Saturday 10 October 2020
Books – Sayed Metwally
Some patients with the emerging corona virus suffer from great risks that may reach a threat to their lives and face the risk of death, although some may produce antibodies to fight Covid-19.
In severe cases of Covid-19, researchers at Emory University in the United States of America have observed profuse activation of immune cells, similar to acute flares of systemic lupus erythematosus (SLE), an autoimmune disease.
The researchers’ findings indicate that tests can separate some Covid-19 patients who need treatments to calm the immune system from others who may not.
The researchers also revealed why some people with SARS-Cove-2 produce abundant antibodies against the virus, yet have poor results.
The results are published online in Nature Immunology.
The results of the Emory University team converge with the recent findings of other researchers, who have found that high inflammation in patients with Covid-19 may disrupt the formation of germ centers in the lymph nodes where the cells producing antibodies are trained.
The Emory University research group observed that cell activation moves forward along a pathway outside the germinal centers, which appears similar to what they observed in SLE patients.
Known as “B”, these cells represent the equivalent of a library of antibody blueprints that the immune system can click to fight infection.
In severe cases of Covid-19, the immune system withdraws antibodies and distributes them in the body in an unregulated manner, which explains the suffering of these people who are exposed to severe risks when contracting the virus.
Before the Corona pandemic, study co-lead author Ignacio Sanz and his lab focused on studying SLE and how it affects B-cell development.
Sanz is the chair of rheumatology in the department of medicine, director of the Lowance Center for Human Immunology, and a senior scientist with the Georgia Research Alliance.
“When analyzing the cells of a Covid patient in the ICU, we saw patterns that were very reminiscent of acute attacks in SLE,” says Sanz.
In people with SLE, B cells are activated abnormally and avoid the controls and balances that normally restrict them. This often results in the production of autoantibodies that react against the body’s cells, resulting in symptoms such as fatigue, joint pain, rashes, and kidney problems. (Seizures are times when symptoms get worse.)
The Emory University team is looking into whether high-risk Covid-19 leads to the production of antibodies with clinical risks.
Sanz notes that other researchers have observed the presence of autoantibodies in the acute phase of the disease, and it will be important to understand whether long-term autoimmune responses may be related to fatigue, joint pain and other symptoms experienced by some survivors.
The researcher says: “It is an important question that we need to address through long-term careful follow-up of Corona patients who suffer from great risks, not all severe infections do this.”
The study compared 10 patients infected with the emerging coronavirus (4 of them died) in intensive care units in Emory University hospitals, with 7 people with Covid-19 who were treated outside the hospital and 37 healthy people.
People in the critical condition group had higher levels of antibody-secreting cells early in the infection, and in addition, the B cells and the antibodies they made showed characteristics that indicate cell activation in the extracollicular pathway (where the virus is resistant to), on the face In particular, the cells underwent fewer mutations in the antibody genes compared to the focused immune response, which is usually sharpened within the germinal centers.
The team’s findings could help in the controversy surrounding Covid-19 patients who should be given immunomodulatory therapies, such as dexamethasone, or patients with greater expansion of B cells that undergo extra-follicular activation also have higher levels of inflammatory cytokines.
Sanz suggests that patients with signs of disorganized immune responses may be suitable candidates for anti-inflammatory drug therapy.