B2M and Dravet syndrome: Intravenous injection of plasma from the subjects with DS, but not non-DS siblings, into immunodeficient B-NDG mice induced similar synaptic deficits and deficient cognition-related behaviors, pointing to a negative effect of DS plasma on synaptic function.1 β2-microglobulin (B2M), a hub in the immune network in DS plasma, was identified with B2M levels significantly increased in both plasma and brains in both human and DS mouse models.