People with selected variants of the ERAP2 and TICAM2 genes were 40% more likely to survive the Black Death, researchers discovered. However, in modern humans, those with the ERAP2 gene are more likely to suffer autoimmune disorders such as Crohn's disease.
Bubonic plague, or the "Black Death" placed significantly selective pressure on humans, changing the frequency of certain immune-related genes and affecting our susceptibility to modern diseases.