The heterogeneity of serologic findings and predisposing host factors in drug‐induced lupus erythematosus

Systemic lupus erythematosus (SLE) is a multifaceted disease in which the etiologic agent is unknown. Various factors associated with its pathogenesis include antinuclear antibodies (ANA) especially antinative DNA (a-nDNA) complement activation, an abnormal immunologic balance with decreased T lymphocyte supressor activity and increased antibody production, and host factors such as gender and histocompatibility antigens. Because drug-induced lupus erythematosus (DLE) is triggered by a known agent, analysis of this type of lupus may lead to a better understanding of the development of SLE. Recent studies from this unit suggest that pathogenetic mechanisms in drug-induced lupus may also differ depending on the causative drug. By analogy, the diversity of clinical, laboratory, and immunologic findings in systemic lupus erythematosus may indicate that different etiologic factors are operative.