# In platelet single donor apheresis, platelet factor 4 levels correlated with donor’s age and decreased during storage

## TL;DR

Older blood donors have higher levels of a brain-boosting protein in platelets, which could affect transfusion therapy.

## Contribution

This study is the first to show that PF4 levels in platelet concentrates correlate with donor age but not storage duration.

## Key findings

- PF4 levels in platelet concentrates are higher in elderly donors compared to younger ones.
- Storage time of platelet concentrates does not affect PF4 levels.

## Abstract

The human population is ageing worldwide. The World Health Organization estimated that the world’s population of people aged 60 years and older will increase to at least 30%, coinciding with a growing frequency of cognitive and cardiovascular disease. Recently, in preclinical studies platelet Factor 4 (PF4) was presented as a pro-cognitive factor. This molecule is released by platelets in the circulation and could be present in blood products destined for transfusion. We wondered if PF4 levels are correlated to the age of the blood donor or to the storage time of platelet concentrates (PCs) intended for transfusion? We observed higher levels of PF4 in PCs from elderly donors compared to younger donors, while PC storage time did not determine PF4 levels expression.