The pathogenesis of cognitive dysfunction in SLE patients is likely multifactorial, including vascular origin, direct neuronal damage due to autoantibodies or cytokines, metabolic effects, or effects of certain medications. More than one half of SLE patients have anti-DNA antibodies, and it was recently demonstrated that a subset of anti-DNA antibodies cross-reacts with a pentapeptide consensus sequence (residues 283-287) of the human N-methyl-D-aspartate (NMDA) receptor NR2a and NR2b subunits and can cause excitotoxic death of neurons. NMDA receptors are important in memory function and learning, and thus such antibodies may mediate cognitive dysfunction in SLE.