Researchers have developed a genetically modified protein that, in experiments with animals, reverses vitiligo, an autoimmune disorder that causes large patches of unsightly discoloration on the skin.
Vitiligo affects an estimated 1 in 200 people worldwide. The autoimmune disorder is most dramatic in darker-skinned individuals because of the patchy loss of brown pigment. But it also can affect people with lighter complexions.
There is no successful treatment. Steroid creams are largely ineffective, and skin grafts are painful and expensive.
The depigmentation is the result of an immune system attack on melanocytes, cells responsible for skin color. Caroline Le Poole, a researcher with Loyola University in Chicago, says people usually develop the disorder after an extreme environmental exposure or trauma.
“They would for example go on a very sunny vacation and come back and then all of a sudden it starts taking off," said Le Poole. "Or they were maybe bitten by a dog and then it starts from there. But there’s even psychological factors that also come into play.”
Such as the loss of a job or a loved one. Le Poole and her colleagues discovered how a stress protein called “heat shock protein 70,” plays a role in triggering vitiligo.
That stress protein, also called HSP, kicks the body’s natural immunity into overdrive in some individuals, targeting and killing skin pigment cells.
Researchers made the discovery while studying ways to direct immune system T cells against melanoma, a deadly form of skin cancer. By genetically modifying HSP, scientists say they also were able to switch off the body’s attack on the pigment cells.
In experiments on black mice, co-researcher Jose Alejandro Guevara says scientists were able to change the animals’ fur color by genetically manipulating their HSP.
“When we treated [them] to induce vitiligo they turned white; and when we treated [the mice] with the mutant HSP [protein] we prevent[ed] that," said Guevara.
Scientists also saw the patchy white fur of mice with vitiligo transform to black after the animals were vaccinated with the modified stress protein, which calmed the immune attack. Experiments using human skin tissue samples also showed similar immune responses.
Researchers hope to formulate a vaccine and conduct human trials within the next few years.
An article on the genetically modified skin protein to reverse vitiligo is published in the journal Science Translational Medicine.