The participation of immune mechanisms in the pathogenesis of dementia of Alzheimer type （AD） has been suggested. We examined T cell responses to myelin basic protein （MBP） and myelin proteolipid protein （PLP） using an enzyme linked immunospot （ELISPOT） assay by enumerating mononuclear cells （MNC） that in blood and cerebrospinal fluid （CSF） secreted the cytokine interferon γ （IFN γ） spontaneously and after short time culture of the cells in presence of MBP or PLP. These myelin components are supposed to induce autoaggressive immunity in multiple sclerosis. MBP and PLP reactive IFN γ secreting cells were detected in patients with AD and

for comparison

in patients with other non inflammatory neurological diseases（OND） and patients with tension type headache （TH）. Elevated levels of MBP and PLP reactive IFN γ secreting cells were found in blood in AD patients compared to OND and TH

such cells in AD patients were further enriched in CSF. Levels of MBP reactive as well as spontaneously IFN γ secreting cells in CSF were about 180 fold and 250 fold higher than in blood of AD patients

and also higher than the corresponding data in OND（30 fold and 20 fold） and in TH （120 fold and 20 fold）. It is unclear whether the autoreactive T cell responses to MBP and PLP

especially accumulated in CSF

have any importance for the pathogenesis of AD.