C Tremblay

Inside the arteries of a person with HIV, a fuse smolders that does not go out even when the viral load is suppressed. That fuse is chronic inflammation, and a new study shows it is kept alive by a special kind of immune cell that processes vitamin A. Scientists from the Canadian CHACS cohort compared blood from 51 people with HIV on therapy and 63 people without HIV.

The brain as a house built too spacious: lovely to live in, but expensive to maintain. Parkinson's disease is usually pictured as the destruction of that house, with neurons dying and structures shrinking.