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A groundbreaking genetic study has identified 22 human genes that appear to make certain individuals significantly more likely to develop a long-term, active infection with the Epstein-Barr virus (EBV). This persistent viral state is strongly linked to a much higher risk for specific cancers and autoimmune disorders, including multiple sclerosis and lupus. Published in the journal Nature, this research utilizes massive DNA databases to connect minute genetic differences to a weakened immune response against this exceptionally common virus. The findings suggest that for a subset of the population, the body's defense mechanisms struggle to keep the virus in check, allowing it to cause lasting damage.
The Epstein-Barr virus is one of the most widespread human infections on the planet. It affects approximately 90% of people globally at some point in their lives. The initial infection typically occurs during childhood or young adulthood and often proceeds without any noticeable symptoms. When symptoms do manifest, the illness is frequently infectious mononucleosis, commonly known as "mono." This condition is characterized by severe fatigue, fever, and a persistent sore throat. Crucially, after this acute phase passes, the virus does not leave the human body. Instead, it establishes a quiet, dormant infection, primarily hiding within memory B cells. These cells are a specific type of white blood cell that is essential for maintaining the body's long-term immunity.
For the vast majority of people, this dormant EBV infection remains harmless and is effectively controlled by the immune system for a lifetime. However, for a smaller group of individuals, the virus remains at unusually high levels of activity. Medical professionals recognize this as a serious condition known as chronic, active EBV infection. It is a known contributor to certain cancers, such as Hodgkin lymphoma and nasopharyngeal carcinoma. Furthermore, a growing body of evidence strongly links chronic EBV to autoimmune disorders. In these conditions, the immune system mistakenly attacks the body's own tissues. The most significant link exists with multiple sclerosis (MS), though connections to lupus and rheumatoid arthritis are also under intense study. More tentatively, chronic EBV has been associated with elevated risks for heart disease, lung disease, and stroke.
For a long time, a critical question remained unanswered: Why do only some people progress from a common, usually harmless infection to a chronic state that makes them prone to severe, life-altering diseases?
To solve this complex puzzle, researchers led by Ryan Dhindsa of the Baylor College of Medicine employed an innovative strategy. They analyzed large-scale human DNA biobanks. These repositories, such as the U.K. Biobank and the U.S. National Institutes of Health's All of Us program, hold the complete genome sequences and detailed health records of hundreds of thousands of volunteers. Standard human genome analysis typically looks only at human DNA, discarding all genetic sequences that do not match the human reference genome. Dhindsa's team realized that within this discarded genetic material could be the DNA of viruses living inside human cells.