Decreased mRNA expression of CCL5 [RANTES] in Alzheimer's disease blood samples

Background: A recent study reported that an 18-analyte multiplexed plasma panel of signaling proteins differentiated Alzheimer's disease (AD) from controls. This study measured mRNA expression for nine of these promising bio-markers in 23 AD patients and 23 age- and sex-matched controls. Methods: Total RNA was isolated from PaxGene RNA tubes. Relative mRNA expression levels of CCL5 [RANTES], CSF1, ICAM1, IGFBP6, ILIA, IL3, IL8, PDGFB and TNF were determined by Q-RT-PCR, with GAPDH as housekeeping gene. Results: A panel of five markers (CCL5, CSFI, ICAM1, IL8, TNF) with detectable expression levels in all individuals differed between AD patients and controls (p interaction <0.10). Especially, the relative expression level of CCL5 was lower in AD patients than in controls (p<0.005). Across groups, levels of both CCL5 and TNF were correlated to CSF levels of tau (r =0.39, r=0.32), p tau-181 (r=0.38, r=0.33), and MMSE (r=-0.31, r=-0.33, all p<0.05). Conclusions: The measured panel, and especially CCL5, could aid in the differentiation of AD from controls.