IL-8, MCP-1, and IP-10 production by SSc/control fibroblasts in response to TGF-β and T cell cytokines. Fibroblasts were plated at 2 × 104 cells/well; 72 hours later the culture medium was replaced and TGF-β (10 ng/ml), IFN-γ (1,000 U/ml), IL-4 (10 ng/ml) and IL-13 (10 ng/ml) were added to the wells in triplicate cultures. When used in combination TGF-β, IL-4 and IL-13 were used at 5 ng/ml each. Chemokine levels were determined in the supernatants by enzyme-linked immunosorbent assay upon 48 hours of further culture. The bars represent the mean ± standard error of eight distinct experiments in which SSc and control fibroblasts, matched for passage, age and sex of the donor, were cultured in parallel. IFN, interferon; IL, interleukin; IP, interferon-γ inducible protein; ND, not detectable; MCP, monocyte chemoattractant protein; SSc, systemic sclerosis; TGF, transforming growth factor; Th, T-helper.