Sometimes our immune systems can work against us. In the case of autoimmune diseases, for example, the immune system attacks the body’s own tissue to cause the illness.
Autoimmune involvement has come up in the context of the COVID-19 pandemic, with numerous reports describing so-called cytokine storm in severe cases of the disease.
Cytokine storm happens when an immune response releases more cytokines than are beneficial. Cytokines play a number of important roles in the immune system, but when too many are released, it can cause a severe inflammatory reaction that can be fatal.
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On the basis of these reports, researchers have suggested that the use of anti-cytokine therapies could be beneficial in the treatment of patients with severe COVID-19.
However, a study recently appearing in JAMA Network suggests otherwise.
The new article compares levels of inflammatory cytokines in COVID-19 patients with those in other patient groups, finding no evidence of cytokine storm in patients with COVID-19.
The authors, therefore, suggest that anti-cytokine therapies may not be beneficial in the treatment of the disease.
The study used data from patients admitted to the intensive care unit (ICU) of Radboud University Medical Center, in the Dutch city of Nijmegen.
The researchers measured the levels of three inflammatory cytokines, tumor necrosis factor-alpha and interleukins 6 and 8 (IL-6, IL-8), in the blood of 46 COVID-19 patients. All of these patients were seriously ill, having severe acute respiratory infections and receiving mechanical ventilation.
The team then compared their findings with those of people admitted to the ICU with other conditions: bacterial septic shock, cardiac arrest, or severe trauma, such as that sustained from an accident. These groups collectively contained 156 people.
The same technician performed all the measurements, using the same equipment and protocol.
The researchers found significantly lower levels of cytokines in people with COVID-19, compared with those who had septic shock — a condition that causes a surge in cytokine levels.
“The level of cytokines was significantly less elevated in COVID-19 patients than in patients with septic shock and [acute respiratory distress syndrome (ARDS)]. Compared to patients with septic shock without ARDS, so without severe pulmonary disease, patients with COVID-19 also displayed markedly lower levels of IL-6 and IL-8,” explains the study’s first author, Matthijs Kox, an assistant professor of intensive care medicine.
Instead, the cytokine levels seen in COVID-19 patients were closer to those in people who had come to the ICU due to trauma or cardiac arrest — issues that are not associated with cytokine storm.
Based on their results, the researchers did not find COVID-19 to be associated with cytokine storm, in contrast to some previous findings.
If validated, this means that anti-inflammatory agents targeting cytokines may not be beneficial in treating COVID-19.
“Critically ill COVID-19 patients likely will not benefit from specific anti-cytokine therapies.”
– Peter Pickkers, senior author of the study and professor of intensive care medicine at Radboud University Medical Center
Although this study is one of the first to directly compare cytokine levels in patients with COVID-19 to those in other patient groups, the sample sizes were relatively small, and the participants all received treatment in a single hospital.
Additional, larger studies will be necessary to confirm these findings.
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