Highly cationic anti-DNA antibodies in patients with lupus nephritis analyzed by two-dimensional electrophoresis and immunoblotting

The relationship between chemical properties of anti-DNA antibodies (Abs) and lupus nephritis was investigated. The anti-DNA Abs in sera from systemic lupus erythematosus (SLE) patients were separated by two-dimensional electrophoresis (2-DE) and immunoblotting with goat anti-human IgG Abs. Highly cationic anti-DNA Abs were detected in deoxyribonuclease I (DNase I)-treated sera from patients with lupus nephritis (in 8 of 9 cases) but not in the sera from SLE patients without nephritis (in 0 of 9 cases), normal subjects, or patients with other renal diseases (in 0 of 7 cases). The mean titers of anti-dsDNA Abs in patients with lupus nephritis were not significantly different from those in SLE patients without nephritis. The highly cationic anti-DNA Abs in the sera disappeared after incubation with heparin-Sepharose. These results suggest that highly cationic anti-DNA Abs are specific for lupus nephritis and may be involved in development of lupus nephritis via the binding to glycosaminoglycans on the endothelial cell surface.