Profiles of antibodies to histones, DNA and IgG in patients with systemic rheumatic diseases determined by ELISA.

The occurrence of antibodies against the total histone complex and the histone fraction H1, antibodies against denatured (ss) DNA and the synthetic double stranded polynucleotide poly dAT, as well as rheumatoid factors (RF) was determined in patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS) using enzyme linked immunosorbent assays (ELISA). Antihistone antibodies could be demonstrated at a frequency of about 17% in the patients with systemic rheumatic disease with no differences between the groups, even if there was a tendency for anti-H1 antibodies to occur more often in the SLE and SS patients than in the RA patients. Some of the antihistone antibody activity seen in the RA patients seems to be due to crossreactive RF. All patient groups showed significant IgG anti-ssDNA antibody activity compared to the controls, but the highest antibody levels were seen in the SLE patients. IgG antipoly dAT antibodies occurred significantly more often and at higher levels in the SLE patients than in the other patient groups. Although the individual tests did not readily distinguish the 3 diseases from each other, the antibody profiles were different. Patients with SS had the broadest reactivity, and the SLE patients had antibodies predominantly restricted to polynucleotides.