AUTHOR=De Jesús-Gil Carmen , Ruiz-Romeu Ester , Ferran Marta , Chiriac Anca , Deza Gustavo , Hóllo Péter , Celada Antonio , Pujol Ramon M. , Santamaria-Babí Luis F. 

TITLE=CLA+ T Cell Response to Microbes in Psoriasis

JOURNAL=Frontiers in Immunology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2018.01488

DOI=10.3389/fimmu.2018.01488

ISSN=1664-3224

ABSTRACT=<p><italic>Streptococcus pyogenes</italic> throat infection is a clinically relevant trigger of both guttate and chronic plaque psoriasis, and it provides an ideal context in which to study the pathogenesis of these diseases using an antigen-dependent approach. Circulating cutaneous lymphocyte-associated antigen (CLA) positive (+) memory T cells are a subset of peripheral lymphocytes whose phenotype and function are related to immunological mechanisms in the skin. These cells are considered peripheral biomarkers of T-cell-mediated skin diseases. The coculture of autologous epidermal cells with CLA<sup>+</sup> T cells from psoriasis patients activated by <italic>S. pyogenes</italic> allows the reproduction of the <italic>ex vivo</italic> initial molecular events that occur during psoriatic lesion formation. With cooperation of autologous epidermal cells, <italic>S. pyogenes</italic> selectively activates CLA<sup>+</sup> T cells both in guttate and plaque psoriasis, inducing key mediators, including an IL-17 response. Here, we explore potential new mechanisms of psoriasis development including the influence of HLA-Cw6 on <italic>S. pyogenes</italic> CLA<sup>+</sup> T cell activation in guttate psoriasis, the relevance of IL-9 on microbe induced IL-17 response in guttate and plaque psoriasis, and novel effector functions of <italic>Candida albicans</italic>. This review will summarize recent knowledge of psoriatic mechanisms elicited by microbes that have been studied through an innovative translational perspective based on CLA<sup>+</sup> T cell-mediated cutaneous immune response.</p>