Human T regulatory cells: on the way to cognition.

Forkhead box P3 (Foxp3)(+) T regulatory (Treg) cells are powerful controllers of the immune response and their role in the human immune system is indispensable. Since a number of revolutionary and very convincing results were brought to light, Foxp3 has unquestionably been thought to be the "master regulator" of Treg lineage commitment. Herein, we depict the revised view on the role of Foxp3 transcription factor, challenging this theory, as well as the growing significance of Runt-related transcription factor (RUNX) family proteins for Treg lineage. The review presents the current notion of Treg cell heterogeneity, molecular characteristics and their mechanisms of action.