Blood from systemic lupus erythematosus (SLE) patients and healthy individuals (NHS) was analyzed for antibodies to Z-DNA using ELISA with brominated poly(dGdC) as an antigen. Both groups exhibited Z-DNA antibody binding. In SLE patients, antibody levels to Z-DNA correlated with B-DNA antibodies, indicating cross-reactivity confirmed through DNA cellulose adsorption experiments. Ionic strength affected SLE anti-Z-DNA antibody binding, implying electrostatic interactions. These findings suggest that SLE anti-DNA antibody responses might be triggered by bacterial DNA, potentially due to cross-reactivity with Z-DNA found in bacterial DNA and biofilms.
