Interleukin 1 Alpha and Beta in Psoriatic Skin: Enzymoimmunoassay, Immunoblot Studies and Effect of Systemic Retinoids

Interleukin 1 alpha (IL-1 alpha) and interleukin 1 beta (IL-1 beta) 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-1 alpha was the principal form detected in all the specimens, which contrasts with the predominance of IL-1 beta in human blood monocytes. In psoriatic plaques relatively less IL-1 alpha and more IL-1 beta 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.