Figure 1: Artificially colored coronaviruses under an electron microscope
Source Credit: Fred Hutchinson Cancer Research Center (LINK)
The clear atmosphere that seems deceptively empty is in fact bursting with all sorts of harmful microorganisms, ready to invade the human body at all times. While millions of these foreign invaders infiltrate our systems at every moment, a significant portion of the attempts are rendered obsolete thanks to the immune system, a set of lymphocytes dedicated for the purpose of identifying and removing harmful antigens from the body. However, as odd as it may sound, these loyal defenders sometimes strike down their own allies, a phenomenon that scientists refer to as “autoimmune responses.”
Possible causes that lead to autoimmune responses can mainly be divided into four categories: genetic, hormonal, environmental, and infectious. Autoimmune responses are caused by a variety of different components, with examples ranging from the failure of specific gene expressions to heavy exposure of ultraviolet rays, and even affliction of certain diseases like the Human Immunodeficiency Virus. While autoimmune responses could be categorized in numerous ways depending on their distinct causes and consequences, a shared aspect among all types is the activation of defect immune cells that misidentify normal host cells as sources of danger, eradicating them like how they would do so against foreign pathogens. This deliberate act of self-harm not only damages organs, but also impairs the existing immune system, thus weakening the body and making it more vulnerable to outside forces. Common examples of diseases resulting from autoimmune responses include arthritis, type one diabetes, and sclerosis.
While these autoimmune responses generally tend to be caused by internal factors of the human body, they could also come to be as a byproduct of infections caused by external antigens, as stated previously. Like the Human Immunodeficiency Virus, Researchers have recently discovered that the COVID-19 virus may have close connections with autoimmune responses. A key symptom of COVID-19 is that it triggers the body to release an abnormally large amount of cytokines, a type of hormone that initiates the immune response against pathogens. Cytokines are regulatory hormones that mark the transition from an innate immune response to an adaptive immune response, initializing the CD4 Helper T Cells which in turn allows the activation of Plasma B Cells and CD8 Cytotoxic T Cells. While an appropriate amount of cytokines is necessary in order to empower the immune system, an excessive amount can deregulate the immune system and trigger autoimmune responses. Scientists have named this phenomenon of excess cytokine production as the “cytokine storm syndrome”. Rather than simply activating a greater number of immune cells for longer periods of time, the cytokine storm syndrome is also accompanied by the loss of control over the activated immune cells, preventing the immune system from recognizing healthy cells as harmful pathogens and proceeding to assault them. This indiscriminate attack damages and causes inflammatory responses in multiple sections of the body.
However, this phenomenon also hints at the possibility of utilizing autoimmune disease drugs to alleviate symptoms displayed by patients of COVID-19. As the main problem at hand is the increased degree of inflammation that takes place all over the body, a key consequence of the cytokine storm syndrome, scientists project that taking medication that reduces the production of cytokine, and thus preventing the over activation of the immune system, could potentially lessen the critical effects of COVID-19. As much as how COVID-19 has shown to instigate various critical autoimmune responses and related disorders, such as arthritis and the Guillain-Barré syndrome, multiple researchers have also proven that immunomodulatory drugs like cytokine blockers and inflammation reducing drugs like glucocorticoids are effective at assuaging the viral infection cases.
Q&A:
Xavier: Have scientists begun developing medication that could counteract the overactivation of the immune system mentioned in the final paragraph?
Yes! There are existing medications that combat the overactivation of the immune system, most of which involve immune-suppressing hormones such as cytokine blockers and glucocorticoids.
Jiwon: How are these immunomodulatory and inflammation reducing drugs effective in countering infection cases? In other words, what is the mechanism behind how they work?
Like how their names suggest, immunomodulatory drugs function by suppressing unnecessary immune activation responses. Thus, it could be said that they are effective against infection cases only when there is an excessive immune reaction.
John: What are the socio economic implications of these findings? How can they help alleviate the effects of the current pandemic? Are the side effects of the cytokine inhibitor drugs (some of which are increased susceptibility to pathogens) a logical payoff for dulling the effects of coronavirus on the immune system?
These findings not only provide temporary solutions to some, but also help the development of future medications to combat the current COVID pandemic.
Works Cited:
Ehrenfeld, Michael, et al. "Covid-19 and Autoimmunity." Autoimmunity Reviews, vol. 19, no. 8, Aug. 2020, p. 102597. ncbi, doi:10.1016/j.autrev.2020.102597. Accessed 30 Jan. 2021.
Novelli, Lucia, et al. "The JANUS of Chronic Inflammatory and Autoimmune Diseases Onset
during COVID-19 – a Systematic Review of the Literature." Journal of Autoimmunity, vol. 117, Feb. 2021, p. 102592. ScienceDirect, doi:10.1016/j.jaut.2020.102592. Accessed 30 Jan. 2021.
Shoenfeld, Yehuda, and David A. Isenberg. "The Mosaic of Autoimmunity."Immunology Today, vol. 10, no. 4, Apr. 1989, pp. 123-26. ScienceDirect, doi:10.1016/0167-5699(89)90245-4. Accessed 30 Jan. 2021.
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