Antibodies from patients with rheumatoid arthritis and juvenile chronic arthritis analyzed with core histone synthetic peptides.

Antihistone antibodies were detected in the sera of a randomly selected group of patients with rheumatoid arthritis (RA) and juvenile chronic arthritis (JCA) by an enzyme-linked immunosorbent assay (ELISA) with the five individual histones and by immunoblotting. In ELISA, the overall frequency of antihistone antibodies in RA and JCA was 51 and 44%, respectively. Antibodies present in these serum samples were further studied by ELISA by means of 17 core histone synthetic peptides. The fragment 1-21 of H3 was recognized by 60% of RA sera and by 62% of JCA sera. In addition, at least four terminal or internal peptides of H3 and H4 were recognized by more than a third of JCA sera, while only two of these peptides reacted with 20% of RA sera. Many of the sera that did not show any reactivity with the whole histone reacted with various histone peptides. This finding demonstrates the usefulness of synthetic peptides for identifying autoantibodies.