Antibody Responses to DNA in Normal Immunity and Aberrant Immunity

Among antibodies directed to biological macromolecules, antibodies to DNA (anti-DNA) are unique in their association with the pathological state. These antibodies are the serologic hallmark of systemic lupus erythematosus (SLE) and serve as markers for diagnosis and prognosis. Furthermore, as indicated by the correlation of antibody levels with disease activity, anti-DNA play a major role in the pathogenesis of lupus nephritis. The close association of anti-DNA with SLE has implied that immune responses to DNA are an exclusive feature of autoimmune disease (5). Although assessment of anti-DNA remains clinically valuable, recent data suggest that the current conceptualization of anti-DNA needs revision. These data provide a new perspective on lupus serology and show clearly that production of anti-DNA occurs in hosts with normal immunity as well as those with aberrant immunity. The salient feature of the production of normal anti-DNA, however, is its specificity for bacterial DNA. Furthermore, as shown in studies with both mice and humans, antibody induction is just one facet of bacterial DNA’s far-reaching immunological properties. This review considers current information on antibody responses to DNA, focusing on their role in SLE as well as normal host defense.