α1-acid glycoprotein in late-life depression:: Relationship to medical burden and genetics

Serum alpha1-acid glycoprotein (AAG) concentrations were examined in relationship to age, medical burden, depression, and mental status in elderly control (n = 19, mean age = 72.1 +/- 6.8 years) and depressed (n = 58, mean age = 71.9 +/- 7.1 years) subjects. DNA was analyzed for allelic variants of the AGP1 (ORM1) gene in both groups. Depressed subjects' AAG serum levels were measured at baseline and after 6 weeks of antidepressant treatment. Before treatment, depressed subjects had significantly higher serum AAG concentrations than nondepressed controls (t(49.2) = -3.48, P =.0011). Pretreatment AAG levels also correlated with degree of medical burden, measured by the Cumulative Illness Rating Scale-Geriatrics (r = 0.28, P =.0303), but not with age, depression severity, or cognitive scores. There was no significant difference between responders and nonresponders on changes in AAG levels from baseline to week 6. Frequency differences in ORM1 allelic variants apparently did not influence increased AAG concentrations in depressed patients.