TNF and psoriasis: In contrast, the progression of psoriasis in the subnetwork formed by \documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\hbox {TNF}_{\alpha }$$\end{document}TNFα is found to occur without bistability, instead giving rise to a monotonic increase in the keratinocyte population.