Q: What is a cytokine storm and how is it related to Covid-19?
A: Cytokines are small proteins released by cells in the immune system that signal other cells and so help modulate the body’s immune response, making it more efficient in dealing with an invading pathogen. What sometimes happens in the case of certain infections, including Covid-19, is that the immune system goes into overdrive and oversecretes cytokines, leading to a hyperinflammatory state known as a cytokine storm.
Cytokine storms are extremely serious, carrying a 40 to 80 percent death rate. Doctors and nurses on the front lines of the current pandemic have described seeing patients who seem to be improving and then suddenly experience multiorgan failure with lung involvement. Studies have shown that elevated proinflammatory cytokine blood levels are associated with this kind of lung inflammation and damage, which could mean that blood work may help doctors predict which patients might experience a cytokine storm. Patients admitted to the intensive care unit tend to have higher blood levels of certain cytokines, suggesting that more severe Covid-19 symptoms may be a harbinger of a cytokine storm.
Initially, the use of corticosteroids was not routinely recommended in Covid-19 patients based on lung damage seen in patients with other respiratory viruses. However, experts now recognize that the critical need to halt the hyperimmune response may allow for the strategically timed administration of steroids, ideally for short periods. Some other drug therapies are being studied as to their effectiveness. These drugs include intravenous immunoglobulin and biopharmaceuticals such as anakinra, tocilizumab, and Janus kinase inhibitors, which work by reducing the inflammatory response to cytokines.
This article first appeared in the August 2020 issue of UC Berkeley Health After 50.
Also see How to Fortify Your Immune System.