IL-4 expression by neutrophils in psoriasis lesional skin upon high-dose UVB exposure.

BACKGROUND

Upon a single high dose of UVB irradiation of psoriatic lesional skin, IFN-gamma expression is decreased, whereas IL-4 expression is enhanced. A similar type 1 to type 2 shift was found in dermal T cells derived from irradiated lesional skin as compared to unexposed lesional psoriatic skin. We have found recently that the IL-4 protein detected in situ upon UVB exposure of normal skin was not associated with T cells but with infiltrating neutrophils.

OBJECTIVE

To determine which cell types express IL-4 in psoriatic skin after UVB irradiation.

METHODS

Skin biopsies were obtained from healthy controls and psoriasis patients before and after local UVB exposure. Double immunohistochemical stainings were performed to determine the identity of IL-4-expressing cells.

RESULTS

In the irradiated skin of both healthy controls and patients, IL-4-positive cells coexpressed elastase and CD15, but not CD3.

CONCLUSION

IL-4-expressing cells found in psoriatic skin after a single high-dose UVB exposure appeared to be neutrophils.