We all know that vitiligo can cause disfiguring white spots to appear anywhere on the body. John Harris, (director, the Vitiligo Clinic, and Research Center at the University of Massachusetts Medical School) has been working for years to find a cure for the chronic skin disorder. And, recently his team has managed to find the first clue towards restoring the pigmentation in the skin. Harris successfully tested an experiment on a mice that developed vitiligo on his ears, feet, and tail.
The researcher began studying vitiligo in 2008 to discover better treatments for vitiligo. In a recent report published in Science Translational Medicine, he describes a new therapy that is showing promise in mice with vitiligo.
The skin has a memory.
Existing vitiligo treatments like topical steroids and phototherapy, though not FDA-approved to treat vitiligo, can produce effective results in many people. These treatments often succeed in reversing the disease by stimulating brown spots to appear around hair follicles within the affected areas of the skin. As these brown dots grow and merge, vitiligo starts disappearing. However, in many cases, vitiligo reappears at the same location within just one year after stopping the treatments.
Harris’ team suspected that “memory” forms within the skin can make patches to reappear or return when the chosen treatment is stopped. The memory cells that protect the skin from the second exposure to a viral infection misread the pigment-producing cells as infection and kill them. These cells are called “resident memory T cells.” Harris hypothesized that if he and his team could remove these memory cells from the skin, then treatments to pigment the skin would be long-lasting and probably permanent.
Because the vitiligo skin in mice or humans looks a lot alike (mice also have memory T-cells), the hypothesis was tested on a mice with vitiligo. Since the vitiligo-causing memory cells require a special protein called “IL-15” to survive, Harris’ team injected the mice with an antibody that blocks the IL-15 protein from interacting with the memory cells. After just a few weeks, the treatment wiped out the memory cells from the mouse skin, allowing the brown pigment to return in a patchy pattern.
Clinical trial to start next summer
Although this antibody-drug has only been proven to work in mice, testing the same method in humans would be worth a try, to sustain the positive results of topical steroids and light therapy. Harris is working with the National Institutes of Health-funded Immune Tolerance Network (ITN) for a clinical trial to test this antibody treatment in human with vitiligo. The trial is expected to begin recruiting patients next summer.