A common childhood virus appears to be a trigger for the autoimmune disease lupus, according to groundbreaking research, The Guardian reports, writes UNN.
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The study suggests that the Epstein-Barr virus (EBV), which is harmless for most people, can cause immune cells to "go out of control" and mistakenly attack the body's own tissues. The team that conducted the study said that finding the cause of lupus could revolutionize treatment.
"We believe this is applicable to 100% of lupus cases," said Professor William Robinson, Professor of Immunology and Rheumatology at Stanford University and lead author of the study. "I think this really lays the groundwork for a new generation of treatments that could fundamentally cure and thus benefit lupus patients."
Lupus is a chronic autoimmune disease in which the immune system produces antibodies that attack the body's own tissues. The causes of this disease are not fully understood, and there is no known cure for this condition, which can cause joint and muscle pain, severe fatigue, and skin rashes.
Epidemiological studies have previously hinted at a link between Epstein-Barr virus (EBV) and lupus. This idea gained widespread attention after a recent breakthrough that proved a link between EBV and multiple sclerosis, another autoimmune disease. The latest work helps to uncover at the cellular level the mechanism by which EBV apparently causes lupus by causing a malfunction in the immune system.
"This research unravels a long-standing mystery," said Shadi Younis, an immunologist at Stanford and the first author of the paper.
EBV is usually mild, causing a sore throat, fever, and tonsillitis. By adulthood, about 19 out of 20 people are infected and, because the virus deposits its genetic material in DNA, become carriers of the dormant virus in their cells.
"The reason this is so strange is that it's a common virus that most of us get from a sibling at the kitchen table as children, and if not, then when kissing someone as teenagers," Robinson said. "Practically the only way not to get EBV is to live in isolation."
Among the types of cells in which EBV permanently resides are B cells, part of the immune system. These cells specialize in binding to viral surface proteins known as antigens. About 20% of B cells also have the potential to bind to parts of the body's own cells, but in healthy people, these "autoreactive" B cells remain largely inactive.
Scientists for the first time used high-precision genetic sequencing to identify differences in the number and type of B cells infected in 11 lupus patients compared to 10 healthy control subjects.
In the control group, Epstein-Barr virus (EBV) was present in less than 1 in 10,000 cells, compared to approximately 1 in 400 cells in the lupus group – a 25-fold difference. EBV was also most often found in autoreactive B cells.
The presence of the dormant virus apparently put these cells into a hyperactive state, in which they not only attacked antigens within the body, but also recruited other immune cells, including killer T cells, to participate in the attack, the publication writes.
"We consider this discovery critically important: EBV… then activates B cells, triggering an autoimmune response that mediates lupus," Robinson said.
If the results are confirmed, they will give impetus to clinical trials of an Epstein-Barr virus (EBV) vaccine, which are already underway. In addition, several groups are exploring the possibility of repurposing cancer treatments aimed at destroying B cells in severe cases of lupus.
The results of the study are published in the journal Science Translational Medicine.