Intrathecal levels of IL-6 in Alzheimer’s disease

Excerpt

In a recent study, Galimberti et al. [2] reported a significant increase of IL-11 disease (AD n = 43) and frontotomporal lobar degeneration (FTLD n = 24) in patients with Alzheimer’s disease in comparison to age-matched controls (n = 30). At the same time, IL-6 showed only a non-significant increase in demented subjects. Measurement of CSF IL-6 levels in AD have revealed contradictory results—unchanged [3, 5] and increased [1, 8, 9]. In our personal studies in a cohort of 169 aged subjects, we found probable AD (n = 27), non-AD dementia (n = 24, including FTLD n = 10 and vascular dementia n = 5), and other CNS disorders without cognitive impairment (infections, vascular, neurodegenerative diseases n = 69). A specific immunoabsorbent assay (ELISA, R&D Systems, Minneapolis, MN, USA) revealed a significant increase of IL-6 immunoreactivity in CSF of both AD and non-AD dementias compared to controls (P < 0.03), despite broad overlap. AD patients with late onset (>65 years) had significantly higher values than those with early onset (P < 0.05), but, as in Galimberti’s cohort, there were no correlations of CSF IL-6 with age, MMSE scores, disease duration, or CSF Aβ-42 and T-tau [4, 6]. These data and increased CSL IL-6 levels in hypertensive encephalopathy [7] suggest that it may reflect IL-mediated immunologic phenomena in the course of neurodegenerative processes. …