There is much to be learned still as to why some people with COVID-19 are asymptomatic while others develop symptoms, sometimes severe. The prevailing theory is that their immune systems fight off the virus so efficiently that they never get sick. But some scientists are confident that the immune system’s aggressive response, the churning out of antibodies and other molecules to eliminate an infection, is only part of the story.
Our knowledge of how our immune system fights off a virus is constantly evolving and involves both disease tolerance and resistance. The phenomenon of disease tolerance, which is an inherent component of immunity, is defined as the ability of a host to limit the impact of pathogens. In other words, it is the mechanism that limits tissue damage independent of changes to pathogen burden. This is different from disease resistance, in which the host is able to prevent infection or reduce the number of pathogens. Disease tolerance is well-known in plants but has only been documented in animals within the last 15 years. Disease tolerance may at least partially explain why some infected people have mild symptoms or none at all.
Dr. Irah King sheds some light about disease tolerance in light of the recent COVID-19 pandemic. Read the full article here:
Why Do Some People Weather Coronavirus Infection Unscathed? Some scientists are confident that the immune system’s aggressive response to infection is only part of the story.by Emily Laber-Warren
Editorial: Evolving Mechanisms of Disease Tolerance. King IL, Divangahi M. Front Immunol. 2019 Dec 20;10:2974.
In this editorial, Divangahi and King discuss the history of disease tolerance. The concept of disease tolerance was first introduced following observations in plants in the late 19th century. It was only more than a century later that similar observations were seen in animals following infection. This then opened up a whole new field of immunology that started to tease out the cellular and molecular mechanisms of this concept.
A deeper understanding of disease tolerance could lead to “a new golden age of infectious disease research and discovery,”Irah King and Maziar Divangahi
A series of reviews are featured in this issue that detail how this defense strategy is conserved from plants to humans against diverse forms of infection. Reviews by Meakins members are prominently featured, including:
- Beyond Killing Mycobacterium tuberculosis: Disease Tolerance. Divangahi M, Khan N, Kaufmann E. Front Immunol. 2018 Dec 19;9:2976.
- Resistance and Tolerance to Cryptococcal Infection: An Intricate Balance That Controls the Development of Disease. Shourian M, Qureshi ST. Front Immunol. 2019 Jan 29;10:66.
- Pseudomonas aeruginosa in Chronic Lung Infections: How to Adapt Within the Host? Faure E, Kwong K, Nguyen D. Front Immunol. 2018 Oct 22;9:2416.
- Alveolar Macrophages in the Resolution of Inflammation, Tissue Repair, and Tolerance to Infection. Allard B, Panariti A, Martin JG. Front Immunol. 2018 Jul 31;9:1777.
- Host–Parasite Interactions Promote Disease Tolerance to Intestinal Helminth Infection. King IL, Li Y. Front Immunol. 2018 Sep 20;9:2128.