EBV infection in immunocompetent patient: problems and solutions in serological diagnosis

Serological tests for antibodies against specific EBV antigens are commonly used to define the state of the infection as well as for differential diagnosis with the other agents responsible for mononucleosis syndrome.The use of only three parameters (VCA IgG and IgM and IgG EBNA-1) is normally enough to distinguish acute and past infection in immunocompetent patients: the presence of VCA IgG and IgM without EBNA-1 IgG indicates acute infection, whereas the presence of VCA IgG and EBNA-1 IgG without VCA IgM is typical of past infection. These profiles (beyond the negative profile for all three markers indicating the absence of infection) cover the vast majority of situations that can be found in the routine laboratory. In a minority of cases, however, the serological pattern may sometimes be difficult to interpret: presence of VCA IgG without either VCA IgM or EBNA-1 IgG, simultaneous presence of VCA IgG,VCA IgM and EBNA-1 IgG, presence of EBNA-1 IgG without either VCA IgM or VCA-1 IgG. In order to interpret these serological patterns correctly, it is necessary to use other laboratory tests: VCA IgG avidity, immunoblotting for EBV IgG and IgMV, or a search for heterophile antibodies, anti-EA antibodies or viral genome by means of gene amplification techniques.