Association of elevated alpha 1-antichymotrypsin with cognitive impairment in a prospective study of the very old

The authors investigated the relationships between concentrations of two acute-phase proteins, alpha 1-antichymotrypsin (ACT) and alpha 2-macroglobulin (MAC), and cognitive impairment in the very old. 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. Concentrations of ACT were associated with greater cognitive impairment, as reflected by lower Mini-Mental State scores. This relationship did not exist for MAC. 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.