Summary: A new study reports that prior infection with human herpesviruses is associated with a faster, age-related rise in blood biomarkers linked to dementia, even among cognitively healthy women. Researchers measured five key serum biomarkers in 167 women and found that seropositivity for one or more HHVs was associated with roughly double the rate of biomarker accumulation compared with women without evidence of prior infection.
The strongest viral associations were observed for Epstein‑Barr virus (HHV4) and HHV6, with the greatest effects on amyloid‑beta and phosphorylated tau measures. These results add support to the idea that chronic viral infections could accelerate neurodegenerative processes and raise dementia risk independently of common genetic risk factors.
Key Facts
- Biomarker acceleration: Women who were HHV‑seropositive showed a 2.15× faster age-dependent increase in dementia-related blood biomarkers.
- Viral impact: The strongest associations were seen for HHV4 (Epstein‑Barr virus) and HHV6, followed by HHV1 (herpes simplex virus).
- Independent of APOE4: The APOE4 genetic risk factor did not significantly modify the relationship between HHV seropositivity and biomarker increases.
Context
This research examined whether prior exposure to common human herpesviruses correlates with longitudinal changes in blood markers that are increasingly used to detect Alzheimer’s disease–related biology before cognitive symptoms appear. The study focused on cognitively unimpaired women spanning a wide adult age range to assess how viral seroprevalence relates to trajectories of established dementia biomarkers.
Researchers analyzed 345 blood samples collected over time from 167 cognitively healthy women aged 26–98. They measured five serum biomarkers commonly linked to Alzheimer’s disease and neurodegeneration: amyloid‑beta 40 (Aβ40), amyloid‑beta 42 (Aβ42), the Aβ42/Aβ40 ratio, phosphorylated tau 181 (pTau181), and phosphorylated tau 217 (pTau217). At the same time, they tested samples for antibodies to six human herpesviruses (HHV1–HHV6) to determine prior exposure.
Across the cohort, all biomarkers except the Aβ42/Aβ40 ratio increased with age. However, the rate of increase for Aβ40, Aβ42, pTau217 and pTau181 was substantially greater in women who were seropositive for at least one HHV. On average, the normalized rate of biomarker increase with age was about 2.15 times higher in the HHV‑seropositive group than in seronegative participants (statistically significant).
When comparing specific viruses, HHV4 (Epstein‑Barr virus) and HHV6 showed the strongest associations with steeper biomarker trajectories, followed by HHV1. HHV3 (varicella zoster) was seropositive in all samples analyzed. Importantly, having the apolipoprotein E4 (APOE4) genotype — a known genetic risk factor for Alzheimer’s disease — did not significantly alter these associations, suggesting the viral link to biomarker change may act independently of this common genetic predisposition.
Why these observations matter: blood biomarkers such as amyloid‑beta and phosphorylated tau can become abnormal years before cognitive decline and are used as proxies for underlying brain pathology. The finding that prior herpesvirus exposure is associated with faster increases in these markers supports the hypothesis that chronic or latent viral infections could act as a trigger or accelerator of pathological processes that lead to dementia. The study also notes a provocative biological possibility: amyloid‑beta and tau proteins have antimicrobial properties, so their accumulation in response to persistent infection may initially be protective, but over time could contribute to neurodegeneration.
These results reinforce calls for further investigation into infectious contributors to dementia risk and suggest that antiviral strategies, vaccination, or other infection‑targeted interventions warrant exploration as potential preventive approaches. Additional studies are needed to confirm whether the same patterns occur in men and in more diverse populations, and to determine whether treating or preventing chronic infections can slow biomarker progression or reduce dementia incidence.
About this neurology and dementia research news
Author: Neuroscience News Communications
Source: Neuroscience News
Contact: Neuroscience News Communications – Neuroscience News
Image: The image is credited to Neuroscience News
Original research (open access): “Human herpes viruses are associated with steeper age-dependent increases of serum biomarkers for dementia in cognitively unimpaired women” by Lisa M. James et al., published in Scientific Reports.
Abstract
Human herpes viruses are associated with steeper age-dependent increases of serum biomarkers for dementia in cognitively unimpaired women
Blood biomarkers are increasingly used to screen for and detect early biological signs of dementia in people without cognitive impairment. In this study, investigators measured serum levels of five dementia‑related biomarkers — Aβ1–40 (Aβ40), Aβ1–42 (Aβ42), the Aβ42/Aβ40 ratio, pTau181, and pTau217 — and determined seroprevalence for six human herpesviruses (HHV1–HHV6) using 345 samples collected from 167 cognitively unimpaired women aged 26–98.
All biomarkers except the Aβ42/Aβ40 ratio showed significant increases with age, particularly among women who were seropositive for HHVs. The order of biomarker increase was greatest for Aβ40, then Aβ42, pTau217, and pTau181. With respect to viruses, the strongest associations were noted for HHV4, followed by HHV6, HHV1, HHV2, and HHV5; HHV3 was seropositive in all samples.
Overall, the average normalized rate of biomarker increase with age was 2.15× higher in the HHV‑seropositive group compared with the seronegative group (P = 0.003). Presence of the apolipoprotein E4 (apoE4) allele did not have a significant effect on these rates. These findings document a link between prior herpesvirus exposure and dementia‑related blood biomarker trajectories, supporting the hypothesis that HHVs may contribute to the development of dementia independently of apoE4 status.