The definition and characterization of the reactivity of ANA in patients with SS are greatly improved with the current advances in cellular and molecular biology. Based on the characteristic autoantibody profiles in different systemic rheumatic diseases and the nature of the defined autoantigens, it has been proposed that the polyclonal autoimmune response is induced and maintained through an antigen-driven mechanism. The autoantigens are presented in the cell as components of large particles or structures composed of protein-protein or RNA-protein complexes; however, the role of these autoantibodies in the etiology and immunopathogenesis of SS remains to be determined.