Association of elevated α₁-antichymotrypsin with cognitive impairment in a prospective study of the very old

Objective: The authors investigated the relationships between concentrations of two acute-phase proteins, α₁-antichymotrypsin (ACT) and α₂-macroglobulin (MAC), and cognitive impairment in the very old. Method: Concentrations of ACT and MAC were determined in a prospective study using sera from medically stable elderly nursing home residents. Cognitive impairment was assessed with the Mini-Mental State. Results: Concentrations of ACT were associated with greater cognitive impairment, as reflected by lower Mini-Mental State scores. This relationship did not exist for MAC. Conclusions: These data extend previous reports that patients with Alzheimer's disease have greater concentrations of ACT in their blood by demonstrating in a diagnostically diverse nursing home population a relationship between serum ACT and mental status. Elevated serum ACT in patients with compromised mental status may reflect a cerebral acute-phase response.