Q. What is cytokine storm?
A. A cytokine storm, also called cytokine storm syndrome (CSS) or hypercytokinemia, is a physiological reaction in humans and other animals in which the innate immune system causes an uncontrolled and excessive release of pro-inflammatory signalling molecules called cytokines. It is basically an overproduction of immune cells and their activating compounds (cytokines), which, in a flu infection, is often associated with a surge of activated immune cells into the lungs.
The resulting lung inflammation and fluid buildup can lead to respiratory distress and can be contaminated by a secondary bacterial pneumonia often enhancing the mortality in patients.
Of all the possible compounding effects of COVID-19, the disease caused by the novel coronavirus, the cytokine storm is one of the most feared.
Q. What is its occurrence?
A. A cytokine storm can occur due to an infection, auto-immune condition, or other diseases. Signs and symptoms include high fever, inflammation (redness and swelling), severe fatigue, and nausea.
Q. Is it exclusively deals with corona patients?
A. No, Cytokine storms are not exclusive to coronavirus patients. It is an immune reaction that can occur during other infectious and non-infectious diseases as well.
Q. How does our immune systems generally work?
1. The immune systems in our bodies protect us from bacteria, viruses, and parasites by removing them from our systems.
2. The immune system gets activated by things that the body does not recognise as its own. These things are called antigens, and include bacteria, fungi and viruses.
3. An effective immune system response involves inflammation, an important and indispensable part of the process.
4. Inflammation has an important protective function. The release of inflammatory mediators increases the blood flow to the area, which allows larger numbers of immune system cells to be carried to the injured tissue, thereby aiding the repairing process.
If this inflammatory response is not regulated, a ‘cytokine storm’ can be triggered.
Q. What then, is the role of cytokines in the immune system?
A. Cytokines are signalling proteins that are released by cells at local high concentrations a cytokine storm or CSS is characterised by the overproduction of immune cells and the cytokines themselves because of a dysregulation in the process.
A severe immune reaction, leading to the secretion of too many cytokines in the bloodstream, can be harmful since an excess of immune cells can attack healthy tissue as well.
Q. How does CSS impact a COVID-19 patient?
A. In the case of any flu infection, a cytokine storm is associated with a surge of activated immune cells into the lungs, which, instead of fighting off the antigen, leads to lung inflammation and fluid build-up, and respiratory distress.
Q. What are the previous instances of it?
A. It is seen as a likely major cause of mortality in the 1918-20 "Spanish flu" which killed more than 50 million people worldwide and the H1N1 "swine flu" and H5N1 "bird flu" of recent years. Cytokine storm has also been implicated in hantavirus pulmonary syndrome.