Exposure to dust mites, a trigger for vitiligo?

Invisible to the naked eye, dust mites belong to the arthropod family. They typically live for around three months and thrive in warm, humid environments, ideally at a temperature of 25-30°C. This is why these microorganisms are predominantly found in bedding, household linen, upholstered furniture, and carpets. Contrary to popular belief, they can proliferate even in a clean home. While they are primarily associated with allergic reactions, dust mites are also suspected to contribute to the development of vitiligo, an autoimmune dermatosis that is characterised by the appearance of white patches on the skin. This is at least what a recent study published by researchers from INSERM suggests.

As a reminder, vitiligo is characterised by a loss of melanocytes, the cells responsible for skin pigmentation. This phenomenon, maintained by the immune system, occurs particularly through the destruction of E-cadherins, proteins that allow the cells of the epidermis to adhere to each other. However, several previously conducted studies have shown that mites produce proteases, enzymes that break down the peptide bonds of proteins. The question that arises is: do mites produce a protease that destroys E-cadherins?

To answer this question and better understand the role of mites in the onset of vitiligo, researchers used samples of epidermis taken from patients with vitiligo and from unaffected volunteers. They then exposed these samples to mites and observed that this contact triggered the secretion of chemokines and pro-inflammatory cytokines, as well as an increase in the concentration of proteases, with dose-dependent responses: the higher the quantity of mites used for the experiment, the stronger the concentrations of cytokines and proteases. Furthermore, they confirmed that one of the proteases released by the mites, Der p1, is responsible for the destruction of E-cadherins in the epidermis and the detachment of melanocytes.

These various phenomena, observed across all samples, were approximately a hundred times more significant in those derived from patients suffering from vitiligo. This led the researchers to suspect a heightened susceptibility to mites in certain skin types, with more fragile cellular junctions at the epidermis level and a more reactive immune system. However, some areas of uncertainty remain: is exposure to mites a genuine trigger factor for vitiligo, or do mite allergies simply represent a common associated comorbidity? To answer these questions, further research is still needed, as the aforementioned study is, to date, the only one conducted on this subject.