Dust Mites Produce Skin-Degrading Allergen

It breaks down skin's barrier to other allergens and environmental irritants

THURSDAY, Sept. 28 (HealthDay News) -- House dust mites produce an allergen that degrades the skin's barrier to environmental irritants, according to a letter published online Sept. 28 in the Journal of Investigative Dermatology.

Toshiro Takai, Ph.D., of Juntendo University School of Medicine in Tokyo, Japan, and colleagues conducted experiments in nude mice using recombinant Der f 1 (Dermatophagoides farinae).

The experiments used two parameters to assess barrier function: transepidermal water loss, as a measure of skin dryness; and penetration by riboflavin of the stratum corneum, a measure of the skin's accessibility to environmental allergens and irritants. The presence of Der f 1 exacerbated both conditions in a time- and dose-dependent manner.

"The barrier dysfunction and morphological changes caused by the cysteine protease activity of recombinant Der f 1 suggest that repeated exposure to mite bodies and fecal pellets could disrupt the local skin's barrier function," the authors write, adding that these sites could become portals for the entry of allergens and irritants.

"As far as we know, this is the first demonstration of the barrier function of the skin being disrupted by the proteolytic activity of an allergen in vivo. Dry skin and an impaired barrier function are hallmarks of the pathogenesis of atopic dermatitis," the authors conclude.

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