Hypothesis and Theory ARTICLE
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome as a hyper-regulated immune system driven by an interplay between regulatory T cells and chronic human herpesvirus infections
- 1Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
- 2Centre of Statistics and its Applications, University of Lisbon, Portugal
- 3Gulbenkian Institute of Science, Portugal
- 4Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
Autoimmunity and chronic viral infections are recurrent clinical observations in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), a complex disease with an unknown cause. Given these observations, the regulatory CD4+ T cells (Tregs) show promise to be good candidates for the underlying pathology due to their known capacity to suppress the immune responses not only to body components but also against infections. Here we discussed the overlooked role of these cells in the chronicity of Human Herpes Virus 6 (HHV6), Herpes Simplex 1 (HSV1) and Epstein-Barr virus (EBV), as often reported as triggers of ME/CFS. Using simulations of the Cross-regulation model for the dynamics of Tregs, we illustrated that mild infections might lead to a chronically activated immune responses under control of Tregs if the responding clone has a high autoimmune potential. Such infections promote persistent inflammation and possibly fatigue. We then hypothesized that ME/CFS is a condition characterized by a predominance of this type of infections under control of Tregs. In contrast, healthy individuals are hypothesized to trigger immune responses of a virus-specific clone with a low autoimmune potential. According to this hypothesis, simple model simulations of the CD4+ T-cell repertoire could reproduce the increased density and percentages of Tregs observed in patients suffering from the disease when compared to healthy controls. A deeper analysis of Tregs in the pathogenesis of ME/CFS will help to assess the validity of this hypothesis.
Keywords: viral infection, Autoimmunity, Immunological theory, Immunological Tolerance and Regulation, hypothesis, mathematical modelling, Disease pathology
Received: 19 Jun 2019;
Accepted: 31 Oct 2019.
Copyright: © 2019 Sepúlveda, Carneiro, Lacerda and Nacul. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Mx. Nuno Sepúlveda, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Department of Infection Biology, London, WC1E 7HT, United Kingdom, email@example.com