Humans lack robust regeneration of hair follicles after skin wounding. George Cotsarelis and colleagues now show that γδ T cells are not present at high levels in human skin, that in mice they are a key initial source of the protein fibroblast growth factor 9 and that this factor modulates hair follicle regeneration during skin wound healing. These results suggest a possible topical clinical treatment to regrow hair after wounding and perhaps for other conditions of hair loss.
- Denise Gay
- Ohsang Kwon
- George Cotsarelis