In the new study, published June 7, 2018 in PLOS Genetics, Christine Ambrozone of the Center for the integrated Rouzvell cancer and his colleagues have identified a genetic difference between people with African and European ancestry, which affect the way the immune system causes inflammation. They suspect that these differences are rooted in how to develop the immune system of people living in Africa, that are affected by malaria.
For thousands of years the human immune system has evolved to fight off constant attacks from various infections, adapting its response to protect against local threats. Thanks to modern hygiene immune system is now faced with far fewer attacks, but the differences between the ancestors are still present, as evidenced by the difference in incidence between populations. In order to get a better understanding of how different people's immune system to respond to the current way of life, the researchers combined genetic, molecular and epidemiological data from 914 people of African descent and 855 people with European ancestry. These blood samples were analyzed to detect 14 different chemical elements involved in inflammation, and revealed significant differences between the populations in seven of these chemicals. Lifestyle factors, such as age, level of education, obesity, smoking and alcohol consumption, can explain many differences, but the researchers have identified a genetic variant that took place, especially in people with African ancestry. One of the options controlling the levels of two key chemicals involved in the recruitment of white blood cells in the inflammation, and previous studies have suggested that it evolved to protect Africans from malaria infection.
Immune differences between people with European and African ancestry may have important health consequences that deserve further study. Inflammation has evolved as a response to injury and infection, but is associated with several types of cancer and chronic diseases. Ancestral "traces" of the genome have been identified in the study may contribute to health differences observed between the two groups.
Author Christine Ambroson adds: "We conducted this study based on the hypothesis that the adaptation for millennia to protect against infectious diseases in Africa, resulting in a more robust immune response may be associated with more aggressive breast cancer in the modern environment. When we compared the levels of certain inflammatory markers between women of African and European descent, we noticed a lot of differences. Once we exclude the effect of lifestyle factors, we found that many of these differences may be linked to the antigen receptor Duffy, resulting in African Americans have genotype, which helps protect against malaria. "
"These data show that the evolutionary adaptation of many thousands of years ago formed our immune system and may still have a significant impact on immune function today," - explains the first author Dr. Song Yao. "The next question that we pursue is whether to play these evolutionary signs of any significant role in influencing inequalities in breast cancer."