No abstract

No abstract

Interleukin 1α (IL-1α) and interleukin 1β (IL-1β) proteins were studied by enzymoimmunoassay (EIA) and Immunoblot analysis in the 10,000 g supernatant of normal and psoriatic (lesional and nonlesional) human skin specimens. By EIA IL-1α was the principal form detected in all the specimens which contrasts with the predominance of IL-1β in human blood monocytes. In psoriatic plaques relatively less IL-1α and more IL-1β were detected. On Immunoblot analysis the mature form (17 kD) was not detected in normal skin, which showed only 52-kD immunoreactive forms. In contrast the 17-kD form was found in psoriatic skin. This indicates either a distinct processing of IL-1 molecules or a contribution of inflammatory cells infiltration to the IL-1 pool in psoriatic plaques. During systemic retinoids therapy the amount of both IL-1 species decreased in lesional and nonlesional psoriatic skin.

The topical application of 0.1% retinoic acid (RA) on human skin over a period of 4 days, whether or not under occlusion, did not increase either IL-1 alpha or beta immunoreactivity as determined by a sensitive enzymoimmunoassay. No down modulation was seen following the application of a potent topical corticosteroid. Occlusion increased the yield of IL-1 beta immunoreactivity. Immunoblot patterns of epidermal extracts revealed both the mature form of IL-1 (17 kDa) and the precursor (36 kDa) and were identical in amounts whether the specimens were from controls or from RA- or corticosteroid-treated skin. There was a slight modification in the pattern of high molecular weight proteins (52 kDa) probed by the anti-IL-1 alpha and beta sera. It appears that the IL-1 epidermal immunoreactive pools are barely amenable to modulation because they represent a storage form linked to end-stages of keratinocyte differentiation.

No abstract