Scientists may have uncovered an important aspect of long covid. Recent research appears to show that the blood of these patients often contains unusual clusters of microscopic material.
Researchers at Stellenbosch University in South Africa examined the blood of people with and without long covid. Those with the chronic condition had a greater amount of microclots combined with web-like structures called neutrophil extracellular traps (NETs), the study found. The findings could help doctors better identify long covid cases and might even help explain some of the symptoms these patients experience, the researchers say.
“Our findings present a significant advancement in the understanding of the interactions between NETs and microclots in long covid,” the researchers wrote in their paper, published last month in The Journal of Medical Virology.
Microclots and NETs
Long covid is a complex condition and is likely to be caused by a mix of factors, including viral persistence or an ongoing dysfunctional immune response to the earlier covid infection. But some research has suggested that the symptoms of long covid, such as lasting fatigue or brain fog, can be linked to chronic inflammation and blood clotting issues, at least for some cases.
The team’s past work and others have found that people with long covid are more likely to have tiny fiber-like particles in their blood, dubbed microclots, than the average person, for instance. Other studies have found that long covid patients also have higher amounts of NETs, sticky structures produced by immune cells called neutrophils that help trap germs. Though NETs are important to combatting infections, their excess presence may contribute to harmful inflammation.
In this latest research, the Stellenbosch team wanted to better understand how the NETs and microclots seen in long covid patients might interact with one another, if at all. They compared the blood of 50 people diagnosed with long covid to healthy controls.
They found that people with long covid had higher levels of biomarkers linked to both NETs and microclots than the controls. Long covid patients seemed to have larger microclots on average as well. And perhaps most importantly, those with long covid also appeared to have more microclots that were structurally connected to NETs.
According to the researchers, NETs might play an important role in keeping microclots safe from eradication by the body, which could then explain why people’s long covid symptoms continue to linger.
“We suggest that higher NETs formation might promote the stabilization of microclots in the circulation, potentially leading to deleterious effects which contribute causally to the LC syndrome,” they wrote. If so, finding a safe and effective way to clear microclots and NETs could potentially alleviate symptoms as well, they add.
More research needed
Intriguing as these findings are, they’re certainly not the end of the road.
While research has found that people with long covid are more likely to have microclots, for instance, it’s not clear yet if and to what extent these structures are responsible for causing people’s illness. And given the complicated nature of the condition, it’s certainly possible only some people’s long covid will end up conclusively linked to these particles.
The researchers say their work could still help doctors devise tests that can easily identify long covid cases—something that isn’t possible today. In this current study, they developed an algorithm that appeared to accurately distinguish between long covid patients and controls, based on their distinctive biomarkers.
Though covid-19 is no longer the pandemic threat it once was, the infectious disease is not gone. And there are still millions of people worldwide believed to be afflicted by long covid. The more we understand about its mechanisms, the greater the chance we can develop effective treatments for these individuals.