Interleukin-1β serum levels is increased in antidepressant-free elderly depressed patients

Objective: To assess the serum levels of interleukin 1β (IL-1β) in elderly depressed patients in comparison with nondepressed healthy elderly subjects. Design: Cross-sectional study. Setting:Tertiary memory clinic. Participants: Twenty-three antidepressant-free elderly depressed patients and 44 nondepressed healthy elderly comparison group were enrolled to this study. MEASUREMENT: Serum IL-1β levels were determined with highly sensitive colorimetric sandwich enzyme-linked immunosorbent assay. Severity of the depressive episode was determined by scores on the Hamilton Depression Scale-21 item and cognitive performance by the scores on the Cambridge Cognition Examination, Mini Mental State Examination clock drawing test, and verbal fluency. Results: IL-1β serum levels were increased in elderly patients versus nondepressed elderly (t = 2.21, df = 65, p = 0.04). After categorizing elderly depressed subjects into late onset (LOD) versus early onset (EOD), patients with EOD had the highest IL-1β levels, when compared with nondepressed elderly patients and patients with LOD in analysis of variance (F = 4.9, df = 2, 64, p <0.01). Conclusions: Late-life depression is associated with higher IL-1β levels suggesting that increased proinflammatory state may play a role in the physiopathology of depression in the elderly. The authors further show that this might be more prominent in those patients with EOD geriatric depression.