The most readily observed subsets were those accumulating and forming microscopic structures, most notably Hassall's corpuscles resembling skin keratinocytes.
Substantial progress has been made in recent years owing to the rapid development of single cell sequencing methods, such as scRNA-seq or scATAC-seq.
[1][2] Since its discovery in 2001,[3] AIRE (Autoimmune regulator) has been the main focus of studies of thymic (central) immune tolerance.
[6] The expression of peripheral antigens in mimetic cells strongly implies a function in establishing central immune tolerance.
It is unknown what prompts the mTECs to differentiate into mimetic cells, the lineage specific transcription factors could be induced by AIRE or perhaps other signals.