Researchers showed previously entirely unknown types of immune cells are present in the inflamed brain in the course of multiple sclerosis. The discovery by scientists at the University of Freiburg Medical Center, in Germany, was made by means of a new, high-resolution method for analyzing single cells. The method allowed the researchers to create a kind of immune cell atlas for the brain. They also showed how these cells promote the development of MS. 

The fact that phagocytes from the blood and the brain play a role in MS has already long been known, but it was unclear up to now precisely which subtypes are involved. After years of research work, the scientists have now identified these subtypes in an animal model of MS.

The researchers succeeded in mapping the complex composition of cells located at the focus of inflammation. This enabled them to create a new immune cell atlas. The single-cell analyses used by the researchers are new and can be used in medicine for studying individual cells from tissues. Results of animal model studies sometimes do not translate to humans and may be years away from being a marketable treatment. However, the researchers see them as having enormous potential.

The researchers also managed to demonstrate that different phagocytes in the brain remain chronically activated in the course of the disease. It was previously assumed that they were quickly renewed by circulating blood cells.

The study was published in the journal Science.