The Black Plague depicted in the Dance of Death, one of the cultures of the late Middle Ages. In the Middle Ages, people believed that dancing like a god in a churchyard could commune with the dead. Courtesy of Michel Wolgemut, Wilhelm Pleydenwurff
The Black Death, an infectious disease that killed half of Europe’s population in the Middle Ages, changed the human immune system, according to a study. It is a study that continues the research and context of the academic world that has evolved along with infectious diseases.
An international joint research team including the University of Chicago in the United States, McMaster University in Canada, and the Pasteur Institute in France published the results of a study in the international scientific journal ‘Nature’ on October 19 (local time) which showed that the gene mutation changed human immunity during the Black Death epidemic. .
The Black Death is an infectious disease caused by Yersinia pestis being transmitted by fleas that parasitize the host animal, rats. It is believed that the mass death from the Black Death led to significant changes from an evolutionary point of view.
The research team obtained 318 bones from two cemeteries, including East Smithfield Cemetery, London, England, where a large number of people who died of the Black Death were buried between 1348 and 1349, and 198 bones from five cemeteries in Denmark. These are the bones of people who lived about 100 years ago during the epidemic period. After extracting DNA from the bones, the research team analyzed the nucleotide sequences and found that 245 of the 356 genes associated with the immune response were mutated after the Black Death.
The research team identified genes that are thought to have played a role in protecting against the plague bacteria. One of them is the ‘ERAP2’ gene. The ERAP2 gene is known to play a role in the immune system’s recognition of infectious agents. The research team found that mutations in ERAP2 (rs2549794) help the immune system to better identify the source of the infection by making more protein.
Luis Barreiro, professor of genetic medicine at the University of Chicago, said, “Macrophages transfer part of the bacteria to other immune cells and send a signal that they are infected. The researchers estimated that people with mutations in the ERAP2 gene were 40 to 50 percent more likely to survive the plague than those who did not.
The team concluded that the mutation in the ERAP2 gene that favored survival was evolutionarily selected. “This is the first demonstration that the Black Death played an important role in the evolution of the human immune system,” said Barreiro.
Meanwhile, the ERAP2 gene, which helped survive the Black Death in the Middle Ages, is now a disease-causing factor. The ERAP2 gene is known as a risk factor for causing Crohn’s disease. Crohn’s disease is a chronic inflammatory disease that occurs in the digestive system and is considered a disease of modern people along with hypertension, diabetes and obesity.
