The heterogeneity of anti-DNA antibodies in systemic lupus erythematosus and other diseases.

The antigenic specificities of antinucleic acid antibodies occurring in systemic lupus erythematosus (SLE), chronic active liver disease, and progressive systemic sclerosis (PSS) have been studied by means of haptenic nucleosides and nucleotides coupled to human serum albumin. SLE sera were also tested with dinucleotides. SLE and chronic active liver disease sera showed marked heterogeneity, producing precipitin lines with nucleosides or nucleotides, or both. The reaction might occur with a nucleoside and not with the corresponding nucleotide, or vice versa. The SLE sera reacted to dinucleotides with marked specificity, being able to recognize base sequences or to react with a dinucleotide despite the absence of a reaction with the individual bases. All sera from patients with PSS showed precipitins with RNA, uridine and UMP. PSS sera which reacted with a nucleoside also reacted with the corresponding nucleotide. Antibodies to DNA were found in a smaller proportion of PSS sera than in sera from SLE or chronic active liver disease. Their presence was confirmed by reactivity with thymidine and TMP.