Interaction between APOE4 and herpes simplex virus type 1 in Alzheimer's disease

Abstract

Introduction: Numerous results suggest the implication of infectious agents in the onset of Alzheimer's disease (AD). Methods: In the Bordeaux-3C prospective cohort, we assessed the impact of herpes simplex virus type 1 (HSV-1) infection on the incidence of AD according to apolipoprotein E (APOE) status, a genetic susceptibility factor. Cox models were performed to estimate the 10-year risk of AD associated with anti-HSV antibodies in 1037 participants according to APOE4 status. Results: Among APOE4 carriers, subjects for whom the frequency of HSV-1 reactivation is supposed to be high, that is, immunoglobulin M (IgM) positive or elevated levels of IgG, had an increased risk of AD with adjusted hazard ratios (HRs) of 3.68 (1.08–12.55) and 3.28 (1.19–9.03), respectively. No significant association was found in APOE4-negative subjects. Discussion: These results, in accordance with a solid pathophysiological rationale, suggest a role for HSV-1 in AD development among subjects with a genetic susceptibility factor, the APOE4 allele.