The idiotypic network in antinuclear-antibody-associated diseases

Antinuclear antibodies (ANA) entail a large group of autoantibodies (Abs) that bind certain nuclear antigens. The ANA test is a useful screening test for many autoimmune diseases and the presence of a specific binding pattern directs secondary testing for specific Abs associated with the suspected disease. Idiotypes (Ids) are the antigenic constitution of the variable region of an Ab, and they are recognized by anti-Ids Abs. The Id network is composed of interacting Abs in which the Id determinants of each Ab are complemented by those of another. It has a role in both physiologic and pathologic conditions. In this communication, we review the induction of autoimmune diseases via Id manipulation, the Ids of some ANA-associated Abs (DNA, SS-A, SS- B, Sm Abs), the pathogenic role of Abs carrying Ids, and the clinical implications of the Id network in autoimmunity.