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Cencioni. Neuroimmunol Neuroinflammation 2020;7:277-90 Neuroimmunology
DOI: 10.20517/2347-8659.2020.18 and Neuroinflammation

Review Open Access

The immune regulation of PD-1/PDL-1 axis, a
potential biomarker in multiple sclerosis

Maria Teresa Cencioni

Division of clinical neurology, Brain Sciences department, Imperial College London, London W12 0NN, UK.
Correspondence to: Dr. Maria Teresa Cencioni, Clinical neurology division, Brain sciences department, Imperial College London,
Du cane road, London W12 0NN, UK. E-mail: m.cencioni@imperial.ac.uk

How to cite this article: Cencioni MT. The immune regulation of PD-1/PDL-1 axis, a potential biomarker in multiple sclerosis.
Neuroimmunol Neuroinflammation 2020;7:277-90. http://dx.doi.org/10.20517/2347-8659.2020.18

Received: 20 Feb 2020 First Decision: 31 Mar 2020 Revised: 16 Apr 2020 Accepted: 24 Apr 2020 Available Online: 30 Jul 2020

Academic Editor: Roberta Magliozzi Copy Editor: Jing-Wen Zhang Production Editor: Jing Yu

Abstract
Multiple sclerosis is an autoimmune disease characterised by a chronic inflammation within the central
nervous system. In the last ten years, studies on multiple sclerosis have been concentrated on the discovery
of new biomarkers of disease and potential therapeutic targets. In chronic infection or in cancer, the immune
system response is faulty and maintained in a condition defined as T-cell exhaustion induced by expression of
co-inhibitory receptors. The PD-1/PDL-1 pathway is demonstrated to be the main one responsible for promoting
T-cell exhaustion, and immunotherapies targeting PD-1 or PDL-1 have shown beneficial clinical outcomes in several
tumours and chronic diseases. Contrarily, transcriptional T-cell exhaustion signature and high expression of
co-inhibitor receptor PD-1 are associated with favourable prognosis in multiple sclerosis and other autoimmune
diseases. Several studies have clearly demonstrated PD-1 has a dual role in immune self-tolerance: to constrain
autoreactive T cells in anergic condition and to protect the tissue from the damage caused by the activation of
endogenous autoreactive T cells. Consequently, immune checkpoint inhibitor therapies that target inhibitory
receptors in cancer cause an exacerbation of autoimmune diseases. This review describes the roles of the PD-1/
PDL-1 pathway in cancer and autoimmune diseases, especially in multiple sclerosis, and how manipulating PD-1
can be a therapeutic approach in multiple sclerosis.

Keywords: T-cell exhaustion, inhibitory checkpoints pathways, PD-1/PDL-1 axis in autoimmune disease, multiple
sclerosis, immune checkpoint inhibitor treatments, multiple sclerosis biomarkers

© The Author(s) 2020. Open Access This article is licensed under a Creative Commons Attribution 4.0
International License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use,
sharing, adaptation, distribution and reproduction in any medium or format, for any purpose, even commercially, as long
as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license,
and indicate if changes were made.

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