Eosin treatment for psoriasis reduces skin leukocyte infiltration and secretion of inflammatory chemokines and angiogenic factors

BACKGROUND: Eosin has been traditionally employed as a topical treatment for psoriasis, but the biological mechanism of its therapeutic action has not been fully elucidated. OBJECTIVES: To analyse eosin effects on psoriatic skin in vivo and keratinocytes and endothelial cells in vitro. MATERIALS & METHODS: Skin biopsies were taken from psoriatic plaques before and after a three-day eosin treatment and processed for histological analysis. Cultured human psoriatic keratinocytes and dermal endothelial cells were treated with eosin, and release of inflammatory chemokines was analysed by multiplexed bead-based immunoassay and ELISA. RESULTS: In patients, the three-day eosin treatment significantly reduced the number of infiltrating T lymphocytes, neutrophilic granulocytes, and dermal dendritic cells. A reduction in VEGF-A expression was also observed. In vitro, eosin treatment significantly decreased the release of CCL2, CCL5, and VEGF-A by keratinocytes and angiopoietin-2 by endothelial cells. CONCLUSIONS: Eosin treatment impacts on psoriatic inflammatory infiltrates and dampens the release of proinflammatory chemokines and angiogenic factors.