Defective Immune Cells May Cause Male Pattern Baldness

Links between hair loss caused by the autoimmune disorder Alopecia Areata and the genetic condition Male Pattern Baldness are surprisingly thin on the ground. Beyond the obvious a loss of hair their idiosyncrasies mark them out as very different; one is caused by a ‘trigger’ incident that causes the body to attack healthy cells, while the other is a genetically pre-programmed, biological response to a by-product of testosterone.

Although Male Pattern Hair Loss treatment and Alopecia Areata treatments are not identical, they do share a common option: minoxidil. This is a topical drug administered to the affected areas of the scalp which, despite only being proven to treat male and female pattern hair loss, Belgravia specialists find using high strength minoxidil can have a significant, positive impact on cases of patchy alopecia areata.

Although research into each of these conditions tends to follow different paths, a new study by the University of California, San Francisco, suggests that the two conditions may have important common ground after all.

That common ground, says a research team led by Niwa Ali PhD, is something called regulatory T-cells, also known as Tregs (pronounced “tee-regs”).

Controlling inflammation

The UCSF website explains that Tregs are a type of immune cell most commonly associated with controlling inflammation. In mice, researchers found that Tregs directly trigger stem cells in the skin to promote healthy hair growth.

“Without these immune cells as partners,” note the doctors, “the stem cells cannot regenerate hair follicles, leading to baldness.”

Dr Michael Rosenblum, senior author of a paper about the study, goes on to explain that hair follicles are constantly recycling, and that when hair falls out a portion of the follicle has to grow back in order for a new hair to appear. “This has been thought to be an entirely stem cell-dependent process,” he says, “but it turns out Tregs are essential. If you knock out this one immune cell type, hair just doesn’t grow.”

The research team’s conclusion is that defects in Tregs could be responsible not just for Alopecia Areata, but that they could play a part in Male Pattern Baldness as well.

The article on the UCSF website explains that Tregs have an important role when it comes to a whole host of immune system functions, and that when they are defective people may become allergic to things like peanuts or cat dander. Autoimmune disorders can result, too.

Their importance in the hair growth cycle was discovered by Rosenblum and his colleagues when they developed a technique to remove Tregs from the skin of mice, whose fur was then shaved of in patches. It didn’t grow back ever.

Treg clustering increases

Investigating further, the team looked at imaging scans that helped better show exactly what is going on at a cellular level during normal hair growth. They could see that the number of active Tregs clustering around follicle stem cells increases three-fold as follicles enter the hair growth cycle. Interestingly, it was found that if they removed Tregs from the skin within three days of shaving a patch of skin, when follicle regeneration would normally be activated, growth was blocked. If, however, removal of Tregs was performed after the three-day window, this had no effect and hair would grow as normal adding further evidence to the idea that Tregs and stem cells enjoy a special synergy that enables the growth phase to begin.

“It’s as if the skin stem cells and Tregs have co-evolved, so that the Tregs not only guard the stem cells against inflammation but also take part in their regenerative work,” Rosenblum said.

Inspired by its findings, the team delved into existing studies into Alopecia Areata and found that almost all of the genes associated with the condition were related to Tregs, and that treatments which boosted Tregs function were proving effective. A better understanding of this, says Rosenblum, may lead to new treatments for all hair loss conditions. For now, however, whether it is male pattern baldness, alopecia areata or female pattern hair loss, there are a range of effective hair loss treatments available for those wanting to take a proactive approach to preventing baldness and promoting hair growth.