Serum alpha 1-antichymotrypsin level as a marker for Alzheimer-type dementia.
Excessive alpha 1-antichymotrypsin (ACT) in brain has been postulated to play a role in the pathogenesis of Alzheimer's disease (AD). We measured serum ACT by radial immunodiffusion in 57 patients with presumed AD, 110 healthy controls (24 children; 86 adults), 67 non-AD patients from a geriatric private practice and a VA nursing home, and 136 asthmatics (56 adults; 80 children) as an inflammatory disease control group. Serum ACT was significantly higher in AD (73.1 +/- 22 mg/dl) than in healthy controls (47.9 +/- 8.1 mg/dl) or non-AD patients (61.8 +/- 23.9 mg/dl). A level of 60 mg/dl best separated AD patients from controls or non-AD patients. Serial measurements served to distinguish elevations of ACT level in AD from non-AD inflammatory conditions; the ACT level in the latter returned to normal with therapy or time, but the levels in AD remained elevated. A measure of serum ACT by radial immunodiffusion can be used to support a diagnosis of AD disease but not necessarily as a screening test due to the potentially large number of false positives (26% in the population studied) should malignancy or inflammatory disease be concurrent.
Lieberman
J
J
Department of Medicine, Veterans Affairs/UCLA Medical Center, Sepulveda 91343, USA.
Schleissner
L
L
Tachiki
K H
KH
Kling
A S
AS
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000097:blood / Q000175:diagnosis*; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D002648:Child; D002675:Child, Preschool; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D005779:Immunodiffusion; D007223:Infant; D008297:Male; D008875:Middle Aged; D000514:alpha 1-Antichymotrypsin / Q000097:blood*; D000515:alpha 1-Antitrypsin / Q000378:metabolism
D015415:Biomarkers; D000514:alpha 1-Antichymotrypsin; D000515:alpha 1-Antitrypsin