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New characteristics of aging unraveled within our immune system during the flu and COVID-19

Respiratory infections caused by viruses often hit hard in older adults. Generally, susceptibility to the flu and COVID-19 is much higher at older age. This is caused by a gradual loss of the capacity of our immune system to respond to infections. Doctoral candidate Daan Pieren unraveled new characteristics of aging within cells of the immune system that may explain susceptibility at older age. He identified a new type of white blood cell that may have an important role in viral respiratory infections. Immune cells called T cells clear viral infections. Pieren discovered that at older age, T cells express higher levels of molecules that slow down immune reactions. A new variant of T cells discovered by Pieren expressed high levels of these molecules, suppressed other T cells, and is present at higher numbers in the blood of older adults. This cell type also appeared to be highly activated as a consequence of the flu in older adults and could be linked to a longer duration of illness in these flu patients. These cells also appeared to be highly activated during COVID-19, which warrants additional research into this cell type to provide insight into the susceptibility to COVID-19 and the flu.

Daan Pieren performed his research at the RIVM and graduates March 2nd 2021 at the Utrecht ľ¹Ï¸£ÀûÓ°ÊÓ with his PhD thesis entitled ‘Aging with T cells: The rise of regulatory T-cell features at older age’.