Cytokine storms (related to covid 19)

IMPORTANT CONCEPT FOR GK AND EXAMINATION

Many Diseases like  covid-19 and influenzas can be fatal due to an overactivation of the body’s immune system called a cytokine storm.

Cytokines are small proteins produced  by many different cells in the body, including those of the immune system (our defense system)  , where they coordinate the body’s response against infection and trigger inflammation.

The name ‘cytokine’ is derived from the Greek words for cell (cyto) and movement (kinos).

Many a times the body’s response to infection can go into overdrive. For example, when SARS -CoV-2 – the virus behind the covid-19 pandemic – enters the lungs, it initiates  an immune response, attracting immune cells to the region to attack the virus, resulting in localised inflammation. But in some patients, excessive or uncontrolled levels of cytokines are released which then activate more immune cells, resulting in hyperinflammation. This can seriously harm or even kill the patient.

inflammation is  a localized physical condition in which part of the body becomes reddened, swollen, hot, and often painful, especially as a reaction to injury or infection.

Cytokine storms are a common matter of complication not only of covid-19 and flu but of many respiratory diseases caused by coronaviruses such as SARS and MERS.

The phenomenon became more popularly known after the 2005 outbreak of the avian H5N1 influenza virus, also called  as “bird flu”, when the high fatality rate was linked to an out-of-control cytokine response.

When the immune system is fighting pathogens, cytokines send signals to  immune cells such as T-cells and macrophages to travel to the site of infection , so that it can be neutralized. In addition, cytokines activate those cells, stimulating them to produce more cytokines. Normally, this feedback loop regulated well  by the body. However, in some cases, the reaction becomes uncontrolled, and too many immune cells are activated.

The precise reason for this is not entirely understood but may be caused by an exaggerated response when the immune system encounters a new and highly pathogenic invader like nCoV 2019. Cytokine storms have potential to do significant damage to body tissues and organs. If a cytokine storm occurs in the lungs, for example, fluids and immune cells such as macrophages may accumulate and eventually block off the airways, potentially resulting in death.