What are cytokines? What are cytokine storms?

 Cytokines, those unknown protagonists of the immune system that often act as the first responders to infection, are molecules that allow the body's cells to communicate with each other, and are essential to the function of the immune system. Nevertheless, many cytokines may have a negative effect and result in what is known as a "cytokine storm."

Many different immune cells produce these small signaling molecules, such as neutrophils - some of the first cells to travel to the site of infection - and mast cells - responsible for allergic reactions - macrophages, B cells and T cells, according to a 2014 review published in the journal Frontiers of Immunology.

Immune biologist at the University of Arizona in Tucson Joyce Wu said: “Cytokines are transmitted from cells and then bind to specific receptors in both immune and non-immune cells, and they may send signals to the cell to modify how it grows or behaves, as almost every organ of the body has cells with receptors. 

Chemokines are cytokines that act as a beacon that directs immune cells where to go, helping them to find and destroy any harmful foreign substance in the body.

So how do cytokines work?

When a pathogen or foreign body enters the body, immune cells, cytokines, and organs respond by working together like an orchestra. The first immune cell notices the pathogen, directing all other cells by creating messages - cytokines - and sending them to the rest of the body's organs or cells, which respond according to directions. Says Dr. Mandy Ford: "The initiation of cytokine secretion informs the rest of the immune cells and the non-immune cells as well that there is a pathogen that requires an immune response."

One of the immune responses that cytokines may trigger is inflammation, as Ford says that cytokines aid tissue inflammation by directing blood vessel cell walls to become more porous by reducing connections between cells, so blood vessels leak blood into surrounding tissues, allowing immune cells to move through the leaking fluid to the affected area. To start the recovery process.

While cytokine is produced primarily when the body is infected with pathogens, inflammatory responses caused by the cytokine also occur when tissues are physically damaged, for example if you trip and cut your knee on the sidewalk.

Ford says that cytokines are a mediator between innate and adaptive immune responses, because the amount and type of cytokines secreted by cells varies with the type of pathogen, and these differences help the immune system adapt its response to an appropriate adaptation to be innate or adaptive, and some cytokines can stimulate the innate or adaptive immune system. Or both, depending on the type of infection.

Cytokines can also direct brain cells to release chemicals that tell your body that you have had a disease, which leads you to rest and avoid activities that might expose you to pathogens. "Fatigue, lethargy, feeling upset, and feeling pain are the effects of the cytokines in our bodies," says Ford.

The innate immune system without cytokines will not know when to activate, as there is no indication of a health threat, says Dr. Ford says that once the innate immune cells are activated, they do not secrete cytokines assigned to any specific receptors at first, but rather target the secreted cytokines the entire body, causing fever, joint pain and fatigue, according to a 2007 study published in the International Journal of Anesthesiology. A 2010 study in the Journal of Allergy and Clinical Immunology reported that the adaptive immune system ultimately secretes specific cytokines that target and activate T cells, to adjust the immune response to the specific pathogen that entered the body.

Cytokines direct the activation of the adaptive immune system, when the innate immune system fails to eliminate the infection. The innate immune system is good at warding off public health threats, but it may fail to destroy alien pathogens. Cytokines direct the adaptive immune system to produce pathogen-specific antigens that quickly identify the pathogen so that the immune system can destroy it.

The cytokine response is slow for good reason, Wu says, as a rapid immune response in which large amounts of cytokines are released can cause excessive inflammation that can lead to shock and organ damage.

The slow initial response of the innate immune system prevents the release of too many cytokines simultaneously and avoids collateral damage to the body, and according to a 2007 study published in the journal Nature Public Health Emergency Collection, the micro T-cell response may attack infection without causing excessive damage to the body.

When do cytokines harm the body?

Cytokines help your body fight and eliminate infection, but too many cytokines overwhelm the body and create what is known as a "cytokine storm".

A cytokine storm may occur when several pathogens enter the body simultaneously, or if the body secretes the wrong type of cytokine early in the immune response, in which case the excessive cytokines cannot accurately direct the immune system to get rid of the causative agent. Almost every organ contains cytokine receptors, so every part of the body is exposed to the negative effects of the cytokine storm.

The natural release of cytokines causes fluid to leak in the blood vessel walls to promote healing of damaged tissues through inflammation, but too many cytokines may make the blood vessels over porous, leading to a drop in blood pressure. Ford says this, in turn, depletes oxygen and can be fatal.

Patients with sepsis or untreated bacterial infections usually experience a cytostorm, which is a symptom of some diseases, such as Covid-19. Says Dr. Ford The cytokine storm is essentially an uncontrolled immune response, which leads to low oxygen in the blood, fluid accumulation in the lungs, difficulty breathing, and many other symptoms observed in people with Covid-19.

Cytokine storms can cause neurological problems, as the brain is naturally protected from harmful chemicals thanks to the blood-brain barrier, but cytokines are much smaller than cells so they can slip through the protective membrane of the brain. Cytokine storms are known to cause symptoms such as headaches, migraines, decreased appetite, increased need for sleep, and extreme fatigue, according to a 2009 review published in the Journal of Psychiatry.

Treating cytokine storms caused by Covid-19

Some research suggests that cytokine storms are a major cause of illness and death among coronavirus patients, according to the JAMA Journal of Internal Medicine. A 2020 study published in the Journal of Clinical Infectious Diseases found that the cytokine inhibitor tocilizumab has been shown to reduce mortality in Covid-19 patients who use ventilators by 45%.

Cytokine levels may also affect the care that Covid-19 patients receive, as a recent study published in the Journal of Natural Medicine reported that the presence of a certain amount of cytokines may predict the survival of Covid-19 cases, which may help doctors develop an effective treatment protocol that depends On cytokine severity, and although the mechanisms associated with the severity of COVID-19 are still poorly understood, a recent review published in the Journal of Cardiology and Nephrology found that timely anti-inflammatory strategies may help reduce the severity of cytokine storms and may improve the health of a patient with HIV Corona.