Alopecia areata is a common autoimmune disease that causes hair loss. The disease can occur at any age and affects men and women equally. Hair is often lost in patches on the scalp, but in some patients it also causes loss of facial and body hair. There are no known treatments that can completely restore hair, and patients with the disease experience significant psychological stress and emotional suffering. Hair loss in Alopecia Areata occurs when cells from the immune system surround and attack the base of the hair follicle, causing the hair to fall out and enter a dormant state.
A team first studied mice with the disease, then tracked backward from the danger signal to identify the specific set of T cells responsible for attacking the hair follicles. Further investigation of mouse and patient cells revealed how the T cells are instructed to attack and identified the immune pathways. Two FDA-approved JAK inhibitors tested separately by the researchers, (ruxolitinib and tofacitinib), were able to block these immune pathways and stop the attack on the hair follicles. In mice with extensive hair loss from the disease, both drugs completely restored the animals’ hair within 12 weeks. Each drug’s effect was also long-lasting, as the new hair persisted for several months after stopping treatment.
In three of the trial’s ruxolitinib completely restored hair growth within four to five months of starting treatment, and the attacking T cells disappeared from the scalp. This is a major step forward in improving the standard of care for patients suffering from Alopecia Areata.