T Cells in Skin Inflammatory Disorders

The skin is comprised of structural, innate and adaptive immune cells. Defects in any of the three arms disrupts skin homeostasis leading to impaired host defence responses and/or skin inflammatory disorders. Skin inflammatory disorders are a group of heterogenous diseases comprised of immunodeficiencies and autoimmune disorders (Psoriasis, Vitiligo, Alopecia areata, Scleroderma) and immune hyperreactivity (atopic dermatitis, allergic contact dermatitis, prurigo nodularis). For many of these diseases, it is well accepted that dysregulated T cell responses drive disease pathogenesis. Given the heterogeneity of T cells as well as the lack of disease specific model systems, what remains unclear is the impact of these T cell subsets as well as their relative contribution to skin inflammation. As mentioned, T cells are a heterogenous group of cells that include conventional T cells, innate-like T cells (NKT and MAIT cells) and  T cells. Conventional T cells, based on differentiation status, are divided into naïve, effector and memory T cells. The latter can be further segregated into central memory (TCM), peripheral memory (TPM) and tissue resident memory (TRM) T cell types, based on their location and migratory patterns. While different studies have elucidated the development, localization and function of different T cell subsets in the context of infectious diseases, there is still a limited understanding of the relative roles of these T cell subsets in the context of inflammatory disorders. This is particularly evident in the context of skin inflammatory diseases, where, due to both a paucity of disease relevant model systems as well as inability to specifically target subsets of T cells, the contribution of different T cell populations to the disease pathology is still unclear.

The proposed Research Topic aims to provide an overview of current investigations of the role of skin T cells during inflammatory diseases. Our goal is to reach out to the immunology and dermatology communities, which we are members of, to submit cutting edge Original Research articles and Reviews focused on various aspects of T cell biology in skin disorders, including spatio-temporal localization of responses, novel model systems and state-of-the art technologies. The aim is to define the role of T cells and the cross talk between T cell populations in the context of skin inflammatory disorders. We welcome submissions covering the following subtopics:

• Spatio-temporal regulation of T cell activation in the skin and skin draining lymph nodes
• Contribution of various resident memory T cell populations including MAIT cells, T cells and conventional T cell subsets to skin immune responses
• Cross-talk between skin resident and systemic memory T cell pool during skin inflammation
• Cross-talk between T cells and non-immune skin cells (keratinocytes, neurons, fibroblasts etc) in skin inflammatory diseases
• Novel animal models of skin inflammatory diseases delineating pathogenic mechanisms driven by tissue resident T cells
• Deep immunophenotyping of skin pathogenic T cells in inflammatory diseases
• Pre-clinical and clinical studies focusing on T cells in skin inflammatory disorders

Dr. Julia and Dr. Krishnaswamy are employees of Galderma, a private pharmaceutical company involved in the production of dermatology related products. The other Topic Editors declare no potential conflicts of interest related to this Research Topic.