Blood Interleukin-6 (IL-6) mRNA Expression in Alzheimer's Disease: A Preliminary Analysis

IntroductionAlzheimers Disease (AD) is a neurodegenerative disorder characterized by amyloid protein deposition, phosphorylated tau and neurodegeneration. Interleukin-6 (IL-6) is a pro-inflammatory cytokine implicated in neurodegenerative diseases (9,10). ObjectiveThis study aimed to investigate the expression level of the IL-6 probe in blood samples from the GSE63060 dataset to determine if it significantly differs between individuals with AD, Mild Cognitive Impairment (MCI), and healthy controls (CTL), while accounting for potential confounding effects of age, gender and ethnicity. MethodsBlood transcriptome data (GSE63060) from 329 participants (145 AD, 80 MCI, 104 CTL) was obtained from the Gene Expression Omnibus (GEO). Metadata, including diagnosis, age, ethnicity, and gender, was processed. The specific probe data for IL-6 ILMN_1699651 was extracted, transposed, and merged with the metadata in SPSS Statistics v25. A General Linear Model (GLM) - Univariate was employed to test the effect of Diagnosis on IL-6 expression, with Age and Gender included as covariates. ResultsThe GLM analysis revealed no statistically significant difference in blood IL-6 expression among the diagnostic groups (F (2, 312) = 0.136, p=0.873). ConclusionBased on this analysis of the GSE63060 dataset, blood IL-6 mRNA expression, as measured by this probe and platform, did not significantly differ across diagnostic groups AD, MCI, and healthy control individuals when controlling for ethnicity, age, and gender. This finding suggests a need to measure plasma IL-6 protein levels, analyze other cohorts, and determine whether blood mRNA is a suitable biomarker for AD.