IL-7 plays a key role in lymphopoiesis and lymphoid homeostasis (1). Stromal and epithelial cells within the bone marrow and thymus produce IL-7 (1). The primary targets of IL-7 are T cells, B cells, and dendritic cells (1). IL-7 is crucial for T cell development, the importance of which is underscored by the lack of T cells in both mice and humans that are deficient in IL-7/IL-7R signaling (1,2). While IL-7 appears to be required for B cell development in mice, the role of IL-7 in human B cell development is unclear (1,3). In addition to its effects on T cell lymphopoiesis, IL-7 promotes the maintenance and survival of na?ve and memory αβ T cells, as well as γδ T cells (1). The IL-7 receptor is a heterodimer of the common γ chain, γc, and the IL-7-specific IL-7Rα (1). IL-7 activates PI3K/Akt, Jak1/2, and Stat1, 3, and 5 (1).
