"This offers hope for the tens of thousands of Australian children and adults affected by this auto-immune disease": Rod Sinclair. Photo: Craig Sillitoe
Medical researchers have identified the immune cell responsible for disfiguring hair loss in people with a common auto-immune disease, alopecia areata, a condition that can have a significant psychological impact on many patients.
The same group has also identified potential treatments based on drugs that have already been approved for other conditions.
Melbourne dermatologist Rod Sinclair, who was not involved in the study, said the research was ‘‘extremely exciting’’ because it had unravelled the cause of an extremely complex disease and identified a potential treatment.
‘‘This offers hope for the tens of thousands of Australian children and adults affected by this auto-immune disease,’’ said Professor Sinclair, who is the director of dermatology at Epworth Hospital and holds an honourary position at the University of Melbourne.
Professor Sinclair said the condition was emotionally distressing for many patients and had been a significant factor in some youth committing suicide.
Four years ago, a team led by Professor Angela Christiano from the Columbia University Medical Centre discovered the genetic basis of alopecia areata, the most common auto-immune disease in humans.
In this latest research, published in the scientific journal Nature Medicine, the same group had discovered the specific white blood cell, a type of t-cell, responsible for causing hair loss.
The t-cell releases a chemical that diffuses into the skin, triggering the immune system to attack hair follicles.
In people without the condition, the body knows not to attack hair cells because they are ‘‘immune privileged’’, Professor Sinclair said.
Professor Christiano’s group also identified several pathways in the immune system that could be targeted by drugs.
In mice with significant hair loss, a trial of two drugs, both approved by the American Food and Drug Administration for other conditions such as rheumatoid arthritis and a bone marrow disease, completely restored hair growth within 12 weeks.
One of the drugs, known as a JAK inhibitor, also resulted in total hair regrowth in a small number of patients with severe alopecia areata.
"We've only begun testing the drug in patients, but if the drug continues to be successful and safe, it will have a dramatic positive impact on the lives of people with this disease," said one of the research leaders, Dr Raphael Clynes.
Professor Sinclair said although alopecia areata was a common disease in men and women, many people had never heard of it.
‘‘As soon as someone gets it, they disguise it,’’ he said. ‘‘People just assume these people are bald or women wear wigs and you can’t tell.’’
While the condition often presented in children, it could occur at any age, with hair loss ranging from one or two bald patches to people who lost all their body hair.
Patients with the disease often experience significant psychological and emotional distress.
‘‘I’ve seen teenagers with it become socially withdrawn, anxious and self conscious,’’ Professor Sinclair said.
In 2012 he reported in the Medical Journal of Australia several cases of teenagers with alopecia areata committing suicide.
‘‘Intuitively we thought girls would be the most severely affected by this, but what we found was that all the suicides were in young boys,’’ he said.
‘‘It’s because they’ve got short hair and can’t disguise it, so they get a [bald] patch and they refuse to go to school.’’
Current treatments included steroids or strong immune suppressing drugs, but both can have substantial side-effects and rarely restored hair growth completely.