Singapore: People who have recovered from Covid-19, especially those with pre-existing cardiovascular disease, may be at risk of developing blood clots due to a persistent and hyperactive immune response, according to a study.
The study, led by researchers at Nanyang University of Technology in Singapore, found that patients recovering from Covid-19 had twice the number of circulating endothelial cells (CECs) that were shed from the walls of damaged blood vessels.
Elevated CEC levels indicate that blood vessel lesions are still evident after recovery from viral infection.
Patients recovered from Covid-19 also continued to produce high levels of cytokines – proteins produced by immune cells that activate the immune response against pathogens – even in the absence of the virus.
An unusually large number of immune cells, known as T cells, which attack and destroy viruses, have also been present in the blood of patients with recovered Covid-19.
The presence of both cytokines and higher levels of immune cells suggests that the immune systems of patients with recovered Covid-19 remained active even after the virus disappeared, the findings published in the scientific journal eLife.
The researchers hypothesize that these permanently activated immune responses may attack the blood vessels of patients recovered with Covid-19, causing even more damage and increasing the risk of blood clots.
“While Covid-19 is primarily a respiratory infection, the virus can also attack the lining of the blood vessels, causing inflammation and damage. Leaks in these damaged vessels trigger the formation of blood clots that can lead to some sort of complication in patients. during hospitalization, “said Florence Chioh, a research assistant at Lee Kong Chian Medical School in NTU.
The study “is a powerful case for close monitoring of patients recovering with Covid-19, especially those with pre-existing cardiovascular conditions such as hypertension and diabetes, which have weakened blood vessels,” said Christine Cheung, an assistant professor at Lee. Kong Chian School of NTU Medicine.
The team collected and analyzed blood samples from 30 patients with Covid-19 per month after recovering from the infection and being discharged from the hospital.
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