Cross-reactivity of anti-ssDNA antibodies with heparan sulfate in patients with type I diabetes mellitus

Anti-single-stranded–DNA antibodies cross-reactive with heparan sulfate were detected in serums of patients with type I (insulin-dependent) diabetes mellitus. The results suggested that heparan sulfate, the major glycosaminoglycan constituent of the glomerular basement membrane, may serve as a target antigen in vivo for cross-reactive anti-DNA antibodies. These polyreactive antibodies, directed toward repeating negatively charged units, may neutralize the heparan sulfate–associated polyanionic sites in the glomerulus, leading to an abnormal permeability of anionic plasma proteins.