HERPES SIMPLEX VIRUS, EARLY NEUROIMAGING MARKERS AND INCIDENCE OF ALZHEIMER’S DISEASE
- Morgane Linard, France
Abstract
Aims
While previous studies suggest the implication of herpes simplex virus (HSV) in the onset of Alzheimer’s disease (AD), no study has examined its association with early neuroimaging markers of AD. Here, we aimed to further investigate this hypothesis by combining data from two French cohorts.
Methods
In the Three-City and the AMI cohorts, associations between HSV infection and i) hippocampal volume (n=352), ii) white matter alterations in the parahippocampal cingulum and fornix using diffusion tensor imaging (n=260) and iii) incidence of AD (n=1599) were assessed according to APOE4 status.
Results
Infected subjects presented significantly more microstructural alterations of the parahippocampal cingulum and fornix including lower fractional anisotropy and higher mean and radial diffusivities. Regarding more advanced markers of the disease (hippocampal volume and incidence of AD), an interaction was found between being infected with HSV and APOE4 status. Among APOE4 carriers, infected subjects presented lower hippocampal volumes, although not significant (p=0.09), and had a twice higher risk of developing AD (aHR=2.72 [1.07–6.91] p=0.04) and a 3-times higher risk if their anti-HSV IgG level was in the highest tercile, possibly reflecting more frequent reactivations over time (aHR=3.87 [1.45–10.28] p=0.007). Among APOE4 noncarriers, no associations were observed between HSV status and hippocampal volume or incidence of AD.
Conclusions
Our findings suggest an increased risk of AD in subjects infected by HSV. These results reinforce the need to further investigate the infectious hypothesis of AD and the possibility of related preventive treatments.