CD40LG and systemic lupus erythematosus: To determine if SLE patients produced IgG or IgM against a set of synthetic peptides corresponding to the 1–19 N-terminal residues of H3 (i.e., peptides without modifications (H31–19), acetylation on lysine 9 (H31–19K9ac) and mono-, di-, or trimethylation on lysine 4 or lysine 9 (H31–19K4me, H31–19K4me2, H31–19K4me3, H31–19K9me, H31–19K9me2 and H31–19K9me3)), we performed an ELISA using sera from 62 pSLE and 75 aSLE patients.