The production of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) from cultured dermal fibroblasts. Dermal fibroblasts were obtained from affected skin of two patients with systemic sclerosis (SSc) and two healthy controls. Second- or third-passage fibroblasts (5 × 104 cells) were cultured for 24 hours in Dulbecco's modified Eagle's medium alone and in the presence of IL-1β (10 ng/ml), tumor necrosis factor (TNF)-α (10 ng/ml), transforming growth factor β (TGFβ) (10 ng/ml), IL-1β (10 ng/ml) plus cyclosporin A (CsA) (500 ng/ml), or TNF-α (10 ng/ml) plus CsA (500 ng/ml). The concentrations of MMP-9 in the supernatants were determined by ELISA. Data are expressed as means ± standard error of the mean (SEM) of two independent experiments performed in triplicate using different cell lines. *P < 0.05, **P < 0.01, ***P < 0.001 versus medium alone (Mann–Whitney rank sum test).