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

AbstractThe 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.