Anti-EBV (VCA) IgG
Etiology. Human herpesvirus type 4 ( HHV-IV ) , or the Epstein-Barr virus , is a lymphotropic virus whose etiological role is known in infectious mononucleosis, Burkitt's lymphoma, nasopharyngeal carcinoma, lymphoproliferative syndrome associated with the X chromosome , and chronic fatigue syndrome. This DNA genomic virus of the genus Lymphocryptovirus of the subfamily Gammaherpesvirinae of the Herpesviridae family has 4 main antigens: early antigen (EA), capsid antigen (viral capcide antigen - VCA), membrane antigen (MA);nuclear antigen ( Epstain-Barr Nuclea antigen - EBNA). Each of them is formed in a certain sequence and induces the synthesis of the corresponding antibodies. Epidemiology. The source of infection is an infected person (with a manifest or erased form of the disease, as well as a virus carrier). Primary infection often occurs in childhood or young age. Ways of transmission of the virus: airborne , contact-household , transfusion, sexual, transplacental. After infection, replication of the virus in the human body and the formation of an immune response can occur asymptomatically, or manifest as minor signs of acute respiratory viral infection. In some cases, more often when there is a significant weakening of the immune system at this time, the patient may develop a picture of infectious mononucleosis. About 90% of the world's adult population is infected with the Epstein-Barr virus and after the primary infection remain lifelong carriers of the virus. Pathogenesis. The entrance gates for infectious mononucleosis is the mucous membrane of the mouth and upper respiratory tract. The Epstein-Barr virus penetrates through intact epithelial layers by transcytosis into the underlying lymphoid tissue of the tonsils, in particular B-lymphocytes . After infection, the number of affected cells is increased by means of virus-dependent cell proliferation. Infected B-lymphocytescan be a significant time in tonsillar crypts, which allows the virus to be released into the external environment with saliva. With infected cells, the virus spreads through other lymphoid tissues and peripheral blood. In virus-infected cells, two kinds of reproduction are possible: lytic, that is, leading to death, lysis of the host cell , and latent, when the number of viral copies is small and the cell does not collapse. With acute or active infection, lytic replication of the virus predominates. The virus can be in the B-lymphocytes and epitheliocytes of the nasopharyngeal region and salivary glands for a long time . In addition, it is capable of infecting other cells: T-lymphocytes , NK cells , macrophages, neutrophils, and vascular epitheliocytes. In the corethe host cell of the virus DNA can be inserted into the genome, causing chromosomal abnormalities. Active virus multiplication can occur as a result of weakening of immunological control, as well as stimulation of multiplication of cells infected by the virus under the influence of a number of factors: acute bacterial or viral infection, vaccination, stress , etc. Clinical manifestations. Infectious mononucleosis is an acute anthroponous viral infectious disease characterized by fever, infection of the oropharynx, lymph nodes, liver and spleen, and specific changes in the hemogram. The incubation period of the disease is 4-6 weeks. In the prodromal period, the infection manifests itself in muscle pain, fatigue, and general malaise. Then they are joined by fever, sore throat, enlarged lymph nodes, spleen and sometimes liver. In some cases, there is a rash on the arms and trunk. Symptoms persist for 2-4 weeks. In children, the infection is often asymptomatic. Perhaps several options for the outcome of an acute infectious process: 1. Recovery. 2. Asymptomatic virus or latent infection. 3. Chronic recurrent infection: a) chronic active infection (persistence of symptoms of infectious mononucleosis more than 6 months); b) generalized form (possible damage to the nervous system (encephalitis, polyneuropathy, meningitis), other internal organs (myocarditis, glomerulonephritis, lymphocytic interstitial pneumonia, hepatitis), c) hemophagocytic syndrome associated with EBV infection; d) erased or atypical forms (prolonged subfebrile condition of unknown origin, clinic of secondary immunodeficiency - recurrent bacterial, fungal, often - mixed infections of the respiratory and gastrointestinal tract, furunculosis , etc. ); e) development of the oncological (lymphoproliferative) process (multiple polyclonal lymphomas, nasopharyngeal carcinoma, leukoplakia of the tongue and oral mucosa, stomach and intestinal cancer, etc.); e) development of autoimmune processes (SLE, rheumatoid arthritis, Sjogren's syndrome, etc.); g) the Epstein-Barr virus can play an important role in the onset of chronic fatigue syndrome. The prognosis for a patient with an acute infection caused by the Epstein-Barr virus depends on the presence and severity of immune dysfunction,