Expression of interleukin (IL)-1 family members upon stimulation with IL-17 differs in keratinocytes derived from patients with psoriasis and healthy donors.

BACKGROUND: A number of studies have challenged the T-cell-centred pathogenetic view of psoriasis by the finding that epithelium-expressed genes are intimately involved in the inflammatory process. Interleukin (IL)-17 is an important inflammatory mediator in skin psoriasis.
OBJECTIVE: IL-17 is known to act on keratinocytes and we were interested in its impact on the expression of pro- and anti-inflammatory IL-1 family members.
METHODS: We compared human keratinocytes derived from epidermal stem cells of hair follicles plucked from patients with psoriasis and healthy individuals using quantitative reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assays.
RESULTS: In the presence of IL-17, psoriasis-derived keratinocytes showed a significantly higher induction of the proinflammatory IL-1 family members IL-1F6 and IL-1F9, but not of anti-inflammatory members IL-1F5, IL-1F7 or IL-1F3 compared with keratinocytes from healthy individuals. Both basal and IL-17-induced levels of IL-1F2 and IL-1F1 were found to be significantly lower in psoriasis keratinocytes.
CONCLUSION: As keratinocytes were derived from epidermal stem cells of the hair follicles and were obtained from nonlesional sites, differences found are likely to present an intrinsic feature of psoriasis epithelium. Our data support the significance of IL-1 family members as therapeutic targets in psoriasis conditions.