News came through this week of three human trial subjects suffering alopecia areata who grew back a full head of hair within five months. It has certainly flared up a lot of excitement, and these three people are reportedly very happy with the results. But how has this happened, and does it mean that we could kiss goodbye to baldness for good?

Believe me when I say the investigation into this one has been a real challenge. Biochemistry doesn't come naturally to most people, myself included, so I'll try to make this as simplified as I can whilst still giving you all the information.

First off, let's whet our appetites with the human trial results published by the researchers:


Yep, it's pretty remarkable. Now on to all the 'smallprint'.

I'm going to start by throwing out a few truths so as not to make anybody overly-hopeful about this. First, alopecia areata is distingushed from the much-more common androgenetic alopecia (male-pattern baldness) that sets in with age and is characterised by a thinning crown and receding hairline. You know the type. Put simple, nobody has cured that. Also, it differs from alopecia universalis/alopecia totalis (baldness over the entire body), although this form is more closely related to what these studies cover. Alopecia areata (referred to as AA hereafter), for those that don't know, is a condition where scalp hair falls out in patches. I'll go into more detail about the causes in a moment.

Second, there is no specifically-created drug available here, just a pre-existing one that isn't diagnosed for alopecia. It does have a couple of very important drawbacks, and the clinical trials are still going on as we speak - some subjects have yet to see results.

With that out of the way, let's do some science.

What causes Alopecia Areata?

The researchers heading this study, Raphael Clynes,MD,PhD and Angela Christiano,PhD, discovered that the cells responsible for the production of hair protein, keratin, were sending out false 'danger signals' in AA sufferers.

The image above shows a super, super close-up of the hair bulb. there is one of these beauties for every single hair on your head. (Yeah, when people say the human body is amazing, they aren't kidding). The part we are concerned with is the epithelial sheath - that's the second and third on the list in figures (c) and (d). This is where each hair is made. Cells called trichocytes make proteins that link and coil and stick together, eventually forming one single hair.

Now, all cells in the human body are capable of sending signals to one another. If you catch a virus, that virus will attack certain cells in your body and then those cells will make chemicals that release into the bloodstream and are then picked up by white blood cells, the body's natural disease-fighting army. White blood cells are formally called T-cells (or T-lymphocytes).

What happens in AA sufferers is that the cells in the epithelial sheath think that they're under attack when they're not, forcing T-cells to invade and disable them.

How do we stop this from happening?

A relatively recent FDA-approved drug called Ruxolitinib, which is used to treat a type of bone marrow cancer, uses a mechanism called a JAK inhibitor. Ruxolitinib is sold in the USA under the brand name Jakafi.

When a T-cell receives the danger signal, a kind of 'on/off' switch is activated inside the cell. The enzyme that carries this out is called a Janus kinase (JAK) - it's how the cell knows that it needs to jump into action. Ruxolitinib essentially disarms this switch. So, when the cells in the hair follicle send out the false danger signal, this drug stops the T-cells from reacting to it, and the hair follicle cells aren't attacked.

And this is how we got three AA sufferers to grow back a full head of hair. Fascinating, right?

Drawbacks - there are a few.

This is an ongoing study. Most of the success was found in mice before the human trials. The three that have been published are the first three of a dozen. The next three hadn't recovered any of their hair at the time the research was published. This is just something we will have to wait and see. It is worth noting, though, that most drugs don't have a 100% success rate.

Next, there is a major contra-indication to a drug that inhibits your white blood cells. The researchers mention that all of the test subjects are young and healthy, and suggest that this is the best condition for the drug to be used. It can lead to low blood counts and infections, as you're tampering with the body's immune system. Its certainly not a good idea for people with immune deficiencies to use a drug like this. There are, however, implications for the drug to be administered topically (i.e. applied to the skin rather than take orally), which could localise the T-cell reaction.

And lastly, this is not cheap. Jakafi costs $8,753 per month, amounting to $35,000 - 40,000 for the time suggested to recover a full head of hair, or in excess of $100,000 in a year. That's a staggering price. Researchers are suggesting that doctors could prescribe this to AA sufferers at their own discretion, if the patients have no concerning health issues that could be affected by it, but it would not be covered by insurance under the drugs intended purposes.

Let's not get too bogged down by 'ifs' and 'buts', though. The fact is, the results are certainly impressive and this is definitely breakthrough research. Clynes and Christiano are continuing the studies, and when asked about the implications for the more common male-pattern baldness, Christiano said she was looking into the question. So watch this space for more info.

If you're a science boffin, find all the nitty-gritty here:

And find a full FAQ and a few questions put to the researchers here: