EBV Early Antigen Ab, IgG

Serologic testing for EBV infection (including EBV- EA[D]) may be merited because characteristic time-dependent antibody responses occur. Most (> 80%) symptomatic IM patients show near peak antibody levels of VCA IgG and IgM when first examined. VCA IgM antibodies usually disappear in 2-3 months while IgG antibodies persist indefinitely. Most patients transiently develop antibodies to EA(D), but IgG antibodies against Epstein-Barr Nuclear Antigen (EBNA) appear several weeks or months after the onset of disease and persist for years or even life. Because of the complex relationship that exists between the EBV virus/host reaction and clinical manifestations, tracking of EBV antibody patterns may assist in diagnosis of EBV infection. Individual levels of specific antibodies are not necessarily indicative of disease state but can be of diagnostic significance when tracked as an antibody response profile. Antibody response profiles for the different EBV antigens demonstrate a characteristic pattern for silent primary or persistent latent EBV infections, as well as for each of the EBV infectious mononucleosis-associated stages.
As mentioned previously, the appearance of IgG antibodies to EA(D) is generally associated with the primary (acute) stage of EBV infection. For most individuals, these antibodies fade in time and are often undetectable after six months. It is estimated that 60-80% of EBV-mediated IM patients will exhibit EA(D) at some point in the infection course.