Some of the same mutations that allow humans to fend off deadly infections also make us more prone to certain inflammatory and autoimmune diseases, like the disease of Crohn.
Researchers describe how ancestral origins impact the likelihood that people of African or Eurasian descent may develop immune-related diseases in a study published in the journal Trends in Immunology on November 27.
The authors also share evidence of the continued evolution of the human immune system depending on the location or lifestyle of a person.
First author Jorge Dominguez-Andres (@dominjor), a postdoctoral researcher at the Netherlands ‘ Radboud Institute for Molecular Life Science, said: “In the past, people’s lifespans were much shorter, so some of these inflammatory and autoimmune diseases that can appear in the second half of life were not so relevant,” added that, “Now that we live so much longer, we can see the consequences of infections that happened to our ancestors.”
Inflammation is one of the best defenses of the body against infectious diseases.
Dominguez-Andres and senior author Mihai Netea, an immunologist and evolutionary biologist at Radboud University, compiled data from studies in genetics, immunology, microbiology, and virology, and described how DNA from people in different communities commonly infected with bacterial or viral diseases were altered to enable inflammation.
While these changes made it harder for some pathogens to infect these communities they were also connected with the emergence of new inflammatory diseases, such as Crohn’s disease, Lupus, and inflammatory bowel disease, over time.
“There seems to be a balance. People are developing to build defenses against disease, but we can’t stop disease from happening, so the benefits we get on the one hand also make us more sensitive to new diseases on the other,” Dominguez-Andres’s said.
Dominguez-Andres’s added: “Today, we are suffering or benefiting from defenses built into our DNA by our ancestors’ immune systems fighting off infections or growing accustomed to new lifestyles.”
Dominguez-Andres and Netea also write about how Eurasians ‘ early human ancestors lived in regions still inhabited and interbred by Neanderthals. People with Neanderthal DNA remainders today may be more resistant to HIV-1 and staph infections, but they are also more likely to develop allergies, asthma, and hay fever.
A relatively recent finding is the negative side effects of changes in the immune systems of each population. “We know some things about what’s going on in our ancestors at the genetic level, but we need more powerful technology. So the next-generation sequencing is now bursting and allowing us to research the interplay between DNA and host responses at much deeper levels, “says Dominguez-Andres.” “So, we are obtaining a much more comprehensive point of view.”
In the future, Dominguez-Andres and Netea will expand their research to communities outside the populations of Africa and Eurasia.
Dominguez-Andres’s said. “So far, all of the studies we went through are focused on populations with European and African descent, but they must also be extended to indigenous and other populations to improve the representation of human genetic diversity,”
Dominguez-Andres’s added that: “Lifestyles and ecologic natures can really differ and influence immune responses. So, more work needs to be done.”
The Netherlands Organization for Scientific Research and an ERC Advanced Grant supported this research.


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