We also noticed that some of the SLE sera exhibited obvious reactivity with acetylated H2B peptides (e.g., H2B K20Ac 8th row; H2B K15Ac, K12Ac and K5Ac, 1st, 2nd and 3rd rows) but with little reactivity to whole H2B histone antigen (9th row) or unmodified H2B peptide (6th row). This evidence concerns the gene H2BC21 and systemic lupus erythematosus.