Lobbins MLB, et al. - The effect of IL-13 on TNF-α-induced matrix metalloproteinase-1 expression in normal and scleroderma human dermal fibroblast lines, was investigated and the involvement of serine/threonine kinase B/Akt in this response was tested, in order to elucidate the mechanism(s) involved. In TNF-α-stimulated normal and scleroderma dermal fibroblast, MMP- was suppressed by Il-13. The suppressive effect of IL-13 on MMP-1 expression and protein synthesis was reversed by Akt inhibitor VIII.