However, stimulation of SSc fibroblasts with IL-1β, TNF-α, or TGFβ strongly increased MMP-9 production relative to the unstimulated concentration, by factors of 3.5, 3.2, and 2.3, respectively, whereas fibroblasts of healthy controls responded weakly to these cytokines (by factors of 1.6, 1.5, and 1.2, respectively). The gene discussed is MMP9; the disease is systemic sclerosis.