Epstein-Barr virus (EBV) antigen is an antigen associated with the Epstein-Barr virus. There are a number of EBV antigens associated with different stages of latency and infection. Laboratory testing can be used to look for specific antibodies to these antigens to screen someone for a history of infection or an active infection. These tests are more sensitive than quick tests such as mononucleosis screenings used in the doctor's office, and may be requested when a doctor wants to know if a patient has a history of the disease, or if a doctor believes a patient has Epstein-Barr virus even though a basic mono screen was negative.
Like other viruses, EBV is covered with an assortment of antigens it uses to perform various functions, including viral capsid antigens, membrane antigens, early antigens, and nuclear antigens. There are a number of different types of nuclear EBV antigen. When people are exposed to this virus, the body develops antibodies to the various kinds of EBV antigen, allowing it to recognize the virus in the future and flag it for destruction by the immune system.
Exposure to this virus is extremely common. Many people get it when they are young and may not be diagnosed, as the course of infection can seem like a routine childhood illness and it will resolve on its own. Some people are infected in their teens and develop mononucleosis. This virus has been linked with complications including autoimmune diseases and cancers, and because it is so widespread, it is a topic of interest for researchers who want to learn more about how such conditions develop and how they can be treated or prevented.
If testing shows that a patient has antibodies to nuclear EBV antigen, it means the person has a history of exposure to the virus. This testing can be used to look for traces of exposure years after infection, as the body retains antibodies in case it needs to use them. The presence of antibodies to viral capsid antigens is indicative of an ongoing and active infection. Rises in antibodies to the early EBV antigen are a sign of a recurrence of EBV in a patient with a history of infection.
These tests to look for antibodies to various types of EBV antigen can be combined with diagnostic screening to look for changes in white blood cells and other signs of infection. If a patient is suspected of having an EBV infection, treatment can be provided to help the patient recover. A history of infection can also be important for studying the origins of a medical problem.
