Meningoencephalitis associated with passive immunization of a transgenic murine model of Alzheimer’s amyloidosis

Immunization against the Aβ peptide reverses the pathologic and behavioral manifestations of Alzheimer’s disease in murine models. Since active immunization is associated with an autoimmune meningoencephalitis in a subset of humans, passive transfer of anti-Aβ immunoglobulin is being pursued as a potentially safer alternative. We have identified cases of meningoencephalitis subsequent to peripheral and intracerebral passive immunization of Tg2576 mice. The vasocentric mononuclear infiltrate localized only to brain regions affected by Aβ amyloid deposits suggesting that the inflammatory reaction was Aβ specific. This report indicates that current passive immunization in humans should proceed with careful regard for autoimmune complications.