Abstract
In this issue of Blood, He et al show that a tumor necrosis factor α (TNFα)-mediated pathway regulating interleukin-27 receptor subunit α (IL-27Ra) expression on hematopoietic stem cells (HSCs) mediates changes in HSCs that occur in old age, including myeloid skewing, reduced reconstitution potential, impaired self-renewal, and a proinflammatory phenotype.