EB virus is an important DNA virus that infects human beings. There are many diseases related to EBV infection, especially nasopharyngeal carcinoma. With the development of modern molecular biology, the diagnosis of EBV infection has made rapid progress from principle to method. Due to the high operational requirements, expensive equipment and reagents, the application of pathogen detection is limited, so the immunoserological detection of EBV infection is the most commonly used method for NPC screening at present. The early diagnosis and clinical stage of NPC are of great significance to the curative effect of radiotherapy. The earlier the disease stage, the higher the curative effect; The later the disease, the lower the curative effect. The new generation of serological diagnostic reagent for EBV infection developed by us can be used as the main screening reagent for NPC at present (see the information of WHO IARC 2005 annual meeting for details, which lists a variety of EBV antibody diagnostic indicators, and specifically quotes our published articles).
EBV-infected B lymphocytes can be divided into two types: latent infection and lytic infection. There are three types of latent infection. Each type of infection expresses EBNA1 antigen. Therefore, it is most representative to select various antibodies produced by EBNA1 antigen immune response as the serological indicators of EBV infection.
Because the main manifestation of nasopharyngeal carcinoma is latent infection of EBV with a small amount of soluble infection (about 15%~20%), there are three phases of soluble infection. First, the expression of immediate early antigen (Zebra); Then the early antigen was expressed; Finally, the nuclear membrane of lymphocytes ruptures, and the capsid antigen (VCA) and membrane antigen (MA) are synthesized and expressed. Some of this process will lead to abortion, without producing capsid antigen and membrane antigen. The released EBV synthesized complete viral particles and then absorbed and invaded B lymphocytes and other cells. During this transformation process, the virus genome was expanded. It can be seen that the traditional selection of various antibodies produced by VCA or MA antigen immune response as the screening test index of EBV infection has some defects, while the selection of various antibodies produced by Zcbra antigen immune response as the serological index of the turning point of EBV from latent infection to soluble infection is superior to VCA.
In addition, VCA-IgA antibody and EA-IgA antibody, because of their long half-life in vivo, still have high concentrations for a long time even if EBV is cleared in vivo, and there is no evidence that they can be used as indicators to monitor the metastasis and recurrence of NPC after treatment.
Immunoserological detection of EBV infection is a common method for early diagnosis of NPC. Because NPC is mainly characterized by EBV latent infection with a small amount of soluble infection, the traditional VCA and EA immunofluorescence or immunoenzyme methods (using the expression antigen of soluble infection) are not targeted, and the judgment of results is not objective; The new generation of EBV IgA enzyme-linked immunosorbent assay kit selects the main expressed antigen EBNA1 of latent infection, which can overcome the shortcomings of traditional methods and provide a powerful means for the early detection, diagnosis and treatment of NPC.