Apolipoprotein E ε4-Specific Relationship Between Serum Olfactomedin 4 and Alzheimer's Disease.

Olfactomedin 4 (OLFM4) plays important roles in inflammation, immune regulation, apoptosis, and neurodevelopment. This study aimed to investigate the correlation of serum OLFM4 with Alzheimer's disease (AD) and its clinical phenotype in different apolipoprotein E (APOE) ε4 status. Serum OLFM4 levels were measured in 122 AD patients and 113 healthy controls (HC). Correlations between OLFM4 levels and cognitive function and brain volume were analyzed in the context of APOE ε4 status. Multivariate logistic regression modeling was used to assess the contribution of high OLFM4 levels and APOE ε4 status to the risk of AD. It turns out that serum OLFM4 levels were significantly higher in patients with AD than in HC and were associated with APOE ε4 status but not sex. Serum OLFM4 levels showed a dose-response relationship with cognitive function and were correlated with brain atrophy. The combination of high OLFM4 levels and APOE ε4 expression was a risk factor for AD (odds ratio = 5.440; p = 0.017). In conclusion, serum OLFM4 may be involved in the pathology of AD and holds promise as a potential biomarker of AD as well as a therapeutic target. And the effects of OLFM4 for AD may be mediated by APOE ε4.