England – Results of a British study of patients hospitalized with SARS-CoV-2 infection show that “long Covid” leads to persistent inflammation that can be detected in the blood.
In an analysis of more than 650 people who were hospitalized with severe Covid-19, patients with long-term symptoms showed evidence of immune system activation.
How this activation occurs depends on what type of symptoms they are experiencing, for example mainly fatigue, brain fog or cognitive impairment.
The study, led by researchers from Imperial College London, indicates that existing drugs that modify the body’s immune system might be useful in treating “long Covid” and should be investigated in future clinical trials.
Professor Peter Openshaw, from the Imperial National Heart and Lung Institute and principal investigator of ISARIC-4C, said: “This study, which includes detailed clinical data on symptoms and a wide range of inflammatory blood plasma markers, is an important step forward and provides crucial insights into the causes of Covid.” “Long-term.”
The study included a total of 426 people who were suffering from symptoms consistent with “long Covid” and were hospitalized due to “Covid-19” infection at least six months before the study.
They were compared to 233 people who were hospitalized due to Covid-19, but fully recovered.
The researchers took blood plasma samples and measured a total of 368 proteins known to interfere with inflammation and modulate the immune system.
They found that compared to patients who had fully recovered, those with long Covid showed a pattern of immune system activation, indicating inflammation of myeloid cells and activation of a family of immune system proteins called the complement system.
Myeloid cells form in the bone marrow and produce different types of white blood cells that circulate in the blood and migrate to organs and tissues, where they respond to damage and infection.
The complement system consists of a series of interconnected proteins that are activated in response to infection or tissue damage.
Overactivity of the complement system is known to be associated with many autoimmune and inflammatory conditions.
Dr Felicity Liu, from the National Heart and Lung Institute at Imperial, said: “Our findings suggest that complement activation and myelitis might be a common feature of long Covid disease following hospitalization, regardless of the type of symptoms. It is unusual to find evidence of persistent complement activation several months following the acute infection has resolved, suggesting that the symptoms of long Covid are a result of active inflammation. However, we cannot be sure that this applies to all types of long Covid, especially if symptoms appear following infection outside of a hospital.”
The researchers were able to obtain comprehensive information regarding the group of symptoms that the patients were suffering from and which ones were most common. They found that certain sets of symptoms seemed to be linked to certain proteins.
Overall, there were five overlapping subtypes of “long Covid” with different immune signatures, despite some commonalities, namely fatigue, cognitive impairment, anxiety and depression, and cardiac, respiratory, and gastrointestinal diseases.
Source: Medical Express
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2024-04-12 05:24:39
