After vaccination, it has been observed that the group of infected individuals experienced a reduction in severe symptoms. However, the majority of those with severe symptoms are typically found in the group of individuals with underlying health conditions such as heart disease, high blood pressure, and diabetes.
In addition to this, in the group of critically ill patients, approximately 15% have immune system deficiencies related to the Type I interferon pathway, which was discovered in 1957 as a mechanism that directly destroys viruses. Furthermore, research led by Professor Witkowski has shown that patients with severe infections have high levels of anti-inflammatory substances in their bloodstream, which is associated with the response of NK cells to the SAR-CoV-2 virus.
It has recently been discovered that NK cells, a type of white blood cell, can function in various ways, relying solely on the innate immune system. One of their mechanisms involves monitoring cells infected by viruses and then immediately destroying them upon detection by releasing cytotoxic granules. Moreover, NK cells also have a mechanism that involves collaboration between the innate and adaptive immune systems. They produce a substance called chemokines, which modulate the behavior of other immune cells, leading to a coordinated immune response. Thus, NK cells play a crucial role in the immune system.
The diversity of antiviral mechanisms that NK cells possess has garnered interest, particularly during the Covid-19 pandemic. Scientists have begun to collect data and study the number and ability of NK cells to destroy viruses, leading to an increase in information about NK cells. It has been concluded that if the number of NK cells is lower than normal, the likelihood of viral infection increases. Further studies have been conducted in groups of people infected with Covid to determine the relationship between NK cell levels and symptom severity. Scientists have found that in the early stages of infection, the amount of virus decreases rapidly while the number of NK cells in the bloodstream is very high.
The results of this data have led scientists to experiment with NK cells from healthy individuals in the laboratory to observe their effectiveness in destroying the Covid-19 virus. It was found that they could effectively destroy the virus. However, when compared with NK cells obtained from Covid patients with moderate to severe symptoms, it was found that in patients with moderate symptoms, NK cells still had the efficiency to bind to infected cells and release Cytotoxic substances to destroy the virus at higher levels than normal. In contrast, NK cells from patients with severe symptoms were found to produce less Chemokine and Cytokine than those from healthy individuals and patients with mild to moderate symptoms.
The inability of NK cells to function normally in patients with severe symptoms has led scientists to recognize the importance of NK cells beyond their role in destroying cancer cells or common flu viruses. The ability of NK cells to destroy newly emerging viruses such as SAR CoV2, which causes Covid-19, is also significant. Additionally, NK cells can protect the lungs from a condition called lung fibrosis, which prevents the lungs from functioning normally in some infected individuals.
Scientists are now looking into treatments for patients by finding ways to enhance the efficiency of NK cells. Given the uncertainty of what viruses we may encounter in the future that could potentially cause harm to both life and the economy, similar to Covid-19, our first line of defense against emerging diseases is our immune system. It is not surprising, therefore, that NK cells have become a focus of attention for scientists in conjunction with future treatments to prevent and cure diseases. The intelligence of NK cells to destroy viruses, even those that the body encounters for the first time or those that evade or mutate, is remarkable. Knowing the number and efficiency of NK cells in our body allows us to maintain and improve their performance, which is undoubtedly beneficial for our future health.
Reference documents
- Narni-Mancinelli, E. and Vivier, E., 2021. Clues that natural killer cells help to control COVID.
- Ghasemzadeh, M., Ghasemzadeh, A. and Hosseini, E., 2021. Exhausted NK cells and cytokine storms in COVID-19: Whether NK cell therapy could be a therapeutic choice. Human immunology.
- Jeyaraman, M., Muthu, S., Bapat, A., Jain, R., Sushmitha, E.S., Gulati, A., Anudeep, T.C., Dilip, S.J., Jha, N.K., Kumar, D. and Kesari, K.K., 2021. Bracing NK cell based therapy to relegate pulmonary inflammation in COVID-19. Heliyon, 7(7), p.e07635.
- Soleimanian, S. and Yaghobi, R., 2020. Harnessing memory NK cell to protect against COVID-19. Frontiers in Pharmacology, p.1309.
- Alrubayyi, A., 2020. NK cells in COVID-19: protectors or opponents?. Nature Reviews Immunology, 20(9), pp.520-520.