Scientists may have revealed an important aspect of Long Covid. Recent research shows that the blood of these patients often contains abnormal clusters of microscopic material.
Researchers at Stellenbosch University in South Africa examined the blood of people with and without long-term Covid. The study found that people with the chronic condition had larger amounts of microclots with web-like structures called neutrophil extracellular traps (NETs). Researchers say the findings could help doctors better identify long-lasting Covid cases and may also help explain some of the symptoms experienced by these patients.
“Our findings represent an important advance in the understanding of the interactions between NETs and microclots in long COVID,” the researchers write in their paper published last month in The Journal of Medical Virology.
microclots and net
Long COVID is a complex condition and is likely to be caused by a combination of factors, including viral persistence or an ongoing passive immune response to a prior COVID infection. But some research has suggested that long-lasting Covid symptoms, such as permanent fatigue or brain fog, may be linked to chronic inflammation and blood clotting problems, at least in some cases.
Previous work by the team and others has found that, for example, people with long COVID are more likely to have tiny fiber-like particles, called microclots, in their blood than the average person. Other studies have found that long-lived Covid patients also have higher amounts of NETs, sticky structures produced by immune cells called neutrophils that help trap germs. Although NETs are important for combating infection, their excess presence can contribute to harmful inflammation.
In this latest research, the Stellenbosch team wanted to better understand how NETs and microclots seen in long-stay COVID patients might interact with each other, if at all. They compared the blood of 50 people suffering from Long Covid with those of healthy controls.
They found that people with long-term COVID had higher levels of biomarkers associated with both NETs and microclots compared to controls. Larger microclots on average were also found in long-stay Covid patients. And perhaps most importantly, people with long-term COVID also found more microclots that were structurally associated with NETs.
According to the researchers, NETs may play a key role in keeping microclots protected from elimination by the body, which may explain why people continue to have long-lasting COVID symptoms.
They wrote, “We suggest that high NET formation may promote stabilization of microclots in the circulation, potentially leading to harmful effects that contribute to LC syndrome.” If so, finding a safe and effective way to clear microclots and NETs could potentially reduce symptoms, he adds.
More research is needed
As interesting as these findings are, they are certainly not the end of the road.
While research has found that people with long Covid are more likely to have microclots, for example, it is not yet clear to what extent these formations are responsible for people’s illness. And given the complex nature of the situation, it is certainly possible that only some people’s long Covid will be conclusively linked to these particles.
The researchers say their work could still help doctors develop tests that can more easily identify long-lasting Covid cases – something that is not possible today. In this current study, they developed an algorithm that appears to accurately distinguish between long-lived Covid patients and controls based on their specific biomarkers.
Although COVID-19 is no longer the pandemic threat it once was, the infectious disease is not gone. And millions of people around the world are still believed to be suffering from Long Covid. The more we understand about its mechanisms, the greater the chances of developing effective treatments for these individuals.