IL-25 keratinocyte priming enhances paracrine fibroblast inflammatory responses

(A) Experimental design. HD fibroblasts (HDF) were cultured in the presence of 12.5% conditioned medium (CM) from HD (blue) or SSc (pink) keratinocytes primed or not with IL-25 (IL-25⁺KCM). Keratinocyte culture medium ±IL-25, with no cells, was used as negative control, and HDF cultured with IL-25 (12.5 ng/ml) as control for possible carryover. IL-6, IL-8, MMP-1 and collagen-I levels assessed by ELISA in HDF supernatants. Circles represent KCM from independent donors. Horizontal lines represent medians. Wilcoxon signed-rank-test, *P ≤ 0.05. Full data set reported in Supplementary Tables S3A and B, available at Rheumatology online. Col I: type-I collagen; HD: healthy donor; IL-25⁺KCM: CM from keratinocytes primed with IL-25; KCM: CM from keratinocytes.