Differential CSF biomarker levels in APOE-ε4-positive and -negative patients with memory impairment

Objectives: To investigate the relationships between episodic memory, APOE genotype, CSF markers (total tau, T-tau; phospho-tau, P-tau; beta-amyloid, A beta 42) and longitudinal cognitive decline. Methods: 124 memory clinic patients were retrospectively divided into 6 groups based on (i) episodic memory function (Rey Auditory Verbal Learning Test, RAVLT): severe, moderate or no impairment (SIM, MIM or NIM), and (ii) APOE genotype (epsilon 4+ or epsilon 4-). CSF marker levels and cognitive decline were compared across groups. Results: Episodic memory function, according to RAVLT scores, was significantly correlated with CSF marker levels only among epsilon 4+ subjects and not among epsilon 4- subjects. When comparing the 6 subgroups, SIM epsilon 4+ and MIM epsilon 4+ groups showed significantly lower A beta 42 levels than the other groups. T-tau and P- tau levels were significantly increased in SIM epsilon 4+ when compared to all the other groups, including the SIM epsilon 4- group. However, both SIM epsilon 4+ and SIM epsilon 4- declined cognitively during the follow-up. Conclusion: It remains to be determined whether APOE genotype affects the expression of biomarkers in CSF, or whether the different biomarker patterns reflect different types of disease processes in patients with progressive cognitive dysfunction. Copyright (C) 2007 S. Karger AG, Basel.