Development of a Method to Measure mRNA Levels in Skin Samples

Subjects underwent skin squame collection by scraping. The investigator gently scraped the surface of a lesional skin area for patients with psoriasis, and of a non-lesional skin area for healthy volunteers to collect superficial cells. These samples were analyzed by gene expression analyses.

The first subjects had up to 35 tape strips from a maximum of 4 areas (4 X 35 strippings) on the trunk or limbs (excluding the genital area). Patients with atopic dermatitis or psoriasis had tape stripping performed on lesional skin areas and the control subjects had tape stripping performed on nonlesional skin areas. The next subjects were used to determine the optimal number of tape strips required to obtain a good signal by gene expression analyses.

Subjects had tape stripping on up to 3 different skin areas (2 areas on lesional skin and one area of nonlesional skin for patients with atopic dermatitis or psoriasis, and 2 areas of healthy skin for control subjects) using the optimal number of tape strips, as determined in the previous part. One 4-mm skin biopsy on a tape stripped area plus one 4-mm biopsy on non-tape-stripped skin (2 biopsies per subject) were also collected.