Immune-mediated Inflammation: Human T CD4 helper lymphocyte diversity and plasticity in Health and Disease

RODOLFO KOLLIKER FRERS; FRANCISCO CAPANI

Cell of the inmuno system

intechopen

Año: 2019; p. 24 - 72

The CD4+ T helper (Th) cells have a critical role in organizing the adaptiveimmune response. The emerging cells of the differentiation after the immunesynapse produce helper T cell subpopulations that activate, suppress, or regulatethe immune response upon interaction with varying immune cells. There are twomain Th cell functional categories: the ?effector cells? and the ?regulatory T cells.?Classic T helper lymphocytes can also be distinguished by their lineage accordingto the developmental microenvironment, the expression of cell adhesion-homingreceptors, the profile of cytokines they are exposed to, and the involved transcriptionfactors. Traditionally, the CD4+ and CD8+ phenotypes have been consideredas helper and cytotoxic/suppressor T lymphocytes, respectively. Currently, thedistinction is little rigorous. The immune response is exceedingly complex beyondthe classic Th1 and Th2 effector cells? involvement, and other populations ofhelper T lymphocytes like the Th17, Tfh, Th22, and Th9 lymphocytes have beenphenotypically characterized. These lymphocytes also participate in the pathogenesisof several immune-mediated inflammatory disorders. Here, we revisit anddiscuss the essential aspects of the state of the art regarding phenotypic diversityand plasticity of TCD4 cells in the T lymphocyte repertoire frame and theirpotential implication in human inflammatory diseases.