Singapore: People who have recovered from Covid-19, especially those with cardiovascular conditions, may be at risk of developing blood clots due to a delayed and overactive immune response, according to a study.
The study, led by researchers from Nanyang Technological University in Singapore, found that patients with Covid-19 who had twice the normal number of circulating endothelial cells (CECs) shed from damaged blood vessel walls.
The elevated levels of CECs indicate that vascular injury is still evident after recovery from viral infection.
The recovered Covid-19 patients 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.
Unusually many immune cells, known as T cells, which attack and destroy viruses, were also present in the blood of recovered Covid-19 patients.
The presence of both cytokines and higher levels of immune cells suggests that the immune systems of recovered Covid-19 patients remain activated even after the virus has disappeared, the findings published in the peer-reviewed scientific journal eLife .
The researchers hypothesized that these persistent activated immune responses could attack the blood vessels of recovered Covid-19 patients, which could cause even more damage and further increase the risk of blood clot formation.
“While Covid-19 is primarily an airway infection, the virus can also attack the lining of blood vessels and cause inflammation and damage. Leakage of these damaged vessels causes the formation of blood clots that can lead to the kind of complications that occur in patients. hospitalization, ‘says Florence Chioh, research assistant at the Lee Kong Chian School of Medicine at NTU.
Christine Cheung, Assistant Professor at NTU’s Lee Kong Chian School of Medicine.
The team collected and analyzed blood samples from 30 Covid-19 patients a month after they recovered from the infection and were discharged from the hospital.
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