Drivers of Inflammation in Psoriatic Arthritis: the Old and the New

TY - JOUR

T1 - Drivers of Inflammation in Psoriatic Arthritis

T2 - the Old and the New

AU - O’Brien-Gore, Charlotte

AU - Gray, Elizabeth H.

AU - Durham, Lucy E.

AU - Taams, Leonie S.

AU - Kirkham, Bruce W.

N1 - Funding Information: This work was funded by a Medical Research Council clinical training fellowship to LED (Ref MR/P018904/1), a King’s College London funded studentship to EHG and the National Institute for Health Research (NIHR) Biomedical Research Centre based at Guy’s and St Thomas’ NHS Foundation Trust and King’s College London. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. Publisher Copyright: © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2021/6

Y1 - 2021/6

N2 - Purpose of Review: The recognition that IL-17 is produced by many lymphoid-like cells other than CD4+ T helper (Th17) cells raises the potential for new pathogenic pathways in IBD/psoriasis/SpA. We review recent knowledge concerning the role of unconventional and conventional lymphocytes expressing IL-17 in human PsA and axSpA. Recent Findings: Innate-like lymphoid cells, namely gamma delta (γδ) T-cells, invariant natural killer T (iNKT) cells and mucosal-associated invariant T (MAIT) cells, together with innate lymphoid cells (ILCs) are found at sites of disease in PsA/SpA. These cells are often skewed to Type-17 profiles and may significantly contribute to IL-17 production. Non-IL-23 dependent IL-17 production pathways, utilising cytokines such as IL-7 and IL-9, also characterise these cells. Both conventional CD4 and CD8 lymphocytes show pathogenic phenotypes at sites of disease. Summary: A variety of innate-like lymphoid cells and conventional lymphocytes contribute towards IL-17-mediated pathology in PsA/SpA. The responses of these cells to non-conventional immune and non-immune stimuli may explain characteristic clinical features of these diseases and potential therapeutic mechanisms of therapies such as Jak inhibitors.

AB - Purpose of Review: The recognition that IL-17 is produced by many lymphoid-like cells other than CD4+ T helper (Th17) cells raises the potential for new pathogenic pathways in IBD/psoriasis/SpA. We review recent knowledge concerning the role of unconventional and conventional lymphocytes expressing IL-17 in human PsA and axSpA. Recent Findings: Innate-like lymphoid cells, namely gamma delta (γδ) T-cells, invariant natural killer T (iNKT) cells and mucosal-associated invariant T (MAIT) cells, together with innate lymphoid cells (ILCs) are found at sites of disease in PsA/SpA. These cells are often skewed to Type-17 profiles and may significantly contribute to IL-17 production. Non-IL-23 dependent IL-17 production pathways, utilising cytokines such as IL-7 and IL-9, also characterise these cells. Both conventional CD4 and CD8 lymphocytes show pathogenic phenotypes at sites of disease. Summary: A variety of innate-like lymphoid cells and conventional lymphocytes contribute towards IL-17-mediated pathology in PsA/SpA. The responses of these cells to non-conventional immune and non-immune stimuli may explain characteristic clinical features of these diseases and potential therapeutic mechanisms of therapies such as Jak inhibitors.

KW - Innate immunity

KW - Interleukin-17

KW - Psoriatic arthritis

KW - Spondyloarthritis

KW - Synovial fluid

UR - http://www.scopus.com/inward/record.url?scp=85104962637&partnerID=8YFLogxK

U2 - 10.1007/s11926-021-01005-x

DO - 10.1007/s11926-021-01005-x

M3 - Review article

AN - SCOPUS:85104962637

SN - 1523-3774

VL - 23

JO - Current Rheumatology Reports

JF - Current Rheumatology Reports

IS - 6

M1 - 40

ER -