Type 2 Innate Immunity Regulates Hair Follicle Homeostasis to Control Demodex Pathosymbionts
March 2021
in “
bioRxiv (Cold Spring Harbor Laboratory)
”
type 2 innate immunity skin group 2 innate lymphoid cells ILC2s IL-13 hair follicle homeostasis epithelial cell proliferation Demodex musculi topical anti-parasitic agents inflammatory response immune cells type 2 immunity hair follicle health epithelial proliferation Demodex mites topical anti-parasitics inflammation immune response
TLDR A specific immune response helps control mite populations on the skin, maintaining healthy hair follicles.
The study demonstrated that type 2 innate immunity, particularly through skin group 2 innate lymphoid cells (ILC2s) that secrete IL-13, plays a crucial role in maintaining hair follicle homeostasis by regulating epithelial cell proliferation. In the absence of type 2 immunity, hair follicles appeared normal; however, when colonized by the commensal mite Demodex musculi, there was an increase in epithelial proliferation and abnormal hair follicle morphology. This was associated with a loss of stable commensalism, leading to a massive infestation and an inflammatory response involving ILC2s and other immune cells. Treatment with topical anti-parasitic agents, but not antibiotics, reversed these effects. This research highlights the importance of ILC2s and type 2 immunity in controlling the population of Demodex mites on mammalian skin, including humans, to maintain skin and hair follicle health.
