Revealing a new thymus compartment

The thymus is responsible for the T cell-mediated adaptive immune system, yet to this day it is not fully understood. We used advanced x-ray imaging methods to study its volumetric evolution over age, from pre- to post-natal, and used the quantitative nature of the images to track the evolution of the various thymus compartments with development. This revealed that Hassall’s bodies grow to occupy approximately 25% of the total volume, indicating they should be considered a third compartment alongside cortex and medulla and that further research may be needed on their function.

Cross-section through the three-dimensional image of a foetal thymus, with (brighter) cortex and (darker) medulla clearly visible alongside blood vessels (BV) and Hassall’s bodies (HB in the zoomed-in volume on the right hand side). Scale bars 0.5 mm.