Multiple sclerosis (MS) affects over 400,000 people in the EU, causing problems with vision, movement and speech. In MS, the protective layer that surrounds nerves in the brain and spinal cord, called myelin, is destroyed. As the disease progresses, this damage often goes unchecked because the regenerative process for replacing myelin (‘remyelination’) fails. There are currently no approved therapies that tackle this problem by promoting remyelination. Researchers hope a new study published in the journal Nature Neuroscience will contribute to the development of new therapies by helping to explain how remyelination is controlled. The scientists studied immune cells called macrophages, which are involved in remyelination. They found that the macrophages must become anti-infammatory for remyelination to proceed, and identified a protein released by macrophages which encourages remyelination.