Hassall's corpuscles

Hassall's corpuscles (or thymic corpuscles) are structures in the human thymus, composed of epithelial reticular cells. They are named for Arthur Hill Hassall, who discovered them in 1849.

The function of Hassall's corpuscles is currently unclear, and the absence of this structure in the murine thymus has restricted mechanistic dissection. It is known that Hassall's corpuscles are a potent source of the cytokine TSLP. In vitro, TSLP directs the maturation of dendritic cells, and increases the ability of dendritic cells to convert naive thymocytes to a Foxp3+ regulatory T cell lineage. It is unknown if this is the physiological function of Hassall's corpuscles in vivo.