**1. Introduction**

The development of immunodeficiency leads to the spread of persistent and/or chronic herpesvirus infection, in which the pathogen is not eliminated from the host's body for months, years, or even throughout life. Each herpesvirus in the host organism has its own target tissue, where the virus persists with the ability to enter and exit the tissue using a developed strategic mechanism, which consists of the minimum expression of viral genes in a small number of infected cells or their elimination at the protein level. This allows the virus to evade the immune response and remain in very small quantities (1 infected cell per 5 ml of blood) with minimal impact on the patient's body, remaining in it for the rest of its life. In this case, the immune response is unable to eliminate the infectious pathogen from the body.
