# Latent Toxoplasma gondii Infection Does Not Modulate Immune Aging in a Cross-Sectional Working-Age Population Study

## TL;DR

This study found that a common parasite, Toxoplasma gondii, does not significantly affect immune aging in healthy adults.

## Contribution

The study is the first to evaluate the impact of latent T. gondii infection on immune aging in a working-age population.

## Key findings

- Latent T. gondii infection was not associated with immune aging after adjusting for age and sex.
- Seroprevalence of T. gondii increased with age but did not accelerate immune aging.
- The parasite's presence did not modify the natural trend of immunosenescence.

## Abstract

Latent, i.e., asymptomatic Toxoplasma gondii (T. gondii) infection might accelerate or modulate the aging process of cognitive and sensory functions involving pro-inflammatory immune responses. For evaluating a potential role of latent T. gondii infection in immunological aging, we determined T. gondii antibody levels and immunosenescence biomarkers in a cross-sectional sample of 584 volunteers aged 20–70 years from the Dortmund Vital Study (ClinicalTrials.gov Identifier NCT05155397) representing the regional population. One-hundred-sixty-one participants were seropositive, representing an overall 28% latent T. gondii seroprevalence, which did not significantly differ between males and females, but increased with age. Consequently, seropositive individuals were older than the seronegative participants. Latent T. gondii infection exhibited significant bivariate associations with the composite immune age index IMMAX pointing to accelerated immune aging in seropositive individuals. In addition, IMMAX increased with age and in males. However, associations of latent T. gondii infection with immunosenescence biomarkers disappeared when adjusting the analyses for sex and age. Moreover, the non-significant interaction between T. gondii status and age when predicting biomarker levels indicated that latent T. gondii infection did not modify the immunosenescence trend. Summarized, our results suggest that latent T. gondii infection is unlikely to modulate immune aging concerning cellular senescence in otherwise healthy working-age adults.