Characterization of the epitopes of monoclonal autoantibodies derived from lupus mice previously led to the identification of several apoptosis-associated histone modifications, including histone H4 acetylation at lysines 8, 12 and 16 [8], H2B acetylation at lysine 12 [9], and H3 trimethylation at lysine 27 [10]. The gene discussed is H2BC21; the disease is systemic lupus erythematosus.