MODULATION OF CUTANEOUS SP RECEPTORS IN ATOPIC-DERMATITIS AFTER UVA IRRADIATION

Atopic dermatitis is a pruritic inflammatory skin disorder, involving immunological and non-immunological factors. Substance P seems to be i nvolved in the pathogenesis of atopic dermatitis. Substance P-containi ng nerve fibers are increased in the lesional skin of patients with at opic dermatitis and a reduced weal and hare reaction to intradermal in jection of substance P has been observed. We investigated the distribu tion of substance P receptors in the involved skin of patients before and after single or repetitive UVA irradiations. Our results indicate that substance P receptors of the NK-1 subtype are ex-pressed on blood vessels and on epidermal keratinocytes of involved skin of patients w ith atopic dermatitis. UVA irradiations did not modify the epidermal d istribution of substance P receptors but decreased their expression in tensity on blood vessels. UVA irradiations seem to decrease skin infla mmation through the modulation of NK-1 receptor expression on endothel ial cells.