Peripheral Immune Cells and Cerebrospinal Fluid Biomarkers of Alzheimer’s Disease Pathology in Cognitively Intact Older Adults: The CABLE Study

BACKGROUND: Inflammation plays a role in occurrence and progression of Alzheimer's disease (AD). Whether peripheral immune cells are involved in major pathological processes including amyloid-β plaques and tau tangles is still controversial. OBJECTIVE: We aimed to examine whether peripheral immune cells counts were associated with early changes in cerebrospinal fluid (CSF) biomarkers of AD pathology in cognitively intact older adults. METHODS: This study included 738 objective cognitive normal participants from the Chinese Alzheimer's Biomarker and Lifestyle (CABLE) database. Group comparisons of peripheral immune cells counts were tested by analysis of covariance. Multiple linear regression models were used to examine the associations of peripheral immune cells counts with CSF AD biomarkers. RESULTS: In preclinical AD, peripheral lymphocytes and eosinophils changed dynamically along with disease progression. Consistently, regression analysis showed that lymphocytes and eosinophils were associated with Aβ pathology. There were no interaction effects of peripheral immune cells counts with APOE ɛ4, gender, age, and educate. Eosinophil to lymphocyte ratio were also significantly associated with Aβ-related biomarkers. CONCLUSION: Our findings showed the relationship between peripheral immune cells and Aβ pathological biomarkers, which indicated that peripheral immune might play a role in progression of AD pathology.