Category Archives: Tregs

Tregs and Hair Growth

In May, two new major hair loss related discoveries received widespread coverage in English language newspapers around the world. Not something you see regularly.

  1. I covered the first of these two in my post on a protein in skin cells called Krox20 that impacts hair growth and pigmentation. This discovery came about accidentally via unrelated research on cancer at University of Texas Southwestern.
  2. The second discovery from the University of California at San Francisco (UCSF) was also accidental. Skin and immune cell related dermatological research led to surprising hair growth findings. This second development is summarized below.

Regulatory T Cells (Tregs)

The latest big development concerns regulatory T Cells (nicknamed “Tregs”) which modulate the immune system. In a new study led by Dr. Michael Rosenblum, it was found that Tregs are directly responsible for triggering stem cells in the skin to promote healthy hair growth. Historically, it was thought that hair growth was entirely related to stem cell activity. The new findings suggest that certain immune cells (i.e., Tregs) are also essential for hair growth and their is some sort of symbiotic communication between immune cells and hair cells.

Increasing Evidence that the Immune System Plays a Role in all Types of Hair Loss

There have been several papers in recent years that have implicated the immune system in hair loss and hair growth. However, in general, scientist continue to believe that immune system defect and inflammation related hair loss only affects 2-3 percent of hair loss sufferers, and they label that type of hair loss as alopecia areata (AA).

For the vast majority (>95 percent) of hair loss sufferers, male hormones (androgens) are causing their hair loss and the condition is therefore labeled as “male pattern baldness (MPB)” or “androgenetic alopecia (AGA)”. The immune system was until recently not thought to play any major role in AGA.

However, famous researcher Dr. Angela Christiano’s findings from Columbia University research in 2014 and 2015 changed all that. Her work implicated the immune system in both AA and AGA (albeit far more clearly in the former). Her team found that certain types of covalently bound topical JAK inhibitors led to hair regrowth in mice suffering from AGA and not just in those suffering from AA. Her AGA related patents were later sold to Aclaris Therapeutics, a company that plans to test topical JAK inhibitors on AGA in future.

Could Tregs also Play a Role in Male Pattern Baldness?

When I first read about this latest study from UCSF, it was in a few UK newspapers and the wording was sometimes a bit unclear when it comes to Tregs and non-alopecia areata type hair loss (e.g., “could also play a role in other types of hair loss”) .

However, later on I read the official UCSF press release article on this, and the below quote right from the horse’s mouth is extremely encouraging:

The new study – published online May 26 in Cell – suggests that defects in Tregs could be responsible for alopecia areata, a common autoimmune disorder that causes hair loss, and could potentially play a role in other forms of baldness, including male pattern baldness, Rosenblum said.

And another version from The Telegraph:

Tregs could also play a role in other forms of baldness, including the classic “male pattern” variety that causes men to recede and lose their hair, the team believes.


For many years I have noticed that a large number of people (including myself) suffering from male pattern hair loss seem to also have major regular itching and dandruff episodes. Often requiring daily anti-dandruff shampoo use. In the past, I have mentioned that if JAK inhibitors do ever work to treat AGA, there is a good chance they will work the best on people who have these itching symptom.

I think that immune system attack and inflammation are probably at least partially responsible for the itching and skin flaking. Commentator “Netshed” started an interesting survey in the last post related to scalp itching, and he is welcome to re-post it here. I might do an official survey like that in future too.