[The significance of measurement of contents of serum serine protease inhibitors in senile dementia of the Alzheimer type].

We have evaluated serum alpha 1-antichymotrypsin content in dementia of the Alzheimer type (DAT). The subjects consisted of 26 patients with DAT, 15 with cerebrovascular dementia, 10 with mixed type dementia, 2 with Down syndrome, 17 with Parkinson disease, 14 with spinocerebellar degeneration, 14 with cerebrovascular disease without dementia, 12 with Duchenne muscular dystrophy and 77 normal controls. DAT group showed statistically significant increase of serum alpha 1-antichymotrypsin content, as compared with normal control group (p less than 0.001), mixed type dementia group (p less than 0.05) and other 6 groups (p less than 0.001). However, the levels of both alpha 1-antitrypsin content and inter-alpha-trypsin inhibitor content, included in serine protease inhibitors, were not significantly different between DAT and normal control groups. These findings indicated that measurement of serum alpha 1-antichymotrypsin is useful as the diagnostic marker of DAT.