One cell to rule them all: Immune regulation of the brain in autism spectrum disorder.

Abstract

For 80 years there has been a link between autism and immune activation. Studies point to dysfunction in immune responses in peripheral blood, gut mucosa, and brain. Human postmortem brain studies in autism show increased differential expression of inflammatory immune genes, increased pro-inflammatory cytokine levels, and glial activation. Immune cells in the brain are comprised of both tissue-resident cells and those recruited from the blood. This includes regulatory T cells (Tregs) that foster immune tolerance and tissue repair. Tregs reduce microglial reactivity, assist in regenerative and reparative processes, and promote differentiation of myelin-producing oligodendrocytes in the brain, thus modulating white matter development. Neuroinflammation may be a universal autism phenotype independent of the underlying etiology that can be controlled by Tregs promoting homeostasis, microglia and oligodendrocyte function, and white matter development.