Genetics

Multiple sclerosis genetics settled which cell types matter decades ago. Three 2026 papers work a level down. Van Puijfelik and colleagues find a CCR5-high Th17.1 cell primed to kill but not yet killing: granzyme B and perforin appear only once interleukin 12 and 18 arrive together. Van den Bosch and colleagues sort lesions by the shape of the microglia inside them, with repair programmes around ramified cells and demyelination around foamy ones. Aboelnour and colleagues then report that neither standard mouse model contains the states patients have.