All cells in our body contain exactly the same DNA sequence, but they look and behave completely differently. Diversity is provided by chemical markers that lie on top of the genetic code, like bookmarks in a book. The totality of these labels is called the epigenome. Unlike the stable DNA we inherited from our parents, this layer of information is extremely flexible and constantly changing under the influence of external circumstances. To understand the mechanism of interaction between innate and acquired, biologists analyzed blood samples from 110 donors. The sample includes people from a wide variety of backgrounds: those who have been infected with HIV, influenza or coronavirus, vaccinated against anthrax, as well as those who have been exposed to agricultural poisons. Attention was focused on four key types of protective cells. T lymphocytes and B cells are responsible for long-term memory of infections, while monocytes and natural killers provide a quick response to invasion. Analysis of the data showed that genetic variations often act precisely through a change in DNA methylation, turning on or off certain protective mechanisms in response to the disease. The authors of the project managed to divide the tags into two categories: hereditary and empirically obtained. It turned out that they are located in different regions of the genome. Innate markers cluster around stable sites, providing basic system tuning, especially in long-lived memory cells. Acquired tags that have arisen after diseases or environmental influences are located in flexible regulatory areas. They determine how the body will react to new threats here and now. This proves that our immune biography is literally recorded at the molecular level, affecting our ability to resist future virus attacks. The created catalog opens up fantastic prospects for medicine. Having accumulated enough information, doctors will be able to predict the patient’s reaction to the infection even before infection. For example, knowing the epigenetic profile of people who have easily survived covid, it will be possible to identify in advance those who lack the necessary protective tags. This approach will allow you to move from treating symptoms to accurate prevention. The doctor will be able to read in the blood test exactly how your epigenome will react to encountering the virus, and activate the necessary protective mechanisms therapeutically in advance.