IL-10 levels are decreased in psoriatic lesional skin as compared to the psoriatic lesion-free and normal skin suction blister fluids.

IL-10 is a cytokine produced by B and T-cells, monocytes and keratinocytes with pleiotropic effects, some of which are directed towards suppressing monocyte activities (anti-inflammatory cytokine). No information at the protein level is available concerning IL-10 in suction blister fluids from psoriatic skin, even if contrasting data have been reported on IL-10 mRNA of psoriatic biopsies and on the cytokine patterns of the T-cell clones, isolated from psoriatic skin. The IL-10 blister fluid concentrations in psoriatic lesions were compared to those found in the non-lesional skin of 14 patients effected with plaque-type psoriasis, and to those found in the skin of healthy controls (9 subjects sharing sex ratio and age with psoriatic patients). No difference in the IL-10 levels was found between non-lesional and control skin. In contrast, lower IL-10 levels were observed in blister fluids obtained from lesional psoriatic skin (p < 0.0005). The possible meanings of these results have been evaluated in the context of the mechanisms activating or maintaining the chronic inflammatory components of psoriasis.