A team of Swiss researchers has identified that the complement system, a part of the body’s immune system, plays an important role in long Covid.
Most people infected with the SARS-CoV-2 virus recover after the acute illness. However, a significant proportion of infected individuals develop long-lasting symptoms with a wide range of manifestations.
Long Covid's causes and disease mechanisms are still unknown, and there are no diagnostic tests or targeted treatments.
The study by the University of Zurich (UZH) in Switzerland pinpointed the role of the complement system -- part of the innate immune system which normally helps to fight infections and eliminate damaged and infected body cells.
"In patients with long Covid, the complement system no longer returns to its basal state, but remains activated and, thus, also damages healthy body cells," said Onur Boyman, professor of immunology at UZH.
In the study, published in the journal Science, the researchers followed 113 Covid patients for up to one year after their acute SARS-CoV-2 infection and compared them with 39 healthy controls.
After six months, 40 patients had active long Covid disease. More than 6,500 proteins in the blood of the study participants were analysed both during the acute infection and six months later.
"The analyses of which proteins were altered in long Covid confirmed the excessive activity of the complement system. Patients with active long Covid disease also had elevated blood levels indicating damage to various body cells, including red blood cells, platelets, and blood vessels," explained Carlo Cervia-Hasler, a postdoctoral researcher in Boyman's team.
The measurable changes in blood proteins in active long Covid indicate an interaction between proteins of the complement system, which are involved in blood clotting and the repair of tissue damage and inflammation.
In contrast, the blood levels of long Covid patients, who recovered from the disease, returned to normal within six months. Active long Covid is therefore characterised by the protein pattern in the blood.
"Our work not only lays the foundation for better diagnosis, but also supports clinical research into substances that could be used to regulate the complement system. This opens up new avenues for the development of more targeted therapies for patients with long Covid," Boyman said.
Manipur: Arms and ammunition recovered; two held with drugs
Manipur Police and other security forces recovered some arms and ammunition from different fringe and vulnerable areas and arrested two persons with drugs on Saturday, officials said.
Northeast celebrates 53rd anniversary of ‘Vijay Diwas’
Various northeastern state governments, the Army and other organisations on Monday celebrated the 53rd anniversary of 'Vijay Diwas' with wreath-laying ceremonies and other events organised at the war memorials and other places.
India sends 60 tonnes of medical aid to disaster-hit Jamaica
A fresh consignment of around 60 tonnes of emergency medical equipment, generators, and other utilities have been sent by India to Jamaica to support the country's healthcare needs and enhance their disaster preparedness.
RG tragedy: Aggressive protests only alternative now, feel junior doctors and victim’s father
Renewed and aggressive protests on the streets are the only alternative now to get justice for the Kolkata-based R.G. Kar Medical College & Hospital doctor who became the victim of a brutal rape and murder within the hospital premises in August this year, opined the junior doctors as well as parents of the victim on Saturday.