Minimizing responses from a type of immune cell could help to treat influenza in old people.
The vast majority of influenza deaths are among older people. To find out what makes them vulnerable, Akiko Iwasaki at Yale School of Medicine in New Haven, Connecticut, and her colleagues compared white blood cells from healthy volunteers in their 20s with those from people over 65. When infected with flu virus, cells from the older group produced lower levels of virus-fighting proteins called type 1 interferons.
In mice, knocking out two genes (Mavs and Tlr7) that help to trigger interferon responses made the animals more vulnerable to both flu and bacterial lung infections. But deleting the Casp1/11 genes, which help to activate immune cells called neutrophils, protected the mice. The authors suggest that reducing the inflammatory responses of these cells could be a way to treat flu in older adults.