion, behind the epithelial damage caused by the chronic inflammatory infiltrates. The continuous T cell-related stimulation and activation of B cells may induce neoplastic transformation and development of lymphomas.