Antibodies to synthetic peptides from Epstein-Barr nuclear antigen-1 in sera of patients with early rheumatoid arthritis and in preillness sera.

We studied IgG antibody levels to synthetic peptides (p62, E11 and E3) from Epstein-Barr nuclear antigen-1 (EBNA-1) protein sequence in sera of patients with rheumatoid arthritis (RA), in pre-RA and in rheumatoid factor (RF) positive non-RA sera from Finland. Anti-E11 and anti-E3 antibody levels were significantly elevated in RA sera, compared with both RF negative and RF positive nonrheumatoid controls. The concentrations of anti-E11 and anti-E3 antibodies in the preillness sera were lower than those in RA sera. Eight-year followup samples of patients with RA had slightly decreased levels of anti-E3 and anti-E11 antibodies compared with samples taken within 6 months of the disease onset. Anti-p62 antibody levels did not differ significantly between any of the groups studied. Thus, elevated levels of antibodies to 2 of the glycine containing EBNA-1 peptides were associated with clinical RA.