They discover why the flu is more deadly for older people.

The flu tends to have more serious consequences for older people than for younger people. And now we know why.

A study published in the journal ' PNAS ' reveals that older people produce a glycosylated protein called apoptolipoprotein D (ApoD), which is involved in lipid metabolism and inflammation, at much higher levels than younger people.

This reduces the patient's ability to resist viral infection, resulting in a more severe course of the disease.

“Aging is a major risk factor for influenza-related deaths. Furthermore, the global population is aging at a rate unprecedented in human history, posing significant challenges for healthcare and the economy. Therefore, we need to understand why older patients tend to experience more severe influenza virus infection,” says Kin-Chow Chang of the School of Veterinary Medicine and Science at the University of Nottingham (UK), a co-author of the paper.

The University of Nottingham team has found that exaggerated ApoD production in the lung causes extensive tissue damage during infection, reducing the protective response of antiviral type I interferon.

Using an aging mouse model and human tissue sections from appropriate donors, researchers analyzed the mechanisms underlying the increasing severity of influenza virus infection with age.

In this way, they identified ApoD as an age-associated factor that weakens the antiviral response to the influenza virus by causing the degradation of mitochondria, which are essential for cellular energy and the production of protective interferons. This promotes increased viral replication and lung damage.

Therefore, ApoD is proposed as a possible therapeutic target to prevent severe forms of influenza in older adults and thus reduce morbidity and mortality in this population.

"Now, by targeting ApoD inhibition, we have an opportunity to treat the severity of illness in older adults caused by influenza virus infection," Chang adds.