Researchers may have found how the Epstein-Barr virus (EBV), which causes mononucleosis, is linked to several autoimmune diseases, including lupus. Other autoimmune diseases with a possible link to the virus include type 1 diabetes, juvenile idiopathic arthritis, multiple sclerosis, rheumatoid arthritis, inflammatory bowel disease and celiac disease.
EBV is typically contracted in early childhood and may not present symptoms. Any symptoms noticed typically resemble the common cold. If the virus is contracted in adolescence or young adulthood, it can lead to mononucleosis (also known as “mono”).
Once infected, you carry the virus your entire life, though you won’t exhibit symptoms. According to David Johnson, who works in the autoimmunology and mucosal immunology branch at the National Institute of Allergy and Infectious Diseases (NIAID), which funded the research, 9 out of 10 adults in the U.S. have been infected with EBV. EBV infection in childhood is associated with lupus later in life as opposed to having the virus in adolescence or young adulthood, Johnson noted. Of course, most of those who have the virus do not get mono or develop an autoimmune disease.
Johnson said it isn’t necessary for people with an autoimmune disease to check whether or not they have the inactive virus, especially since so many people have it anyway.
“By revealing more about how autoimmunity develops in some people, this research allows us to ask important questions about how to better treat these patients,” Johnson said. “Researchers are in the early stages, but basic research that furthers understanding of these mechanisms is critical to informing treatment and prevention in the future.”
While the link between the virus and systemic lupus erythematosus (SLE) was first discovered in the early 2000s, the way the two were connected wasn’t clear. Now researchers believe a protein found in cells infected by the virus activates genes that increase a person’s risk of developing some autoimmune diseases. The link was stronger between lupus and the virus, but was still significant for the other diseases.
Finding a cause for some autoimmune diseases could point researchers to more targeted and better treatments. While not every disease is preventable, pinpointing a cause could also help develop prevention plans for some illnesses.
“Many cases of autoimmune illness are difficult to treat and can result in debilitating symptoms,” Anthony S. Fauci, the director National Institute of Allergy and Infectious Diseases, said in a press release. “Studies like this are allowing us to untangle environmental and genetic factors that may cause the body’s immune system to attack its own tissues. A better understanding of the complex causes of autoimmunity promises to lead to better treatment and prevention options.”
Humans carry a plethora of genes, but only some are “expressed.” For example, if your mother has blue eyes and your father has brown eyes, you carry the gene for both, though your eyes typically only show one color. While your eye color won’t change, genes related to diseases may become active at some point in your life. You may carry genes related to an autoimmune disease, but they may lay “dormant” unless something interacts with it. Factors that cause these genes to become active would include environmental factors, such as contracting a viral infection.
“The comprehensive approach taken in this study and the broad perspective provided by these findings will help scientists and clinicians interpret links between diseases and genes and the environment,” Johnson said. “Future research will probably pursue how different genes are activated in different diseases and how therapies might interrupt, or even reverse, disease progression.”