DETECTION OF INFLAMMATORY CYTOKINES IN PSORIATIC SKIN

Recent investigations have revealed the involvement of cytokines in th e pathogenesis of psoriasis. This study examined the amount of inflamm atory cytokines - interleukin-1 (IL-1), interleukin-6 (IL-6) and granu locyte macrophage colony-stimulating factor (GM-CSF) - released into t he supernatants of organ cultures of involved and uninvolved skin from psoriatic patients and normal skin from healthy individuals. Bioassay s were employed to detect the activities of IL-1 and IL-6. Enzyme-link ed immunosorbent assay (ELISA) methods were used to quantitate immunor eactive IL-1 alpha, IL-1 beta, IL-6 and GM-CSF. The activity of IL-1 i n uninvolved psoriatic skin was found to be increased relative to that in involved and normal skin, while immunoreactive IL-1 beta was found only in involved skin. A neutralization experiment showed that bioact ive IL-1 was mostly attributable to IL-1 alpha. Uninvolved psoriatic s kin also secreted higher amounts of both bioactive and immunoreactive IL-6 compared with involved skin. Immunoreactive GM-CSF was detected i n uninvolved skin only. These cytokines detected in uninvolved skin ma y have been released from epidermal or mesenchymal cells, since uninvo lved skin contained fewer inflammatory infiltrates. Our results offer additional evidence that increased amounts of inflammatory cytokines i n uninvolved skin may provide a preliminary condition and play importa nt roles in the initial events in the evolution of psoriatic lesions.