Antihistone antibodies in systemic lupus erythematosus.

Antihistone antibodies are prevalent in systemic lupus erythematosus (SLE) and are the predominant autoantibody in patients treated with various drugs. Total histones consist of 5 classes and various histone-histone and DNA-histone complexes. Antibody binding to these various potential antigens has been measured by solid phase and Western blot immunoassays. Relatively unique profiles tend to characterize disease groups, but SLE sera were heterogeneous, displaying reactivity with only 1 to all 5 histones. Antihistone antibodies from human sera as well as murine monoclonal antibodies showed the capacity to react with more than 1 histone class. However, the fine specificities of antihistone antibodies were often assay dependent. Explanations for these discrepancies include degraded and impure histone preparations, irreversible denaturation and the role of soluble histones in biological fluids.