Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học General Psychiatry cung cấp cho các bạn kiến thức về ngành y đề tài: Heterogeneity of human effector CD4+ T cells. | Available online http content 11 6 257 Review Heterogeneity of human effector CD4 T cells Francesco Annunziato and Sergio Romagnani Center of Excellence for Research Transfer of Research and High Education for the Development of Novel Therapies DENOthe Department of Internal Medicine University of Florence Viale Morgagni 85 Florence 50134 Italy Corresponding author Sergio Romagnani Published 9 December 2009 This article is online at http content 11 6 257 2009 BioMed Central Ltd Arthritis Research Therapy 2009 11 257 doi ar2843 Abstract For many years the heterogeneity of CD4 T-helper Th cells has been limited to Th1 and Th2 cells which have been considered not only to be responsible for different types of protective responses but also for the pathogenesis of many disorders. Th1 cells are indeed protective against intracellular microbes and they are thought to play a pathogenic role in organ-specific autoimmune and other chronic inflammatory disorders. Th2 cells provide protection against helminths but are also responsible for the pathogenesis of allergic diseases. The identification and cloning of new cytokines has allowed one to enlarge the series of functional subsets of CD4 Th effector cells. In particular CD4 Th cells producing IL-17 and IL-22 named Th17 have been initially implicated in the pathogenesis of many chronic inflammatory disorders instead of Th1 cells. However the more recent studies in both humans and mice suggest that Th17 cells exhibit a high plasticity toward Th1 cells and that both Th17 and Th1 cells may be pathogenic. More recently another two subsets of effector CD4 Th cells named Th9 and Th22 cells have been described even if their pathophysiological meaning is still unclear. Despite the heterogeneity of CD4 effector Th cells being higher than previously thought and some of their subsets exhibiting high plasticity the Th1 Th2 paradigm still maintains a strong .
