News - 05 Mar `19HSP70i is back to spotlight as potential therapy for vitiligo


Vitiligo is a T-cell mediated autoimmune disease of the skin. Half of all cases begin in childhood and women are 25% more likely than men to develop vitiligo. No association has been established with patient's ethnic or socio-economic background. However, the disease severity seems to be higher in the industrialized regions -- suggesting a substantial role of chemical or environmental triggers in vitiligo development. 

There are no effective therapies available for vitiligo at the moment. Existing treatments seldom induce lasting repigmentation, an average relapse time is under five years. Halting the disease progression and re-establishing pigmentation are two different phases that require different treatment strategies working alongside. While the latter phase -- repigmentation process -- has been relatively well understood, the same isn't true for the first phase. 

Inducible heat shock protein 70 (HSP70i) has gained attention for its role in precipitating vitiligo about ten years ago. Activity of a mutant version of HSP70i was first researched at Loyla University by Prof. Caroline Le Poole and colleagues. In theory, HSP70i mediates depigmentation process driven by the normal defensive immune mechanicsm known as "killer" T-cells. Rouge T-cells mistakenly identify healthy melanocytes as intruders and kill them. HSP70i may be regarded as a target candidate for stopping rouge T-cells and thereby reversing an autoimmune process

HSP70i consists of 641 building blocks called amino acids. By genetically editing just one or two amino acids researchers are able to change the desired protein activity. Injection of the modifed protein stops vitiligo progression in lab mice. Preclinical data obtained in mouse models support the trial of the mutant HSP70i in humans. 

However, other researchers express their concrens about potential complications. The HSP70 family of proteins is quite extensive. It is yet unknown whether a single stress protein mediates the destruction of skin color or there are more out there. It is also unknown whether selective inactivation of T-cells and dampening autoimmune responses will have consequences for other, healthy immune responses. Toxicity effects in real humans also remain unclear. 

HSP70i-based therapy for vitiligo is now being developed by Temprian Therapeutics Inc. from Chicago, IL. The company is seeking regulatory approval and funding for clinical trials.