High-TECh thymus

摘要

The thymus is a dynamic organ with regard to both the lymphoid and stromal compartments. The 3-dimensional thymic stromal compartment, composed primarily of cortical and medullary thymic epithelial cells (TECs), fibroblasts, and endothelial cells, directly supports thymocyte development and selection. Myeloablative conditioning prior to hemato-poietic stem-cell transplantation (HSCT) damages and depletes TECs. Because T-cell reconstitution and the generation of a broad T-cell repertoire require factors supplied by TECs, prolonged T-cell immune deficiency due to TEC injury predisposes patients to infections. Adults who undergo allogeneic HSCT, and who typically have poor age- and chemotherapy-related TEC support of thy-mopoiesis, are especially vulnerable.2 Low TEC levels would impede T-cell reconstitution, regardless of the number of stem and thymic progenitor cells infused